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// 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.
#ifndef CC_TREES_DAMAGE_TRACKER_H_
#define CC_TREES_DAMAGE_TRACKER_H_
#include <vector>
#include "base/containers/hash_tables.h"
#include "base/memory/scoped_ptr.h"
#include "cc/base/cc_export.h"
#include "cc/layers/layer_lists.h"
#include "ui/gfx/rect_f.h"
class SkImageFilter;
namespace gfx {
class Rect;
}
namespace cc {
class FilterOperations;
class LayerImpl;
class RenderSurfaceImpl;
// Computes the region where pixels have actually changed on a
// RenderSurfaceImpl. This region is used to scissor what is actually drawn to
// the screen to save GPU computation and bandwidth.
class CC_EXPORT DamageTracker {
public:
static scoped_ptr<DamageTracker> Create();
~DamageTracker();
void DidDrawDamagedArea() { current_damage_rect_ = gfx::RectF(); }
void AddDamageNextUpdate(gfx::RectF dmg) { current_damage_rect_.Union(dmg); }
void UpdateDamageTrackingState(
const LayerImplList& layer_list,
int target_surface_layer_id,
bool target_surface_property_changed_only_from_descendant,
gfx::Rect target_surface_content_rect,
LayerImpl* target_surface_mask_layer,
const FilterOperations& filters,
SkImageFilter* filter);
gfx::RectF current_damage_rect() { return current_damage_rect_; }
private:
DamageTracker();
gfx::RectF TrackDamageFromActiveLayers(
const LayerImplList& layer_list,
int target_surface_layer_id);
gfx::RectF TrackDamageFromSurfaceMask(LayerImpl* target_surface_mask_layer);
gfx::RectF TrackDamageFromLeftoverRects();
gfx::RectF RemoveRectFromCurrentFrame(int layer_id, bool* layer_is_new);
void SaveRectForNextFrame(int layer_id, const gfx::RectF& target_space_rect);
// These helper functions are used only in TrackDamageFromActiveLayers().
void ExtendDamageForLayer(LayerImpl* layer, gfx::RectF* target_damage_rect);
void ExtendDamageForRenderSurface(LayerImpl* layer,
gfx::RectF* target_damage_rect);
// To correctly track exposed regions, two hashtables of rects are maintained.
// The "current" map is used to compute exposed regions of the current frame,
// while the "next" map is used to collect layer rects that are used in the
// next frame.
typedef base::hash_map<int, gfx::RectF> RectMap;
scoped_ptr<RectMap> current_rect_history_;
scoped_ptr<RectMap> next_rect_history_;
gfx::RectF current_damage_rect_;
DISALLOW_COPY_AND_ASSIGN(DamageTracker);
};
} // namespace cc
#endif // CC_TREES_DAMAGE_TRACKER_H_
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