add helper static to SkColorSpaceXform

Bug: skia:
Change-Id: I62525b392dfbae3d7075cf7f14e30780bad41279
Reviewed-on: https://skia-review.googlesource.com/17485
Reviewed-by: Matt Sarett <msarett@google.com>
Commit-Queue: Mike Reed <reed@google.com>

1 files changed, 9 insertions, 0 deletions

diff --git a/include/core/SkColorSpaceXform.h b/include/core/SkColorSpaceXform.h
index ccd36bc128..1e761a9b7f 100644
--- a/include/core/SkColorSpaceXform.h
+++ b/include/core/SkColorSpaceXform.h
@@ -60,6 +60,15 @@ public:
 
     virtual ~SkColorSpaceXform() {}
 
+    enum AlphaOp {
+        kPreserve_AlphaOp,      // just transfer src-alpha to dst-alpha
+        kPremul_AlphaOp,        // like kPreserve, but multiplies RGB by it
+        kSrcIsOpaque_AlphaOp,   // src alphas are all 1, this is a perf hint
+    };
+    static bool Apply(SkColorSpace* dstCS, ColorFormat dstFormat, void* dst,
+                      SkColorSpace* srcCS, ColorFormat srcFormat, const void* src,
+                      int count, AlphaOp);
+
 protected:
     SkColorSpaceXform() {}
 };