Explicit tile bounds for SkPictureShader

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"
 #include "SkBitmapProcShader.h"
 #include "SkCanvas.h"
 #include "SkMatrixUtils.h"
 #include "SkPicture.h"
 #include "SkReadBuffer.h"
 
 #if SK_SUPPORT_GPU
 #include "GrContext.h"
 #endif
 
 SkPictureShader::SkPictureShader(const SkPicture* picture, TileMode tmx, TileMode tmy,
-                                 const SkMatrix* localMatrix)
+                                 const SkMatrix* localMatrix, const SkRect* tile)
     : INHERITED(localMatrix)
     , fPicture(SkRef(picture))
     , fTmx(tmx)
-    , fTmy(tmy) { }
+    , fTmy(tmy) {
+    fTile = tile ? *tile : SkRect::MakeWH(SkIntToScalar(picture->width()),
+                                          SkIntToScalar(picture->height()));
+}
 
 SkPictureShader::SkPictureShader(SkReadBuffer& buffer)
         : INHERITED(buffer) {
     fTmx = static_cast<SkShader::TileMode>(buffer.read32());
     fTmy = static_cast<SkShader::TileMode>(buffer.read32());
+    buffer.readRect(&fTile);
     fPicture = SkPicture::CreateFromBuffer(buffer);
 }
 
 SkPictureShader::~SkPictureShader() {
     fPicture->unref();
 }
 
 SkPictureShader* SkPictureShader::Create(const SkPicture* picture, TileMode tmx, TileMode tmy,
-                                         const SkMatrix* localMatrix) {
-    if (!picture || 0 == picture->width() || 0 == picture->height()) {
+                                         const SkMatrix* localMatrix, const SkRect* tile) {
+    if (!picture || 0 == picture->width() || 0 == picture->height()
+        || (NULL != tile && tile->isEmpty())) {
         return NULL;
     }
-    return SkNEW_ARGS(SkPictureShader, (picture, tmx, tmy, localMatrix));
+    return SkNEW_ARGS(SkPictureShader, (picture, tmx, tmy, localMatrix, tile));
 }
 
 void SkPictureShader::flatten(SkWriteBuffer& buffer) const {
     this->INHERITED::flatten(buffer);
 
     buffer.write32(fTmx);
     buffer.write32(fTmy);
+    buffer.writeRect(fTile);
     fPicture->flatten(buffer);
 }
 
 SkShader* SkPictureShader::refBitmapShader(const SkMatrix& matrix, const SkMatrix* localM) const {
     SkASSERT(fPicture && fPicture->width() > 0 && fPicture->height() > 0);
 
     SkMatrix m;
     m.setConcat(matrix, this->getLocalMatrix());
     if (localM) {
         m.preConcat(*localM);
     }
 
     // Use a rotation-invariant scale
     SkPoint scale;
     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(scale.x() * fPicture->width(), scale.y() * fPicture->height());
+    SkSize scaledSize = SkSize::Make(scale.x() * fTile.width(), scale.y() * fTile.height());
 
     SkISize tileSize = scaledSize.toRound();
     if (tileSize.isEmpty()) {
         return NULL;
     }
 
     // The actual scale, compensating for rounding.
-    SkSize tileScale = SkSize::Make(SkIntToScalar(tileSize.width()) / fPicture->width(),
-                                    SkIntToScalar(tileSize.height()) / fPicture->height());
+    SkSize tileScale = SkSize::Make(SkIntToScalar(tileSize.width()) / fTile.width(),
+                                    SkIntToScalar(tileSize.height()) / fTile.height());
 
     SkAutoMutexAcquire ama(fCachedBitmapShaderMutex);
 
     if (!fCachedBitmapShader || tileScale != fCachedTileScale) {
         SkBitmap bm;
         if (!bm.allocN32Pixels(tileSize.width(), tileSize.height())) {
             return NULL;
         }
         bm.eraseColor(SK_ColorTRANSPARENT);
 
         SkCanvas canvas(bm);
         canvas.scale(tileScale.width(), tileScale.height());
+        canvas.translate(fTile.x(), fTile.y());
         canvas.drawPicture(fPicture);
 
         fCachedTileScale = tileScale;
 
         SkMatrix shaderMatrix = this->getLocalMatrix();
         shaderMatrix.preScale(1 / tileScale.width(), 1 / tileScale.height());
         fCachedBitmapShader.reset(CreateBitmapShader(bm, fTmx, fTmy, &shaderMatrix));
     }
 
     // Increment the ref counter inside the mutex to ensure the returned pointer is still valid.
@@ skipping 92 matching lines @@
     return bitmapShader->asNewEffect(context, paint, NULL, paintColor, effect);
 }
 #else
 bool SkPictureShader::asNewEffect(GrContext* context, const SkPaint& paint,
                                   const SkMatrix* localMatrix, GrColor* paintColor,
                                   GrEffect** effect) const {
     SkDEBUGFAIL("Should not call in GPU-less build");
     return false;
 }
 #endif