frame clock: Track if paint is caused by thaw or not

When we get to a paint cycle we now know if this was caused by a
thaw, which typically means last frame was drawn, or some other event.

In the first case the time of the cycle is tied to the vblank in some
sense, and in the others it is essentially random. We can use this
information to compute better frame times. (Will be done in later
commits.)

diff --git a/gdk/gdkframeclockidle.c b/gdk/gdkframeclockidle.c
index ef32ad518a75b15d415a87bbf43227a7827d87b2..cf43f7442fd3483938b22d42c662448756a586ed 100644 (file)
--- a/gdk/gdkframeclockidle.c
+++ b/gdk/gdkframeclockidle.c
@@ -56,6 +56,7 @@ struct _GdkFrameClockIdlePrivate
   GdkFrameClockPhase phase;
 
   guint in_paint_idle : 1;
+  guint paint_is_thaw : 1;
 #ifdef G_OS_WIN32
   guint begin_period : 1;
 #endif
@@ -275,7 +276,8 @@ gdk_frame_clock_idle_get_frame_time (GdkFrameClock *clock)
     (priv)->updating_count > 0))
 
 static void
-maybe_start_idle (GdkFrameClockIdle *clock_idle)
+maybe_start_idle (GdkFrameClockIdle *clock_idle,
+                  gboolean caused_by_thaw)
 {
   GdkFrameClockIdlePrivate *priv = clock_idle->priv;
 
@@ -303,6 +305,7 @@ maybe_start_idle (GdkFrameClockIdle *clock_idle)
       if (!priv->in_paint_idle &&
          priv->paint_idle_id == 0 && RUN_PAINT_IDLE (priv))
         {
+          priv->paint_is_thaw = caused_by_thaw;
           priv->paint_idle_id = g_timeout_add_full (GDK_PRIORITY_REDRAW,
                                                     min_interval,
                                                     gdk_frame_clock_paint_idle,
@@ -560,7 +563,7 @@ gdk_frame_clock_paint_idle (void *data)
     {
       priv->min_next_frame_time = compute_min_next_frame_time (clock_idle,
                                                                priv->frame_time);
-      maybe_start_idle (clock_idle);
+      maybe_start_idle (clock_idle, FALSE);
     }
 
   if (priv->freeze_count == 0)
@@ -580,7 +583,7 @@ gdk_frame_clock_idle_request_phase (GdkFrameClock      *clock,
   GdkFrameClockIdlePrivate *priv = clock_idle->priv;
 
   priv->requested |= phase;
-  maybe_start_idle (clock_idle);
+  maybe_start_idle (clock_idle, FALSE);
 }
 
 static void
@@ -599,7 +602,7 @@ gdk_frame_clock_idle_begin_updating (GdkFrameClock *clock)
 #endif
 
   priv->updating_count++;
-  maybe_start_idle (clock_idle);
+  maybe_start_idle (clock_idle, FALSE);
 }
 
 static void
@@ -649,7 +652,7 @@ gdk_frame_clock_idle_thaw (GdkFrameClock *clock)
   priv->freeze_count--;
   if (priv->freeze_count == 0)
     {
-      maybe_start_idle (clock_idle);
+      maybe_start_idle (clock_idle, TRUE);
       /* If nothing is requested so we didn't start an idle, we need
        * to skip to the end of the state chain, since the idle won't
        * run and do it for us.