SkPictureShader: scale down if width or height is larger than maxTextureSize

src/core/SkPictureShader.cpp

 /*
  * Copyright 2014 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkPictureShader.h"
 
 #include "SkBitmap.h"
@@ skipping 123 matching lines @@
 }
 
 void SkPictureShader::flatten(SkWriteBuffer& buffer) const {
     buffer.writeMatrix(this->getLocalMatrix());
     buffer.write32(fTmx);
     buffer.write32(fTmy);
     buffer.writeRect(fTile);
     fPicture->flatten(buffer);
 }
 
-SkShader* SkPictureShader::refBitmapShader(const SkMatrix& matrix, const SkMatrix* localM) const {
+SkShader* SkPictureShader::refBitmapShader(const SkMatrix& matrix, const SkMatrix* localM,
+                                            const int maxTextureSize) const {
     SkASSERT(fPicture && !fPicture->cullRect().isEmpty());
 
     SkMatrix m;
     m.setConcat(matrix, this->getLocalMatrix());
     if (localM) {
         m.preConcat(*localM);
     }
 
     // Use a rotation-invariant scale
     SkPoint scale;
     //
     // TODO: replace this with decomposeScale() -- but beware LayoutTest rebaselines!
     //
     if (!SkDecomposeUpper2x2(m, NULL, &scale, NULL)) {
         // Decomposition failed, use an approximation.
         scale.set(SkScalarSqrt(m.getScaleX() * m.getScaleX() + m.getSkewX() * m.getSkewX()),
                   SkScalarSqrt(m.getScaleY() * m.getScaleY() + m.getSkewY() * m.getSkewY()));
     }
     SkSize scaledSize = SkSize::Make(SkScalarAbs(scale.x() * fTile.width()),
                                      SkScalarAbs(scale.y() * fTile.height()));
 
     // Clamp the tile size to about 4M pixels
     static const SkScalar kMaxTileArea = 2048 * 2048;
     SkScalar tileArea = SkScalarMul(scaledSize.width(), scaledSize.height());
     if (tileArea > kMaxTileArea) {
         SkScalar clampScale = SkScalarSqrt(SkScalarDiv(kMaxTileArea, tileArea));
         scaledSize.set(SkScalarMul(scaledSize.width(), clampScale),
                        SkScalarMul(scaledSize.height(), clampScale));
     }
+#if SK_SUPPORT_GPU
+    // Scale down the tile size if larger than maxTextureSize for GPU Path or it should fail on create texture
+    if (maxTextureSize) {
+        if (scaledSize.width() > maxTextureSize || scaledSize.height() > maxTextureSize) {
+            SkScalar downScale = SkScalarDiv(maxTextureSize,
+                                            SkMax32(scaledSize.width(), scaledSize.height()));
+            scaledSize.set(SkScalarMul(scaledSize.width(), downScale),
+                           SkScalarMul(scaledSize.height(), downScale));
+        }
+    }
+#endif
 
     SkISize tileSize = scaledSize.toRound();
     if (tileSize.isEmpty()) {
         return NULL;
     }
 
     // The actual scale, compensating for rounding & clamping.
     SkSize tileScale = SkSize::Make(SkIntToScalar(tileSize.width()) / fTile.width(),
                                     SkIntToScalar(tileSize.height()) / fTile.height());
 
@@ skipping 108 matching lines @@
 
     this->INHERITED::toString(str);
 }
 #endif
 
 #if SK_SUPPORT_GPU
 bool SkPictureShader::asFragmentProcessor(GrContext* context, const SkPaint& paint,
                                           const SkMatrix& viewM, const SkMatrix* localMatrix,
                                           GrColor* paintColor,
                                           GrFragmentProcessor** fp) const {
-    SkAutoTUnref<SkShader> bitmapShader(this->refBitmapShader(viewM, localMatrix));
+    int maxTextureSize = 0;
+    if (context) {
+        maxTextureSize = context->getMaxTextureSize();
+    }
+    SkAutoTUnref<SkShader> bitmapShader(this->refBitmapShader(viewM, localMatrix, maxTextureSize));
     if (!bitmapShader) {
         return false;
     }
     return bitmapShader->asFragmentProcessor(context, paint, viewM, NULL, paintColor, fp);
 }
 #else
 bool SkPictureShader::asFragmentProcessor(GrContext*, const SkPaint&, const SkMatrix&,
                                           const SkMatrix*, GrColor*,
                                           GrFragmentProcessor**) const {
     SkDEBUGFAIL("Should not call in GPU-less build");
     return false;
 }
 #endif