Add flipped gradient branch to two point conical gradient

src/effects/gradients/SkGradientShader.cpp

Index: src/effects/gradients/SkGradientShader.cpp
diff --git a/src/effects/gradients/SkGradientShader.cpp b/src/effects/gradients/SkGradientShader.cpp
index 3547fbec94f4e372c5ee3dc70e7c0bd4a03effdd..b54971954e11a6ce97083878a49e46f613c9997f 100644
--- a/src/effects/gradients/SkGradientShader.cpp
+++ b/src/effects/gradients/SkGradientShader.cpp
@@ -203,6 +203,20 @@ void SkGradientShaderBase::flatten(SkWriteBuffer& buffer) const {
     buffer.writeMatrix(fPtsToUnit);
 }
 
+// V23_COMPATIBILITY_CODE
+void SkGradientShaderBase::flipGradientColors() {
+    SkColor colorsTemp[fColorCount];
+    Rec recsTemp[fColorCount];
+    for (int i = 0; i < fColorCount; ++i) {
+        int offset = fColorCount - i - 1;
+        colorsTemp[i] = fOrigColors[offset];
+        recsTemp[i].fPos = 1 - fRecs[offset].fPos;
+        recsTemp[i].fScale = fRecs[offset].fScale;
+    }
+    memcpy(fOrigColors, colorsTemp, fColorCount * sizeof(SkColor));
+    memcpy(fRecs, recsTemp, fColorCount * sizeof(Rec));
+}
+
 bool SkGradientShaderBase::isOpaque() const {
     return fColorsAreOpaque;
 }
@@ -793,12 +807,36 @@ SkShader* SkGradientShader::CreateTwoPointConical(const SkPoint& start,
     if (start == end && startRadius == endRadius) {
         return SkNEW(SkEmptyShader);
     }
+
     EXPAND_1_COLOR(colorCount);
 
+    bool flipGradient = startRadius > endRadius;
+
     SkGradientShaderBase::Descriptor desc;
-    desc_init(&desc, colors, pos, colorCount, mode, mapper, flags);
-    return SkNEW_ARGS(SkTwoPointConicalGradient,
-                      (start, startRadius, end, endRadius, desc));
+
+    if (!flipGradient) {
+        desc_init(&desc, colors, pos, colorCount, mode, mapper, flags);
+        return SkNEW_ARGS(SkTwoPointConicalGradient,
+                          (start, startRadius, end, endRadius, flipGradient, desc));
+    } else {
+        SkColor colorsNew[colorCount];

[bsalomon, 2014/04/16 19:12:56]

woah.. this looks like a compiler extension. colorCount isn't a compile time
constant.

[mtklein, 2014/04/16 19:20:50]

Yeah, this will be more or less supported depending on the compiler.  It's a C99
feature, and may make it into C++17.  I actually like it, but we can't write it.
 If nothing else, it's safer than alloca...

+        SkScalar posNew[colorCount];
+        for (int i = 0; i < colorCount; ++i) {
+            colorsNew[i] = colors[colorCount - i - 1];
+        }
+
+        if (pos) {
+            for (int i = 0; i < colorCount; ++i) {
+                posNew[i] = 1 - pos[colorCount - i - 1];
+            }
+            desc_init(&desc, colorsNew, posNew, colorCount, mode, mapper, flags);
+        } else {
+            desc_init(&desc, colorsNew, NULL, colorCount, mode, mapper, flags);
+        }
+
+        return SkNEW_ARGS(SkTwoPointConicalGradient,
+                          (end, endRadius, start, startRadius, flipGradient, desc));
+    }
 }
 
 SkShader* SkGradientShader::CreateSweep(SkScalar cx, SkScalar cy,