Improvement handling of background and outline paint phases

third_party/WebKit/Source/core/paint/PaintPhase.h

 /*
  * Copyright (C) 2000 Lars Knoll (knoll@kde.org)
  *           (C) 2000 Antti Koivisto (koivisto@kde.org)
  *           (C) 2000 Dirk Mueller (mueller@kde.org)
  *           (C) 2004 Allan Sandfeld Jensen (kde@carewolf.com)
  * Copyright (C) 2003, 2004, 2005, 2006, 2007, 2008, 2009 Apple Inc. All rights reserved.
  * Copyright (C) 2009 Google Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
@@ skipping 32 matching lines @@
     // Background phase
     //
     // Paint background of the current object and non-self-painting descendants.
     PaintPhaseBlockBackground = 0,
     //
     // The following two values are added besides the normal PaintPhaseBlockBackground
     // to distinguish backgrounds for the object itself and for descendants, because
     // the two backgrounds are often painted with different scroll offsets and clips.
     //
     // Paint background of the current object only.
-    PaintPhaseSelfBlockBackground = 1,
+    PaintPhaseSelfBlockBackgroundOnly = 1,
     // Paint backgrounds of non-self-painting descendants only. The painter should call
     // each non-self-painting child's paint method by passing paintInfo.forDescendants() which
-    // converts PaintPhaseDescendantsBlockBackgrounds to PaintPhaseBlockBackground.
-    PaintPhaseDescendantBlockBackgrounds = 2,
+    // converts PaintPhaseDescendantsBlockBackgroundsOnly to PaintPhaseBlockBackground.
+    PaintPhaseDescendantBlockBackgroundsOnly = 2,
 
     // Float phase
     PaintPhaseFloat = 3,
 
     // Foreground phase
     PaintPhaseForeground = 4,
 
     // Outline phase
     //
     // Paint outline for the current object and non-self-painting descendants.
     PaintPhaseOutline = 5,
     //
     // Similar to the background phase, the following two values are added for painting
     // outlines of the object itself and for descendants.
     //
     // Paint outline for the current object only.
-    PaintPhaseSelfOutline = 6,
+    PaintPhaseSelfOutlineOnly = 6,
     // Paint outlines of non-self-painting descendants only. The painter should call each
     // non-self-painting child's paint method by passing paintInfo.forDescendants() which
-    // converts PaintPhaseDescendantsOutliness to PaintPhaseBlockOutline.
-    PaintPhaseDescendantOutlines = 7,
+    // converts PaintPhaseDescendantsOutlinesOnly to PaintPhaseBlockOutline.
+    PaintPhaseDescendantOutlinesOnly = 7,
 
     // The below are auxiliary phases which are used to paint special effects.
     PaintPhaseSelection = 8,
     PaintPhaseTextClip = 9,
     PaintPhaseMask = 10,
     PaintPhaseClippingMask = 11,
 
     PaintPhaseMax = PaintPhaseClippingMask,
     // These values must be kept in sync with DisplayItem::Type and DisplayItem::typeAsDebugString().
 };
 
+inline bool shouldPaintSelfBlockBackground(PaintPhase phase)
+{
+    return phase == PaintPhaseBlockBackground || phase == PaintPhaseSelfBlockBackgroundOnly;

[pdr., 2016/01/14 19:56:45]

(not for this patch) We might want to consider using a mask here for
performance, instead of two conditionals.

[Xianzhu, 2016/01/15 01:05:33]

Thought of this but it will cause difficulties to synchronize between PaintPhase
and DisplayItem::Type. Perhaps we should consider to move PaintPhase.h to
Source/platform/graphics/paint?

+}
+
+inline bool shouldPaintSelfOutline(PaintPhase phase)
+{
+    return phase == PaintPhaseOutline || phase == PaintPhaseSelfOutlineOnly;
+}
+
+inline bool shouldPaintDescendantBlockBackgrounds(PaintPhase phase)
+{
+    return phase == PaintPhaseBlockBackground || phase == PaintPhaseDescendantBlockBackgroundsOnly;
+}
+
+inline bool shouldPaintDescendantOutlines(PaintPhase phase)
+{
+    return phase == PaintPhaseOutline || phase == PaintPhaseDescendantOutlinesOnly;
+}
+
 // Those flags are meant as global tree operations. This means
 // that they should be constant for a paint phase.
 enum GlobalPaintFlag {
     GlobalPaintNormalPhase = 0,
     // Used when painting selection as part of a drag-image. This
     // flag disables a lot of the painting code and specifically
     // triggers a PaintPhaseSelection.
     GlobalPaintSelectionOnly = 1 << 0,
     // Used when painting a drag-image or printing in order to
     // ignore the hardware layers and paint the whole tree
     // into the topmost layer.
     GlobalPaintFlattenCompositingLayers = 1 << 1,
     // Used when printing in order to adapt the output to the medium, for
     // instance by not painting shadows and selections on text, and add
     // URL metadata for links.
     GlobalPaintPrinting = 1 << 2
 };
 
 typedef unsigned GlobalPaintFlags;
 
 } // namespace blink
 
 #endif // PaintPhase_h