lcd blits for sRGB

include/core/SkXfermode.h

Index: include/core/SkXfermode.h
diff --git a/include/core/SkXfermode.h b/include/core/SkXfermode.h
index 21d77f874768bcf03ef28607285377b55ab2b045..9e708ea319a87e32fdc614af65b98da834eeb9c9 100644
--- a/include/core/SkXfermode.h
+++ b/include/core/SkXfermode.h
@@ -248,6 +248,16 @@ public:
     static U64Proc1 GetU64Proc1(Mode, uint32_t flags);
     static U64ProcN GetU64ProcN(Mode, uint32_t flags);
 
+    enum LCD32Flags {
+        kSrcIsOpaque_LCDFlag    = 1 << 0,
+        kSrcIsSingle_LCDFlag    = 1 << 1,
+        kDstIsLinearInt_LCDFlag = 1 << 2,   // srgb or float

[mtklein, 2016/02/18 13:35:55]

LinearInt  // srgb or float?

What's Int mean here?  Maybe just kDstIsLinear?

[reed1, 2016/02/18 15:11:35]

Yea, incomplete comment. fixed.

[f(malita), 2016/02/18 15:37:14]

I take it "Int" here stands for interpolation?  kDstIsLinear_LCDFlag seems less
confusing to me too.

+    };
+    typedef void (*LCD32Proc)(uint32_t* dst, const SkPM4f* src, int count, const uint16_t lcd[]);
+    typedef void (*LCD64Proc)(uint64_t* dst, const SkPM4f* src, int count, const uint16_t lcd[]);
+    static LCD32Proc GetLCD32Proc(uint32_t flags);
+    static LCD64Proc GetLCD64Proc(uint32_t) { return nullptr; }
+
 protected:
     SkXfermode() {}
     /** The default implementation of xfer32/xfer16/xferA8 in turn call this