Merge pull request #368 from VincentRouvreau/matplotlib_latex_desactivation

Add mechanism to deactivate LaTeX matplotlib rendering

3 files changed, 56 insertions, 6 deletions

diff --git a/src/python/doc/installation.rst b/src/python/doc/installation.rst
index 525ca84e..78e1af73 100644
--- a/src/python/doc/installation.rst
+++ b/src/python/doc/installation.rst
@@ -323,6 +323,35 @@ The following examples require the `Matplotlib <http://matplotlib.org>`_:
     * :download:`euclidean_strong_witness_complex_diagram_persistence_from_off_file_example.py <../example/euclidean_strong_witness_complex_diagram_persistence_from_off_file_example.py>`
     * :download:`euclidean_witness_complex_diagram_persistence_from_off_file_example.py <../example/euclidean_witness_complex_diagram_persistence_from_off_file_example.py>`
 
+LaTeX
+~~~~~
+
+If a sufficiently complete LaTeX toolchain is available (including dvipng and ghostscript), the LaTeX option of
+matplotlib is enabled for prettier captions (cf.
+`matplotlib text rendering with LaTeX <https://matplotlib.org/3.3.0/tutorials/text/usetex.html>`_).
+It also requires `type1cm` LaTeX package (not detected by matplotlib).
+
+If you are facing issues with LaTeX rendering, like this one:
+
+.. code-block:: none
+
+    Traceback (most recent call last):
+      File "/usr/lib/python3/dist-packages/matplotlib/texmanager.py", line 302, in _run_checked_subprocess
+        report = subprocess.check_output(command,
+    ...
+    ! LaTeX Error: File `type1cm.sty' not found.
+    ...
+
+This is because the LaTeX package is not installed on your system. On Ubuntu systems you can install texlive-full
+(for all LaTeX packages), or more specific packages like texlive-latex-extra, cm-super.
+
+You can still deactivate LaTeX rendering by saying:
+
+.. code-block:: python
+
+    import gudhi
+    gudhi.persistence_graphical_tools._gudhi_matplotlib_use_tex=False
+
 PyKeOps
 -------
 
diff --git a/src/python/doc/persistence_graphical_tools_user.rst b/src/python/doc/persistence_graphical_tools_user.rst
index b5a38eb1..d95b9d2b 100644
--- a/src/python/doc/persistence_graphical_tools_user.rst
+++ b/src/python/doc/persistence_graphical_tools_user.rst
@@ -90,3 +90,14 @@ If you want more information on a specific dimension, for instance:
     gudhi.plot_persistence_density(persistence=pers_diag,
         dimension=1, legend=True, axes=axes[1])
     plt.show()
+
+LaTeX support
+-------------
+
+If you are facing issues with `LaTeX <installation.html#latex>`_ rendering, you can still deactivate LaTeX rendering by
+saying:
+
+.. code-block:: python
+
+    import gudhi
+    gudhi.persistence_graphical_tools._gudhi_matplotlib_use_tex=False
diff --git a/src/python/gudhi/persistence_graphical_tools.py b/src/python/gudhi/persistence_graphical_tools.py
index c6766c70..848dc03e 100644
--- a/src/python/gudhi/persistence_graphical_tools.py
+++ b/src/python/gudhi/persistence_graphical_tools.py
@@ -20,6 +20,7 @@ __author__ = "Vincent Rouvreau, Bertrand Michel, Theo Lacombe"
 __copyright__ = "Copyright (C) 2016 Inria"
 __license__ = "MIT"
 
+_gudhi_matplotlib_use_tex = True
 
 def __min_birth_max_death(persistence, band=0.0):
     """This function returns (min_birth, max_death) from the persistence.
@@ -117,10 +118,13 @@ def plot_persistence_barcode(
     try:
         import matplotlib.pyplot as plt
         import matplotlib.patches as mpatches
-        if _matplotlib_can_use_tex():
-            from matplotlib import rc
+        from matplotlib import rc
+        if _gudhi_matplotlib_use_tex and _matplotlib_can_use_tex():
             plt.rc('text', usetex=True)
             plt.rc('font', family='serif')
+        else:
+            plt.rc('text', usetex=False)
+            plt.rc('font', family='DejaVu Sans')
 
         if persistence_file != "":
             if path.isfile(persistence_file):
@@ -263,10 +267,13 @@ def plot_persistence_diagram(
     try:
         import matplotlib.pyplot as plt
         import matplotlib.patches as mpatches
-        if _matplotlib_can_use_tex():
-            from matplotlib import rc
+        from matplotlib import rc
+        if _gudhi_matplotlib_use_tex and _matplotlib_can_use_tex():
             plt.rc('text', usetex=True)
             plt.rc('font', family='serif')
+        else:
+            plt.rc('text', usetex=False)
+            plt.rc('font', family='DejaVu Sans')
 
         if persistence_file != "":
             if path.isfile(persistence_file):
@@ -436,10 +443,13 @@ def plot_persistence_density(
         import matplotlib.pyplot as plt
         import matplotlib.patches as mpatches
         from scipy.stats import kde
-        if _matplotlib_can_use_tex():
-            from matplotlib import rc
+        from matplotlib import rc
+        if _gudhi_matplotlib_use_tex and _matplotlib_can_use_tex():
             plt.rc('text', usetex=True)
             plt.rc('font', family='serif')
+        else:
+            plt.rc('text', usetex=False)
+            plt.rc('font', family='DejaVu Sans')
 
         if persistence_file != "":
             if dimension is None: