Handling large jpegs in CPU raster - downsample to display res and 565

src/core/SkDevice.cpp

 /*
  * Copyright 2011 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkColorFilter.h"
 #include "SkDevice.h"
 #include "SkDraw.h"
@@ skipping 137 matching lines @@
     SkBitmap bm;
     if (as_IB(image)->getROPixels(&bm)) {
         this->drawBitmap(draw, bm, SkMatrix::MakeTrans(x, y), paint);
     }
 }
 
 void SkBaseDevice::drawImageRect(const SkDraw& draw, const SkImage* image, const SkRect* src,
                                  const SkRect& dst, const SkPaint& paint,
                                  SkCanvas::SrcRectConstraint constraint) {
     // Default impl : turns everything into raster bitmap
+
     SkBitmap bm;
-    if (as_IB(image)->getROPixels(&bm)) {
-        this->drawBitmapRect(draw, bm, src, dst, paint, constraint);
+    SkScalar scaleX = draw.fMatrix->getScaleX();
+    SkScalar scaleY = draw.fMatrix->getScaleY();
+
+    SkScalar scale = SkMaxScalar(scaleX * dst.width() / src->width(),
+                                 scaleY * dst.height() / src->height());
+    if (as_IB(image)->getROPixels(&bm, scale)) {
+        scale = SkIntToScalar(bm.width()) / SkIntToScalar(image->width());
+        if (scale == SK_Scalar1) {
+            this->drawBitmapRect(draw, bm, src, dst, paint, constraint);
+        } else {
+            SkRect srcScaled;
+            srcScaled.set(src->left() * scale, src->top() * scale, src->right() * scale, src->bottom() * scale);
+            this->drawBitmapRect(draw, bm, &srcScaled, dst, paint, constraint);
+        }
     }
 }
 
 void SkBaseDevice::drawImageNine(const SkDraw& draw, const SkImage* image, const SkIRect& center,
                                  const SkRect& dst, const SkPaint& paint) {
     SkNinePatchIter iter(image->width(), image->height(), center, dst);
 
     SkRect srcR, dstR;
     while (iter.next(&srcR, &dstR)) {
         this->drawImageRect(draw, image, &srcR, dstR, paint, SkCanvas::kStrict_SrcRectConstraint);
@@ skipping 241 matching lines @@
     if (kUnknown_SkPixelGeometry == fSurfaceProps.pixelGeometry()
         || this->onShouldDisableLCD(paint)) {
 
         flags &= ~SkPaint::kLCDRenderText_Flag;
         flags |= SkPaint::kGenA8FromLCD_Flag;
     }
 
     return flags;
 }