make explicit the requirement that all colorfilters are reentrant-safe

BUG=
R=mtklein@google.com

Review URL: https://codereview.chromium.org/26876002

git-svn-id: http://skia.googlecode.com/svn/trunk@11705 2bbb7eff-a529-9590-31e7-b0007b416f81

2 files changed, 18 insertions, 7 deletions

diff --git a/include/core/SkColorFilter.h b/include/core/SkColorFilter.h
index 6359563d51..46ecedc6df 100644
--- a/include/core/SkColorFilter.h
+++ b/include/core/SkColorFilter.h
@@ -18,6 +18,14 @@ class SkBitmap;
 class GrEffectRef;
 class GrContext;
 
+/**
+ *  ColorFilters are optional objects in the drawing pipeline. When present in
+ *  a paint, they are called with the "src" colors, and return new colors, which
+ *  are then passed onto the next stage (either ImageFilter or Xfermode).
+ *
+ *  All subclasses are required to be reentrant-safe : it must be legal to share
+ *  the same instance between several threads.
+ */
 class SK_API SkColorFilter : public SkFlattenable {
 public:
     SK_DECLARE_INST_COUNT(SkColorFilter)
diff --git a/include/core/SkXfermode.h b/include/core/SkXfermode.h
index ed07bd5821..f4df226950 100644
--- a/include/core/SkXfermode.h
+++ b/include/core/SkXfermode.h
@@ -19,13 +19,16 @@ class GrTexture;
 class SkString;
 
 /** \class SkXfermode
-
-    SkXfermode is the base class for objects that are called to implement custom
-    "transfer-modes" in the drawing pipeline. The static function Create(Modes)
-    can be called to return an instance of any of the predefined subclasses as
-    specified in the Modes enum. When an SkXfermode is assigned to an SkPaint,
-    then objects drawn with that paint have the xfermode applied.
-*/
+ *
+ *  SkXfermode is the base class for objects that are called to implement custom
+ *  "transfer-modes" in the drawing pipeline. The static function Create(Modes)
+ *  can be called to return an instance of any of the predefined subclasses as
+ *  specified in the Modes enum. When an SkXfermode is assigned to an SkPaint,
+ *  then objects drawn with that paint have the xfermode applied.
+ *
+ *  All subclasses are required to be reentrant-safe : it must be legal to share
+ *  the same instance between several threads.
+ */
 class SK_API SkXfermode : public SkFlattenable {
 public:
     SK_DECLARE_INST_COUNT(SkXfermode)