GdkFrameClock: add freeze/thaw

Add the ability to freeze a frame clock, which pauses its operation,
then thaw it again later to resume.

Initially this is used to implement freezing updates when we are
waiting for ConfigureNotify in response to changing the size of
a toplevel.

We need a per-window clock for this to work properly, so add that
for the X11 backend.

https://bugzilla.gnome.org/show_bug.cgi?id=685460

1 files changed, 80 insertions, 14 deletions

diff --git a/gdk/gdkframeclockidle.c b/gdk/gdkframeclockidle.c
index bdcb16a08a..2911237687 100644
--- a/gdk/gdkframeclockidle.c
+++ b/gdk/gdkframeclockidle.c
@@ -37,6 +37,7 @@ struct _GdkFrameClockIdlePrivate
   guint64 frame_time;
 
   guint idle_id;
+  guint freeze_count;
 
   GdkFrameClockPhase requested;
   GdkFrameClockPhase phase;
@@ -72,6 +73,7 @@ gdk_frame_clock_idle_init (GdkFrameClockIdle *frame_clock_idle)
   priv = frame_clock_idle->priv;
 
   priv->timer = g_timer_new ();
+  priv->freeze_count = 0;
 }
 
 static void
@@ -138,7 +140,7 @@ maybe_start_idle (GdkFrameClockIdle *clock_idle)
 {
   GdkFrameClockIdlePrivate *priv = clock_idle->priv;
 
-  if (priv->idle_id == 0 && priv->requested != 0)
+  if (priv->idle_id == 0 && priv->freeze_count == 0 && priv->requested != 0)
     {
       priv->idle_id = gdk_threads_add_idle_full (GDK_PRIORITY_REDRAW,
                                                  gdk_frame_clock_paint_idle,
@@ -160,19 +162,51 @@ gdk_frame_clock_paint_idle (void *data)
 
   priv->frame_time = compute_frame_time (clock_idle);
 
-  priv->phase = GDK_FRAME_CLOCK_PHASE_BEFORE_PAINT;
-  priv->requested &= ~GDK_FRAME_CLOCK_PHASE_BEFORE_PAINT;
-  g_signal_emit_by_name (G_OBJECT (clock), "before-paint");
-  priv->phase = GDK_FRAME_CLOCK_PHASE_LAYOUT;
-  priv->requested &= ~GDK_FRAME_CLOCK_PHASE_LAYOUT;
-  g_signal_emit_by_name (G_OBJECT (clock), "layout");
-  priv->phase = GDK_FRAME_CLOCK_PHASE_PAINT;
-  priv->requested &= ~GDK_FRAME_CLOCK_PHASE_PAINT;
-  g_signal_emit_by_name (G_OBJECT (clock), "paint");
-  priv->phase = GDK_FRAME_CLOCK_PHASE_AFTER_PAINT;
-  priv->requested &= ~GDK_FRAME_CLOCK_PHASE_AFTER_PAINT;
-  g_signal_emit_by_name (G_OBJECT (clock), "after-paint");
-  priv->phase = GDK_FRAME_CLOCK_PHASE_NONE;
+  switch (priv->phase)
+    {
+    case GDK_FRAME_CLOCK_PHASE_NONE:
+    case GDK_FRAME_CLOCK_PHASE_BEFORE_PAINT:
+      if (priv->freeze_count == 0)
+	{
+	  priv->phase = GDK_FRAME_CLOCK_PHASE_BEFORE_PAINT;
+          priv->requested &= ~GDK_FRAME_CLOCK_PHASE_BEFORE_PAINT;
+          /* We always emit ::before-paint and ::after-paint even if
+           * not explicitly requested, and unlike other phases,
+           * they don't get repeated if you freeze/thaw while
+           * in them. */
+	  g_signal_emit_by_name (G_OBJECT (clock), "before-paint");
+	  priv->phase = GDK_FRAME_CLOCK_PHASE_LAYOUT;
+	}
+    case GDK_FRAME_CLOCK_PHASE_LAYOUT:
+      if (priv->freeze_count == 0)
+	{
+	  priv->phase = GDK_FRAME_CLOCK_PHASE_LAYOUT;
+          if (priv->requested & GDK_FRAME_CLOCK_PHASE_LAYOUT)
+            {
+              priv->requested &= ~GDK_FRAME_CLOCK_PHASE_LAYOUT;
+              g_signal_emit_by_name (G_OBJECT (clock), "layout");
+            }
+	}
+    case GDK_FRAME_CLOCK_PHASE_PAINT:
+      if (priv->freeze_count == 0)
+	{
+	  priv->phase = GDK_FRAME_CLOCK_PHASE_PAINT;
+          if (priv->requested & GDK_FRAME_CLOCK_PHASE_PAINT)
+            {
+              priv->requested &= ~GDK_FRAME_CLOCK_PHASE_PAINT;
+              g_signal_emit_by_name (G_OBJECT (clock), "paint");
+            }
+	}
+    case GDK_FRAME_CLOCK_PHASE_AFTER_PAINT:
+      if (priv->freeze_count == 0)
+	{
+	  priv->phase = GDK_FRAME_CLOCK_PHASE_AFTER_PAINT;
+          priv->requested &= ~GDK_FRAME_CLOCK_PHASE_AFTER_PAINT;
+	  g_signal_emit_by_name (G_OBJECT (clock), "after-paint");
+          /* the ::after-paint phase doesn't get repeated on freeze/thaw */
+	  priv->phase = GDK_FRAME_CLOCK_PHASE_NONE;
+	}
+    }
 
   maybe_start_idle (clock_idle);
 
@@ -199,11 +233,43 @@ gdk_frame_clock_idle_get_requested (GdkFrameClock *clock)
 }
 
 static void
+gdk_frame_clock_idle_freeze (GdkFrameClock *clock)
+{
+  GdkFrameClockIdlePrivate *priv = GDK_FRAME_CLOCK_IDLE (clock)->priv;
+
+  priv->freeze_count++;
+
+  if (priv->freeze_count == 1)
+    {
+      if (priv->idle_id)
+	{
+	  g_source_remove (priv->idle_id);
+	  priv->idle_id = 0;
+	}
+    }
+}
+
+static void
+gdk_frame_clock_idle_thaw (GdkFrameClock *clock)
+{
+  GdkFrameClockIdle *clock_idle = GDK_FRAME_CLOCK_IDLE (clock);
+  GdkFrameClockIdlePrivate *priv = clock_idle->priv;
+
+  g_return_if_fail (priv->freeze_count > 0);
+
+  priv->freeze_count--;
+  if (priv->freeze_count == 0)
+    maybe_start_idle (clock_idle);
+}
+
+static void
 gdk_frame_clock_idle_interface_init (GdkFrameClockInterface *iface)
 {
   iface->get_frame_time = gdk_frame_clock_idle_get_frame_time;
   iface->request_phase = gdk_frame_clock_idle_request_phase;
   iface->get_requested = gdk_frame_clock_idle_get_requested;
+  iface->freeze = gdk_frame_clock_idle_freeze;
+  iface->thaw = gdk_frame_clock_idle_thaw;
 }
 
 GdkFrameClock *