implement SkRasterPipelineBlitter::blitAntiH2()

The default blitAntiH2() calls blitAntiH() with two length-1 runs, but
for this blitter creating a small mask is better.  We can stamp both
pixels out with a single pipeline invocation.

Change-Id: If356975e85310a4545e54f2231a142d6e537944d
Reviewed-on: https://skia-review.googlesource.com/18581
Reviewed-by: Mike Reed <reed@google.com>

1 files changed, 17 insertions, 3 deletions

diff --git a/src/core/SkRasterPipelineBlitter.cpp b/src/core/SkRasterPipelineBlitter.cpp
index 3d60d756f6..cba39f021d 100644
--- a/src/core/SkRasterPipelineBlitter.cpp
+++ b/src/core/SkRasterPipelineBlitter.cpp
@@ -36,9 +36,10 @@ public:
         , fColorPipeline(alloc)
     {}
 
-    void blitH    (int x, int y, int w)                            override;
-    void blitAntiH(int x, int y, const SkAlpha[], const int16_t[]) override;
-    void blitMask (const SkMask&, const SkIRect& clip)             override;
+    void blitH     (int x, int y, int w)                            override;
+    void blitAntiH (int x, int y, const SkAlpha[], const int16_t[]) override;
+    void blitAntiH2(int x, int y, U8CPU a0, U8CPU a1)               override;
+    void blitMask  (const SkMask&, const SkIRect& clip)             override;
 
     // TODO: The default implementations of the other blits look fine,
     // but some of them like blitV could probably benefit from custom
@@ -316,6 +317,19 @@ void SkRasterPipelineBlitter::blitAntiH(int x, int y, const SkAlpha aa[], const
     }
 }
 
+void SkRasterPipelineBlitter::blitAntiH2(int x, int y, U8CPU a0, U8CPU a1) {
+    SkIRect clip = {x,y, x+2,y+1};
+    uint8_t coverage[] = { (uint8_t)a0, (uint8_t)a1 };
+
+    SkMask mask;
+    mask.fImage    = coverage;
+    mask.fBounds   = clip;
+    mask.fRowBytes = 2;
+    mask.fFormat   = SkMask::kA8_Format;
+
+    this->blitMask(mask, clip);
+}
+
 void SkRasterPipelineBlitter::blitMask(const SkMask& mask, const SkIRect& clip) {
     if (mask.fFormat == SkMask::kBW_Format) {
         // TODO: native BW masks?