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/gfx/geometry/rect.h"
  10
  11 namespace gfx {
  12 class Canvas;
  13 }
  14
  15 namespace ui {
  16 class PaintRecorder;
  17
  18 class PaintContext {
  19  public:
  20   // Construct a PaintContext that can only re-paint the area in the
  21   // |invalidation|.
  22   PaintContext(gfx::Canvas* canvas, const gfx::Rect& invalidation)
  23       : canvas_(canvas), invalidation_(invalidation) {
  24 #if DCHECK_IS_ON()
  25     root_visited_ = nullptr;
  26 #endif
  27   }
  28
  29   // Construct a PaintContext that will re-paint everything (no consideration
  30   // for invalidation).
  31   explicit PaintContext(gfx::Canvas* canvas)
  32       : PaintContext(canvas, gfx::Rect()) {}
  33
  34   ~PaintContext() {}
  35
  36   // Clone a PaintContext with an additional |offset|.
  37   PaintContext CloneWithPaintOffset(const gfx::Vector2d& offset) const {
  38     return PaintContext(*this, offset);
  39   }
  40
  41   // Clone a PaintContext that has no consideration for invalidation.
  42   PaintContext CloneWithoutInvalidation() const {
  43     return PaintContext(canvas_);
  44   }
  45
  46   // TODO(danakj): Remove this once everything is painting to display lists.
  47   gfx::Canvas* canvas() const { return canvas_; }
  48
  49   // When true, IsRectInvalidated() can be called, otherwise its result would be
  50   // invalid.
  51   bool CanCheckInvalidated() const { return !invalidation_.IsEmpty(); }
  52
  53   // When true, the |bounds| touches an invalidated area, so should be
  54   // re-painted. When false, re-painting can be skipped. Bounds should be in
  55   // the local space with offsets up to the painting root in the PaintContext.
  56   bool IsRectInvalidated(const gfx::Rect& bounds) const {
  57     DCHECK(CanCheckInvalidated());
  58     return invalidation_.Intersects(bounds + offset_);
  59   }
  60
  61 #if DCHECK_IS_ON()
  62   void Visited(void* visited) const {
  63     if (!root_visited_)
  64       root_visited_ = visited;
  65   }
  66   void* RootVisited() const { return root_visited_; }
  67   const gfx::Vector2d& PaintOffset() const { return offset_; }
  68 #endif
  69
  70   const gfx::Rect& InvalidationForTesting() const { return invalidation_; }
  71
  72  private:
  73   // The PaintRecorder needs access to the internal canvas and friends, but we
  74   // don't want to expose them on this class so that people must go through the
  75   // recorder to access them.
  76   friend class PaintRecorder;
  77
  78   // Clone a PaintContext with an additional |offset|.
  79   PaintContext(const PaintContext& other, const gfx::Vector2d& offset)
  80       : canvas_(other.canvas_),
  81         invalidation_(other.invalidation_),
  82         offset_(other.offset_ + offset) {
  83 #if DCHECK_IS_ON()
  84     root_visited_ = other.root_visited_;
  85 #endif
  86   }
  87
  88   gfx::Canvas* canvas_;
  89   // Invalidation in the space of the paint root (ie the space of the layer
  90   // backing the paint taking place).
  91   gfx::Rect invalidation_;
  92   // Offset from the PaintContext to the space of the paint root and the
  93   // |invalidation_|.
  94   gfx::Vector2d offset_;
  95
  96 #if DCHECK_IS_ON()
  97   // Used to verify that the |invalidation_| is only used to compare against
  98   // rects in the same space.
  99   mutable void* root_visited_;
 100 #endif
 101 };
 102
 103 }  // namespace ui
 104
 105 #endif  // UI_COMPOSITOR_PAINT_CONTEXT_H_