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

src/core/SkDevice.cpp

Index: src/core/SkDevice.cpp
diff --git a/src/core/SkDevice.cpp b/src/core/SkDevice.cpp
index 1f270af57245cc51e908163a87b2391b136d676d..af7f9215f5ce8130a886f3641e9deb98fa03b6e5 100644
--- a/src/core/SkDevice.cpp
+++ b/src/core/SkDevice.cpp
@@ -155,9 +155,22 @@ void SkBaseDevice::drawImageRect(const SkDraw& draw, const SkImage* image, const
                                  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);
+        }
     }
 }