Fix for crash on large image blur sigma values.

src/effects/SkGpuBlurUtils.cpp

 /*
  * Copyright 2013 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkGpuBlurUtils.h"
 
 #include "SkRect.h"
@@ skipping 10 matching lines @@
 
 #define MAX_BLUR_SIGMA 4.0f
 
 static void scale_rect(SkRect* rect, float xScale, float yScale) {
     rect->fLeft   = SkScalarMul(rect->fLeft,   xScale);
     rect->fTop    = SkScalarMul(rect->fTop,    yScale);
     rect->fRight  = SkScalarMul(rect->fRight,  xScale);
     rect->fBottom = SkScalarMul(rect->fBottom, yScale);
 }
 
-static float adjust_sigma(float sigma, int *scaleFactor, int *radius) {
+static float adjust_sigma(float sigma, int maxTextureSize, int *scaleFactor, int *radius) {
     *scaleFactor = 1;
     while (sigma > MAX_BLUR_SIGMA) {
         *scaleFactor *= 2;
         sigma *= 0.5f;
+        if (*scaleFactor > maxTextureSize) {
+            *scaleFactor = maxTextureSize;
+            sigma = MAX_BLUR_SIGMA;
+        }
     }
     *radius = static_cast<int>(ceilf(sigma * 3.0f));
     SkASSERT(*radius <= GrConvolutionEffect::kMaxKernelRadius);
     return sigma;
 }
 
 static void convolve_gaussian_pass(GrContext* context,
                                    const SkRect& srcRect,
                                    const SkRect& dstRect,
                                    GrTexture* texture,
@@ skipping 76 matching lines @@
     SkASSERT(NULL != context);
 
     GrContext::AutoRenderTarget art(context);
 
     GrContext::AutoMatrix am;
     am.setIdentity(context);
 
     SkIRect clearRect;
     int scaleFactorX, radiusX;
     int scaleFactorY, radiusY;
-    sigmaX = adjust_sigma(sigmaX, &scaleFactorX, &radiusX);
-    sigmaY = adjust_sigma(sigmaY, &scaleFactorY, &radiusY);
+    int maxTextureSize = context->getMaxTextureSize();
+    sigmaX = adjust_sigma(sigmaX, maxTextureSize, &scaleFactorX, &radiusX);
+    sigmaY = adjust_sigma(sigmaY, maxTextureSize, &scaleFactorY, &radiusY);
 
     SkRect srcRect(rect);
     scale_rect(&srcRect, 1.0f / scaleFactorX, 1.0f / scaleFactorY);
     srcRect.roundOut();
     scale_rect(&srcRect, static_cast<float>(scaleFactorX),
                          static_cast<float>(scaleFactorY));
 
     GrContext::AutoClip acs(context, SkRect::MakeWH(srcRect.width(), srcRect.height()));
 
     SkASSERT(kBGRA_8888_GrPixelConfig == srcTexture->config() ||
@@ skipping 112 matching lines @@
     } else if (srcTexture == temp2.texture()) {
         return temp2.detach();
     } else {
         srcTexture->ref();
         return srcTexture;
     }
 }
 #endif
 
 }