cc: Stop converting Rect to QuadF to map to an enclosed rect.

cc/trees/occlusion_tracker.cc

 // Copyright 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "cc/trees/occlusion_tracker.h"
 
 #include <algorithm>
 
 #include "cc/base/math_util.h"
 #include "cc/base/region.h"
@@ skipping 66 matching lines @@
   // Verify that rects within the |surface| will remain rects in its target
   // surface after applying |transform|. If this is true, then apply |transform|
   // to each rect within |region| in order to transform the entire Region.
 
   // TODO(danakj): Find a rect interior to each transformed quad.
   if (!transform.Preserves2dAxisAlignment())
     return SimpleEnclosedRegion();
 
   SimpleEnclosedRegion transformed_region;
   for (size_t i = 0; i < region.GetRegionComplexity(); ++i) {
-    bool clipped;
-    gfx::QuadF transformed_quad =
-        MathUtil::MapQuad(transform, gfx::QuadF(region.GetRect(i)), &clipped);
     gfx::Rect transformed_rect =
-        gfx::ToEnclosedRect(transformed_quad.BoundingBox());
-    DCHECK(!clipped);  // We only map if the transform preserves axis alignment.
+        MathUtil::MapEnclosedRectWith2dAxisAlignedTransform(transform,
+                                                            region.GetRect(i));
     if (have_clip_rect)
       transformed_rect.Intersect(clip_rect_in_new_target);
     transformed_region.Union(transformed_rect);
   }
   return transformed_region;
 }
 
 static inline bool LayerOpacityKnown(const Layer* layer) {
   return !layer->draw_opacity_is_animating();
 }
@@ skipping 322 matching lines @@
   gfx::Rect clip_rect_in_target = ScreenSpaceClipRectInTargetSurface(
       layer->render_target()->render_surface(), screen_space_clip_rect_);
   if (layer->is_clipped()) {
     clip_rect_in_target.Intersect(layer->clip_rect());
   } else {
     clip_rect_in_target.Intersect(
         layer->render_target()->render_surface()->content_rect());
   }
 
   for (size_t i = 0; i < opaque_contents.GetRegionComplexity(); ++i) {
-    bool clipped;
-    gfx::QuadF transformed_quad =
-        MathUtil::MapQuad(layer->draw_transform(),
-                          gfx::QuadF(opaque_contents.GetRect(i)),
-                          &clipped);
     gfx::Rect transformed_rect =
-        gfx::ToEnclosedRect(transformed_quad.BoundingBox());
-    DCHECK(!clipped);  // We only map if the transform preserves axis alignment.
+        MathUtil::MapEnclosedRectWith2dAxisAlignedTransform(
+            layer->draw_transform(), opaque_contents.GetRect(i));
     transformed_rect.Intersect(clip_rect_in_target);
     if (transformed_rect.width() < minimum_tracking_size_.width() &&
         transformed_rect.height() < minimum_tracking_size_.height())
       continue;
     stack_.back().occlusion_from_inside_target.Union(transformed_rect);
 
     if (!occluding_screen_space_rects_)
       continue;
 
     // Save the occluding area in screen space for debug visualization.
+    bool clipped;
     gfx::QuadF screen_space_quad = MathUtil::MapQuad(
         layer->render_target()->render_surface()->screen_space_transform(),
         gfx::QuadF(transformed_rect), &clipped);
     // TODO(danakj): Store the quad in the debug info instead of the bounding
     // box.
     gfx::Rect screen_space_rect =
         gfx::ToEnclosedRect(screen_space_quad.BoundingBox());
     occluding_screen_space_rects_->push_back(screen_space_rect);
   }
 
   if (!non_occluding_screen_space_rects_)
     return;
 
   Region non_opaque_contents(gfx::Rect(layer->content_bounds()));
   non_opaque_contents.Subtract(opaque_contents);
 
   for (Region::Iterator non_opaque_content_rects(non_opaque_contents);
        non_opaque_content_rects.has_rect();
        non_opaque_content_rects.next()) {
-    // We've already checked for clipping in the MapQuad call above, these calls
-    // should not clip anything further.
-    gfx::Rect transformed_rect = gfx::ToEnclosedRect(
-        MathUtil::MapClippedRect(layer->draw_transform(),
-                                 gfx::RectF(non_opaque_content_rects.rect())));
+    gfx::Rect transformed_rect =
+        MathUtil::MapEnclosedRectWith2dAxisAlignedTransform(
+            layer->draw_transform(), non_opaque_content_rects.rect());
     transformed_rect.Intersect(clip_rect_in_target);
     if (transformed_rect.IsEmpty())
       continue;
 
     bool clipped;
     gfx::QuadF screen_space_quad = MathUtil::MapQuad(
         layer->render_target()->render_surface()->screen_space_transform(),
         gfx::QuadF(transformed_rect),
         &clipped);
     // TODO(danakj): Store the quad in the debug info instead of the bounding
@@ skipping 142 matching lines @@
   for (size_t i = 0; i < occluded.GetRegionComplexity(); ++i)
     visible_region.Subtract(occluded.GetRect(i));
   return visible_region;
 }
 
 // Instantiate (and export) templates here for the linker.
 template class OcclusionTracker<Layer>;
 template class OcclusionTracker<LayerImpl>;
 
 }  // namespace cc