lcd blits for sRGB

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 230 matching lines @@
         const SkXfermode* fXfer;
         uint32_t          fFlags;
     };
     typedef void (*U64Proc1)(const U64State&, uint64_t dst[], const SkPM4f& src, int count,
                              const SkAlpha coverage[]);
     typedef void (*U64ProcN)(const U64State&, uint64_t dst[], const SkPM4f src[], int count,
                              const SkAlpha coverage[]);
     static U64Proc1 GetU64Proc1(Mode, uint32_t flags);
     static U64ProcN GetU64ProcN(Mode, uint32_t flags);
 
+    enum LCDFlags {
+        kSrcIsOpaque_LCDFlag    = 1 << 0,   // else src(s) may have alpha < 1
+        kSrcIsSingle_LCDFlag    = 1 << 1,   // else src[count]
+        kDstIsLinearInt_LCDFlag = 1 << 2,   // else srgb/half-float

[mtklein, 2016/02/18 16:10:20]

Ah,

  IsLinearInt -> u32 == 8888, u64 = 16161616
 !IsLinearInt -> u32 == sRGB, u64 = hhhh

?

Guess this is so confusing because 3 of the destination options are int,
3 of the options are linear.

+    };
+    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
         method, 1 color at a time (upscaled to a SkPMColor). The default
         implementation of this method just returns dst. If performance is
         important, your subclass should override xfer32/xfer16/xferA8 directly.
 
         This method will not be called directly by the client, so it need not
         be implemented if your subclass has overridden xfer32/xfer16/xferA8
     */
     virtual SkPMColor xferColor(SkPMColor src, SkPMColor dst) const;
 
 private:
     enum {
         kModeCount = kLastMode + 1
     };
 
     typedef SkFlattenable INHERITED;
 };
 
 #endif