Turn InputDelegate into a protocol

We require support for the @optional keyword, so we should make use of
it.

5 files changed, 17 insertions, 15 deletions

diff --git a/tikzit/src/gtk/GraphInputHandler.h b/tikzit/src/gtk/GraphInputHandler.h
index caf1528..4dbe5ca 100644
--- a/tikzit/src/gtk/GraphInputHandler.h
+++ b/tikzit/src/gtk/GraphInputHandler.h
@@ -40,7 +40,7 @@ typedef enum {
     CanvasDragState
 } MouseState;
 
-@interface GraphInputHandler: NSObject {
+@interface GraphInputHandler: NSObject <InputDelegate> {
     GraphRenderer *renderer;
     InputMode      mode;
     MouseState     state;
diff --git a/tikzit/src/gtk/InputDelegate.h b/tikzit/src/gtk/InputDelegate.h
index 1e35223..9f9b426 100644
--- a/tikzit/src/gtk/InputDelegate.h
+++ b/tikzit/src/gtk/InputDelegate.h
@@ -38,7 +38,8 @@ typedef enum {
     ScrollRight = 4,
 } ScrollDirection;
 
-@interface NSObject (InputDelegate)
+@protocol InputDelegate <NSObject>
+@optional
 /**
  * A mouse button was pressed.
  */
diff --git a/tikzit/src/gtk/Surface.h b/tikzit/src/gtk/Surface.h
index 449721f..b6d8d2e 100644
--- a/tikzit/src/gtk/Surface.h
+++ b/tikzit/src/gtk/Surface.h
@@ -33,7 +33,7 @@ typedef enum {
 
 @protocol Surface;
 
-@protocol RenderDelegate
+@protocol RenderDelegate <NSObject>
 - (void) renderWithContext:(id<RenderContext>)context onSurface:(id<Surface>)surface;
 @end
 
@@ -47,7 +47,7 @@ typedef enum {
  * The surface should send a "SurfaceSizeChanged" notification
  * when the width or height changes.
  */
-@protocol Surface
+@protocol Surface <NSObject>
 
 /**
  * The width of the surface, in surface units
diff --git a/tikzit/src/gtk/WidgetSurface.h b/tikzit/src/gtk/WidgetSurface.h
index 32c8222..02f2cbf 100644
--- a/tikzit/src/gtk/WidgetSurface.h
+++ b/tikzit/src/gtk/WidgetSurface.h
@@ -17,6 +17,7 @@
 
 #import "TZFoundation.h"
 #import <gtk/gtk.h>
+#import <InputDelegate.h>
 #import <Surface.h>
 
 /**
@@ -26,7 +27,7 @@
     GtkWidget           *widget;
     Transformer         *transformer;
     id <RenderDelegate>  renderDelegate;
-    id                   inputDelegate;
+    id <InputDelegate>   inputDelegate;
     BOOL                 keepCentered;
     BOOL                 grabsFocusOnClick;
     CGFloat              defaultScale;
@@ -36,8 +37,8 @@
 - (id) initWithWidget:(GtkWidget*)widget;
 - (GtkWidget*) widget;
 
-- (id) inputDelegate;
-- (void) setInputDelegate:(id)delegate;
+- (id<InputDelegate>) inputDelegate;
+- (void) setInputDelegate:(id<InputDelegate>)delegate;
 
 - (BOOL) keepCentered;
 - (void) setKeepCentered:(BOOL)centered;
diff --git a/tikzit/src/gtk/WidgetSurface.m b/tikzit/src/gtk/WidgetSurface.m
index 14d799b..91e0218 100644
--- a/tikzit/src/gtk/WidgetSurface.m
+++ b/tikzit/src/gtk/WidgetSurface.m
@@ -170,11 +170,11 @@ static gboolean scroll_event_cb (GtkWidget *widget, GdkEventScroll *event, Widge
     }
 }
 
-- (id) inputDelegate {
+- (id<InputDelegate>) inputDelegate {
     return inputDelegate;
 }
 
-- (void) setInputDelegate:(id)delegate {
+- (void) setInputDelegate:(id<InputDelegate>)delegate {
     if (delegate == inputDelegate) {
         return;
     }
@@ -471,7 +471,7 @@ static gboolean button_press_event_cb(GtkWidget *widget, GdkEventButton *event,
         }
     }
 
-    id delegate = [surface inputDelegate];
+    id<InputDelegate> delegate = [surface inputDelegate];
     if (delegate != nil) {
         NSPoint pos = NSMakePoint (event->x, event->y);
         MouseButton button = (MouseButton)event->button;
@@ -491,7 +491,7 @@ static gboolean button_press_event_cb(GtkWidget *widget, GdkEventButton *event,
 static gboolean button_release_event_cb(GtkWidget *widget, GdkEventButton *event, WidgetSurface *surface) {
     NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
 
-    id delegate = [surface inputDelegate];
+    id<InputDelegate> delegate = [surface inputDelegate];
     if (delegate != nil) {
         if ([delegate respondsToSelector:@selector(mouseReleaseAt:withButton:andMask:)]) {
             NSPoint pos = NSMakePoint (event->x, event->y);
@@ -508,7 +508,7 @@ static gboolean button_release_event_cb(GtkWidget *widget, GdkEventButton *event
 static gboolean motion_notify_event_cb(GtkWidget *widget, GdkEventMotion *event, WidgetSurface *surface) {
     NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
 
-    id delegate = [surface inputDelegate];
+    id<InputDelegate> delegate = [surface inputDelegate];
     if (delegate != nil) {
         if ([delegate respondsToSelector:@selector(mouseMoveTo:withButtons:andMask:)]) {
             NSPoint pos = NSMakePoint (event->x, event->y);
@@ -525,7 +525,7 @@ static gboolean motion_notify_event_cb(GtkWidget *widget, GdkEventMotion *event,
 static gboolean key_press_event_cb(GtkWidget *widget, GdkEventKey *event, WidgetSurface *surface) {
     NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
 
-    id delegate = [surface inputDelegate];
+    id<InputDelegate> delegate = [surface inputDelegate];
     if (delegate != nil) {
         if ([delegate respondsToSelector:@selector(keyPressed:withMask:)]) {
             InputMask mask = mask_from_gdk_modifier_state (event->state);
@@ -540,7 +540,7 @@ static gboolean key_press_event_cb(GtkWidget *widget, GdkEventKey *event, Widget
 static gboolean key_release_event_cb(GtkWidget *widget, GdkEventKey *event, WidgetSurface *surface) {
     NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
 
-    id delegate = [surface inputDelegate];
+    id<InputDelegate> delegate = [surface inputDelegate];
     if (delegate != nil) {
         if ([delegate respondsToSelector:@selector(keyReleased:withMask:)]) {
             InputMask mask = mask_from_gdk_modifier_state (event->state);
@@ -555,7 +555,7 @@ static gboolean key_release_event_cb(GtkWidget *widget, GdkEventKey *event, Widg
 static gboolean scroll_event_cb (GtkWidget *widget, GdkEventScroll *event, WidgetSurface *surface) {
     NSAutoreleasePool *pool = [[NSAutoreleasePool alloc] init];
 
-    id delegate = [surface inputDelegate];
+    id<InputDelegate> delegate = [surface inputDelegate];
     if (delegate != nil) {
         if ([delegate respondsToSelector:@selector(mouseScrolledAt:inDirection:withMask:)]) {
             NSPoint pos = NSMakePoint (event->x, event->y);