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 "base/memory/scoped_ptr.h"
  10 #include "ui/compositor/compositor_export.h"
  11 #include "ui/gfx/geometry/rect.h"
  12
  13 namespace cc {
  14 class DisplayItemList;
  15 }
  16
  17 namespace gfx {
  18 class Canvas;
  19 }
  20
  21 class SkPictureRecorder;
  22
  23 namespace ui {
  24 class ClipTransformRecorder;
  25 class CompositingRecorder;
  26 class PaintRecorder;
  27
  28 class COMPOSITOR_EXPORT PaintContext {
  29  public:
  30   // Construct a PaintContext that may only re-paint the area in the
  31   // |invalidation|.
  32   PaintContext(cc::DisplayItemList* list,
  33                float device_scale_factor,
  34                const gfx::Rect& invalidation);
  35
  36   // Clone a PaintContext with an additional |offset|.
  37   PaintContext(const PaintContext& other, const gfx::Vector2d& offset);
  38
  39   // Clone a PaintContext that has no consideration for invalidation.
  40   enum CloneWithoutInvalidation {
  41     CLONE_WITHOUT_INVALIDATION,
  42   };
  43   PaintContext(const PaintContext& other, CloneWithoutInvalidation c);
  44
  45   ~PaintContext();
  46
  47   // When true, IsRectInvalid() can be called, otherwise its result would be
  48   // invalid.
  49   bool CanCheckInvalid() const { return !invalidation_.IsEmpty(); }
  50
  51   // When true, the |bounds| touches an invalidated area, so should be
  52   // re-painted. When false, re-painting can be skipped. Bounds should be in
  53   // the local space with offsets up to the painting root in the PaintContext.
  54   bool IsRectInvalid(const gfx::Rect& bounds) const {
  55     DCHECK(CanCheckInvalid());
  56     return invalidation_.Intersects(bounds + offset_);
  57   }
  58
  59 #if DCHECK_IS_ON()
  60   void Visited(void* visited) const {
  61     if (!root_visited_)
  62       root_visited_ = visited;
  63   }
  64   void* RootVisited() const { return root_visited_; }
  65   const gfx::Vector2d& PaintOffset() const { return offset_; }
  66 #endif
  67
  68   const gfx::Rect& InvalidationForTesting() const { return invalidation_; }
  69
  70  private:
  71   // The Recorder classes need access to the internal canvas and friends, but we
  72   // don't want to expose them on this class so that people must go through the
  73   // recorders to access them.
  74   friend class ClipTransformRecorder;
  75   friend class CompositingRecorder;
  76   friend class PaintRecorder;
  77   // The Cache class also needs to access the DisplayItemList to append its
  78   // cache contents.
  79   friend class PaintCache;
  80
  81   cc::DisplayItemList* list_;
  82   scoped_ptr<SkPictureRecorder> owned_recorder_;
  83   // A pointer to the |owned_recorder_| in this PaintContext, or in another one
  84   // which this was copied from. We expect a copied-from PaintContext to outlive
  85   // copies made from it.
  86   SkPictureRecorder* recorder_;
  87   // The device scale of the frame being painted. Used to determine which bitmap
  88   // resources to use in the frame.
  89   float device_scale_factor_;
  90   // Invalidation in the space of the paint root (ie the space of the layer
  91   // backing the paint taking place).
  92   gfx::Rect invalidation_;
  93   // Offset from the PaintContext to the space of the paint root and the
  94   // |invalidation_|.
  95   gfx::Vector2d offset_;
  96
  97 #if DCHECK_IS_ON()
  98   // Used to verify that the |invalidation_| is only used to compare against
  99   // rects in the same space.
 100   mutable void* root_visited_;
 101   // Used to verify that paint recorders are not nested. True while a paint
 102   // recorder is active.
 103   mutable bool inside_paint_recorder_;
 104 #endif
 105
 106   DISALLOW_COPY_AND_ASSIGN(PaintContext);
 107 };
 108
 109 }  // namespace ui
 110
 111 #endif  // UI_COMPOSITOR_PAINT_CONTEXT_H_