[dia/zbrown/test-build: 3/6] areas: use gtk3 style drawing with a gtk2 thunk

[Zander Brown <zbrown src gnome org>]

commit 36f931cb234bdc026d2fb4cc21e7e969bcf0d976
Author: Zander Brown <zbrown gnome org>
Date:   Fri Sep 24 03:15:44 2021 +0100

    areas: use gtk3 style drawing with a gtk2 thunk
    
    In theory they now build against both 2 and (with lots of warnings) 3
    
    Once we are gtk3 we can just drop the thunks
    
    Ironically gtk4 will need cairo glue again, ce'st la vie

 app/dia-colour-area.c     | 32 ++++++++++++++++++++++++++------
 app/dia-line-width-area.c | 32 ++++++++++++++++++++++++++------
 2 files changed, 52 insertions(+), 12 deletions(-)
---
diff --git a/app/dia-colour-area.c b/app/dia-colour-area.c
index 8008d1b1c..5c457977e 100644
--- a/app/dia-colour-area.c
+++ b/app/dia-colour-area.c
@@ -67,15 +67,14 @@ dia_colour_area_target (DiaColourArea *self,
     return -1;
 }
 
+
 static gboolean
-dia_colour_area_draw (GtkWidget      *self, /*cairo_t *ctx*/
-                      GdkEventExpose *event)
+dia_colour_area_draw (GtkWidget *self, cairo_t *ctx)
 {
   GdkColor fg, bg;
   int rect_w, rect_h;
   int img_width, img_height;
   DiaColourArea *priv = DIA_COLOUR_AREA (self);
-  cairo_t *ctx = gdk_cairo_create (gtk_widget_get_window (self));
   GtkAllocation alloc;
 
   gtk_widget_get_allocation (GTK_WIDGET (self), &alloc);
@@ -116,6 +115,24 @@ dia_colour_area_draw (GtkWidget      *self, /*cairo_t *ctx*/
 }
 
 
+#if !GTK_CHECK_VERSION (3, 0, 0)
+static gboolean
+dia_colour_area_expose_event (GtkWidget *widget, GdkEventExpose *event)
+{
+  cairo_t *ctx;
+  gboolean res;
+
+  ctx = gdk_cairo_create (GDK_DRAWABLE (gtk_widget_get_window (widget)));
+
+  res = dia_colour_area_draw (widget, ctx);
+
+  cairo_destroy (ctx);
+
+  return res;
+}
+#endif
+
+
 static void
 dia_colour_area_response (GtkDialog     *chooser,
                           int            response,
@@ -266,10 +283,13 @@ dia_colour_area_button_press_event (GtkWidget      *widget,
 static void
 dia_colour_area_class_init (DiaColourAreaClass *class)
 {
-  GtkWidgetClass *widget_class;
+  GtkWidgetClass *widget_class = GTK_WIDGET_CLASS (class);
 
-  widget_class = GTK_WIDGET_CLASS (class);
-  widget_class->expose_event = dia_colour_area_draw;
+#if GTK_CHECK_VERSION (3, 0, 0)
+  widget_class->draw = dia_colour_area_draw;
+#else
+  widget_class->expose_event = dia_colour_area_expose_event;
+#endif
   widget_class->button_press_event = dia_colour_area_button_press_event;
 
   attributes_set_foreground (persistence_register_color ("fg_color",
diff --git a/app/dia-line-width-area.c b/app/dia-line-width-area.c
index d1ad0df69..c0d569d83 100644
--- a/app/dia-line-width-area.c
+++ b/app/dia-line-width-area.c
@@ -140,9 +140,9 @@ dia_line_width_area_create_dialog (DiaLineWidthArea *self,
   persistence_register_window (GTK_WINDOW (self->dialog));
 }
 
+
 static gboolean
-dia_line_width_area_draw (GtkWidget      *self, /*cairo_t *ctx*/
-                          GdkEventExpose *event)
+dia_line_width_area_draw (GtkWidget *self, cairo_t *ctx)
 {
   GdkColor fg;
   int i;
@@ -151,7 +151,6 @@ dia_line_width_area_draw (GtkWidget      *self, /*cairo_t *ctx*/
   double dashes[] = { 3 };
   DiaLineWidthArea *priv = DIA_LINE_WIDTH_AREA (self);
   GtkAllocation alloc;
-  cairo_t *ctx = gdk_cairo_create (gtk_widget_get_window (self));
 
   gtk_widget_get_allocation (self, &alloc);
 
@@ -186,6 +185,24 @@ dia_line_width_area_draw (GtkWidget      *self, /*cairo_t *ctx*/
 }
 
 
+#if !GTK_CHECK_VERSION (3, 0, 0)
+static gboolean
+dia_line_width_area_expose_event (GtkWidget *widget, GdkEventExpose *event)
+{
+  cairo_t *ctx;
+  gboolean res;
+
+  ctx = gdk_cairo_create (GDK_DRAWABLE (gtk_widget_get_window (widget)));
+
+  res = dia_line_width_area_draw (widget, ctx);
+
+  cairo_destroy (ctx);
+
+  return res;
+}
+#endif
+
+
 static gboolean
 dia_line_width_area_button_press_event (GtkWidget      *self,
                                         GdkEventButton *event)
@@ -221,10 +238,13 @@ dia_line_width_area_button_press_event (GtkWidget      *self,
 static void
 dia_line_width_area_class_init (DiaLineWidthAreaClass *class)
 {
-  GtkWidgetClass *widget_class;
+  GtkWidgetClass *widget_class = GTK_WIDGET_CLASS (class);
 
-  widget_class = GTK_WIDGET_CLASS (class);
-  widget_class->expose_event = dia_line_width_area_draw;
+#if GTK_CHECK_VERSION (3, 0, 0)
+  widget_class->draw = dia_line_width_area_draw;
+#else
+  widget_class->expose_event = dia_line_width_area_expose_event;
+#endif
   widget_class->button_press_event = dia_line_width_area_button_press_event;
 
   attributes_set_default_linewidth (persistence_register_real ("linewidth", 0.1));