Fix overlooked bilerp fallback.

src/core/SkLinearBitmapPipeline.cpp

 /*
  * Copyright 2016 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkLinearBitmapPipeline.h"
 #include "SkPM4f.h"
 
@@ skipping 405 matching lines @@
         const Sk4f kXOffsets{-0.5f,  0.5f, -0.5f, 0.5f},
                    kYOffsets{-0.5f, -0.5f,  0.5f, 0.5f};
         fNext->bilerpList(Sk4s{xs[0]} + kXOffsets, Sk4s{ys[0]} + kYOffsets);
         fNext->bilerpList(Sk4s{xs[1]} + kXOffsets, Sk4s{ys[1]} + kYOffsets);
         fNext->bilerpList(Sk4s{xs[2]} + kXOffsets, Sk4s{ys[2]} + kYOffsets);
         fNext->bilerpList(Sk4s{xs[3]} + kXOffsets, Sk4s{ys[3]} + kYOffsets);
     }
 
     void pointSpan(Span span) override {
         SkASSERT(!span.isEmpty());
-        span_fallback(span, fNext);
+        SkPoint start; SkScalar length; int count;
+        std::tie(start, length, count) = span;
+        float dx = length / (count - 1);
+
+        Sk4f Xs = Sk4f{X(start)} + Sk4f{-0.5f,  0.5f, -0.5f, 0.5f};
+        Sk4f Ys = Sk4f{Y(start)} + Sk4f{-0.5f, -0.5f,  0.5f, 0.5f};
+
+        Sk4f dXs{dx};
+        while (count > 0) {
+            fNext->bilerpList(Xs, Ys);
+            Xs = Xs + dXs;

[mtklein_C, 2016/02/29 20:19:45]

Xs = Xs + dx

[herb_g, 2016/02/29 20:57:40]

Acknowledged.

+            count -= 1;
+        }
     }
 
 private:
     Next* const fNext;
 };
 
 static SkLinearBitmapPipeline::PointProcessorInterface* choose_filter(
     SkLinearBitmapPipeline::BilerpProcessorInterface* next,
     SkFilterQuality filterQuailty,
     SkLinearBitmapPipeline::FilterStage* filterProc) {
@@ skipping 497 matching lines @@
 
 void SkLinearBitmapPipeline::shadeSpan4f(int x, int y, SkPM4f* dst, int count) {
     SkASSERT(count > 0);
     fPixelStage->setDestination(dst);
     // The count and length arguments start out in a precise relation in order to keep the
     // math correct through the different stages. Count is the number of pixel to produce.
     // Since the code samples at pixel centers, length is the distance from the center of the
     // first pixel to the center of the last pixel. This implies that length is count-1.
     fFirstStage->pointSpan(Span{SkPoint{x + 0.5f, y + 0.5f}, count - 1.0f, count});
 }