Bug 1196462 - Add a pref to highlight checkerboarded areas for debugging. r=kats

--HG--
extra : source : 9d1aa5ad7e6fcb15a2b5c570115702499b75aaaf

gfx/layers/composite/ContainerLayerComposite.cpp

@@ -520,6 +520,9 @@ RenderLayers(ContainerT* aContainer,
     gfxRGBA color;
     if ((layer->GetContentFlags() & Layer::CONTENT_OPAQUE) &&
         LayerHasCheckerboardingAPZC(layer, &color)) {
+      if (gfxPrefs::APZHighlightCheckerboardedAreas()) {
+        color = gfxRGBA(255 / 255.0, 188 / 255.0, 217 / 255.0, 1);  // "Cotton Candy"
+      }
       // Ideally we would want to intersect the checkerboard region from the APZ with the layer bounds
       // and only fill in that area. However the layer bounds takes into account the base translation
       // for the painted layer whereas the checkerboard region does not. One does not simply

gfx/thebes/gfxPrefs.h

@@ -160,6 +160,7 @@ private:
   DECL_GFX_PREF(Live, "apz.fling_repaint_interval",            APZFlingRepaintInterval, int32_t, 75);
   DECL_GFX_PREF(Once, "apz.fling_stop_on_tap_threshold",       APZFlingStopOnTapThreshold, float, 0.05f);
   DECL_GFX_PREF(Once, "apz.fling_stopped_threshold",           APZFlingStoppedThreshold, float, 0.01f);
+  DECL_GFX_PREF(Once, "apz.highlight_checkerboarded_areas",    APZHighlightCheckerboardedAreas, bool, false);
   DECL_GFX_PREF(Once, "apz.max_velocity_inches_per_ms",        APZMaxVelocity, float, -1.0f);
   DECL_GFX_PREF(Once, "apz.max_velocity_queue_size",           APZMaxVelocityQueueSize, uint32_t, 5);
   DECL_GFX_PREF(Live, "apz.min_skate_speed",                   APZMinSkateSpeed, float, 1.0f);

modules/libpref/init/all.js

@@ -552,6 +552,7 @@ pref("apz.fling_curve_threshold_inches_per_ms", "-1.0");
 pref("apz.fling_friction", "0.002");
 pref("apz.fling_stop_on_tap_threshold", "0.05");
 pref("apz.fling_stopped_threshold", "0.01");
+pref("apz.highlight_checkerboarded_areas", false);
 pref("apz.max_velocity_inches_per_ms", "-1.0");
 pref("apz.max_velocity_queue_size", 5);
 pref("apz.min_skate_speed", "1.0");