third_party/WebKit/Source/core/style/StyleDifference.h

   1 // Copyright 2014 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 StyleDifference_h
   6 #define StyleDifference_h
   7
   8 #include "wtf/Allocator.h"
   9 #include "wtf/Assertions.h"
  10
  11 namespace blink {
  12
  13 class StyleDifference {
  14     STACK_ALLOCATED();
  15 public:
  16     enum PropertyDifference {
  17         TransformChanged = 1 << 0,
  18         OpacityChanged = 1 << 1,
  19         ZIndexChanged = 1 << 2,
  20         FilterChanged = 1 << 3,
  21         BackdropFilterChanged = 1 << 4,
  22         // The object needs to issue paint invalidations if it contains text or properties dependent on color (e.g., border or outline).
  23         TextOrColorChanged = 1 << 5,
  24         // If you add a value here, be sure to update the number of bits on m_propertySpecificDifferences.
  25     };
  26
  27     StyleDifference()
  28         : m_paintInvalidationType(NoPaintInvalidation)
  29         , m_layoutType(NoLayout)
  30         , m_propertySpecificDifferences(0)
  31     { }
  32
  33     bool hasDifference() const { return m_paintInvalidationType || m_layoutType || m_propertySpecificDifferences; }
  34
  35     bool hasAtMostPropertySpecificDifferences(unsigned propertyDifferences) const
  36     {
  37         return !m_paintInvalidationType && !m_layoutType && !(m_propertySpecificDifferences & ~propertyDifferences);
  38     }
  39
  40     bool needsPaintInvalidation() const { return m_paintInvalidationType != NoPaintInvalidation; }
  41     void clearNeedsPaintInvalidation() { m_paintInvalidationType = NoPaintInvalidation; }
  42
  43     // The object just needs to issue paint invalidations.
  44     bool needsPaintInvalidationObject() const { return m_paintInvalidationType == PaintInvalidationObject; }
  45     void setNeedsPaintInvalidationObject()
  46     {
  47         ASSERT(!needsPaintInvalidationLayer());
  48         m_paintInvalidationType = PaintInvalidationObject;
  49     }
  50
  51     // The layer and its descendant layers need to issue paint invalidations.
  52     bool needsPaintInvalidationLayer() const { return m_paintInvalidationType == PaintInvalidationLayer; }
  53     void setNeedsPaintInvalidationLayer() { m_paintInvalidationType = PaintInvalidationLayer; }
  54
  55     bool needsLayout() const { return m_layoutType != NoLayout; }
  56     void clearNeedsLayout() { m_layoutType = NoLayout; }
  57
  58     // The offset of this positioned object has been updated.
  59     bool needsPositionedMovementLayout() const { return m_layoutType == PositionedMovement; }
  60     void setNeedsPositionedMovementLayout()
  61     {
  62         ASSERT(!needsFullLayout());
  63         m_layoutType = PositionedMovement;
  64     }
  65
  66     bool needsFullLayout() const { return m_layoutType == FullLayout; }
  67     void setNeedsFullLayout() { m_layoutType = FullLayout; }
  68
  69     bool transformChanged() const { return m_propertySpecificDifferences & TransformChanged; }
  70     void setTransformChanged() { m_propertySpecificDifferences |= TransformChanged; }
  71
  72     bool opacityChanged() const { return m_propertySpecificDifferences & OpacityChanged; }
  73     void setOpacityChanged() { m_propertySpecificDifferences |= OpacityChanged; }
  74
  75     bool zIndexChanged() const { return m_propertySpecificDifferences & ZIndexChanged; }
  76     void setZIndexChanged() { m_propertySpecificDifferences |= ZIndexChanged; }
  77
  78     bool filterChanged() const { return m_propertySpecificDifferences & FilterChanged; }
  79     void setFilterChanged() { m_propertySpecificDifferences |= FilterChanged; }
  80
  81     bool backdropFilterChanged() const { return m_propertySpecificDifferences & BackdropFilterChanged; }
  82     void setBackdropFilterChanged() { m_propertySpecificDifferences |= BackdropFilterChanged; }
  83
  84     bool textOrColorChanged() const { return m_propertySpecificDifferences & TextOrColorChanged; }
  85     void setTextOrColorChanged() { m_propertySpecificDifferences |= TextOrColorChanged; }
  86
  87 private:
  88     enum PaintInvalidationType {
  89         NoPaintInvalidation = 0,
  90         PaintInvalidationObject,
  91         PaintInvalidationLayer
  92     };
  93     unsigned m_paintInvalidationType : 2;
  94
  95     enum LayoutType {
  96         NoLayout = 0,
  97         PositionedMovement,
  98         FullLayout
  99     };
 100     unsigned m_layoutType : 2;
 101
 102     unsigned m_propertySpecificDifferences : 6;
 103 };
 104
 105 } // namespace blink
 106
 107 #endif // StyleDifference_h