ui/compositor/paint_context.h

   1 // Copyright 2015 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #ifndef UI_COMPOSITOR_PAINT_CONTEXT_H_
   6 #define UI_COMPOSITOR_PAINT_CONTEXT_H_
   7
   8 #include "base/logging.h"
   9 #include "ui/compositor/compositor_export.h"
  10 #include "ui/gfx/geometry/rect.h"
  11
  12 namespace cc {
  13 class DisplayItemList;
  14 }
  15
  16 namespace gfx {
  17 class Canvas;
  18 }
  19
  20 namespace ui {
  21 class ClipTransformRecorder;
  22 class CompositingRecorder;
  23 class PaintRecorder;
  24
  25 class COMPOSITOR_EXPORT PaintContext {
  26  public:
  27   // Construct a PaintContext that may only re-paint the area in the
  28   // |invalidation|.
  29   PaintContext(gfx::Canvas* canvas, const gfx::Rect& invalidation);
  30
  31   // Construct a PaintContext that may only re-paint the area in the
  32   // |invalidation|.
  33   PaintContext(cc::DisplayItemList* list,
  34                float device_scale_factor,
  35                const gfx::Rect& bounds,
  36                const gfx::Rect& invalidation);
  37
  38   // Construct a PaintContext that will re-paint everything (no consideration
  39   // for invalidation).
  40   explicit PaintContext(gfx::Canvas* canvas);
  41
  42   PaintContext(const PaintContext& other);
  43
  44   ~PaintContext();
  45
  46   // Clone a PaintContext with an additional |offset|.
  47   PaintContext CloneWithPaintOffset(const gfx::Vector2d& offset) const {
  48     return PaintContext(*this, offset);
  49   }
  50
  51   // Clone a PaintContext that has no consideration for invalidation.
  52   PaintContext CloneWithoutInvalidation() const {
  53     return PaintContext(canvas_);
  54   }
  55
  56   // When true, IsRectInvalidated() can be called, otherwise its result would be
  57   // invalid.
  58   bool CanCheckInvalidated() const { return !invalidation_.IsEmpty(); }
  59
  60   // When true, the |bounds| touches an invalidated area, so should be
  61   // re-painted. When false, re-painting can be skipped. Bounds should be in
  62   // the local space with offsets up to the painting root in the PaintContext.
  63   bool IsRectInvalidated(const gfx::Rect& bounds) const {
  64     DCHECK(CanCheckInvalidated());
  65     return invalidation_.Intersects(bounds + offset_);
  66   }
  67
  68 #if DCHECK_IS_ON()
  69   void Visited(void* visited) const {
  70     if (!root_visited_)
  71       root_visited_ = visited;
  72   }
  73   void* RootVisited() const { return root_visited_; }
  74   const gfx::Vector2d& PaintOffset() const { return offset_; }
  75 #endif
  76
  77   const gfx::Rect& InvalidationForTesting() const { return invalidation_; }
  78
  79  private:
  80   // The Recorder classes need access to the internal canvas and friends, but we
  81   // don't want to expose them on this class so that people must go through the
  82   // recorders to access them.
  83   friend class ClipTransformRecorder;
  84   friend class CompositingRecorder;
  85   friend class PaintRecorder;
  86
  87   PaintContext& operator=(const PaintContext& other) = delete;
  88
  89   // Clone a PaintContext with an additional |offset|.
  90   PaintContext(const PaintContext& other, const gfx::Vector2d& offset);
  91
  92   gfx::Canvas* canvas_;
  93   cc::DisplayItemList* list_;
  94   float device_scale_factor_;
  95   // The bounds of the area being painted. Not all of it may be invalidated from
  96   // the previous frame.
  97   gfx::Rect bounds_;
  98   // Invalidation in the space of the paint root (ie the space of the layer
  99   // backing the paint taking place).
 100   gfx::Rect invalidation_;
 101   // Offset from the PaintContext to the space of the paint root and the
 102   // |invalidation_|.
 103   gfx::Vector2d offset_;
 104
 105 #if DCHECK_IS_ON()
 106   // Used to verify that the |invalidation_| is only used to compare against
 107   // rects in the same space.
 108   mutable void* root_visited_;
 109 #endif
 110 };
 111
 112 }  // namespace ui
 113
 114 #endif  // UI_COMPOSITOR_PAINT_CONTEXT_H_