From a115f599507c1e8d33ed0c98298b97e1348d3d70 Mon Sep 17 00:00:00 2001
From: Benjamin Otte <otte@redhat.com>
Date: Mon, 9 Apr 2018 00:35:32 +0200
Subject: [PATCH] drawcontext: Add a surface_resized() vfunc

Call this vfunc whenever the surface's size has changed.
---
 gdk/gdkdrawcontext.c        | 20 ++++++++++++++++++++
 gdk/gdkdrawcontextprivate.h |  3 +++
 gdk/gdksurface.c            |  5 +++++
 3 files changed, 28 insertions(+)

diff --git a/gdk/gdkdrawcontext.c b/gdk/gdkdrawcontext.c
index 0f020f93e3..33324f44e3 100644
--- a/gdk/gdkdrawcontext.c
+++ b/gdk/gdkdrawcontext.c
@@ -67,6 +67,11 @@ static GParamSpec *pspecs[LAST_PROP] = { NULL, };
 
 G_DEFINE_ABSTRACT_TYPE_WITH_PRIVATE (GdkDrawContext, gdk_draw_context, G_TYPE_OBJECT)
 
+static void
+gdk_draw_context_default_surface_resized (GdkDrawContext *context)
+{
+}
+
 static void
 gdk_draw_context_dispose (GObject *gobject)
 {
@@ -137,6 +142,8 @@ gdk_draw_context_class_init (GdkDrawContextClass *klass)
   gobject_class->get_property = gdk_draw_context_get_property;
   gobject_class->dispose = gdk_draw_context_dispose;
 
+  klass->surface_resized = gdk_draw_context_default_surface_resized;
+
   /**
    * GdkDrawContext:display:
    *
@@ -247,6 +254,19 @@ gdk_draw_context_end_frame (GdkDrawContext *context,
   priv->is_drawing = FALSE;
 }
 
+/*< private >
+ * gdk_draw_context_surface_resized:
+ * @context: a #GdkDrawContext
+ *
+ * Called by the #GdkSurface the @context belongs to when the size of the surface
+ * changes.
+ */
+void
+gdk_draw_context_surface_resized (GdkDrawContext *context)
+{
+  GDK_DRAW_CONTEXT_GET_CLASS (context)->surface_resized (context);
+}
+
 /**
  * gdk_draw_context_get_display:
  * @context: a #GdkDrawContext
diff --git a/gdk/gdkdrawcontextprivate.h b/gdk/gdkdrawcontextprivate.h
index 0223787a1d..33c4b72546 100644
--- a/gdk/gdkdrawcontextprivate.h
+++ b/gdk/gdkdrawcontextprivate.h
@@ -45,6 +45,7 @@ struct _GdkDrawContextClass
   void                  (* end_frame)                           (GdkDrawContext         *context,
                                                                  cairo_region_t         *painted,
                                                                  cairo_region_t         *damage);
+  void                  (* surface_resized)                     (GdkDrawContext         *context);
 };
 
 gboolean                gdk_draw_context_is_drawing             (GdkDrawContext         *context);
@@ -54,6 +55,8 @@ void                    gdk_draw_context_end_frame              (GdkDrawContext
                                                                  cairo_region_t         *painted,
                                                                  cairo_region_t         *damage);
 
+void                    gdk_draw_context_surface_resized        (GdkDrawContext         *context);
+
 G_END_DECLS
 
 #endif /* __GDK__DRAW_CONTEXT_PRIVATE__ */
diff --git a/gdk/gdksurface.c b/gdk/gdksurface.c
index bc12fd589d..d9bbcb7534 100644
--- a/gdk/gdksurface.c
+++ b/gdk/gdksurface.c
@@ -622,6 +622,11 @@ gdk_surface_append_old_updated_area (GdkSurface *surface,
 void
 _gdk_surface_update_size (GdkSurface *surface)
 {
+  GSList *l;
+
+  for (l = surface->draw_contexts; l; l = l->next)
+    gdk_draw_context_surface_resized (l->data);
+
   gdk_surface_clear_old_updated_area (surface);
   recompute_visible_regions (surface, FALSE);
 }
-- 
2.30.2