Add luminance mask transfer modes.

include/core/SkXfermode.h

 
 /*
  * Copyright 2006 The Android Open Source Project
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 
 #ifndef SkXfermode_DEFINED
@@ skipping 109 matching lines @@
         kSoftLight_Mode,
         kDifference_Mode,
         kExclusion_Mode,
         kMultiply_Mode,
         kLastSeparableMode = kMultiply_Mode,
 
         kHue_Mode,
         kSaturation_Mode,
         kColor_Mode,
         kLuminosity_Mode,
-        kLastMode = kLuminosity_Mode
+
+        // Luminance mask modes, to support SVG & CSS luminance masks.
+        // http://www.w3.org/TR/SVG/masking.html#Masking
+        // http://www.w3.org/TR/css-masking/
+        kSrcInLum_Mode,

[reed1, 2013/08/20 17:21:35]

Can we initially introduce this xfermode w/o adding it to public SkXfermode.h's
enum? See SkArithmeticMode.h as an example.

+        kDstInLum_Mode,
+
+        kLastMode = kDstInLum_Mode
     };
 
     /**
      * Gets the name of the Mode as a string.
      */
     static const char* ModeName(Mode);
 
     /**
      *  If the xfermode is one of the modes in the Mode enum, then asMode()
      *  returns true and sets (if not null) mode accordingly. Otherwise it
@@ skipping 130 matching lines @@
         fProc = proc;
     }
 
 private:
     SkXfermodeProc  fProc;
 
     typedef SkXfermode INHERITED;
 };
 
 #endif