Optimize CMYK->RGBA (BGRA) transform for jpeg decodes

src/core/SkOpts.h

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkOpts_DEFINED
 #define SkOpts_DEFINED
 
@@ skipping 46 matching lines @@
 
     // Swizzle input into some sort of 8888 pixel, {premul,unpremul} x {rgba,bgra}.
     typedef void (*Swizzle_8888)(uint32_t*, const void*, int);
     extern Swizzle_8888 RGBA_to_BGRA,  // i.e. just swap RB
                         RGBA_to_rgbA,  // i.e. just premultiply
                         RGBA_to_bgrA,  // i.e. swap RB and premultiply
                         RGB_to_RGB1,   // i.e. insert an opaque alpha
                         RGB_to_BGR1,   // i.e. swap RB and insert an opaque alpha
                         gray_to_RGB1,  // i.e. expand to color channels + an opaque alpha
                         grayA_to_RGBA, // i.e. expand to color channels
-                        grayA_to_rgbA; // i.e. expand to color channels and premultiply
+                        grayA_to_rgbA, // i.e. expand to color channels and premultiply
+                        CMYK_to_RGB1,  // i.e. convert color space

[scroggo, 2016/02/08 14:59:43]

I know this isn't the first appearance of it, but what does the "1" mean in this
context?

[mtklein, 2016/02/08 15:08:47]

opaque.  the alpha channel is 1.

+                        CMYK_to_BGR1;  // i.e. convert color space
 }
 
 #endif//SkOpts_DEFINED