cc: Move DamageTracker filter handling to MapRect.

cc/trees/damage_tracker_unittest.cc

 // Copyright 2011 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/damage_tracker.h"
 
 #include <stddef.h>
 
 #include "cc/base/math_util.h"
 #include "cc/layers/layer_impl.h"
@@ skipping 616 matching lines @@
   LayerImpl* child = root->children()[0];
   gfx::Rect root_damage_rect, child_damage_rect;
 
   // Allow us to set damage on child too.
   child->SetDrawsContent(true);
 
   FilterOperations filters;
   filters.Append(FilterOperation::CreateReferenceFilter(
       SkBlurImageFilter::Make(2, 2, nullptr)));
   int outset_top, outset_right, outset_bottom, outset_left;
   filters.GetOutsets(&outset_top, &outset_right, &outset_bottom, &outset_left);

[Stephen White, 2016/06/01 15:50:00]

Out of curiosity, why are we still using outsets here (and elsewhere)? Is the
damage tracker still using them in some places?

[jbroman, 2016/06/01 15:53:37]

They're used to constructed expected values, presumably because the sigma ->
outset calculation was previously non-trivial (now it's "multiply by 3"). I
intend to remove the calls in unit tests in a subsequent CL.

 
   // Setting the filter will damage the whole surface.
   gfx::Transform transform;
   transform.RotateAboutYAxis(60);
   ClearDamageForAllSurfaces(root);
   child->test_properties()->force_render_surface = true;
   child->SetTransform(transform);
   root->layer_tree_impl()->property_trees()->needs_rebuild = true;
   EmulateDrawingOneFrame(root);
   child->OnFilterAnimated(filters);
@@ skipping 48 matching lines @@
   filters.GetOutsets(&outset_top, &outset_right, &outset_bottom, &outset_left);
 
   // Setting the filter will damage the whole surface.
   ClearDamageForAllSurfaces(root);
   child1->SetBackgroundFilters(filters);
   root->layer_tree_impl()->property_trees()->needs_rebuild = true;
   EmulateDrawingOneFrame(root);
 
   // CASE 1: Setting the update rect should cause the corresponding damage to
   //         the surface, blurred based on the size of the child's background
-  //         blur filter.
+  //         blur filter. Note that child1's render surface has a size of
+  //         206x208 due to contributions from grand_child1 and grand_child2.

[jbroman, 2016/06/01 14:32:28]

I was confused until I realized why the surface was larger than its declared
bounds of 100x100; a comment of this would have made understanding the test
easier for me. Let me know if you don't want it in this CL.

   ClearDamageForAllSurfaces(root);
   root->SetUpdateRect(gfx::Rect(297, 297, 2, 2));
   root->layer_tree_impl()->property_trees()->needs_rebuild = true;
   EmulateDrawingOneFrame(root);
 
   gfx::Rect root_damage_rect =
       root->render_surface()->damage_tracker()->current_damage_rect();
   // Damage position on the surface should be a composition of the damage on
   // the root and on child2.  Damage on the root should be: position of
   // update_rect (297, 297), but expanded by the blur outsets.
@@ skipping 45 matching lines @@
   // CASE 4: Setting this update rect inside the blurred content_bounds but
   //         outside the original content_bounds of the blurred child1 will
   //         cause it to be expanded.
   ClearDamageForAllSurfaces(root);
   root->SetUpdateRect(gfx::Rect(99, 99, 1, 1));
   root->layer_tree_impl()->property_trees()->needs_rebuild = true;
   EmulateDrawingOneFrame(root);
 
   root_damage_rect =
           root->render_surface()->damage_tracker()->current_damage_rect();
-  // Damage on the root should be: position of update_rect (99, 99), expanded by
-  // the blurring on child1, but since it is 1 pixel outside the layer, the
-  // expanding should be reduced by 1.
-  expected_damage_rect = gfx::Rect(99, 99, 1, 1);
-
-  expected_damage_rect.Inset(-outset_left + 1,
-                             -outset_top + 1,
-                             -outset_right,
-                             -outset_bottom);
+  // Damage on the root should be: the originally damaged rect (99,99 1x1)
+  // plus the rect that can influence with a 2px blur (93,93 13x13) intersected
+  // with the surface rect (100,100 206x208). So no additional damage occurs
+  // above or to the left, but there is additional damage within the blurred
+  // area.
+  expected_damage_rect = gfx::Rect(99, 99, 7, 7);
   EXPECT_EQ(expected_damage_rect.ToString(), root_damage_rect.ToString());
 
   // CASE 5: Setting the update rect on child2, which is above child1, will
   // not get blurred by child1, so it does not need to get expanded.
   ClearDamageForAllSurfaces(root);
   child2->SetUpdateRect(gfx::Rect(1, 1));
   root->layer_tree_impl()->property_trees()->needs_rebuild = true;
   EmulateDrawingOneFrame(root);
 
   root_damage_rect =
           root->render_surface()->damage_tracker()->current_damage_rect();
   // Damage on child2 should be: position of update_rect offset by the child's
   // position (11, 11), and not expanded by anything.
   expected_damage_rect = gfx::Rect(11, 11, 1, 1);
 
   EXPECT_EQ(expected_damage_rect.ToString(), root_damage_rect.ToString());
 
   // CASE 6: Setting the update rect on child1 will also blur the damage, so
   //         that any pixels needed for the blur are redrawn in the current
   //         frame.
   ClearDamageForAllSurfaces(root);
   child1->SetUpdateRect(gfx::Rect(1, 1));
   root->layer_tree_impl()->property_trees()->needs_rebuild = true;
   EmulateDrawingOneFrame(root);
 
   root_damage_rect =
           root->render_surface()->damage_tracker()->current_damage_rect();
   // Damage on child1 should be: position of update_rect offset by the child's
   // position (100, 100), and expanded by the damage.
-  expected_damage_rect = gfx::Rect(100, 100, 1, 1);
 
-  expected_damage_rect.Inset(-outset_left,
-                             -outset_top,
-                             -outset_right,
-                             -outset_bottom);
+  // Damage should be (0,0 1x1), offset by the 100,100 offset of child1 in
+  // root, and expanded 6px for the 2px blur (i.e., 94,94 13x13), but there
+  // should be no damage outside child1 (i.e. none above or to the left of
+  // 100,100.
+  expected_damage_rect = gfx::Rect(100, 100, 7, 7);
   EXPECT_EQ(expected_damage_rect.ToString(), root_damage_rect.ToString());
 }
 
 TEST_F(DamageTrackerTest, VerifyDamageForAddingAndRemovingLayer) {
   LayerImpl* root = CreateAndSetUpTestTreeWithOneSurface();
   LayerImpl* child1 = root->children()[0];
 
   // CASE 1: Adding a new layer should cause the appropriate damage.
   //
   ClearDamageForAllSurfaces(root);
@@ skipping 801 matching lines @@
     gfx::Rect root_damage_rect =
         root->render_surface()->damage_tracker()->current_damage_rect();
     gfx::Rect damage_we_care_about = gfx::Rect(i, i);
     EXPECT_LE(damage_we_care_about.right(), root_damage_rect.right());
     EXPECT_LE(damage_we_care_about.bottom(), root_damage_rect.bottom());
   }
 }
 
 }  // namespace
 }  // namespace cc