42 files changed, 2435 insertions, 322 deletions

diff --git a/src/data/delimitedstringvalidator.cpp b/src/data/delimitedstringvalidator.cpp
new file mode 100644
index 0000000..9f1057e
--- /dev/null
+++ b/src/data/delimitedstringvalidator.cpp
@@ -0,0 +1,58 @@
+/*
+    TikZiT - a GUI diagram editor for TikZ
+    Copyright (C) 2018 Aleks Kissinger
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+*/
+
+#include "delimitedstringvalidator.h"
+
+DelimitedStringValidator::DelimitedStringValidator(QObject *parent) : QValidator(parent)
+{
+}
+
+QValidator::State DelimitedStringValidator::validate(QString &input, int &/*pos*/) const
+{
+    int depth = braceDepth(input);
+    if (depth == 0) return Acceptable;
+    else if (depth > 0) return Intermediate;
+    else return Invalid;
+}
+
+void DelimitedStringValidator::fixup(QString &input) const
+{
+    int depth = braceDepth(input);
+    if (depth > 0) input.append(QString("}").repeated(depth));
+}
+
+int DelimitedStringValidator::braceDepth(QString input) const
+{
+    int depth = 0;
+    bool escape = false;
+    for (int i = 0; i < input.length(); ++i) {
+        QCharRef c = input[i];
+        if (escape) {
+            escape = false;
+        } else if (c == '\\') {
+            escape = true;
+        } else if (c == '{') {
+            depth++;
+        } else if (c == '}') {
+            depth--;
+            if (depth < 0) return -1;
+        }
+    }
+
+    return depth;
+}
diff --git a/src/data/delimitedstringvalidator.h b/src/data/delimitedstringvalidator.h
new file mode 100644
index 0000000..60c2513
--- /dev/null
+++ b/src/data/delimitedstringvalidator.h
@@ -0,0 +1,57 @@
+/*
+    TikZiT - a GUI diagram editor for TikZ
+    Copyright (C) 2018 Aleks Kissinger
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+*/
+
+/*!
+  * A string validator which keeps curly braces matched. Used in various places
+  * to ensure the user doesn't make non-parseable .tikz or .tikzstyles files.
+  *
+  * Its validation function will return Acceptable if all curly braces are matched
+  * properly, Intermediate if all braces are matched except for possibly some opening
+  * curly braces, and Invalid if there are unmatched closing curly braces.
+  */
+
+#ifndef DELIMITEDSTRINGVALIDATOR_H
+#define DELIMITEDSTRINGVALIDATOR_H
+
+
+#include <QObject>
+#include <QValidator>
+
+
+class DelimitedStringValidator : public QValidator
+{
+    Q_OBJECT
+public:
+    DelimitedStringValidator(QObject *parent);
+    QValidator::State validate(QString &input, int &/*pos*/) const override;
+
+    /*!
+     * \brief fixup adds curly braces until all braces are matched (if possible)
+     * \param input
+     */
+    void fixup(QString &input) const override;
+private:
+    /*!
+     * \brief braceDepth computes the final (non-escaped) curly-brace depth of a given string
+     * \param input a string
+     * \return the final brace depth, or -1 if the depth *ever* drops below 0
+     */
+    int braceDepth(QString input) const;
+};
+
+#endif // DELIMITEDSTRINGVALIDATOR_H
diff --git a/src/data/edge.cpp b/src/data/edge.cpp
index 0ae566b..864d5ed 100644
--- a/src/data/edge.cpp
+++ b/src/data/edge.cpp
@@ -26,8 +26,8 @@
 Edge::Edge(Node *s, Node *t, QObject *parent) :

     QObject(parent), _source(s), _target(t)

 {

-    _data = new GraphElementData();

-    _edgeNode = 0;

+    _data = new GraphElementData(this);

+    _edgeNode = nullptr;

     _dirty = true;

 

     if (s != t) {

@@ -35,24 +35,18 @@ Edge::Edge(Node *s, Node *t, QObject *parent) :
         _bend = 0;

         _inAngle = 0;

         _outAngle = 0;

-        _weight = 0.4f;

+        _weight = 0.4;

     } else {

         _basicBendMode = false;

         _bend = 0;

         _inAngle = 135;

         _outAngle = 45;

-        _weight = 1.0f;

+        _weight = 1.0;

     }

 	_style = noneEdgeStyle;

     updateControls();

 }

 

-Edge::~Edge()

-{

-    delete _data;

-    delete _edgeNode;

-}

-

 /*!

  * @brief Edge::copy makes a deep copy of an edge.

  * @param nodeTable is an optional pointer to a table mapping the old source/target

@@ -63,7 +57,7 @@ Edge::~Edge()
 Edge *Edge::copy(QMap<Node*,Node*> *nodeTable)

 {

     Edge *e;

-    if (nodeTable == 0) e = new Edge(_source, _target);

+    if (nodeTable == nullptr) e = new Edge(_source, _target);

     else e = new Edge(nodeTable->value(_source), nodeTable->value(_target));

     e->setData(_data->copy());

     e->setBasicBendMode(_basicBendMode);

@@ -103,8 +97,9 @@ GraphElementData *Edge::data() const
 

 void Edge::setData(GraphElementData *data)

 {

-    delete _data;

+    GraphElementData *oldData = _data;

     _data = data;

+    oldData->deleteLater();

     setAttributesFromData();

 }

 

@@ -148,13 +143,14 @@ Node *Edge::edgeNode() const
 

 void Edge::setEdgeNode(Node *edgeNode)

 {

-    if (_edgeNode != 0) delete _edgeNode;

+    Node *oldEdgeNode = _edgeNode;

     _edgeNode = edgeNode;

+    if (oldEdgeNode != nullptr) oldEdgeNode->deleteLater();

 }

 

 bool Edge::hasEdgeNode()

 {

-    return _edgeNode != 0;

+    return _edgeNode != nullptr;

 }

 

 void Edge::updateControls() {

@@ -162,22 +158,22 @@ void Edge::updateControls() {
     QPointF src = _source->point();

     QPointF targ = _target->point();

 

-    float dx = (targ.x() - src.x());

-    float dy = (targ.y() - src.y());

+    qreal dx = (targ.x() - src.x());

+    qreal dy = (targ.y() - src.y());

 

-    float outAngleR = 0.0f;

-    float inAngleR = 0.0f;

+    qreal outAngleR = 0.0;

+    qreal inAngleR = 0.0;

 

     if (_basicBendMode) {

-        float angle = std::atan2(dy, dx);

-        float bnd = (float)_bend * (M_PI / 180.0f);

+        qreal angle = std::atan2(dy, dx);

+        qreal bnd = static_cast<qreal>(_bend) * (M_PI / 180.0);

         outAngleR = angle - bnd;

         inAngleR = M_PI + angle + bnd;

-        _outAngle = outAngleR * (180.f / M_PI);

-        _inAngle = inAngleR * (180.f / M_PI);

+        _outAngle = static_cast<int>(round(outAngleR * (180.0 / M_PI)));

+        _inAngle = static_cast<int>(round(inAngleR * (180.0 / M_PI)));

     } else {

-        outAngleR = (float)_outAngle * (M_PI / 180.0f);

-        inAngleR = (float)_inAngle * (M_PI / 180.0f);

+        outAngleR = static_cast<qreal>(_outAngle) * (M_PI / 180.0);

+        inAngleR = static_cast<qreal>(_inAngle) * (M_PI / 180.0);

     }

 

     // TODO: calculate head and tail properly, not just for circles

@@ -196,7 +192,7 @@ void Edge::updateControls() {
     }

 

     // give a default distance for self-loops

-    _cpDist = (dx==0.0f && dy==0.0f) ? _weight : std::sqrt(dx*dx + dy*dy) * _weight;

+    _cpDist = (almostZero(dx) && almostZero(dy)) ? _weight : std::sqrt(dx*dx + dy*dy) * _weight;

 

     _cp1 = QPointF(src.x() + (_cpDist * std::cos(outAngleR)),

                    src.y() + (_cpDist * std::sin(outAngleR)));

@@ -204,9 +200,9 @@ void Edge::updateControls() {
     _cp2 = QPointF(targ.x() + (_cpDist * std::cos(inAngleR)),

                    targ.y() + (_cpDist * std::sin(inAngleR)));

 

-    _mid = bezierInterpolateFull (0.5f, _tail, _cp1, _cp2, _head);

-    _tailTangent = bezierTangent(0.0f, 0.1f);

-    _headTangent = bezierTangent(1.0f, 0.9f);

+    _mid = bezierInterpolateFull (0.5, _tail, _cp1, _cp2, _head);

+    _tailTangent = bezierTangent(0.0, 0.1);

+    _headTangent = bezierTangent(1.0, 0.9);

 }

 

 void Edge::setAttributesFromData()

@@ -218,16 +214,16 @@ void Edge::setAttributesFromData()
         _bend = -30;

     } else if (_data->atom("bend right")) {

         _bend = 30;

-    } else if (_data->property("bend left") != 0) {

+    } else if (_data->property("bend left") != nullptr) {

         _bend = -_data->property("bend left").toInt(&ok);

         if (!ok) _bend = -30;

-    } else if (_data->property("bend right") != 0) {

+    } else if (_data->property("bend right") != nullptr) {

         _bend = _data->property("bend right").toInt(&ok);

         if (!ok) _bend = 30;

     } else {

         _bend = 0;

 

-        if (_data->property("in") != 0 && _data->property("out") != 0) {

+        if (_data->property("in") != nullptr && _data->property("out") != nullptr) {

             _basicBendMode = false;

             _inAngle = _data->property("in").toInt(&ok);

             if (!ok) _inAngle = 0;

@@ -237,10 +233,10 @@ void Edge::setAttributesFromData()
     }

 

     if (!_data->property("looseness").isNull()) {

-        _weight = _data->property("looseness").toFloat(&ok) / 2.5f;

-        if (!ok) _weight = 0.4f;

+        _weight = _data->property("looseness").toDouble(&ok) / 2.5;

+        if (!ok) _weight = 0.4;

     } else {

-        _weight = (isSelfLoop()) ? 1.0f : 0.4f;

+        _weight = (isSelfLoop()) ? 1.0 : 0.4;

     }

 

     //qDebug() << "bend: " << _bend << " in: " << _inAngle << " out: " << _outAngle;

@@ -258,8 +254,6 @@ void Edge::updateData()
     _data->unsetProperty("bend right");

     _data->unsetProperty("looseness");

 

-    // TODO: style handling?

-

     if (_basicBendMode) {

         if (_bend != 0) {

             QString bendKey;

@@ -284,8 +278,8 @@ void Edge::updateData()
     }

 

     if (_source == _target) _data->setAtom("loop");

-    if (!isSelfLoop() && !isStraight() && _weight != 0.4f)

-        _data->setProperty("looseness", QString::number(_weight*2.5f, 'f', 2));

+    if (!isSelfLoop() && !isStraight() && !almostEqual(_weight, 0.4))

+        _data->setProperty("looseness", QString::number(_weight*2.5, 'f', 2));

     if (_source->isBlankNode()) _sourceAnchor = "center";

     else _sourceAnchor = "";

     if (_target->isBlankNode()) _targetAnchor = "center";

@@ -329,7 +323,7 @@ int Edge::outAngle() const
     return _outAngle;

 }

 

-float Edge::weight() const

+qreal Edge::weight() const

 {

     return _weight;

 }

@@ -339,7 +333,7 @@ bool Edge::basicBendMode() const
     return _basicBendMode;

 }

 

-float Edge::cpDist() const

+qreal Edge::cpDist() const

 {

     return _cpDist;

 }

@@ -364,7 +358,7 @@ void Edge::setOutAngle(int outAngle)
     _outAngle = outAngle;

 }

 

-void Edge::setWeight(float weight)

+void Edge::setWeight(qreal weight)

 {

     _weight = weight;

 }

@@ -406,18 +400,18 @@ Style *Edge::style() const
 	return _style;

 }

 

-QPointF Edge::bezierTangent(float start, float end) const

+QPointF Edge::bezierTangent(qreal start, qreal end) const

 {

-	float dx = bezierInterpolate(end, _tail.x(), _cp1.x(), _cp2.x(), _head.x()) -

+	qreal dx = bezierInterpolate(end, _tail.x(), _cp1.x(), _cp2.x(), _head.x()) -

 		bezierInterpolate(start, _tail.x(), _cp1.x(), _cp2.x(), _head.x());

-	float dy = bezierInterpolate(end, _tail.y(), _cp1.y(), _cp2.y(), _head.y()) -

+	qreal dy = bezierInterpolate(end, _tail.y(), _cp1.y(), _cp2.y(), _head.y()) -

 		bezierInterpolate(start, _tail.y(), _cp1.y(), _cp2.y(), _head.y());

 

 	// normalise

-	float len = sqrt(dx*dx + dy * dy);

-	if (len != 0) {

-		dx = (dx / len) * 0.1f;

-		dy = (dy / len) * 0.1f;

+	qreal len = sqrt(dx*dx + dy*dy);

+	if (almostZero(len)) {

+		dx = (dx / len) * 0.1;

+		dy = (dy / len) * 0.1;

 	}

 

 	return QPointF(dx, dy);

diff --git a/src/data/edge.h b/src/data/edge.h
index ad71364..909824b 100644
--- a/src/data/edge.h
+++ b/src/data/edge.h
@@ -16,6 +16,10 @@
     along with this program.  If not, see <https://www.gnu.org/licenses/>.

 */

 

+/*!

+ * Class representing an edge in a Graph.

+ */

+

 #ifndef EDGE_H

 #define EDGE_H

 

@@ -30,9 +34,8 @@ class Edge : public QObject
 {

     Q_OBJECT

 public:

-    explicit Edge(Node *s, Node *t, QObject *parent = 0);

-    ~Edge();

-    Edge *copy(QMap<Node *, Node *> *nodeTable = 0);

+    explicit Edge(Node *s, Node *t, QObject *parent = nullptr);

+    Edge *copy(QMap<Node *, Node *> *nodeTable = nullptr);

 

     Node *source() const;

     Node *target() const;

@@ -68,15 +71,15 @@ public:
     int bend() const;

     int inAngle() const;

     int outAngle() const;

-    float weight() const;

+    qreal weight() const;

     bool basicBendMode() const;

-    float cpDist() const;

+    qreal cpDist() const;

 

     void setBasicBendMode(bool mode);

     void setBend(int bend);

     void setInAngle(int inAngle);

     void setOutAngle(int outAngle);

-    void setWeight(float weight);

+    void setWeight(qreal weight);

 

     int tikzLine() const;

     void setTikzLine(int tikzLine);

@@ -92,7 +95,7 @@ signals:
 public slots:

 

 private:

-	QPointF bezierTangent(float start, float end) const;

+	QPointF bezierTangent(qreal start, qreal end) const;

     QString _sourceAnchor;

     QString _targetAnchor;

 

@@ -112,8 +115,8 @@ private:
     int _bend;

     int _inAngle;

     int _outAngle;

-    float _weight;

-    float _cpDist;

+    qreal _weight;

+    qreal _cpDist;

 

     QPointF _head;

     QPointF _tail;

diff --git a/src/data/graph.cpp b/src/data/graph.cpp
index bba2061..1dd5574 100644
--- a/src/data/graph.cpp
+++ b/src/data/graph.cpp
@@ -152,8 +152,9 @@ GraphElementData *Graph::data() const
 

 void Graph::setData(GraphElementData *data)

 {

-    delete _data;

+    GraphElementData *oldData = _data;

     _data = data;

+    oldData->deleteLater();

 }

 

 const QVector<Node*> &Graph::nodes()

@@ -278,6 +279,7 @@ Graph *Graph::copyOfSubgraphWithNodes(QSet<Node *> nds)
 {

     Graph *g = new Graph();

     g->setData(_data->copy());

+    g->data()->setAtom("tikzfig");

     QMap<Node*,Node*> nodeTable;

     foreach (Node *n, nodes()) {

         if (nds.contains(n)) {

diff --git a/src/data/graphelementdata.cpp b/src/data/graphelementdata.cpp
index 810ebd6..cd09a6d 100644
--- a/src/data/graphelementdata.cpp
+++ b/src/data/graphelementdata.cpp
@@ -23,18 +23,12 @@
 

 GraphElementData::GraphElementData(QVector<GraphElementProperty> init, QObject *parent) : QAbstractItemModel(parent)

 {

-    root = new GraphElementProperty();

     _properties = init;

 }

 

 GraphElementData::GraphElementData(QObject *parent) : QAbstractItemModel(parent) {

-    root = new GraphElementProperty();

 }

 

-GraphElementData::~GraphElementData()

-{

-    delete root;

-}

 

 GraphElementData *GraphElementData::copy()

 {

@@ -103,7 +97,8 @@ bool GraphElementData::hasProperty(QString key)
 

 bool GraphElementData::atom(QString atom)

 {

-    return (indexOfKey(atom) != -1);

+    int idx = indexOfKey(atom);

+    return (idx != -1 && _properties[idx].atom());

 }

 

 int GraphElementData::indexOfKey(QString key)

diff --git a/src/data/graphelementdata.h b/src/data/graphelementdata.h
index 23f0466..dce0d46 100644
--- a/src/data/graphelementdata.h
+++ b/src/data/graphelementdata.h
@@ -16,6 +16,12 @@
     along with this program.  If not, see <https://www.gnu.org/licenses/>.

 */

 

+/*!

+ * A list of GraphElementProperty objects, which convenience methods

+ * for lookup, deletion, re-ordering, etc. It inherits QAbstractItemModel

+ * so it can be used as the model for a QTreeView in the StyleEditor.

+ */

+

 #ifndef GRAPHELEMENTDATA_H

 #define GRAPHELEMENTDATA_H

 

@@ -34,7 +40,6 @@ public:
     explicit GraphElementData(QVector<GraphElementProperty> init,

                               QObject *parent = 0);

     explicit GraphElementData(QObject *parent = 0);

-    ~GraphElementData();

     GraphElementData *copy();

     void setProperty(QString key, QString value);

     void unsetProperty(QString key);

@@ -78,7 +83,6 @@ public slots:
 

 private:

     QVector<GraphElementProperty> _properties;

-    GraphElementProperty *root;

 };

 

 #endif // GRAPHELEMENTDATA_H

diff --git a/src/data/graphelementproperty.h b/src/data/graphelementproperty.h
index 4ebe104..5777c18 100644
--- a/src/data/graphelementproperty.h
+++ b/src/data/graphelementproperty.h
@@ -16,6 +16,11 @@
     along with this program.  If not, see <https://www.gnu.org/licenses/>.

 */

 

+/*!

+ * A class which holds either a single key/value pair (i.e. a proper property)

+ * or simply a key with no value (i.e. an atom).

+ */

+

 #ifndef GRAPHELEMENTPROPERTY_H

 #define GRAPHELEMENTPROPERTY_H

 

@@ -26,13 +31,19 @@ class GraphElementProperty
 public:

     GraphElementProperty();

 

-    // full constructor

     GraphElementProperty(QString key, QString value, bool atom);

 

-    // construct a proper property

+    /*!

+     * \brief GraphElementProperty constructs a proper property with the given key/value

+     * \param key

+     * \param value

+     */

     GraphElementProperty(QString key, QString value);

 

-    // construct an atom

+    /*!

+     * \brief GraphElementProperty constructs an atom with the given key

+     * \param key

+     */

     GraphElementProperty(QString key);

 

     QString key() const;

@@ -40,9 +51,29 @@ public:
     QString value() const;

     void setValue(const QString &value);

     bool atom() const;

+

+    /*!

+     * \brief operator == returns true for atoms if the keys match and for properties

+     * if the keys and values match. Note a property is never equal to an atom.

+     * \param p

+     * \return

+     */

     bool operator==(const GraphElementProperty &p);

 

+    /*!

+     * \brief tikzEscape prepares a property key or value for export to tikz code. If

+     * the property only contains numbers, letters, whitespace, or the characters (<,>,-)

+     * this method does nothing. Otherwise, wrap the property in curly braces.

+     * \param str

+     * \return

+     */

     static QString tikzEscape(QString str);

+

+    /*!

+     * \brief tikz escapes the key/value of a propery or atom and outputs it as "key=value"

+     * for properties and "key" for atoms.

+     * \return

+     */

     QString tikz();

 

 signals:

diff --git a/src/data/node.cpp b/src/data/node.cpp
index 75acd00..8ec5e9b 100644
--- a/src/data/node.cpp
+++ b/src/data/node.cpp
@@ -23,15 +23,11 @@
 

 Node::Node(QObject *parent) : QObject(parent), _tikzLine(-1)

 {

-    _data = new GraphElementData();

+    _data = new GraphElementData(this);

     _style = noneStyle;

     _data->setProperty("style", "none");

 }

 

-Node::~Node()

-{

-    delete _data;

-}

 

 Node *Node::copy() {

     Node *n1 = new Node();

@@ -81,8 +77,9 @@ GraphElementData *Node::data() const
 

 void Node::setData(GraphElementData *data)

 {

-    delete _data;

+    GraphElementData *oldData = _data;

     _data = data;

+    oldData->deleteLater();

 }

 

 QString Node::styleName() const

diff --git a/src/data/node.h b/src/data/node.h
index 490393d..c40627b 100644
--- a/src/data/node.h
+++ b/src/data/node.h
@@ -31,7 +31,6 @@ class Node : public QObject
     Q_OBJECT

 public:

     explicit Node(QObject *parent = 0);

-    ~Node();

 

     Node *copy();

 

diff --git a/src/data/pdfdocument.cpp b/src/data/pdfdocument.cpp
new file mode 100644
index 0000000..c9574b8
--- /dev/null
+++ b/src/data/pdfdocument.cpp
@@ -0,0 +1,134 @@
+#include "pdfdocument.h"
+
+#include <QFile>
+#include <QByteArray>
+#include <QDebug>
+#include <QApplication>
+#include <QClipboard>
+
+PdfDocument::PdfDocument(QString file, QObject *parent) : QObject(parent)
+{
+    // use loadFromData to avoid holding a lock on the PDF file in windows
+    QFile f(file);
+    if (f.open(QFile::ReadOnly)) {
+        QByteArray data = f.readAll();
+        f.close();
+        _doc = Poppler::Document::loadFromData(data);
+    } else {
+        _doc = nullptr;
+    }
+
+    if (!_doc) {
+        _doc = nullptr;
+        _page = nullptr;
+    } else {
+        _doc->setRenderHint(Poppler::Document::Antialiasing);
+        _doc->setRenderHint(Poppler::Document::TextAntialiasing);
+        _doc->setRenderHint(Poppler::Document::TextHinting);
+        _page = _doc->page(0);
+    }
+}
+
+void PdfDocument::renderTo(QLabel *label, QRect rect)
+{
+    if (!isValid()) return;
+
+    QSizeF pageSize = _page->pageSizeF();
+
+    qreal ratio = label->devicePixelRatioF();
+    //QRect rect = ui->scrollArea->visibleRegion().boundingRect();
+    int w = static_cast<int>(ratio * (rect.width() - 20));
+    int h = static_cast<int>(ratio * (rect.height() - 20));
+
+    // not all platforms have fmin, compute the min by hand
+    qreal hscale = static_cast<qreal>(w) / pageSize.width();
+    qreal vscale = static_cast<qreal>(h) / pageSize.height();
+    qreal scale = (hscale < vscale) ? hscale : vscale;
+
+    int dpi = static_cast<int>(scale * 72.0);
+    int w1 = static_cast<int>(scale * pageSize.width());
+    int h1 = static_cast<int>(scale * pageSize.height());
+
+    //qDebug() << "hidpi ratio:" << ratio;
+    //qDebug() << "visible width:" << w;
+    //qDebug() << "visible height:" << h;
+    //qDebug() << "doc width:" << pageSize.width();
+    //qDebug() << "doc height:" << pageSize.height();
+    //qDebug() << "scale:" << scale;
+    //qDebug() << "dpi:" << dpi;
+
+    QPixmap pm = QPixmap::fromImage(_page->renderToImage(dpi, dpi, (w1 - w)/2,  (h1 - h)/2, w, h));
+    pm.setDevicePixelRatio(ratio);
+    label->setPixmap(pm);
+}
+
+bool PdfDocument::isValid()
+{
+    return (_page != nullptr);
+}
+
+bool PdfDocument::exportImage(QString file, const char *format, QSize outputSize)
+{
+    QImage img = asImage(outputSize);
+    if (!img.isNull()) return img.save(file, format);
+    else return false;
+}
+
+bool PdfDocument::exportPdf(QString file)
+{
+    if (!isValid()) return false;
+    Poppler::PDFConverter *conv = _doc->pdfConverter();
+    conv->setOutputFileName(file);
+    bool success = conv->convert();
+    delete conv;
+    return success;
+}
+
+void PdfDocument::copyImageToClipboard(QSize outputSize)
+{
+    QImage img = asImage(outputSize);
+    if (!img.isNull()) {
+        QApplication::clipboard()->setImage(img, QClipboard::Clipboard);
+    }
+}
+
+QImage PdfDocument::asImage(QSize outputSize)
+{
+    if (!isValid()) return QImage();
+    if (outputSize.isNull()) outputSize = size();
+    QSize pageSize = _page->pageSize();
+    int dpix = (72 * outputSize.width()) / pageSize.width();
+    int dpiy = (72 * outputSize.width()) / pageSize.width();
+    QImage img = _page->renderToImage(dpix, dpiy, 0,  0,
+                                      outputSize.width(), outputSize.height());
+    return img;
+}
+
+// CRASHES TikZiT when figures contain text, due to limitations of Arthur backend
+//void PdfDocument::exportToSvg(QString file, QSize size) {
+//    QSvgGenerator gen;
+//    gen.setFileName(file);
+//    gen.setSize(size);
+//    gen.setViewBox(QRect(0,0,size.width(),size.height()));
+//    gen.setDescription("SVG generated from PDF by TikZiT");
+//    QPainter painter;
+
+//    // set the backend to Qt for renderToPainter() support
+//    Poppler::Document::RenderBackend backend = _doc->renderBackend();
+//    _doc->setRenderBackend(Poppler::Document::ArthurBackend);
+//    painter.begin(&gen);
+//    _page->renderToPainter(&painter);
+//    painter.end();
+//    _doc->setRenderBackend(backend);
+//}
+
+QSize PdfDocument::size()
+{
+    if (isValid()) {
+        return _page->pageSize();
+    } else {
+        return QSize();
+    }
+}
+
+
diff --git a/src/data/pdfdocument.h b/src/data/pdfdocument.h
new file mode 100644
index 0000000..ebd33e9
--- /dev/null
+++ b/src/data/pdfdocument.h
@@ -0,0 +1,28 @@
+#ifndef PDFDOCUMENT_H
+#define PDFDOCUMENT_H
+
+#include <QObject>
+#include <QString>
+#include <QLabel>
+
+#include <poppler/qt5/poppler-qt5.h>
+
+class PdfDocument : public QObject
+{
+    Q_OBJECT
+public:
+    explicit PdfDocument(QString file, QObject *parent = nullptr);
+    void renderTo(QLabel *label, QRect rect);
+    bool isValid();
+//    void exportToSvg(QString file, QSize size);
+    bool exportImage(QString file, const char *format, QSize outputSize=QSize());
+    bool exportPdf(QString file);
+    void copyImageToClipboard(QSize outputSize=QSize());
+    QImage asImage(QSize outputSize=QSize());
+    QSize size();
+private:
+    Poppler::Document *_doc;
+    Poppler::Page *_page;
+};
+
+#endif // PDFDOCUMENT_H
diff --git a/src/data/tikzdocument.cpp b/src/data/tikzdocument.cpp
index 24a793b..1099779 100644
--- a/src/data/tikzdocument.cpp
+++ b/src/data/tikzdocument.cpp
@@ -34,16 +34,10 @@ TikzDocument::TikzDocument(QObject *parent) : QObject(parent)
     _parseSuccess = true;

     _fileName = "";

     _shortName = "";

-    _undoStack = new QUndoStack();

+    _undoStack = new QUndoStack(this);

     _undoStack->setClean();

 }

 

-TikzDocument::~TikzDocument()

-{

-    delete _graph;

-    delete _undoStack;

-}

-

 QUndoStack *TikzDocument::undoStack() const

 {

     return _undoStack;

@@ -75,15 +69,18 @@ void TikzDocument::open(QString fileName)
         return;

     }

 

+    addToRecentFiles();

+

     QTextStream in(&file);

     _tikz = in.readAll();

     file.close();

 

+    Graph *oldGraph = _graph;

     Graph *newGraph = new Graph(this);

     TikzAssembler ass(newGraph);

     if (ass.parse(_tikz)) {

-        delete _graph;

         _graph = newGraph;

+        oldGraph->deleteLater();

         foreach (Node *n, _graph->nodes()) n->attachStyle();

         foreach (Edge *e, _graph->edges()) {

             e->attachStyle();

@@ -93,7 +90,7 @@ void TikzDocument::open(QString fileName)
         refreshTikz();

         setClean();

     } else {

-        delete newGraph;

+        newGraph->deleteLater();

         _parseSuccess = false;

     }

 }

@@ -103,10 +100,10 @@ bool TikzDocument::save() {
         return saveAs();

     } else {

         MainWindow *win = tikzit->activeWindow();

-        if (win != 0 && !win->tikzScene()->enabled()) {

+        if (win != nullptr && !win->tikzScene()->enabled()) {

             win->tikzScene()->parseTikz(win->tikzSource());

             if (!win->tikzScene()->enabled()) {

-                auto resp = QMessageBox::question(0,

+                auto resp = QMessageBox::question(nullptr,

                   tr("Tikz failed to parse"),

                   tr("Cannot save file with invalid TiKZ source. Revert changes and save?"));

                 if (resp == QMessageBox::Yes) win->tikzScene()->setEnabled(true);

@@ -128,7 +125,8 @@ bool TikzDocument::save() {
             setClean();

             return true;

         } else {

-            QMessageBox::warning(0, "Save Failed", "Could not open file: '" + _fileName + "' for writing.");

+            QMessageBox::warning(nullptr,

+                "Save Failed", "Could not open file: '" + _fileName + "' for writing.");

         }

     }

 

@@ -145,6 +143,34 @@ void TikzDocument::setClean()
     _undoStack->setClean();

 }

 

+QString TikzDocument::fileName() const

+{

+    return _fileName;

+}

+

+bool TikzDocument::isEmpty()

+{

+    return _graph->nodes().isEmpty();

+}

+

+void TikzDocument::addToRecentFiles()

+{

+    QSettings settings("tikzit", "tikzit");

+    if (!_fileName.isEmpty()) {

+        QStringList recentFiles = settings.value("recent-files").toStringList();

+

+        // if the file is in the list already, shift it to the top. Otherwise, add it.

+        recentFiles.removeAll(_fileName);

+        recentFiles.prepend(_fileName);

+

+        // keep max 10 files

+        while (recentFiles.size() > 10) recentFiles.removeLast();

+

+        settings.setValue("recent-files", recentFiles);

+        tikzit->updateRecentFiles();

+    }

+}

+

 void TikzDocument::setGraph(Graph *graph)

 {

     _graph = graph;

@@ -153,10 +179,10 @@ void TikzDocument::setGraph(Graph *graph)
 

 bool TikzDocument::saveAs() {

     MainWindow *win = tikzit->activeWindow();

-    if (win != 0 && !win->tikzScene()->enabled()) {

+    if (win != nullptr && !win->tikzScene()->enabled()) {

         win->tikzScene()->parseTikz(win->tikzSource());

         if (!win->tikzScene()->enabled()) {

-            auto resp = QMessageBox::question(0,

+            auto resp = QMessageBox::question(nullptr,

               tr("Tikz failed to parse"),

               tr("Cannot save file with invalid TiKZ source. Revert changes and save?"));

             if (resp == QMessageBox::Yes) win->tikzScene()->setEnabled(true);

@@ -175,19 +201,13 @@ bool TikzDocument::saveAs() {
     dialog.setDirectory(settings.value("previous-file-path").toString());

     dialog.setOption(QFileDialog::DontUseNativeDialog);

 

-//    QString fileName = QFileDialog::getSaveFileName(tikzit->activeWindow(),

-//                tr("Save File As"),

-//                settings.value("previous-file-path").toString(),

-//                tr("TiKZ Files (*.tikz)"),

-//                nullptr,

-//                QFileDialog::DontUseNativeDialog);

-

     if (dialog.exec() && !dialog.selectedFiles().isEmpty()) {

         QString fileName = dialog.selectedFiles()[0];

         _fileName = fileName;

         if (save()) {

             // clean state might not change, so update title bar manually

             tikzit->activeWindow()->updateFileName();

+            addToRecentFiles();

             return true;

         }

     }

diff --git a/src/data/tikzdocument.h b/src/data/tikzdocument.h
index fca5434..ad5499f 100644
--- a/src/data/tikzdocument.h
+++ b/src/data/tikzdocument.h
@@ -34,7 +34,6 @@ class TikzDocument : public QObject
     Q_OBJECT

 public:

     explicit TikzDocument(QObject *parent = 0);

-    ~TikzDocument();

 

     Graph *graph() const;

     void setGraph(Graph *graph);

@@ -53,6 +52,10 @@ public:
     bool isClean() const;

     void setClean();

 

+    QString fileName() const;

+

+    bool isEmpty();

+

 private:

     Graph *_graph;

     QString _tikz;

@@ -60,6 +63,7 @@ private:
     QString _shortName;

     QUndoStack *_undoStack;

     bool _parseSuccess;

+    void addToRecentFiles();

 

 signals:

 

diff --git a/src/gui/delimitedstringitemdelegate.cpp b/src/gui/delimitedstringitemdelegate.cpp
new file mode 100644
index 0000000..7b6c58e
--- /dev/null
+++ b/src/gui/delimitedstringitemdelegate.cpp
@@ -0,0 +1,44 @@
+/*
+    TikZiT - a GUI diagram editor for TikZ
+    Copyright (C) 2018 Aleks Kissinger
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+*/
+
+#include "delimitedstringitemdelegate.h"
+
+#include <QLineEdit>
+
+DelimitedStringItemDelegate::DelimitedStringItemDelegate(QObject *parent) : QItemDelegate (parent)
+{
+    _validator = new DelimitedStringValidator(this);
+}
+
+DelimitedStringItemDelegate::~DelimitedStringItemDelegate()
+{
+}
+
+QWidget *DelimitedStringItemDelegate::createEditor(
+        QWidget *parent,
+        const QStyleOptionViewItem &option,
+        const QModelIndex &index) const
+{
+    QWidget *editor = QItemDelegate::createEditor(parent, option, index);
+
+    if (QLineEdit *lineEdit = dynamic_cast<QLineEdit*>(editor)) {
+        lineEdit->setValidator(_validator);
+    }
+
+    return editor;
+}
diff --git a/src/gui/delimitedstringitemdelegate.h b/src/gui/delimitedstringitemdelegate.h
new file mode 100644
index 0000000..bd1a856
--- /dev/null
+++ b/src/gui/delimitedstringitemdelegate.h
@@ -0,0 +1,42 @@
+/*
+    TikZiT - a GUI diagram editor for TikZ
+    Copyright (C) 2018 Aleks Kissinger
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+*/
+
+/*!
+ * A QItemDelete that attaches a DelimitedStringValidator to any QLineEdit
+ */
+
+#ifndef DELIMITEDSTRINGITEMDELEGATE_H
+#define DELIMITEDSTRINGITEMDELEGATE_H
+
+#include "delimitedstringvalidator.h"
+
+#include <QWidget>
+#include <QItemDelegate>
+
+class DelimitedStringItemDelegate : public QItemDelegate
+{
+    Q_OBJECT
+public:
+    DelimitedStringItemDelegate(QObject *parent=nullptr);
+    virtual ~DelimitedStringItemDelegate() override;
+    QWidget *createEditor(QWidget *parent, const QStyleOptionViewItem &option, const QModelIndex &index) const override;
+private:
+    DelimitedStringValidator *_validator;
+};
+
+#endif // DELIMITEDSTRINGITEMDELEGATE_H
diff --git a/src/gui/exportdialog.cpp b/src/gui/exportdialog.cpp
new file mode 100644
index 0000000..bd1ef53
--- /dev/null
+++ b/src/gui/exportdialog.cpp
@@ -0,0 +1,194 @@
+/*
+    TikZiT - a GUI diagram editor for TikZ
+    Copyright (C) 2018 Aleks Kissinger
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+*/
+
+#include "exportdialog.h"
+#include "ui_exportdialog.h"
+
+#include "tikzit.h"
+
+#include <QFileDialog>
+#include <QSettings>
+#include <QStandardPaths>
+
+ExportDialog::ExportDialog(QWidget *parent) :
+    QDialog(parent),
+    ui(new Ui::ExportDialog)
+{
+    QSettings settings("tikzit", "tikzit");
+    ui->setupUi(this);
+
+    QIntValidator *v = new QIntValidator(this);
+    v->setBottom(1);
+    ui->width->setValidator(v);
+    ui->height->setValidator(v);
+    connect(ui->width, SIGNAL(editingFinished()),
+            this, SLOT(setHeightFromWidth()));
+    connect(ui->height, SIGNAL(editingFinished()),
+            this, SLOT(setWidthFromHeight()));
+
+    PdfDocument *doc = tikzit->previewWindow()->doc();
+    if (doc) {
+        QSize size = doc->size() * 4;
+        ui->width->blockSignals(true);
+        ui->height->blockSignals(true);
+        ui->width->setText(QString::number(size.width()));
+        ui->height->setText(QString::number(size.height()));
+        ui->width->blockSignals(false);
+        ui->height->blockSignals(false);
+    }
+
+    if (!settings.value("previous-export-file-format").isNull()) {
+        ui->fileFormat->setCurrentIndex(settings.value("previous-export-file-format").toInt());
+    }
+
+    // set a default export file
+    QString path = (!settings.value("previous-export-file-path").isNull()) ?
+        settings.value("previous-export-file-path").toString() :
+        QStandardPaths::writableLocation(QStandardPaths::DocumentsLocation);
+
+    QString suffix;
+    switch (ui->fileFormat->currentIndex()) {
+        case PNG: suffix = ".png"; break;
+        case JPG: suffix = ".jpg"; break;
+        case PDF: suffix = ".pdf"; break;
+    }
+
+    QString fileName;
+    int i = 0;
+    bool exists = true;
+    while (exists) {
+        fileName = path + "/tikzit_image" + QString::number(i) + suffix;
+        exists = QFileInfo::exists(fileName);
+        ++i;
+    }
+    ui->filePath->setText(QDir::toNativeSeparators(fileName));
+}
+
+ExportDialog::~ExportDialog()
+{
+    delete ui;
+}
+
+QString ExportDialog::filePath()
+{
+    return ui->filePath->text();
+}
+
+QSize ExportDialog::size()
+{
+    return QSize(ui->width->text().toInt(),
+                 ui->height->text().toInt());
+}
+
+ExportDialog::Format ExportDialog::fileFormat()
+{
+    return static_cast<Format>(ui->fileFormat->currentIndex());
+}
+
+void ExportDialog::accept()
+{
+    QSettings settings("tikzit", "tikzit");
+    QFileInfo fi(filePath());
+    settings.setValue("previous-export-file-path", fi.absolutePath());
+    settings.setValue("previous-export-file-format", fileFormat());
+    QDialog::accept();
+}
+
+void ExportDialog::setHeightFromWidth()
+{
+    if (ui->keepAspect->isChecked()) {
+        PdfDocument *doc = tikzit->previewWindow()->doc();
+        if (doc == nullptr || doc->size().width() == 0 || doc->size().height() == 0) return;
+        int w = ui->width->text().toInt();
+        int h = (w * doc->size().height()) / doc->size().width();
+
+        ui->height->blockSignals(true);
+        ui->height->setText(QString::number(h));
+        ui->height->blockSignals(false);
+    }
+}
+
+void ExportDialog::setWidthFromHeight()
+{
+    if (ui->keepAspect->isChecked()) {
+        PdfDocument *doc = tikzit->previewWindow()->doc();
+        if (doc == nullptr || doc->size().width() == 0 || doc->size().height() == 0) return;
+        int h = ui->height->text().toInt();
+        int w = (h * doc->size().width()) / doc->size().height();
+
+        ui->width->blockSignals(true);
+        ui->width->setText(QString::number(w));
+        ui->width->blockSignals(false);
+    }
+}
+
+void ExportDialog::on_keepAspect_stateChanged(int state)
+{
+    if (state == Qt::Checked) setHeightFromWidth();
+}
+
+void ExportDialog::on_browseButton_clicked()
+{
+    QSettings settings("tikzit", "tikzit");
+
+    QString suffix;
+    switch (ui->fileFormat->currentIndex()) {
+        case PNG: suffix = "png"; break;
+        case JPG: suffix = "jpg"; break;
+        case PDF: suffix = "pdf"; break;
+    }
+
+    QFileDialog dialog;
+    dialog.setDefaultSuffix(suffix);
+    dialog.setWindowTitle(tr("Export File Path"));
+    dialog.setAcceptMode(QFileDialog::AcceptSave);
+    dialog.setNameFilter(ui->fileFormat->currentText());
+    dialog.setFileMode(QFileDialog::AnyFile);
+    dialog.setLabelText(QFileDialog::Accept, "Select");
+
+    QFileInfo fi(ui->filePath->text());
+    if (!fi.absolutePath().isEmpty()) {
+        dialog.setDirectory(fi.absolutePath());
+        dialog.selectFile(fi.baseName());
+    }
+
+    dialog.setOption(QFileDialog::DontUseNativeDialog);
+
+    if (dialog.exec()) {
+        ui->filePath->setText(QDir::toNativeSeparators(dialog.selectedFiles()[0]));
+    }
+}
+
+void ExportDialog::on_fileFormat_currentIndexChanged(int f)
+{
+    ui->width->setEnabled(f != PDF);
+    ui->height->setEnabled(f != PDF);
+    ui->keepAspect->setEnabled(f != PDF);
+
+    QString path = ui->filePath->text();
+    if (!path.isEmpty()) {
+        QRegularExpression re("\\.[^.]*$");
+        switch (f) {
+            case PNG: path.replace(re, ".png"); break;
+            case JPG: path.replace(re, ".jpg"); break;
+            case PDF: path.replace(re, ".pdf"); break;
+        }
+
+        ui->filePath->setText(path);
+    }
+}
diff --git a/src/gui/exportdialog.h b/src/gui/exportdialog.h
new file mode 100644
index 0000000..bcb6879
--- /dev/null
+++ b/src/gui/exportdialog.h
@@ -0,0 +1,61 @@
+/*
+    TikZiT - a GUI diagram editor for TikZ
+    Copyright (C) 2018 Aleks Kissinger
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+*/
+
+/*!
+ * A dialog for exporting a LaTeX-generated preview to PNG, JPG, or PDF.
+ */
+
+#ifndef EXPORTDIALOG_H
+#define EXPORTDIALOG_H
+
+#include <QDialog>
+
+namespace Ui {
+class ExportDialog;
+}
+
+class ExportDialog : public QDialog
+{
+    Q_OBJECT
+
+public:
+    explicit ExportDialog(QWidget *parent = nullptr);
+    ~ExportDialog() override;
+    enum Format {
+        PNG = 0,
+        JPG = 1,
+        PDF = 2
+    };
+    QString filePath();
+    QSize size();
+    Format fileFormat();
+public slots:
+    void accept() override;
+
+protected slots:
+    void setHeightFromWidth();
+    void setWidthFromHeight();
+    void on_keepAspect_stateChanged(int state);
+    void on_browseButton_clicked();
+    void on_fileFormat_currentIndexChanged(int f);
+
+private:
+    Ui::ExportDialog *ui;
+};
+
+#endif // EXPORTDIALOG_H
diff --git a/src/gui/exportdialog.ui b/src/gui/exportdialog.ui
new file mode 100644
index 0000000..82cefdc
--- /dev/null
+++ b/src/gui/exportdialog.ui
@@ -0,0 +1,162 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<ui version="4.0">
+ <class>ExportDialog</class>
+ <widget class="QDialog" name="ExportDialog">
+  <property name="geometry">
+   <rect>
+    <x>0</x>
+    <y>0</y>
+    <width>394</width>
+    <height>119</height>
+   </rect>
+  </property>
+  <property name="sizePolicy">
+   <sizepolicy hsizetype="Fixed" vsizetype="Fixed">
+    <horstretch>0</horstretch>
+    <verstretch>0</verstretch>
+   </sizepolicy>
+  </property>
+  <property name="windowTitle">
+   <string>Export Image</string>
+  </property>
+  <layout class="QHBoxLayout" name="horizontalLayout">
+   <item>
+    <layout class="QFormLayout" name="formLayout">
+     <item row="0" column="0">
+      <widget class="QLabel" name="label">
+       <property name="text">
+        <string>File</string>
+       </property>
+      </widget>
+     </item>
+     <item row="1" column="0">
+      <widget class="QLabel" name="label_2">
+       <property name="text">
+        <string>Format</string>
+       </property>
+      </widget>
+     </item>
+     <item row="0" column="1">
+      <layout class="QHBoxLayout" name="horizontalLayout_2">
+       <item>
+        <widget class="QLineEdit" name="filePath"/>
+       </item>
+       <item>
+        <widget class="QToolButton" name="browseButton">
+         <property name="text">
+          <string>...</string>
+         </property>
+        </widget>
+       </item>
+      </layout>
+     </item>
+     <item row="1" column="1">
+      <widget class="QComboBox" name="fileFormat">
+       <item>
+        <property name="text">
+         <string>Portable Network Graphics (*.png)</string>
+        </property>
+       </item>
+       <item>
+        <property name="text">
+         <string>Jpeg Image (*.jpg)</string>
+        </property>
+       </item>
+       <item>
+        <property name="text">
+         <string>Original (*.pdf)</string>
+        </property>
+       </item>
+      </widget>
+     </item>
+     <item row="2" column="0">
+      <widget class="QLabel" name="label_3">
+       <property name="text">
+        <string>Dimensions</string>
+       </property>
+      </widget>
+     </item>
+     <item row="2" column="1">
+      <layout class="QHBoxLayout" name="horizontalLayout_3">
+       <item>
+        <widget class="QLineEdit" name="width"/>
+       </item>
+       <item>
+        <widget class="QLabel" name="label_4">
+         <property name="text">
+          <string> X </string>
+         </property>
+        </widget>
+       </item>
+       <item>
+        <widget class="QLineEdit" name="height"/>
+       </item>
+      </layout>
+     </item>
+     <item row="3" column="0">
+      <widget class="QLabel" name="label_5">
+       <property name="text">
+        <string/>
+       </property>
+      </widget>
+     </item>
+     <item row="3" column="1">
+      <widget class="QCheckBox" name="keepAspect">
+       <property name="text">
+        <string>Keep aspect ratio</string>
+       </property>
+       <property name="checked">
+        <bool>true</bool>
+       </property>
+      </widget>
+     </item>
+    </layout>
+   </item>
+   <item>
+    <widget class="QDialogButtonBox" name="buttonBox">
+     <property name="orientation">
+      <enum>Qt::Vertical</enum>
+     </property>
+     <property name="standardButtons">
+      <set>QDialogButtonBox::Cancel|QDialogButtonBox::Save</set>
+     </property>
+    </widget>
+   </item>
+  </layout>
+ </widget>
+ <resources/>
+ <connections>
+  <connection>
+   <sender>buttonBox</sender>
+   <signal>accepted()</signal>
+   <receiver>ExportDialog</receiver>
+   <slot>accept()</slot>
+   <hints>
+    <hint type="sourcelabel">
+     <x>248</x>
+     <y>254</y>
+    </hint>
+    <hint type="destinationlabel">
+     <x>157</x>
+     <y>274</y>
+    </hint>
+   </hints>
+  </connection>
+  <connection>
+   <sender>buttonBox</sender>
+   <signal>rejected()</signal>
+   <receiver>ExportDialog</receiver>
+   <slot>reject()</slot>
+   <hints>
+    <hint type="sourcelabel">
+     <x>316</x>
+     <y>260</y>
+    </hint>
+    <hint type="destinationlabel">
+     <x>286</x>
+     <y>274</y>
+    </hint>
+   </hints>
+  </connection>
+ </connections>
+</ui>
diff --git a/src/gui/latexprocess.cpp b/src/gui/latexprocess.cpp
new file mode 100644
index 0000000..59db9ea
--- /dev/null
+++ b/src/gui/latexprocess.cpp
@@ -0,0 +1,169 @@
+/*
+    TikZiT - a GUI diagram editor for TikZ
+    Copyright (C) 2018 Aleks Kissinger
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+*/
+
+#include "latexprocess.h"
+#include "tikzit.h"
+
+#include <QDebug>
+#include <QStandardPaths>
+#include <QTemporaryDir>
+#include <QStringList>
+#include <QSettings>
+
+LatexProcess::LatexProcess(PreviewWindow *preview, QObject *parent) : QObject(parent)
+{
+    _preview = preview;
+    _output = preview->outputTextEdit();
+
+    _proc = new QProcess(this);
+    _proc->setProcessChannelMode(QProcess::MergedChannels);
+    _proc->setWorkingDirectory(_workingDir.path());
+
+    connect(_proc, SIGNAL(readyReadStandardOutput()), this, SLOT(readyReadStandardOutput()));
+    connect(_proc, SIGNAL(finished(int)), this, SLOT(finished(int)));
+
+    // for debug purposes
+    //_workingDir.setAutoRemove(false);
+}
+
+void LatexProcess::makePreview(QString tikz)
+{
+    QSettings settings("tikzit", "tikzit");
+    _preview->setStatus(PreviewWindow::Running);
+    _output->clear();
+
+    if (!_workingDir.isValid()) {
+        _output->appendPlainText("COULD NOT WRITE TO TEMP DIR: " + _workingDir.path() + "\n");
+        return;
+    }
+
+    _output->appendPlainText("USING TEMP DIR: " + _workingDir.path() + "\n");
+
+    QString pdflatex;
+
+    if (settings.value("auto-detect-pdflatex", true).toBool()) {
+        _output->appendPlainText("SEARCHING FOR pdflatex IN:");
+        _output->appendPlainText(qgetenv("PATH"));
+        _output->appendPlainText("\n");
+        pdflatex = QStandardPaths::findExecutable("pdflatex");
+        if (pdflatex.isEmpty()) {
+            // if pdflatex is not in PATH, we are probably on mac or windows, so try common
+            // install directories.
+            _output->appendPlainText("NOT FOUND IN PATH, TRYING:");
+
+            QStringList texDirs;
+            // common macOS tex directories:
+            texDirs << "/Library/TeX/texbin";
+            texDirs << "/usr/texbin";
+            texDirs << "/usr/local/bin";
+            texDirs << "/sw/bin";
+
+            // common windows tex directories
+            texDirs << "C:\\Program Files\\MiKTeX 2.9\\miktex\\bin";
+            texDirs << "C:\\Program Files\\MiKTeX 2.9\\miktex\\bin\\x64";
+            texDirs << "C:\\Program Files\\MiKTeX 2.8\\miktex\\bin";
+            texDirs << "C:\\Program Files\\MiKTeX 2.8\\miktex\\bin\\x64";
+            texDirs << "C:\\Program Files\\MiKTeX 2.7\\miktex\\bin";
+            texDirs << "C:\\Program Files\\MiKTeX 2.7\\miktex\\bin\\x64";
+
+            _output->appendPlainText(texDirs.join(":"));
+            pdflatex = QStandardPaths::findExecutable("pdflatex", texDirs);
+        }
+
+        if (pdflatex.isEmpty()) {
+            _output->appendPlainText("pdflatex NOT FOUND, ABORTING.\n");
+            _preview->setStatus(PreviewWindow::Failed);
+            return;
+        } else {
+            _output->appendPlainText("FOUND: " + pdflatex + "\n");
+        }
+    } else {
+        _output->appendPlainText("USING pdflatex:\n");
+        pdflatex = settings.value("pdflatex-path", "/usr/bin/pdflatex").toString();
+        _output->appendPlainText(pdflatex + "\n");
+    }
+
+    // copy tikzit.sty to preview dir
+    QFile::copy(":/tex/sample/tikzit.sty", _workingDir.path() + "/tikzit.sty");
+
+    // write out the file containing the tikz picture
+    QFile f(_workingDir.path() + "/preview.tex");
+    f.open(QIODevice::WriteOnly);
+    QTextStream tex(&f);
+    tex << "\\documentclass{article}\n";
+    tex << "\\usepackage{tikzit}\n";
+    tex << "\\tikzstyle{every picture}=[tikzfig]\n";
+    tex << "\\usepackage[graphics,active,tightpage]{preview}\n";
+    tex << "\\PreviewEnvironment{tikzpicture}\n";
+
+    // copy active *.tikzstyles file to preview dir
+    if (!tikzit->styleFile().isEmpty() && QFile::exists(tikzit->styleFilePath())) {
+        QFile::copy(tikzit->styleFilePath(), _workingDir.path() + "/" + tikzit->styleFile());
+        tex << "\\input{" + tikzit->styleFile() + "}\n";
+
+        // if there is a *.tikzdefs file with the same basename, copy and include it as well
+        QFileInfo fi(tikzit->styleFilePath());
+        QString defFile = fi.baseName() + ".tikzdefs";
+        QString defFilePath = fi.absolutePath() + "/" + defFile;
+        if (QFile::exists(defFilePath)) {
+            QFile::copy(defFilePath, _workingDir.path() + "/" + defFile);
+            tex << "\\input{" + defFile + "}\n";
+        }
+    }
+
+    tex << "\\begin{document}\n\n";
+    tex << tikz;
+    tex << "\n\n\\end{document}\n";
+
+    f.close();
+    _proc->start(pdflatex,
+                 QStringList()
+                 << "-interaction=nonstopmode"
+                 << "-halt-on-error"
+                 << "preview.tex");
+
+}
+
+void LatexProcess::kill()
+{
+    if (_proc->state() == QProcess::Running) _proc->kill();
+}
+
+void LatexProcess::readyReadStandardOutput()
+{
+    QByteArray s = _proc->readAllStandardOutput();
+    _output->appendPlainText(s);
+}
+
+void LatexProcess::finished(int exitCode)
+{
+    QByteArray s = _proc->readAllStandardOutput();
+    _output->appendPlainText(s);
+
+    if (exitCode == 0) {
+        QString pdf = _workingDir.path() + "/preview.pdf";
+        _output->appendPlainText("\n\nSUCCESSFULLY GENERATED: " + pdf + "\n");
+        _preview->setPdf(pdf);
+        _preview->setStatus(PreviewWindow::Success);
+        emit previewFinished();
+    } else {
+        _output->appendPlainText("\n\npdflatex RETURNED AN ERROR\n");
+        _preview->setStatus(PreviewWindow::Failed);
+        emit previewFinished();
+    }
+}
diff --git a/src/gui/latexprocess.h b/src/gui/latexprocess.h
new file mode 100644
index 0000000..9853883
--- /dev/null
+++ b/src/gui/latexprocess.h
@@ -0,0 +1,56 @@
+/*
+    TikZiT - a GUI diagram editor for TikZ
+    Copyright (C) 2018 Aleks Kissinger
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+*/
+
+/*!
+ * Run pdflatex and dump its output to the appropriate tab of
+ * the PreviewWindow.
+ */
+
+#ifndef LATEXPROCESS_H
+#define LATEXPROCESS_H
+
+#include "previewwindow.h"
+
+#include <QObject>
+#include <QProcess>
+#include <QTemporaryDir>
+#include <QPlainTextEdit>
+
+class LatexProcess : public QObject
+{
+    Q_OBJECT
+public:
+    explicit LatexProcess(PreviewWindow *preview, QObject *parent = nullptr);
+    void makePreview(QString tikz);
+    void kill();
+
+private:
+    QTemporaryDir _workingDir;
+    PreviewWindow *_preview;
+    QPlainTextEdit *_output;
+    QProcess *_proc;
+
+public slots:
+    void readyReadStandardOutput();
+    void finished(int exitCode);
+
+signals:
+    void previewFinished();
+};
+
+#endif // LATEXPROCESS_H
diff --git a/src/gui/mainmenu.cpp b/src/gui/mainmenu.cpp
index 8166c59..6f4f8db 100644
--- a/src/gui/mainmenu.cpp
+++ b/src/gui/mainmenu.cpp
@@ -17,6 +17,7 @@
 */
 
 #include "mainmenu.h"
+#include "preferencedialog.h"
 #include "tikzit.h"
 
 #include <QDebug>
@@ -33,6 +34,8 @@ MainMenu::MainMenu()
         ui.actionCheck_for_updates_automatically->setChecked(settings.value("check-for-updates").toBool());
         ui.actionCheck_for_updates_automatically->blockSignals(false);
     }
+
+    updateRecentFiles();
 }
 
 void MainMenu::addDocks(QMenu *m)
@@ -48,6 +51,31 @@ QAction *MainMenu::updatesAction()
     return ui.actionCheck_for_updates_automatically;
 }
 
+void MainMenu::updateRecentFiles()
+{
+    QSettings settings("tikzit", "tikzit");
+    ui.menuOpen_Recent->clear();
+
+    QStringList recentFiles = settings.value("recent-files").toStringList();
+    //qDebug() << "update:" << recentFiles;
+
+    QAction *action;
+    foreach (QString f, recentFiles) {
+        QFileInfo fi(f);
+        action = new QAction(fi.fileName(), ui.menuOpen_Recent);
+        action->setData(f);
+        ui.menuOpen_Recent->addAction(action);
+        connect(action, SIGNAL(triggered()),
+                this, SLOT(openRecent()));
+    }
+
+    ui.menuOpen_Recent->addSeparator();
+    action = new QAction("Clear List", ui.menuOpen_Recent);
+    connect(action, SIGNAL(triggered()),
+            tikzit, SLOT(clearRecentFiles()));
+    ui.menuOpen_Recent->addAction(action);
+}
+
 // File
 void MainMenu::on_actionNew_triggered()
 {
@@ -82,6 +110,15 @@ void MainMenu::on_actionExit_triggered()
     tikzit->quit();
 }
 
+void MainMenu::openRecent()
+{
+    if (sender() != nullptr) {
+        if (QAction *action = dynamic_cast<QAction*>(sender())) {
+            tikzit->open(action->data().toString());
+        }
+    }
+}
+
 
 // Edit
 void MainMenu::on_actionUndo_triggered()
@@ -228,6 +265,18 @@ void MainMenu::on_actionJump_to_Selection_triggered()
     }
 }
 
+void MainMenu::on_actionRun_LaTeX_triggered()
+{
+    tikzit->makePreview();
+}
+
+void MainMenu::on_actionPreferences_triggered()
+{
+    PreferenceDialog *d = new PreferenceDialog(this);
+    d->exec();
+    d->deleteLater();
+}
+
 
 // View
 void MainMenu::on_actionZoom_In_triggered()
@@ -260,5 +309,5 @@ void MainMenu::on_actionCheck_for_updates_automatically_triggered()
 
 void MainMenu::on_actionCheck_now_triggered()
 {
-    tikzit->checkForUpdates();
+    tikzit->checkForUpdates(true);
 }
diff --git a/src/gui/mainmenu.h b/src/gui/mainmenu.h
index c14a284..4d672cd 100644
--- a/src/gui/mainmenu.h
+++ b/src/gui/mainmenu.h
@@ -30,6 +30,7 @@ public:
     MainMenu();
     void addDocks(QMenu *m);
     QAction *updatesAction();
+    void updateRecentFiles();
 
 private:
     Ui::MainMenu ui;
@@ -43,6 +44,8 @@ public slots:
     void on_actionSave_As_triggered();
     void on_actionExit_triggered();
 
+    void openRecent();
+
     // Edit
     void on_actionUndo_triggered();
     void on_actionRedo_triggered();
@@ -63,10 +66,12 @@ public slots:
     void on_actionExtendLeft_triggered();
     void on_actionExtendRight_triggered();
 
-    // Tikz
+    // Tools
     void on_actionParse_triggered();
     void on_actionRevert_triggered();
     void on_actionJump_to_Selection_triggered();
+    void on_actionRun_LaTeX_triggered();
+    void on_actionPreferences_triggered();
 
     // View
     void on_actionZoom_In_triggered();
diff --git a/src/gui/mainmenu.ui b/src/gui/mainmenu.ui
index 0481c1d..08067aa 100644
--- a/src/gui/mainmenu.ui
+++ b/src/gui/mainmenu.ui
@@ -14,8 +14,14 @@
    <property name="title">
     <string>File</string>
    </property>
+   <widget class="QMenu" name="menuOpen_Recent">
+    <property name="title">
+     <string>Open Recent</string>
+    </property>
+   </widget>
    <addaction name="actionNew"/>
    <addaction name="actionOpen"/>
+   <addaction name="menuOpen_Recent"/>
    <addaction name="separator"/>
    <addaction name="actionClose"/>
    <addaction name="actionSave"/>
@@ -69,11 +75,14 @@
   </widget>
   <widget class="QMenu" name="menuTikz">
    <property name="title">
-    <string>Tikz</string>
+    <string>Tools</string>
    </property>
    <addaction name="actionParse"/>
    <addaction name="actionRevert"/>
    <addaction name="actionJump_to_Selection"/>
+   <addaction name="actionRun_LaTeX"/>
+   <addaction name="separator"/>
+   <addaction name="actionPreferences"/>
   </widget>
   <widget class="QMenu" name="menuView">
    <property name="title">
@@ -197,7 +206,7 @@
   </action>
   <action name="actionParse">
    <property name="text">
-    <string>Parse Tikz</string>
+    <string>Parse TikZ</string>
    </property>
    <property name="shortcut">
     <string>Ctrl+T</string>
@@ -226,7 +235,10 @@
   </action>
   <action name="actionRevert">
    <property name="text">
-    <string>Revert Tikz</string>
+    <string>Revert TikZ</string>
+   </property>
+   <property name="shortcut">
+    <string>Ctrl+Alt+T</string>
    </property>
   </action>
   <action name="actionJump_to_Selection">
@@ -335,6 +347,24 @@
     <string>About</string>
    </property>
   </action>
+  <action name="actionRun_LaTeX">
+   <property name="text">
+    <string>Make Preview</string>
+   </property>
+   <property name="shortcut">
+    <string>Ctrl+R</string>
+   </property>
+  </action>
+  <action name="actionClear_Menu">
+   <property name="text">
+    <string>Clear Menu</string>
+   </property>
+  </action>
+  <action name="actionPreferences">
+   <property name="text">
+    <string>Preferences...</string>
+   </property>
+  </action>
   <addaction name="menuFile"/>
   <addaction name="menuEdit"/>
   <addaction name="menuView"/>
diff --git a/src/gui/preferencedialog.cpp b/src/gui/preferencedialog.cpp
new file mode 100644
index 0000000..06159af
--- /dev/null
+++ b/src/gui/preferencedialog.cpp
@@ -0,0 +1,111 @@
+#include "preferencedialog.h"
+#include "ui_preferencedialog.h"
+
+#include <QColorDialog>
+#include <QFileDialog>
+#include <QSettings>
+
+PreferenceDialog::PreferenceDialog(QWidget *parent) :
+    QDialog(parent),
+    ui(new Ui::PreferenceDialog)
+{
+    ui->setupUi(this);
+    QSettings settings("tikzit", "tikzit");
+    ui->autoPdflatex->setChecked(true);
+
+    if (!settings.value("auto-detect-pdflatex").isNull())
+        ui->autoPdflatex->setChecked(settings.value("auto-detect-pdflatex").toBool());
+    if (!settings.value("pdflatex-path").isNull())
+        ui->pdflatexPath->setText(settings.value("pdflatex-path").toString());
+
+
+    setColor(ui->axesColor, settings.value("grid-color-axes",
+      QColor(220,220,240)).value<QColor>());
+    setColor(ui->majorColor, settings.value("grid-color-major",
+      QColor(240,240,250)).value<QColor>());
+    setColor(ui->minorColor, settings.value("grid-color-minor",
+      QColor(250,250,255)).value<QColor>());
+
+
+    connect(ui->axesColor, SIGNAL(clicked()), this, SLOT(colorClick()));
+    connect(ui->majorColor, SIGNAL(clicked()), this, SLOT(colorClick()));
+    connect(ui->minorColor, SIGNAL(clicked()), this, SLOT(colorClick()));
+}
+
+PreferenceDialog::~PreferenceDialog()
+{
+    delete ui;
+}
+
+void PreferenceDialog::accept()
+{
+    QSettings settings("tikzit", "tikzit");
+    settings.setValue("auto-detect-pdflatex", ui->autoPdflatex->isChecked());
+    settings.setValue("pdflatex-path", ui->pdflatexPath->text());
+    settings.setValue("grid-color-axes", color(ui->axesColor));
+    settings.setValue("grid-color-major", color(ui->majorColor));
+    settings.setValue("grid-color-minor", color(ui->minorColor));
+    QDialog::accept();
+}
+
+void PreferenceDialog::on_resetColors_clicked()
+{
+    setColor(ui->axesColor, QColor(220,220,240));
+    setColor(ui->majorColor, QColor(240,240,250));
+    setColor(ui->minorColor, QColor(250,250,255));
+}
+
+void PreferenceDialog::colorClick()
+{
+    if (QPushButton *btn = dynamic_cast<QPushButton*>(sender())) {
+        QColor col = QColorDialog::getColor(
+                        color(btn),
+                        this,
+                        "Set color",
+                        QColorDialog::DontUseNativeDialog);
+        if (col.isValid()) setColor(btn, col);
+    }
+}
+
+void PreferenceDialog::on_autoPdflatex_stateChanged(int state)
+{
+    ui->pdflatexPath->setEnabled(state != Qt::Checked);
+    ui->browsePdflatex->setEnabled(state != Qt::Checked);
+}
+
+void PreferenceDialog::on_browsePdflatex_clicked()
+{
+    QSettings settings("tikzit", "tikzit");
+
+    QFileDialog dialog;
+    dialog.setWindowTitle(tr("pdflatex Path"));
+    dialog.setAcceptMode(QFileDialog::AcceptOpen);
+    dialog.setFileMode(QFileDialog::ExistingFile);
+    dialog.setLabelText(QFileDialog::Accept, "Select");
+
+    QFileInfo fi(ui->pdflatexPath->text());
+    if (!fi.absolutePath().isEmpty()) {
+        dialog.setDirectory(fi.absolutePath());
+        dialog.selectFile(fi.baseName());
+    }
+
+    dialog.setOption(QFileDialog::DontUseNativeDialog);
+
+    if (dialog.exec()) {
+        ui->pdflatexPath->setText(QDir::toNativeSeparators(dialog.selectedFiles()[0]));
+    }
+}
+
+void PreferenceDialog::setColor(QPushButton *btn, QColor col)
+{
+    QPalette pal = btn->palette();
+    pal.setColor(QPalette::Button, col);
+    btn->setPalette(pal);
+    btn->update();
+}
+
+QColor PreferenceDialog::color(QPushButton *btn)
+{
+    QPalette pal = btn->palette();
+    return pal.color(QPalette::Button);
+}
diff --git a/src/gui/preferencedialog.h b/src/gui/preferencedialog.h
new file mode 100644
index 0000000..9da8ae6
--- /dev/null
+++ b/src/gui/preferencedialog.h
@@ -0,0 +1,31 @@
+#ifndef PREFERENCEDIALOG_H
+#define PREFERENCEDIALOG_H
+
+#include <QDialog>
+
+namespace Ui {
+class PreferenceDialog;
+}
+
+class PreferenceDialog : public QDialog
+{
+    Q_OBJECT
+
+public:
+    explicit PreferenceDialog(QWidget *parent = nullptr);
+    ~PreferenceDialog() override;
+
+protected slots:
+    void accept() override;
+    void colorClick();
+    void on_resetColors_clicked();
+    void on_autoPdflatex_stateChanged(int state);
+    void on_browsePdflatex_clicked();
+
+private:
+    Ui::PreferenceDialog *ui;
+    QColor color(QPushButton *btn);
+    void setColor(QPushButton *btn, QColor col);
+};
+
+#endif // PREFERENCEDIALOG_H
diff --git a/src/gui/preferencedialog.ui b/src/gui/preferencedialog.ui
new file mode 100644
index 0000000..9a32e7d
--- /dev/null
+++ b/src/gui/preferencedialog.ui
@@ -0,0 +1,272 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<ui version="4.0">
+ <class>PreferenceDialog</class>
+ <widget class="QDialog" name="PreferenceDialog">
+  <property name="geometry">
+   <rect>
+    <x>0</x>
+    <y>0</y>
+    <width>345</width>
+    <height>176</height>
+   </rect>
+  </property>
+  <property name="windowTitle">
+   <string>Dialog</string>
+  </property>
+  <layout class="QVBoxLayout" name="verticalLayout">
+   <item>
+    <layout class="QFormLayout" name="formLayout">
+     <item row="0" column="0">
+      <widget class="QLabel" name="label">
+       <property name="text">
+        <string>pdflatex Location</string>
+       </property>
+      </widget>
+     </item>
+     <item row="0" column="1">
+      <layout class="QHBoxLayout" name="horizontalLayout">
+       <item>
+        <widget class="QLineEdit" name="pdflatexPath"/>
+       </item>
+       <item>
+        <widget class="QToolButton" name="browsePdflatex">
+         <property name="text">
+          <string>...</string>
+         </property>
+        </widget>
+       </item>
+      </layout>
+     </item>
+     <item row="1" column="1">
+      <widget class="QCheckBox" name="autoPdflatex">
+       <property name="text">
+        <string>Automatically detect pdflatex</string>
+       </property>
+      </widget>
+     </item>
+     <item row="2" column="0">
+      <widget class="QLabel" name="label_3">
+       <property name="text">
+        <string>Grid colors</string>
+       </property>
+      </widget>
+     </item>
+     <item row="2" column="1">
+      <layout class="QHBoxLayout" name="horizontalLayout_2">
+       <item>
+        <widget class="QFrame" name="frame">
+         <property name="frameShape">
+          <enum>QFrame::Box</enum>
+         </property>
+         <property name="frameShadow">
+          <enum>QFrame::Plain</enum>
+         </property>
+         <layout class="QHBoxLayout" name="horizontalLayout_3">
+          <property name="leftMargin">
+           <number>0</number>
+          </property>
+          <property name="topMargin">
+           <number>0</number>
+          </property>
+          <property name="rightMargin">
+           <number>0</number>
+          </property>
+          <property name="bottomMargin">
+           <number>0</number>
+          </property>
+          <item>
+           <widget class="QPushButton" name="axesColor">
+            <property name="autoFillBackground">
+             <bool>true</bool>
+            </property>
+            <property name="text">
+             <string/>
+            </property>
+            <property name="flat">
+             <bool>true</bool>
+            </property>
+           </widget>
+          </item>
+         </layout>
+        </widget>
+       </item>
+       <item>
+        <widget class="QLabel" name="label_4">
+         <property name="text">
+          <string>Axes</string>
+         </property>
+        </widget>
+       </item>
+       <item>
+        <spacer name="horizontalSpacer">
+         <property name="orientation">
+          <enum>Qt::Horizontal</enum>
+         </property>
+         <property name="sizeHint" stdset="0">
+          <size>
+           <width>40</width>
+           <height>20</height>
+          </size>
+         </property>
+        </spacer>
+       </item>
+       <item>
+        <widget class="QFrame" name="frame_2">
+         <property name="frameShape">
+          <enum>QFrame::Box</enum>
+         </property>
+         <property name="frameShadow">
+          <enum>QFrame::Plain</enum>
+         </property>
+         <layout class="QHBoxLayout" name="horizontalLayout_4">
+          <property name="leftMargin">
+           <number>0</number>
+          </property>
+          <property name="topMargin">
+           <number>0</number>
+          </property>
+          <property name="rightMargin">
+           <number>0</number>
+          </property>
+          <property name="bottomMargin">
+           <number>0</number>
+          </property>
+          <item>
+           <widget class="QPushButton" name="majorColor">
+            <property name="autoFillBackground">
+             <bool>true</bool>
+            </property>
+            <property name="text">
+             <string/>
+            </property>
+            <property name="flat">
+             <bool>true</bool>
+            </property>
+           </widget>
+          </item>
+         </layout>
+        </widget>
+       </item>
+       <item>
+        <widget class="QLabel" name="label_5">
+         <property name="text">
+          <string>Major</string>
+         </property>
+        </widget>
+       </item>
+       <item>
+        <spacer name="horizontalSpacer_2">
+         <property name="orientation">
+          <enum>Qt::Horizontal</enum>
+         </property>
+         <property name="sizeHint" stdset="0">
+          <size>
+           <width>40</width>
+           <height>20</height>
+          </size>
+         </property>
+        </spacer>
+       </item>
+       <item>
+        <widget class="QFrame" name="frame_3">
+         <property name="frameShape">
+          <enum>QFrame::Box</enum>
+         </property>
+         <property name="frameShadow">
+          <enum>QFrame::Plain</enum>
+         </property>
+         <layout class="QHBoxLayout" name="horizontalLayout_5">
+          <property name="leftMargin">
+           <number>0</number>
+          </property>
+          <property name="topMargin">
+           <number>0</number>
+          </property>
+          <property name="rightMargin">
+           <number>0</number>
+          </property>
+          <property name="bottomMargin">
+           <number>0</number>
+          </property>
+          <item>
+           <widget class="QPushButton" name="minorColor">
+            <property name="autoFillBackground">
+             <bool>true</bool>
+            </property>
+            <property name="text">
+             <string/>
+            </property>
+            <property name="flat">
+             <bool>true</bool>
+            </property>
+           </widget>
+          </item>
+         </layout>
+        </widget>
+       </item>
+       <item>
+        <widget class="QLabel" name="label_6">
+         <property name="text">
+          <string>Minor</string>
+         </property>
+        </widget>
+       </item>
+      </layout>
+     </item>
+     <item row="3" column="1">
+      <widget class="QPushButton" name="resetColors">
+       <property name="text">
+        <string>Reset colors</string>
+       </property>
+      </widget>
+     </item>
+    </layout>
+   </item>
+   <item>
+    <widget class="QDialogButtonBox" name="buttonBox">
+     <property name="orientation">
+      <enum>Qt::Horizontal</enum>
+     </property>
+     <property name="standardButtons">
+      <set>QDialogButtonBox::Cancel|QDialogButtonBox::Ok</set>
+     </property>
+    </widget>
+   </item>
+  </layout>
+ </widget>
+ <resources/>
+ <connections>
+  <connection>
+   <sender>buttonBox</sender>
+   <signal>accepted()</signal>
+   <receiver>PreferenceDialog</receiver>
+   <slot>accept()</slot>
+   <hints>
+    <hint type="sourcelabel">
+     <x>248</x>
+     <y>254</y>
+    </hint>
+    <hint type="destinationlabel">
+     <x>157</x>
+     <y>274</y>
+    </hint>
+   </hints>
+  </connection>
+  <connection>
+   <sender>buttonBox</sender>
+   <signal>rejected()</signal>
+   <receiver>PreferenceDialog</receiver>
+   <slot>reject()</slot>
+   <hints>
+    <hint type="sourcelabel">
+     <x>316</x>
+     <y>260</y>
+    </hint>
+    <hint type="destinationlabel">
+     <x>286</x>
+     <y>274</y>
+    </hint>
+   </hints>
+  </connection>
+ </connections>
+</ui>
diff --git a/src/gui/previewwindow.cpp b/src/gui/previewwindow.cpp
new file mode 100644
index 0000000..2f47efd
--- /dev/null
+++ b/src/gui/previewwindow.cpp
@@ -0,0 +1,208 @@
+/*
+    TikZiT - a GUI diagram editor for TikZ
+    Copyright (C) 2018 Aleks Kissinger
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+*/
+
+#include "previewwindow.h"
+#include "ui_previewwindow.h"
+
+#include "tikzit.h"
+#include "latexprocess.h"
+#include "exportdialog.h"
+
+#include <QLabel>
+#include <QImage>
+#include <QPixmap>
+#include <QDebug>
+#include <QSettings>
+#include <QTemporaryDir>
+#include <QFile>
+#include <QTextStream>
+#include <QStandardPaths>
+#include <QMessageBox>
+#include <cmath>
+#include <QMovie>
+#include <QAction>
+
+PreviewWindow::PreviewWindow(QWidget *parent) :
+    QDialog(parent),
+    ui(new Ui::PreviewWindow)
+{
+    QSettings settings("tikzit", "tikzit");
+    ui->setupUi(this);
+
+    QVariant geom = settings.value("geometry-preview");
+
+    if (geom.isValid()) {
+        restoreGeometry(geom.toByteArray());
+    }
+
+    _doc = nullptr;
+
+    _loader = new QLabel(ui->tabWidget->tabBar());
+    _loader->setMinimumSize(QSize(16,16));
+    _loader->setMaximumSize(QSize(16,16));
+    _loader->setAutoFillBackground(false);
+    ui->tabWidget->tabBar()->setTabButton(1, QTabBar::RightSide, _loader);
+    
+    connect(ui->tabWidget, SIGNAL(currentChanged(int)),
+            this, SLOT(render()));
+
+    render();
+}
+
+void PreviewWindow::contextMenuEvent(QContextMenuEvent *event)
+{
+    QMenu menu(this);
+    QAction *act;
+
+    act = new QAction("Export Image...");
+    connect(act, SIGNAL(triggered()), this, SLOT(exportImage()));
+    menu.addAction(act);
+
+    act = new QAction("Copy to Clipboard");
+    connect(act, SIGNAL(triggered()), this, SLOT(copyImageToClipboard()));
+    menu.addAction(act);
+
+    menu.exec(event->globalPos());
+}
+
+PdfDocument *PreviewWindow::doc() const
+{
+    return _doc;
+}
+
+PreviewWindow::~PreviewWindow()
+{
+    delete ui;
+}
+
+void PreviewWindow::setPdf(QString file)
+{
+    // use loadFromData to avoid holding a lock on the PDF file in windows
+    //QFile f(file);
+    //f.open(QFile::ReadOnly);
+    //QByteArray data = f.readAll();
+    //f.close();
+    PdfDocument *newDoc = new PdfDocument(file, this);
+
+    if (newDoc->isValid()) {
+        PdfDocument *oldDoc = _doc;
+        _doc = newDoc;
+        if (oldDoc != nullptr) delete oldDoc;
+        render();
+    } else {
+        QMessageBox::warning(nullptr,
+            "Could not read PDF",
+            "Could not read: '" + file + "'.");
+        delete newDoc;
+    }
+}
+
+QPlainTextEdit *PreviewWindow::outputTextEdit()
+{
+    return ui->output;
+}
+
+void PreviewWindow::setStatus(PreviewWindow::Status status)
+{
+    QMovie *oldMovie = _loader->movie();
+    if (status == PreviewWindow::Running) {
+        // loader.gif and loader@2x.gif derived from:
+        //   https://commons.wikimedia.org/wiki/Throbbers#/media/File:Linux_Ubuntu_Loader.gif
+        // licensed GNU Free Documentation License v1.2
+        QMovie *movie = new QMovie(
+                    (devicePixelRatioF() > 1.0) ? ":images/loader@2x.gif" : ":images/loader.gif",
+                    QByteArray(), _loader);
+        _loader->setPixmap(QPixmap());
+        _loader->setMovie(movie);
+        movie->start();
+    } else if (status == PreviewWindow::Success) {
+        _loader->setMovie(nullptr);
+        QIcon accept(":images/dialog-accept.svg");
+        //accept.setDevicePixelRatio(devicePixelRatio());
+        _loader->setPixmap(accept.pixmap(QSize(16,16)));
+    } else if (status == PreviewWindow::Failed) {
+        _loader->setMovie(nullptr);
+        QIcon error(":images/dialog-error.svg");
+        //error.setDevicePixelRatio(devicePixelRatio());
+        _loader->setPixmap(error.pixmap(QSize(16,16)));
+    }
+
+    if (oldMovie != nullptr) oldMovie->deleteLater();
+
+
+    _loader->repaint();
+}
+
+void PreviewWindow::closeEvent(QCloseEvent *e) {
+    QSettings settings("tikzit", "tikzit");
+    settings.setValue("geometry-preview", saveGeometry());
+    QDialog::closeEvent(e);
+}
+
+void PreviewWindow::resizeEvent(QResizeEvent *e) {
+    render();
+    QDialog::resizeEvent(e);
+}
+
+void PreviewWindow::showEvent(QShowEvent *e) {
+    render();
+    QDialog::showEvent(e);
+}
+
+void PreviewWindow::render() {
+    if (_doc != nullptr) {
+        _doc->renderTo(ui->pdf,
+                       ui->scrollArea->visibleRegion().boundingRect());
+        ui->pdf->repaint();
+    }
+}
+
+void PreviewWindow::exportImage()
+{
+    QSettings settings("tikzit", "tikzit");
+    if (_doc == nullptr) return;
+    ExportDialog *d = new ExportDialog(this);
+    int ret = d->exec();
+    if (ret == QDialog::Accepted) {
+        bool success;
+        if (d->fileFormat() == ExportDialog::PDF) {
+            success = _doc->exportPdf(d->filePath());
+        } else {
+            success = _doc->exportImage(
+                        d->filePath(),
+                        (d->fileFormat() == ExportDialog::PNG) ? "PNG" : "JPG",
+                        d->size());
+        }
+
+        if (!success) {
+            QMessageBox::warning(this,
+                "Error",
+                "Could not write to: '" + d->filePath() +
+                   "'. Check file permissions or choose a new location.");
+        }
+    }
+}
+
+void PreviewWindow::copyImageToClipboard()
+{
+    if (_doc != nullptr) {
+        _doc->copyImageToClipboard(_doc->size() * 4);
+    }
+}
+
+
diff --git a/src/gui/previewwindow.h b/src/gui/previewwindow.h
new file mode 100644
index 0000000..a14303b
--- /dev/null
+++ b/src/gui/previewwindow.h
@@ -0,0 +1,72 @@
+/*
+    TikZiT - a GUI diagram editor for TikZ
+    Copyright (C) 2018 Aleks Kissinger
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+*/
+
+/*!
+ * Displays a LaTeX-generated PDF preview using Poppler. The right-click
+ * menu has options for exporting to file or clipboard.
+ */
+
+#ifndef PREVIEWWINDOW_H
+#define PREVIEWWINDOW_H
+
+#include "pdfdocument.h"
+
+#include <QDialog>
+#include <QLabel>
+#include <QPlainTextEdit>
+#include <QContextMenuEvent>
+#include <poppler/qt5/poppler-qt5.h>
+
+namespace Ui {
+class PreviewWindow;
+}
+
+class PreviewWindow : public QDialog
+{
+    Q_OBJECT
+
+public:
+    enum Status {
+        Running, Success, Failed
+    };
+    explicit PreviewWindow(QWidget *parent = nullptr);
+    ~PreviewWindow() override;
+    void setPdf(QString file);
+    QString preparePreview(QString tikz);
+    QPlainTextEdit *outputTextEdit();
+    void setStatus(Status status);
+
+    PdfDocument *doc() const;
+
+public slots:
+    void render();
+    void exportImage();
+    void copyImageToClipboard();
+
+protected:
+    void resizeEvent(QResizeEvent *e) override;
+    void showEvent(QShowEvent *e) override;
+    void closeEvent(QCloseEvent *e) override;
+    void contextMenuEvent(QContextMenuEvent *event) override;
+private:
+    Ui::PreviewWindow *ui;
+    PdfDocument *_doc;
+    QLabel *_loader;
+};
+
+#endif // PREVIEWWINDOW_H
diff --git a/src/gui/previewwindow.ui b/src/gui/previewwindow.ui
new file mode 100644
index 0000000..aa49980
--- /dev/null
+++ b/src/gui/previewwindow.ui
@@ -0,0 +1,107 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<ui version="4.0">
+ <class>PreviewWindow</class>
+ <widget class="QDialog" name="PreviewWindow">
+  <property name="geometry">
+   <rect>
+    <x>0</x>
+    <y>0</y>
+    <width>603</width>
+    <height>480</height>
+   </rect>
+  </property>
+  <property name="windowTitle">
+   <string>Preview</string>
+  </property>
+  <layout class="QVBoxLayout" name="verticalLayout">
+   <property name="leftMargin">
+    <number>3</number>
+   </property>
+   <property name="topMargin">
+    <number>3</number>
+   </property>
+   <property name="rightMargin">
+    <number>3</number>
+   </property>
+   <property name="bottomMargin">
+    <number>3</number>
+   </property>
+   <item>
+    <widget class="QTabWidget" name="tabWidget">
+     <property name="currentIndex">
+      <number>0</number>
+     </property>
+     <property name="documentMode">
+      <bool>true</bool>
+     </property>
+     <property name="tabsClosable">
+      <bool>false</bool>
+     </property>
+     <widget class="QWidget" name="pdfTab">
+      <attribute name="title">
+       <string>PDF</string>
+      </attribute>
+      <layout class="QVBoxLayout" name="verticalLayout_2">
+       <property name="leftMargin">
+        <number>0</number>
+       </property>
+       <property name="topMargin">
+        <number>0</number>
+       </property>
+       <property name="rightMargin">
+        <number>0</number>
+       </property>
+       <property name="bottomMargin">
+        <number>0</number>
+       </property>
+       <item>
+        <widget class="QScrollArea" name="scrollArea">
+         <property name="verticalScrollBarPolicy">
+          <enum>Qt::ScrollBarAlwaysOff</enum>
+         </property>
+         <property name="horizontalScrollBarPolicy">
+          <enum>Qt::ScrollBarAlwaysOff</enum>
+         </property>
+         <property name="widgetResizable">
+          <bool>true</bool>
+         </property>
+         <widget class="QWidget" name="scrollAreaWidgetContents">
+          <property name="geometry">
+           <rect>
+            <x>0</x>
+            <y>0</y>
+            <width>595</width>
+            <height>451</height>
+           </rect>
+          </property>
+          <layout class="QVBoxLayout" name="verticalLayout_4">
+           <item>
+            <widget class="QLabel" name="pdf">
+             <property name="text">
+              <string/>
+             </property>
+            </widget>
+           </item>
+          </layout>
+         </widget>
+        </widget>
+       </item>
+      </layout>
+     </widget>
+     <widget class="QWidget" name="outputTab">
+      <attribute name="title">
+       <string>Output</string>
+      </attribute>
+      <layout class="QVBoxLayout" name="verticalLayout_3">
+       <item>
+        <widget class="QPlainTextEdit" name="output"/>
+       </item>
+      </layout>
+     </widget>
+    </widget>
+   </item>
+  </layout>
+ </widget>
+ <resources/>
+ <connections/>
+</ui>
diff --git a/src/gui/styleeditor.cpp b/src/gui/styleeditor.cpp
index 29192d6..e2ade45 100644
--- a/src/gui/styleeditor.cpp
+++ b/src/gui/styleeditor.cpp
@@ -1,10 +1,30 @@
+/*
+    TikZiT - a GUI diagram editor for TikZ
+    Copyright (C) 2018 Aleks Kissinger
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+*/
+
 #include <QColorDialog>
 #include <QDebug>
 #include <QMessageBox>
 
 #include "tikzit.h"
 #include "styleeditor.h"
+#include "delimitedstringvalidator.h"
 #include "ui_styleeditor.h"
+#include "delimitedstringitemdelegate.h"
 
 StyleEditor::StyleEditor(QWidget *parent) :
     QMainWindow(parent),
@@ -18,6 +38,14 @@ StyleEditor::StyleEditor(QWidget *parent) :
         ui->leftArrow << ui->rightArrow <<
         ui->properties;
 
+    DelimitedStringValidator *v = new DelimitedStringValidator(this);
+    ui->name->setValidator(v);
+    ui->category->lineEdit()->setValidator(v);
+    ui->shape->lineEdit()->setValidator(v);
+
+    DelimitedStringItemDelegate *delegate = new DelimitedStringItemDelegate(ui->properties);
+    ui->properties->setItemDelegate(delegate);
+
     setWindowIcon(QIcon(":/images/tikzit.png"));
     _styles = nullptr;
     _activeStyle = nullptr;
@@ -44,40 +72,6 @@ StyleEditor::StyleEditor(QWidget *parent) :
             SIGNAL(currentIndexChanged(int)),
             this, SLOT(shapeChanged()));
 
-    // setup the color dialog to display only the named colors that tikzit/xcolor knows
-    // about as "standard colors".
-    for (int i = 0; i < 48; ++i) {
-        QColorDialog::setStandardColor(i, QColor(Qt::white));
-    }
-
-    // grayscale in column 1
-    int pos = 0;
-    for (int i=0; i < 5; ++i) {
-        QColorDialog::setStandardColor(pos, tikzit->colorByIndex(i));
-        pos += 1;
-    }
-
-    // rainbow in column 2
-    pos = 6;
-    for (int i=5; i < 11; ++i) {
-        QColorDialog::setStandardColor(pos, tikzit->colorByIndex(i));
-        pos += 1;
-    }
-
-    // brown/green/teal spectrum in column 3
-    pos = 12;
-    for (int i=11; i < 16; ++i) {
-        QColorDialog::setStandardColor(pos, tikzit->colorByIndex(i));
-        pos += 1;
-    }
-
-    // pinks in column 4
-    pos = 18;
-    for (int i=16; i < 19; ++i) {
-        QColorDialog::setStandardColor(pos, tikzit->colorByIndex(i));
-        pos += 1;
-    }
-
     refreshDisplay();
 }
 
diff --git a/src/gui/styleeditor.h b/src/gui/styleeditor.h
index 4bae7db..2c35d56 100644
--- a/src/gui/styleeditor.h
+++ b/src/gui/styleeditor.h
@@ -1,3 +1,25 @@
+/*
+    TikZiT - a GUI diagram editor for TikZ
+    Copyright (C) 2018 Aleks Kissinger
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <https://www.gnu.org/licenses/>.
+*/
+
+/*!
+ * A GUI editor for .tikzstyles files.
+ */
+
 #ifndef STYLEEDITOR_H
 #define STYLEEDITOR_H
 
@@ -17,8 +39,8 @@ class StyleEditor : public QMainWindow
     Q_OBJECT
 
 public:
-    explicit StyleEditor(QWidget *parent = 0);
-    ~StyleEditor();
+    explicit StyleEditor(QWidget *parent = nullptr);
+    ~StyleEditor() override;
 
     void open();
     void save();
diff --git a/src/gui/tikzscene.cpp b/src/gui/tikzscene.cpp
index c061221..31d5bf6 100644
--- a/src/gui/tikzscene.cpp
+++ b/src/gui/tikzscene.cpp
@@ -28,14 +28,15 @@
 #include <QClipboard>
 #include <QInputDialog>
 #include <cmath>
+#include <delimitedstringvalidator.h>
 
 
 TikzScene::TikzScene(TikzDocument *tikzDocument, ToolPalette *tools,
                      StylePalette *styles, QObject *parent) :
     QGraphicsScene(parent), _tikzDocument(tikzDocument), _tools(tools), _styles(styles)
 {
-    _modifyEdgeItem = 0;
-    _edgeStartNodeItem = 0;
+    _modifyEdgeItem = nullptr;
+    _edgeStartNodeItem = nullptr;
     _drawEdgeItem = new QGraphicsLineItem();
     _rubberBandItem = new QGraphicsRectItem();
     _enabled = true;
@@ -43,7 +44,7 @@ TikzScene::TikzScene(TikzDocument *tikzDocument, ToolPalette *tools,
     setSceneRect(-1000,-1000,2000,2000);
 
     QPen pen;
-    pen.setColor(QColor::fromRgbF(0.5f, 0.0f, 0.5f));
+    pen.setColor(QColor::fromRgbF(0.5, 0.0, 0.5));
     //pen.setWidth(3.0f);
     pen.setCosmetic(true);
     _drawEdgeItem->setPen(pen);
@@ -51,7 +52,7 @@ TikzScene::TikzScene(TikzDocument *tikzDocument, ToolPalette *tools,
     _drawEdgeItem->setVisible(false);
     addItem(_drawEdgeItem);
 
-    pen.setColor(QColor::fromRgbF(0.6f, 0.6f, 0.8f));
+    pen.setColor(QColor::fromRgbF(0.6, 0.6, 0.8));
     //pen.setWidth(3.0f);
     //QVector<qreal> dash;
     //dash << 4.0 << 4.0;
@@ -110,7 +111,7 @@ void TikzScene::graphReplaced()
 void TikzScene::extendSelectionUp()
 {
     bool found = false;
-    float m = 0.0f;
+    qreal m = 0.0;
     foreach (Node *n, getSelectedNodes()) {
         if (!found) {
             m = n->point().y();
@@ -128,7 +129,7 @@ void TikzScene::extendSelectionUp()
 void TikzScene::extendSelectionDown()
 {
     bool found = false;
-    float m = 0.0f;
+    qreal m = 0.0;
     foreach (Node *n, getSelectedNodes()) {
         if (!found) {
             m = n->point().y();
@@ -146,7 +147,7 @@ void TikzScene::extendSelectionDown()
 void TikzScene::extendSelectionLeft()
 {
     bool found = false;
-    float m = 0.0f;
+    qreal m = 0.0;
     foreach (Node *n, getSelectedNodes()) {
         if (!found) {
             m = n->point().x();
@@ -164,7 +165,7 @@ void TikzScene::extendSelectionLeft()
 void TikzScene::extendSelectionRight()
 {
     bool found = false;
-    float m = 0.0f;
+    qreal m = 0.0;
     foreach (Node *n, getSelectedNodes()) {
         if (!found) {
             m = n->point().x();
@@ -266,7 +267,7 @@ void TikzScene::mousePressEvent(QGraphicsSceneMouseEvent *event)
             }
         }
 
-        if (_modifyEdgeItem != 0) {
+        if (_modifyEdgeItem != nullptr) {
             // store for undo purposes
             Edge *e = _modifyEdgeItem->edge();
             _oldBend = e->bend();
@@ -337,15 +338,15 @@ void TikzScene::mouseMoveEvent(QGraphicsSceneMouseEvent *event)
 
     switch (_tools->currentTool()) {
     case ToolPalette::SELECT:
-        if (_modifyEdgeItem != 0) {
+        if (_modifyEdgeItem != nullptr) {
             Edge *e = _modifyEdgeItem->edge();
 
             // dragging a control point
             QPointF src = toScreen(e->source()->point());
             QPointF targ = toScreen(e->target()->point());
-            float dx1 = targ.x() - src.x();
-            float dy1 = targ.y() - src.y();
-            float dx2, dy2;
+            qreal dx1 = targ.x() - src.x();
+            qreal dy1 = targ.y() - src.y();
+            qreal dx2, dy2;
             if (_firstControlPoint) {
                 dx2 = mousePos.x() - src.x();
                 dy2 = mousePos.y() - src.y();
@@ -354,25 +355,26 @@ void TikzScene::mouseMoveEvent(QGraphicsSceneMouseEvent *event)
                 dy2 = mousePos.y() - targ.y();
             }
 
-            float baseDist = sqrt(dx1*dx1 + dy1*dy1);
-            float handleDist = sqrt(dx2*dx2 + dy2*dy2);
-            float wcoarseness = 0.1f;
+            qreal baseDist = sqrt(dx1*dx1 + dy1*dy1);
+            qreal handleDist = sqrt(dx2*dx2 + dy2*dy2);
+            qreal wcoarseness = 0.1;
 
             if (!e->isSelfLoop()) {
-                if (baseDist != 0) {
+                if (baseDist != 0.0) {
                     e->setWeight(roundToNearest(wcoarseness, handleDist/baseDist));
                 } else {
                     e->setWeight(roundToNearest(wcoarseness, handleDist/GLOBAL_SCALEF));
                 }
             }
 
-            float control_angle = atan2(-dy2, dx2);
+            qreal control_angle = atan2(-dy2, dx2);
 
             int bcoarseness = 15;
+            qreal bcoarsenessi = 1.0/15.0;
 
             if(e->basicBendMode()) {
-                float bnd;
-                float base_angle = atan2(-dy1, dx1);
+                qreal bnd;
+                qreal base_angle = atan2(-dy1, dx1);
                 if (_firstControlPoint) {
                     bnd = base_angle - control_angle;
                 } else {
@@ -380,12 +382,10 @@ void TikzScene::mouseMoveEvent(QGraphicsSceneMouseEvent *event)
                     if (bnd > M_PI) bnd -= 2*M_PI;
                 }
 
-                e->setBend(round(bnd * (180.0f / M_PI) * (1.0f / (float)bcoarseness)) * bcoarseness);
+                e->setBend(static_cast<int>(round(bnd * (180.0 / M_PI) * bcoarsenessi)) * bcoarseness);
 
             } else {
-                int bnd = round(control_angle * (180.0f / M_PI) *
-                                (1.0f / (float)bcoarseness)) *
-                          bcoarseness;
+                int bnd = static_cast<int>(round(control_angle * (180.0 / M_PI) * bcoarsenessi)) * bcoarseness;
                 if (_firstControlPoint) {
                     // TODO: enable moving both control points
 //                    if ([theEvent modifierFlags] & NSAlternateKeyMask) {
@@ -428,7 +428,7 @@ void TikzScene::mouseMoveEvent(QGraphicsSceneMouseEvent *event)
                 NodeItem *ni = _nodeItems[n];
 
 				// in (rare) cases, the graph can change while we are dragging
-				if (ni != 0) {
+				if (ni != nullptr) {
 					ni->setPos(toScreen(_oldNodePositions[n]) + shift);
 					ni->writePos();
 				}
@@ -454,7 +454,7 @@ void TikzScene::mouseMoveEvent(QGraphicsSceneMouseEvent *event)
         break;
     case ToolPalette::EDGE:
         if (_drawEdgeItem->isVisible()) {
-            _edgeEndNodeItem = 0;
+            _edgeEndNodeItem = nullptr;
             foreach (QGraphicsItem *gi, items(mousePos)) {
                 if (NodeItem *ni = dynamic_cast<NodeItem*>(gi)){
                     _edgeEndNodeItem = ni;
@@ -462,7 +462,7 @@ void TikzScene::mouseMoveEvent(QGraphicsSceneMouseEvent *event)
                 }
             }
             QPointF p1 = _drawEdgeItem->line().p1();
-            QPointF p2 = (_edgeEndNodeItem != 0) ? toScreen(_edgeEndNodeItem->node()->point()) : mousePos;
+            QPointF p2 = (_edgeEndNodeItem != nullptr) ? toScreen(_edgeEndNodeItem->node()->point()) : mousePos;
             QLineF line(p1, p2);
 
             _drawEdgeItem->setLine(line);
@@ -482,11 +482,11 @@ void TikzScene::mouseReleaseEvent(QGraphicsSceneMouseEvent *event)
 
     switch (_tools->currentTool()) {
     case ToolPalette::SELECT:
-        if (_modifyEdgeItem != 0) {
+        if (_modifyEdgeItem != nullptr) {
             // finished dragging a control point
             Edge *e = _modifyEdgeItem->edge();
 
-            if (_oldWeight != e->weight() ||
+            if (!almostEqual(_oldWeight, e->weight()) ||
                 _oldBend != e->bend() ||
                 _oldInAngle != e->inAngle() ||
                 _oldOutAngle != e->outAngle())
@@ -495,7 +495,7 @@ void TikzScene::mouseReleaseEvent(QGraphicsSceneMouseEvent *event)
                 _tikzDocument->undoStack()->push(cmd);
             }
 
-            _modifyEdgeItem = 0;
+            _modifyEdgeItem = nullptr;
         } else {
             // otherwise, process mouse move normally
             QGraphicsScene::mouseReleaseEvent(event);
@@ -517,7 +517,7 @@ void TikzScene::mouseReleaseEvent(QGraphicsSceneMouseEvent *event)
                 QPointF shift = mousePos - _mouseDownPos;
                 shift = QPointF(round(shift.x()/GRID_SEP)*GRID_SEP, round(shift.y()/GRID_SEP)*GRID_SEP);
 
-                if (shift.x() != 0 || shift.y() != 0) {
+                if (shift.x() != 0.0 || shift.y() != 0.0) {
                     QMap<Node*,QPointF> newNodePositions;
 
                     foreach (QGraphicsItem *gi, selectedItems()) {
@@ -557,14 +557,14 @@ void TikzScene::mouseReleaseEvent(QGraphicsSceneMouseEvent *event)
         break;
     case ToolPalette::EDGE:
         // add an edge
-        if (_edgeStartNodeItem != 0 && _edgeEndNodeItem != 0) {
+        if (_edgeStartNodeItem != nullptr && _edgeEndNodeItem != nullptr) {
             Edge *e = new Edge(_edgeStartNodeItem->node(), _edgeEndNodeItem->node(), _tikzDocument);
 			e->setStyleName(_styles->activeEdgeStyleName());
             AddEdgeCommand *cmd = new AddEdgeCommand(this, e);
             _tikzDocument->undoStack()->push(cmd);
         }
-        _edgeStartNodeItem = 0;
-        _edgeEndNodeItem = 0;
+        _edgeStartNodeItem = nullptr;
+        _edgeEndNodeItem = nullptr;
         _drawEdgeItem->setVisible(false);
         break;
     case ToolPalette::CROP:
@@ -613,19 +613,19 @@ void TikzScene::keyPressEvent(QKeyEvent *event)
 
     if (event->modifiers() & Qt::ControlModifier) {
         QPointF delta(0,0);
-        float shift = (event->modifiers() & Qt::ShiftModifier) ? 1.0f : 10.0f;
+        qreal shift = (event->modifiers() & Qt::ShiftModifier) ? 1.0 : 10.0;
         switch(event->key()) {
         case Qt::Key_Left:
-            delta.setX(-0.025f * shift);
+            delta.setX(-0.025 * shift);
             break;
         case Qt::Key_Right:
-            delta.setX(0.025f * shift);
+            delta.setX(0.025 * shift);
             break;
         case Qt::Key_Up:
-            delta.setY(0.025f * shift);
+            delta.setY(0.025 * shift);
             break;
         case Qt::Key_Down:
-            delta.setY(-0.025f * shift);
+            delta.setY(-0.025 * shift);
             break;
         }
 
@@ -665,16 +665,23 @@ void TikzScene::mouseDoubleClickEvent(QGraphicsSceneMouseEvent *event)
             }
 			break;
         } else if (NodeItem *ni = dynamic_cast<NodeItem*>(it)) {
-            bool ok;
-            QString newLabel = QInputDialog::getText(views()[0], tr("Node label"),
-                                                     tr("Label:"), QLineEdit::Normal,
-                                                     ni->node()->label(), &ok);
-            if (ok) {
+            QInputDialog *d = new QInputDialog(views()[0]);
+            d->setLabelText(tr("Label:"));
+            d->setTextValue(ni->node()->label());
+            d->setWindowTitle(tr("Node label"));
+
+            if (QLineEdit *le = d->findChild<QLineEdit*>()) {
+                le->setValidator(new DelimitedStringValidator(le));
+            }
+
+            if (d->exec()) {
                 QMap<Node*,QString> oldLabels;
                 oldLabels.insert(ni->node(), ni->node()->label());
-                ChangeLabelCommand *cmd = new ChangeLabelCommand(this, oldLabels, newLabel);
+                ChangeLabelCommand *cmd = new ChangeLabelCommand(this, oldLabels, d->textValue());
                 _tikzDocument->undoStack()->push(cmd);
             }
+
+            d->deleteLater();
 			break;
         }
     }
@@ -767,7 +774,7 @@ void TikzScene::pasteFromClipboard()
 
         QRectF srcRect = g->realBbox();
         QRectF tgtRect = graph()->realBbox();
-        QPointF shift(tgtRect.right() - srcRect.left(), 0.0f);
+        QPointF shift(tgtRect.right() - srcRect.left(), 0.0);
 
         if (shift.x() > 0) {
             foreach (Node *n, g->nodes()) {
@@ -890,7 +897,7 @@ void TikzScene::refreshAdjacentEdges(QList<Node*> nodes)
 		EdgeItem *ei = _edgeItems[e];
 
 		// the list "nodes" can be out of date, e.g. if the graph changes while dragging
-		if (ei != 0) {
+		if (ei != nullptr) {
 			if (nodes.contains(ei->edge()->source()) || nodes.contains(ei->edge()->target())) {
 				ei->edge()->updateControls();
 				ei->readPos();
diff --git a/src/gui/tikzscene.h b/src/gui/tikzscene.h
index 2a3e988..e8ea2c6 100644
--- a/src/gui/tikzscene.h
+++ b/src/gui/tikzscene.h
@@ -44,7 +44,7 @@ class TikzScene : public QGraphicsScene
     Q_OBJECT
 public:
    TikzScene(TikzDocument *tikzDocument, ToolPalette *tools, StylePalette *styles, QObject *parent);
-    ~TikzScene();
+    ~TikzScene() override;
     Graph *graph();
     QMap<Node*,NodeItem*> &nodeItems();
     QMap<Edge*,EdgeItem*> &edgeItems();
@@ -108,7 +108,7 @@ private:
     bool _draggingNodes;
 
     QMap<Node*,QPointF> _oldNodePositions;
-    float _oldWeight;
+    qreal _oldWeight;
     int _oldBend;
     int _oldInAngle;
     int _oldOutAngle;
diff --git a/src/gui/tikzview.cpp b/src/gui/tikzview.cpp
index 52a32cf..5b0f09c 100644
--- a/src/gui/tikzview.cpp
+++ b/src/gui/tikzview.cpp
@@ -21,6 +21,7 @@
 
 #include <QDebug>
 #include <QScrollBar>
+#include <QSettings>
 
 TikzView::TikzView(QWidget *parent) : QGraphicsView(parent)
 {
@@ -53,6 +54,7 @@ void TikzView::setScene(QGraphicsScene *scene)
 
 void TikzView::drawBackground(QPainter *painter, const QRectF &rect)
 {
+    QSettings settings("tikzit", "tikzit");
     QGraphicsView::drawBackground(painter, rect);
     // draw a gray background if disabled
     TikzScene *sc = static_cast<TikzScene*>(scene());
@@ -63,13 +65,13 @@ void TikzView::drawBackground(QPainter *painter, const QRectF &rect)
     QPen pen1;
     //pen1.setWidthF(0.5);
     pen1.setCosmetic(true);
-    pen1.setColor(QColor(250,250,255));
+    pen1.setColor(settings.value("grid-color-minor", QColor(250,250,255)).value<QColor>());
 
     QPen pen2 = pen1;
-    pen2.setColor(QColor(240,240,250));
+    pen2.setColor(settings.value("grid-color-major", QColor(240,240,250)).value<QColor>());
 
     QPen pen3 = pen1;
-    pen3.setColor(QColor(220,220,240));
+    pen3.setColor(settings.value("grid-color-axes", QColor(220,220,240)).value<QColor>());
 
     painter->setPen(pen1);
 
diff --git a/src/gui/undocommands.cpp b/src/gui/undocommands.cpp
index f713582..8a00536 100644
--- a/src/gui/undocommands.cpp
+++ b/src/gui/undocommands.cpp
@@ -80,7 +80,7 @@ void MoveCommand::redo()
 }
 
 EdgeBendCommand::EdgeBendCommand(TikzScene *scene, Edge *edge,
-                                 float oldWeight, int oldBend,
+                                 qreal oldWeight, int oldBend,
                                  int oldInAngle, int oldOutAngle, QUndoCommand *parent) :
     GraphUpdateCommand(scene, parent),
     _edge(edge),
@@ -405,7 +405,7 @@ void ChangeLabelCommand::undo()
     foreach (Node *n, _oldLabels.keys()) {
         n->setLabel(_oldLabels[n]);
 		NodeItem *ni = _scene->nodeItems()[n];
-		if (ni != 0) ni->updateBounds();
+		if (ni != nullptr) ni->updateBounds();
     }
 
     GraphUpdateCommand::undo();
@@ -416,7 +416,7 @@ void ChangeLabelCommand::redo()
     foreach (Node *n, _oldLabels.keys()) {
         n->setLabel(_newLabel);
 		NodeItem *ni = _scene->nodeItems()[n];
-		if (ni != 0) ni->updateBounds();
+		if (ni != nullptr) ni->updateBounds();
     }
 
     GraphUpdateCommand::redo();
diff --git a/src/gui/undocommands.h b/src/gui/undocommands.h
index dc60549..ff51c90 100644
--- a/src/gui/undocommands.h
+++ b/src/gui/undocommands.h
@@ -36,7 +36,7 @@
 class GraphUpdateCommand : public QUndoCommand {
 public:
     explicit GraphUpdateCommand(TikzScene *scene,
-                                QUndoCommand *parent = 0);
+                                QUndoCommand *parent = nullptr);
     void undo() override;
     void redo() override;
 protected:
@@ -49,7 +49,7 @@ public:
     explicit MoveCommand(TikzScene *scene,
                          QMap<Node*,QPointF> oldNodePositions,
                          QMap<Node*,QPointF> newNodePositions,
-                         QUndoCommand *parent = 0);
+                         QUndoCommand *parent = nullptr);
     void undo() override;
     void redo() override;
 private:
@@ -61,18 +61,18 @@ class EdgeBendCommand : public GraphUpdateCommand
 {
 public:
     explicit EdgeBendCommand(TikzScene *scene, Edge *edge,
-                             float oldWeight, int oldBend,
+                             qreal oldWeight, int oldBend,
                              int oldInAngle, int oldOutAngle,
-                             QUndoCommand *parent = 0);
+                             QUndoCommand *parent = nullptr);
     void undo() override;
     void redo() override;
 private:
     Edge *_edge;
-    float _oldWeight;
+    qreal _oldWeight;
     int _oldBend;
     int _oldInAngle;
     int _oldOutAngle;
-    float _newWeight;
+    qreal _newWeight;
     int _newBend;
     int _newInAngle;
     int _newOutAngle;
@@ -85,7 +85,7 @@ public:
                            QMap<int,Node*> deleteNodes,
                            QMap<int,Edge*> deleteEdges,
                            QSet<Edge*> selEdges,
-                           QUndoCommand *parent = 0);
+                           QUndoCommand *parent = nullptr);
     void undo() override;
     void redo() override;
 private:
@@ -98,7 +98,7 @@ class AddNodeCommand : public GraphUpdateCommand
 {
 public:
     explicit AddNodeCommand(TikzScene *scene, Node *node, QRectF newBounds,
-                            QUndoCommand *parent = 0);
+                            QUndoCommand *parent = nullptr);
     void undo() override;
     void redo() override;
 private:
@@ -110,7 +110,7 @@ private:
 class AddEdgeCommand : public GraphUpdateCommand
 {
 public:
-    explicit AddEdgeCommand(TikzScene *scene, Edge *edge, QUndoCommand *parent = 0);
+    explicit AddEdgeCommand(TikzScene *scene, Edge *edge, QUndoCommand *parent = nullptr);
     void undo() override;
     void redo() override;
 private:
@@ -120,7 +120,7 @@ private:
 class ChangeEdgeModeCommand : public GraphUpdateCommand
 {
 public:
-    explicit ChangeEdgeModeCommand(TikzScene *scene, Edge *edge, QUndoCommand *parent = 0);
+    explicit ChangeEdgeModeCommand(TikzScene *scene, Edge *edge, QUndoCommand *parent = nullptr);
     void undo() override;
     void redo() override;
 private:
@@ -130,7 +130,7 @@ private:
 class ApplyStyleToNodesCommand : public GraphUpdateCommand
 {
 public:
-    explicit ApplyStyleToNodesCommand(TikzScene *scene, QString style, QUndoCommand *parent = 0);
+    explicit ApplyStyleToNodesCommand(TikzScene *scene, QString style, QUndoCommand *parent = nullptr);
     void undo() override;
     void redo() override;
 private:
@@ -141,7 +141,7 @@ private:
 class ApplyStyleToEdgesCommand : public GraphUpdateCommand
 {
 public:
-	explicit ApplyStyleToEdgesCommand(TikzScene *scene, QString style, QUndoCommand *parent = 0);
+	explicit ApplyStyleToEdgesCommand(TikzScene *scene, QString style, QUndoCommand *parent = nullptr);
 	void undo() override;
 	void redo() override;
 private:
@@ -152,7 +152,7 @@ private:
 class PasteCommand : public GraphUpdateCommand
 {
 public:
-    explicit PasteCommand(TikzScene *scene, Graph *graph, QUndoCommand *parent = 0);
+    explicit PasteCommand(TikzScene *scene, Graph *graph, QUndoCommand *parent = nullptr);
     void undo() override;
     void redo() override;
 private:
@@ -167,7 +167,7 @@ public:
     explicit ChangeLabelCommand(TikzScene *scene,
                                 QMap<Node*,QString> oldLabels,
                                 QString newLabel,
-                                QUndoCommand *parent = 0);
+                                QUndoCommand *parent = nullptr);
     void undo() override;
     void redo() override;
 private:
@@ -181,7 +181,7 @@ public:
     explicit ReplaceGraphCommand(TikzScene *scene,
                                  Graph *oldGraph,
                                  Graph *newGraph,
-                                 QUndoCommand *parent = 0);
+                                 QUndoCommand *parent = nullptr);
     void undo() override;
     void redo() override;
 private:
@@ -195,7 +195,7 @@ public:
     explicit ReflectNodesCommand(TikzScene *scene,
                                  QSet<Node*> nodes,
                                  bool horizontal,
-                                 QUndoCommand *parent = 0);
+                                 QUndoCommand *parent = nullptr);
     void undo() override;
     void redo() override;
 private:
@@ -209,7 +209,7 @@ public:
     explicit RotateNodesCommand(TikzScene *scene,
                                 QSet<Node*> nodes,
                                 bool clockwise,
-                                QUndoCommand *parent = 0);
+                                QUndoCommand *parent = nullptr);
     void undo() override;
     void redo() override;
 private:
@@ -225,7 +225,7 @@ public:
                             const QVector<Node*> &newNodeOrder,
                             const QVector<Edge*> &oldEdgeOrder,
                             const QVector<Edge*> &newEdgeOrder,
-                            QUndoCommand *parent = 0);
+                            QUndoCommand *parent = nullptr);
     void undo() override;
     void redo() override;
 private:
diff --git a/src/main.cpp b/src/main.cpp
index 99d23e9..7a282e6 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -16,7 +16,6 @@
     along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */
 
-
 /*!
   * \file main.cpp
   *
@@ -31,21 +30,17 @@
 #include <QDebug>
 #include <QScreen>
 
-// #ifdef Q_OS_WIN
-// #include <Windows.h>
-// #endif
-
 int main(int argc, char *argv[])
 {
     // #ifdef Q_OS_WIN
     //     SetProcessDPIAware();
     // #endif
-//    QCoreApplication::setAttribute(Qt::AA_EnableHighDpiScaling);
+    // QCoreApplication::setAttribute(Qt::AA_EnableHighDpiScaling);
     QCoreApplication::setAttribute(Qt::AA_UseHighDpiPixmaps);
 
     // dummy application for detecting DPI
     QApplication *a0 = new QApplication(argc, argv);
-//    qDebug() << "physical DPI" << QApplication::screens()[0]->physicalDotsPerInch();
+    // qDebug() << "physical DPI" << QApplication::screens()[0]->physicalDotsPerInch();
 
     if (QApplication::screens()[0]->physicalDotsPerInch() >= 100) {
         QApplication::setAttribute(Qt::AA_EnableHighDpiScaling);
@@ -58,14 +53,11 @@ int main(int argc, char *argv[])
     QApplication a(argc, argv);
     a.setQuitOnLastWindowClosed(false);
 
-
-
     tikzit = new Tikzit();
     tikzit->init();
 
     qDebug() << a.arguments().length();
 
-	
     if (a.arguments().length() > 1) {
         tikzit->open(a.arguments()[1]);
     }
diff --git a/src/tikzit.cpp b/src/tikzit.cpp
index c9286c9..8569817 100644
--- a/src/tikzit.cpp
+++ b/src/tikzit.cpp
@@ -19,6 +19,8 @@
 #include "tikzit.h"
 #include "tikzassembler.h"
 #include "tikzstyles.h"
+#include "previewwindow.h"
+#include "latexprocess.h"
 
 #include <QFile>
 #include <QFileDialog>
@@ -28,6 +30,7 @@
 #include <QRegularExpression>
 #include <QVersionNumber>
 #include <QNetworkAccessManager>
+#include <QColorDialog>
 
 // application-level instance of Tikzit
 Tikzit *tikzit;
@@ -35,7 +38,7 @@ Tikzit *tikzit;
 // font to use for node labels
 QFont Tikzit::LABEL_FONT("Courrier", 9);
 
-Tikzit::Tikzit() : _styleFile("[no styles]"), _activeWindow(0)
+Tikzit::Tikzit() : _styleFile("[no styles]"), _activeWindow(nullptr)
 {
 }
 
@@ -43,54 +46,7 @@ void Tikzit::init()
 {
     QSettings settings("tikzit", "tikzit");
 
-	// 19 standard xcolor colours
-    _colNames <<
-		"black" <<
-        "darkgray" <<
-        "gray" <<
-		"lightgray" <<
-		"white" <<
-
-		"red" <<
-		"orange" <<
-		"yellow" <<
-        "green" <<
-		"blue" <<
-		"purple" <<
-
-		"brown" <<
-		"olive" <<
-        "lime" <<
-        "cyan" <<
-        "teal" <<
-
-		"magenta" <<
-		"violet" <<
-		"pink";
-
-    _cols <<
-        QColor::fromRgbF(0,0,0) <<
-        QColor::fromRgbF(0.25,0.25,0.25) <<
-        QColor::fromRgbF(0.5,0.5,0.5) <<
-        QColor::fromRgbF(0.75,0.75,0.75) <<
-        QColor::fromRgbF(1,1,1) <<
-
-        QColor::fromRgbF(1,0,0) <<
-        QColor::fromRgbF(1,0.5,0) <<
-        QColor::fromRgbF(1,1,0) <<
-        QColor::fromRgbF(0,1,0) <<
-        QColor::fromRgbF(0,0,1) <<
-        QColor::fromRgbF(0.75,0,0.25) <<
-
-        QColor::fromRgbF(0.75,0.5,0.25) <<
-        QColor::fromRgbF(0.5,0.5,0) <<
-        QColor::fromRgbF(0.75,1,0) <<
-        QColor::fromRgbF(0,1,1) <<
-        QColor::fromRgbF(0,0.5,0.5) <<
-
-        QColor::fromRgbF(1,0,1) <<
-        QColor::fromRgbF(0.5,0,0.5) <<
-        QColor::fromRgbF(1,0.75,0.75);
+	initColors();
 
     _mainMenu = new MainMenu();
     QMainWindow *dummy = new QMainWindow();
@@ -106,12 +62,14 @@ void Tikzit::init()
     _windows << new MainWindow();
     _windows[0]->show();
 
+    _styleFile = "";
+    _styleFilePath = "";
     QString styleFile = settings.value("previous-tikzstyles-file").toString();
     if (!styleFile.isEmpty()) loadStyles(styleFile);
 
     QVariant check = settings.value("check-for-updates");
     if (check.isNull()) {
-        int resp = QMessageBox::question(0,
+        int resp = QMessageBox::question(nullptr,
           tr("Check for updates"),
           tr("Would you like TikZiT to check for updates automatically?"
              " (You can always change this later in the Help menu.)"),
@@ -124,8 +82,11 @@ void Tikzit::init()
     setCheckForUpdates(check.toBool());
 
     if (check.toBool()) {
-        checkForUpdates();
+        checkForUpdates(false);
     }
+
+    _preview = new PreviewWindow();
+    _latex = nullptr;
 }
 
 //QMenuBar *Tikzit::mainMenu() const
@@ -190,7 +151,7 @@ void Tikzit::newTikzStyles()
 
     if (dialog.exec() && !dialog.selectedFiles().isEmpty()) {
         QString fileName = dialog.selectedFiles()[0];
-        TikzStyles *st = new TikzStyles;
+        TikzStyles *st = new TikzStyles(this);
 
         if (st->saveStyles(fileName)) {
             QFileInfo fi(fileName);
@@ -198,14 +159,14 @@ void Tikzit::newTikzStyles()
             _styleFilePath = fi.absoluteFilePath();
             settings.setValue("previous-tikzstyles-file", fileName);
             settings.setValue("previous-tikzstyles-path", fi.absolutePath());
-            delete _styles;
+            _styles->deleteLater();
             _styles = st;
 
             foreach (MainWindow *w, _windows) {
                 w->tikzScene()->reloadStyles();
             }
         } else {
-            QMessageBox::warning(0,
+            QMessageBox::warning(nullptr,
                 "Could not write to style file.",
                 "Could not write to: '" + fileName + "'. Check file permissions or choose a new location.");
         }
@@ -244,7 +205,7 @@ void Tikzit::removeWindow(MainWindow *w)
     _windows.removeAll(w);
     if (_activeWindow == w) {
         if (_windows.isEmpty()) {
-            _activeWindow = 0;
+            _activeWindow = nullptr;
             // TODO: check if we should quit when last window closed
             quit();
         } else _activeWindow = _windows[0];
@@ -254,7 +215,7 @@ void Tikzit::removeWindow(MainWindow *w)
 void Tikzit::open()
 {
     QSettings settings("tikzit", "tikzit");
-    QString fileName = QFileDialog::getOpenFileName(0,
+    QString fileName = QFileDialog::getOpenFileName(nullptr,
                 tr("Open File"),
                 settings.value("previous-file-path").toString(),
                 tr("TiKZ Files (*.tikz)"),
@@ -269,23 +230,35 @@ void Tikzit::open(QString fileName)
 	if (!fileName.isEmpty()) {
 		if (_windows.size() == 1 &&
 			_windows[0]->tikzDocument()->isClean() &&
-			_windows[0]->tikzDocument()->shortName().isEmpty())
-		{
+            _windows[0]->tikzDocument()->shortName().isEmpty())
+        {
 			_windows[0]->open(fileName);
 			_windows[0]->show();
-		}
-		else {
-			MainWindow *w = new MainWindow();
-			w->show();
-			w->open(fileName);
-			_windows << w;
+        }
+        else
+        {
+            bool found = false;
+            foreach (MainWindow *w, _windows) {
+                if (w->tikzDocument()->fileName() == fileName) {
+                    w->raise();
+                    w->activateWindow();
+                    found = true;
+                }
+            }
+
+            if (!found) {
+                MainWindow *w = new MainWindow();
+                _windows << w;
+                w->show();
+                w->open(fileName);
+            }
 		}
 	}
 }
 
 void Tikzit::openTikzStyles() {
     QSettings settings("tikzit", "tikzit");
-    QString fileName = QFileDialog::getOpenFileName(0,
+    QString fileName = QFileDialog::getOpenFileName(nullptr,
                 tr("Open File"),
                 settings.value("previous-tikzstyles-path").toString(),
                 tr("TiKZ Style Files (*.tikzstyles)"),
@@ -310,7 +283,7 @@ bool Tikzit::loadStyles(QString fileName)
         if (st->loadStyles(fileName)) {
             _styleFile = fi.fileName();
             _styleFilePath = fi.absoluteFilePath();
-            delete _styles;
+            _styles->deleteLater();
             _styles = st;
 
             foreach (MainWindow *w, _windows) {
@@ -318,7 +291,7 @@ bool Tikzit::loadStyles(QString fileName)
             }
             return true;
         } else {
-            QMessageBox::warning(0,
+            QMessageBox::warning(nullptr,
                 "Bad style file.",
                 "Bad style file: '" + fileName + "'. Check the file is properly formatted and try to load it again.");
             return false;
@@ -326,7 +299,8 @@ bool Tikzit::loadStyles(QString fileName)
 
     } else {
         //settings.setValue("previous-tikzstyles-file", "");
-        QMessageBox::warning(0, "Style file not found.", "Could not open style file: '" + fileName + "'.");
+        QMessageBox::warning(nullptr,
+            "Style file not found.", "Could not open style file: '" + fileName + "'.");
         return false;
     }
 }
@@ -346,6 +320,20 @@ QString Tikzit::styleFilePath() const
     return _styleFilePath;
 }
 
+void Tikzit::updateRecentFiles()
+{
+    foreach (MainWindow *w, _windows) {
+        w->menu()->updateRecentFiles();
+    }
+}
+
+void Tikzit::clearRecentFiles()
+{
+    QSettings settings("tikzit", "tikzit");
+    settings.setValue("recent-files", QStringList());
+    updateRecentFiles();
+}
+
 void Tikzit::setCheckForUpdates(bool check)
 {
     QSettings settings("tikzit", "tikzit");
@@ -357,16 +345,32 @@ void Tikzit::setCheckForUpdates(bool check)
     }
 }
 
-void Tikzit::checkForUpdates()
+void Tikzit::checkForUpdates(bool manual)
 {
     QNetworkAccessManager *manager = new QNetworkAccessManager(this);
-    connect(manager, SIGNAL(finished(QNetworkReply*)),
-            this, SLOT(updateReply(QNetworkReply*)));
+
+    if (manual) {
+        connect(manager, SIGNAL(finished(QNetworkReply*)),
+            this, SLOT(updateManual(QNetworkReply*)));
+    } else {
+        connect(manager, SIGNAL(finished(QNetworkReply*)),
+            this, SLOT(updateAuto(QNetworkReply*)));
+    }
 
     manager->get(QNetworkRequest(QUrl("https://tikzit.github.io/latest-version.txt")));
 }
 
-void Tikzit::updateReply(QNetworkReply *reply)
+void Tikzit::updateAuto(QNetworkReply *reply)
+{
+    updateReply(reply, false);
+}
+
+void Tikzit::updateManual(QNetworkReply *reply)
+{
+    updateReply(reply, true);
+}
+
+void Tikzit::updateReply(QNetworkReply *reply, bool manual)
 {
     if (!reply->isReadable()) return;
 
@@ -395,7 +399,7 @@ void Tikzit::updateReply(QNetworkReply *reply)
                 QString::number(latest.minorVersion()) + "." +
                 QString::number(latest.microVersion());
             if (rcLatest != 1000) strLatest += "-rc" + QString::number(rcLatest);
-            QMessageBox::information(0,
+            QMessageBox::information(nullptr,
               tr("Update available"),
               "<p><b>A new version of TikZiT is available!</b></p>"
               "<p><i>current version: " TIKZIT_VERSION "<br />"
@@ -404,13 +408,138 @@ void Tikzit::updateReply(QNetworkReply *reply)
               "<a href=\"https://tikzit.github.io\">tikzit.github.io</a>.</p>");
         }
     } else {
-        QMessageBox::warning(0,
+        // don't complain of invalid response for auto update check
+        if (manual) {
+            QMessageBox::warning(nullptr,
               tr("Invalid response"),
               "<p>Got invalid version response from "
               "<a href=\"https://tikzit.github.io\">tikzit.github.io</a>.</p>");
+        }
+    }
+}
+
+void Tikzit::makePreview()
+{
+    if (activeWindow()) {
+        LatexProcess *oldProc = _latex;
+        _latex = new LatexProcess(_preview, this);
+        if (oldProc != nullptr) {
+            oldProc->kill();
+            oldProc->deleteLater();
+        }
+
+        connect(_latex, SIGNAL(previewFinished()), this, SLOT(cleanupLatex()));
+
+        if (activeWindow()->tikzDocument()->isEmpty()) {
+            _latex->makePreview("\\begin{tikzpicture}\n"
+                                "  \\node [style=none] (0) at (0,0) {};\n"
+                                "\\end{tikzpicture}\n");
+        } else {
+            _latex->makePreview(activeWindow()->tikzSource());
+        }
+        _preview->show();
+        _preview->raise();
     }
 }
 
+void Tikzit::cleanupLatex()
+{
+    LatexProcess *oldProc = _latex;
+    _latex = nullptr;
+    if (oldProc != nullptr) {
+        oldProc->deleteLater();
+    }
+}
+
+void Tikzit::initColors()
+{
+    // 19 standard xcolor colours
+    _colNames <<
+		"black" <<
+        "darkgray" <<
+        "gray" <<
+		"lightgray" <<
+		"white" <<
+
+		"red" <<
+		"orange" <<
+		"yellow" <<
+        "green" <<
+		"blue" <<
+		"purple" <<
+
+		"brown" <<
+		"olive" <<
+        "lime" <<
+        "cyan" <<
+        "teal" <<
+
+		"magenta" <<
+		"violet" <<
+		"pink";
+
+    _cols <<
+        QColor::fromRgbF(0,0,0) <<
+        QColor::fromRgbF(0.25,0.25,0.25) <<
+        QColor::fromRgbF(0.5,0.5,0.5) <<
+        QColor::fromRgbF(0.75,0.75,0.75) <<
+        QColor::fromRgbF(1,1,1) <<
+
+        QColor::fromRgbF(1,0,0) <<
+        QColor::fromRgbF(1,0.5,0) <<
+        QColor::fromRgbF(1,1,0) <<
+        QColor::fromRgbF(0,1,0) <<
+        QColor::fromRgbF(0,0,1) <<
+        QColor::fromRgbF(0.75,0,0.25) <<
+
+        QColor::fromRgbF(0.75,0.5,0.25) <<
+        QColor::fromRgbF(0.5,0.5,0) <<
+        QColor::fromRgbF(0.75,1,0) <<
+        QColor::fromRgbF(0,1,1) <<
+        QColor::fromRgbF(0,0.5,0.5) <<
+
+        QColor::fromRgbF(1,0,1) <<
+        QColor::fromRgbF(0.5,0,0.5) <<
+        QColor::fromRgbF(1,0.75,0.75);
+
+    for (int i = 0; i < 48; ++i) {
+        QColorDialog::setStandardColor(i, QColor(Qt::white));
+    }
+
+    // grayscale in column 1
+    int pos = 0;
+    for (int i=0; i < 5; ++i) {
+        QColorDialog::setStandardColor(pos, _cols[i]);
+        pos += 1;
+    }
+
+    // rainbow in column 2
+    pos = 6;
+    for (int i=5; i < 11; ++i) {
+        QColorDialog::setStandardColor(pos, _cols[i]);
+        pos += 1;
+    }
+
+    // brown/green/teal spectrum in column 3
+    pos = 12;
+    for (int i=11; i < 16; ++i) {
+        QColorDialog::setStandardColor(pos, _cols[i]);
+        pos += 1;
+    }
+
+    // pinks in column 4
+    pos = 18;
+    for (int i=16; i < 19; ++i) {
+        QColorDialog::setStandardColor(pos, _cols[i]);
+        pos += 1;
+    }
+}
+
+PreviewWindow *Tikzit::previewWindow() const
+{
+    return _preview;
+}
+
 //StylePalette *Tikzit::stylePalette() const
 //{
 //    return _stylePalette;
diff --git a/src/tikzit.h b/src/tikzit.h
index d36a940..4797f48 100644
--- a/src/tikzit.h
+++ b/src/tikzit.h
@@ -60,6 +60,8 @@
 #include "propertypalette.h"
 #include "stylepalette.h"
 #include "tikzstyles.h"
+#include "latexprocess.h"
+#include "previewwindow.h"
 
 #include <QObject>
 #include <QVector>
@@ -74,12 +76,13 @@
 // Number of pixels between (0,0) and (1,0) at 100% zoom level. This should be
 // divisible by 8 to avoid rounding errors with e.g. grid-snapping.
 #define GLOBAL_SCALE 40
-#define GLOBAL_SCALEF 40.0f
-#define GLOBAL_SCALEF_INV 0.025f
+#define GLOBAL_SCALEF 40.0
+#define GLOBAL_SCALEF_INV 0.025
 #define GRID_N 4
 #define GRID_SEP 10
 #define GRID_SEPF 10.0f
 
+
 inline QPointF toScreen(QPointF src)
 { src.setY(-src.y()); src *= GLOBAL_SCALEF; return src; }
 
@@ -131,14 +134,26 @@ public:
     //StylePalette *stylePalette() const;
 
     QString styleFilePath() const;
+    void updateRecentFiles();
+
+    PreviewWindow *previewWindow() const;
 
 public slots:
+    void clearRecentFiles();
     void setCheckForUpdates(bool check);
-    void checkForUpdates();
-    void updateReply(QNetworkReply *reply);
+    void checkForUpdates(bool manual);
+    void updateAuto(QNetworkReply *reply);
+    void updateManual(QNetworkReply *reply);
+    void updateReply(QNetworkReply *reply, bool manual);
+    void makePreview();
+    void cleanupLatex();
 
 private:
-    //    void createMenu();
+    /*!
+     * \brief initColors initialises a table of xcolor named colors and their associated
+     * QColor values, and adds them as standard colors to the Qt color dialog.
+     */
+    void initColors();
 
     MainMenu *_mainMenu;
     ToolPalette *_toolPalette;
@@ -152,6 +167,8 @@ private:
     StyleEditor *_styleEditor;
     QStringList _colNames;
     QVector<QColor> _cols;
+    LatexProcess *_latex;
+    PreviewWindow *_preview;
 };
 
 extern Tikzit *tikzit;
diff --git a/src/util.cpp b/src/util.cpp
index d5e2b96..304f9e7 100644
--- a/src/util.cpp
+++ b/src/util.cpp
@@ -19,31 +19,31 @@
 #include "util.h"
 
 
-float bezierInterpolate(float dist, float c0, float c1, float c2, float c3) {
-    float distp = 1 - dist;
+qreal bezierInterpolate(qreal dist, qreal c0, qreal c1, qreal c2, qreal c3) {
+    qreal distp = 1 - dist;
     return	(distp*distp*distp) * c0 +
             3 * (distp*distp) * dist * c1 +
             3 * (dist*dist) * distp * c2 +
             (dist*dist*dist) * c3;
 }
 
-QPointF bezierInterpolateFull (float dist, QPointF c0, QPointF c1, QPointF c2, QPointF c3) {
+QPointF bezierInterpolateFull (qreal dist, QPointF c0, QPointF c1, QPointF c2, QPointF c3) {
     return QPointF(bezierInterpolate (dist, c0.x(), c1.x(), c2.x(), c3.x()),
                    bezierInterpolate (dist, c0.y(), c1.y(), c2.y(), c3.y()));
 }
 
 
-float roundToNearest(float stepSize, float val) {
-    if (stepSize==0.0f) return val;
+qreal roundToNearest(qreal stepSize, qreal val) {
+    if (stepSize==0.0) return val;
     else return round(val/stepSize)*stepSize;
 }
 
-float radiansToDegrees (float radians) {
-    return (radians * 180.0f) / M_PI;
+qreal radiansToDegrees (qreal radians) {
+    return (radians * 180.0) / M_PI;
 }
 
-float degreesToRadians(float degrees) {
-    return (degrees * M_PI) / 180.0f;
+qreal degreesToRadians(qreal degrees) {
+    return (degrees * M_PI) / 180.0;
 }
 
 int normaliseAngleDeg (int degrees) {
@@ -56,7 +56,7 @@ int normaliseAngleDeg (int degrees) {
     return degrees;
 }
 
-float normaliseAngleRad (float rads) {
+qreal normaliseAngleRad (qreal rads) {
     while (rads > M_PI) {
         rads -= 2 * M_PI;
     }
@@ -66,8 +66,17 @@ float normaliseAngleRad (float rads) {
     return rads;
 }
 
-// convert float to string, squashing very small floats to zero
-QString floatToString(float f) {
-    if (f >= -0.000001 && f <= 0.000001) return "0";
+bool almostZero(qreal f) {
+    return (f >= -0.000001 && f <= 0.000001);
+}
+
+bool almostEqual(qreal f1, qreal f2) {
+    return almostZero(f1 - f2);
+}
+
+// convert qreal to string, squashing very small qreals to zero
+QString floatToString(qreal f) {
+    if (almostZero(f)) return "0";
     else return QString::number(f);
 }
+
diff --git a/src/util.h b/src/util.h
index 89d0c5b..5d1073a 100644
--- a/src/util.h
+++ b/src/util.h
@@ -33,17 +33,19 @@
 #endif
 
 // interpolate on a cubic bezier curve
-float bezierInterpolate(float dist, float c0, float c1, float c2, float c3);
-QPointF bezierInterpolateFull (float dist, QPointF c0, QPointF c1, QPointF c2, QPointF c3);
+qreal bezierInterpolate(qreal dist, qreal c0, qreal c1, qreal c2, qreal c3);
+QPointF bezierInterpolateFull (qreal dist, QPointF c0, QPointF c1, QPointF c2, QPointF c3);
 
 // rounding
-float roundToNearest(float stepSize, float val);
-float radiansToDegrees (float radians);
-QString floatToString(float f);
+qreal roundToNearest(qreal stepSize, qreal val);
+qreal radiansToDegrees (qreal radians);
+bool almostZero(qreal f);
+bool almostEqual(qreal f1, qreal f2);
+QString floatToString(qreal f);
 
 // angles
-float degreesToRadians(float degrees);
+qreal degreesToRadians(qreal degrees);
 int normaliseAngleDeg (int degrees);
-float normaliseAngleRad (float rads);
+qreal normaliseAngleRad (qreal rads);
 
 #endif // UTIL_H