frame-clock: Add 'compute-size' phase

This will be handled between 'update' (which may trigger animation
ticks, CSS update, etc) and 'layout' which will allocate the widget
tree. It's meant to perform surface size computation, and is done
between these two phases in order to have an up to date state, and
letting the layout phase have an up to date size to layout in.

gdk/gdkframeclock.c

@@ -78,6 +78,7 @@ enum {
   FLUSH_EVENTS,
   BEFORE_PAINT,
   UPDATE,
+  COMPUTE_SIZE,
   LAYOUT,
   PAINT,
   AFTER_PAINT,
@@ -184,6 +185,21 @@ gdk_frame_clock_class_init (GdkFrameClockClass *klass)
                   NULL, NULL, NULL,
                   G_TYPE_NONE, 0);
 
+  /**
+   * GdkFrameClock::compute-size:
+   * @clock: the frame clock emitting the signal
+   *
+   * This signal is used for computing the size of the underlying
+   * #GdkSurface. Applications should generally not handle this signal.
+   */
+  signals[COMPUTE_SIZE] =
+    g_signal_new (g_intern_static_string ("compute-size"),
+                  GDK_TYPE_FRAME_CLOCK,
+                  G_SIGNAL_RUN_LAST,
+                  0,
+                  NULL, NULL, NULL,
+                  G_TYPE_NONE, 0);
+
   /**
    * GdkFrameClock::layout:
    * @clock: the frame clock emitting the signal
@@ -682,6 +698,18 @@ _gdk_frame_clock_emit_update (GdkFrameClock *frame_clock)
   gdk_profiler_end_mark (before, "frameclock update", NULL);
 }
 
+void
+_gdk_frame_clock_emit_compute_size (GdkFrameClock *frame_clock)
+{
+  gint64 before G_GNUC_UNUSED;
+
+  before = GDK_PROFILER_CURRENT_TIME;
+
+  g_signal_emit (frame_clock, signals[COMPUTE_SIZE], 0);
+
+  gdk_profiler_end_mark (before, "frameclock compute size", NULL);
+}
+
 void
 _gdk_frame_clock_emit_layout (GdkFrameClock *frame_clock)
 {

gdk/gdkframeclock.h

@@ -50,6 +50,7 @@ typedef struct _GdkFrameClockClass         GdkFrameClockClass;
  * @GDK_FRAME_CLOCK_PHASE_FLUSH_EVENTS: corresponds to GdkFrameClock::flush-events. Should not be handled by applications.
  * @GDK_FRAME_CLOCK_PHASE_BEFORE_PAINT: corresponds to GdkFrameClock::before-paint. Should not be handled by applications.
  * @GDK_FRAME_CLOCK_PHASE_UPDATE: corresponds to GdkFrameClock::update.
+ * @GDK_FRAME_CLOCK_PHASE_COMPUTE_SIZE: corresponds to GdkFrameClock::compute-size. Should not be handled by applications.
  * @GDK_FRAME_CLOCK_PHASE_LAYOUT: corresponds to GdkFrameClock::layout.
  * @GDK_FRAME_CLOCK_PHASE_PAINT: corresponds to GdkFrameClock::paint.
  * @GDK_FRAME_CLOCK_PHASE_RESUME_EVENTS: corresponds to GdkFrameClock::resume-events. Should not be handled by applications.
@@ -64,10 +65,11 @@ typedef enum {
   GDK_FRAME_CLOCK_PHASE_FLUSH_EVENTS  = 1 << 0,
   GDK_FRAME_CLOCK_PHASE_BEFORE_PAINT  = 1 << 1,
   GDK_FRAME_CLOCK_PHASE_UPDATE        = 1 << 2,
-  GDK_FRAME_CLOCK_PHASE_LAYOUT        = 1 << 3,
+  GDK_FRAME_CLOCK_PHASE_COMPUTE_SIZE  = 1 << 3,
-  GDK_FRAME_CLOCK_PHASE_PAINT         = 1 << 4,
+  GDK_FRAME_CLOCK_PHASE_LAYOUT        = 1 << 4,
-  GDK_FRAME_CLOCK_PHASE_RESUME_EVENTS = 1 << 5,
+  GDK_FRAME_CLOCK_PHASE_PAINT         = 1 << 5,
-  GDK_FRAME_CLOCK_PHASE_AFTER_PAINT   = 1 << 6
+  GDK_FRAME_CLOCK_PHASE_RESUME_EVENTS = 1 << 6,
+  GDK_FRAME_CLOCK_PHASE_AFTER_PAINT   = 1 << 7
 } GdkFrameClockPhase;
 
 GDK_AVAILABLE_IN_ALL

gdk/gdkframeclockidle.c

@@ -552,6 +552,18 @@ gdk_frame_clock_paint_idle (void *data)
             }
           G_GNUC_FALLTHROUGH;
 
+        case GDK_FRAME_CLOCK_PHASE_COMPUTE_SIZE:
+          if (priv->freeze_count == 0)
+            {
+              priv->phase = GDK_FRAME_CLOCK_PHASE_COMPUTE_SIZE;
+              if ((priv->requested & GDK_FRAME_CLOCK_PHASE_COMPUTE_SIZE) != 0)
+                {
+                  priv->requested &= ~GDK_FRAME_CLOCK_PHASE_COMPUTE_SIZE;
+                  _gdk_frame_clock_emit_compute_size (clock);
+                }
+            }
+          G_GNUC_FALLTHROUGH;
+
         case GDK_FRAME_CLOCK_PHASE_LAYOUT:
           if (priv->freeze_count == 0)
             {

gdk/gdkframeclockprivate.h

@@ -122,6 +122,7 @@ gboolean         _gdk_frame_timings_steal (GdkFrameTimings *timings,
 void _gdk_frame_clock_emit_flush_events  (GdkFrameClock *frame_clock);
 void _gdk_frame_clock_emit_before_paint  (GdkFrameClock *frame_clock);
 void _gdk_frame_clock_emit_update        (GdkFrameClock *frame_clock);
+void _gdk_frame_clock_emit_compute_size  (GdkFrameClock *frame_clock);
 void _gdk_frame_clock_emit_layout        (GdkFrameClock *frame_clock);
 void _gdk_frame_clock_emit_paint         (GdkFrameClock *frame_clock);
 void _gdk_frame_clock_emit_after_paint   (GdkFrameClock *frame_clock);