respect kFast_SrcRectConstraint by allowing shader access to entire bitmap

src/core/SkBitmapDevice.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 "SkBitmapDevice.h"
 #include "SkConfig8888.h"
 #include "SkDraw.h"
@@ skipping 250 matching lines @@
     // needed (if the src was clipped). No check needed if src==null.
     if (src) {
         if (!bitmapBounds.contains(*src)) {
             if (!tmpSrc.intersect(bitmapBounds)) {
                 return; // nothing to draw
             }
             // recompute dst, based on the smaller tmpSrc
             matrix.mapRect(&tmpDst, tmpSrc);
             dstPtr = &tmpDst;
         }
+    }
 
+    if (src && !src->contains(bitmapBounds) &&
+        SkCanvas::kFast_SrcRectConstraint == constraint &&
+        paint.getFilterQuality() != kNone_SkFilterQuality) {
+        // src is smaller than the bounds of the bitmap, and we are filtering, so we don't know
+        // how much more of the bitmap we need, so we can't use extractSubset or drawBitmap,
+        // but we must use a shader w/ dst bounds (which can access all of the bitmap needed).
+        goto USE_SHADER;
+    }
+
+    if (src) {
         // since we may need to clamp to the borders of the src rect within
         // the bitmap, we extract a subset.
         const SkIRect srcIR = tmpSrc.roundOut();
         if(bitmap.pixelRef()->getTexture()) {
             // Accelerated source canvas, don't use extractSubset but readPixels to get the subset.
             // This way, the pixels are copied in CPU memory instead of GPU memory.
             bitmap.pixelRef()->readPixels(&tmpBitmap, kN32_SkColorType, &srcIR);
         } else {
             if (!bitmap.extractSubset(&tmpBitmap, srcIR)) {
                 return;
@@ skipping 21 matching lines @@
         }
     } else {
         USE_DRAWBITMAP:
         // We can go faster by just calling drawBitmap, which will concat the
         // matrix with the CTM, and try to call drawSprite if it can. If not,
         // it will make a shader and call drawRect, as we do below.
         draw.drawBitmap(*bitmapPtr, matrix, dstPtr, paint);
         return;
     }
 
+    USE_SHADER:
     // construct a shader, so we can call drawRect with the dst
     auto s = SkShader::MakeBitmapShader(*bitmapPtr, SkShader::kClamp_TileMode,
                                         SkShader::kClamp_TileMode, &matrix);
     if (!s) {
         return;
     }
 
     SkPaint paintWithShader(paint);
     paintWithShader.setStyle(SkPaint::kFill_Style);
     paintWithShader.setShader(std::move(s));
@@ skipping 99 matching lines @@
         paint.getRasterizer() ||
         paint.getPathEffect() ||
         paint.isFakeBoldText() ||
         paint.getStyle() != SkPaint::kFill_Style ||
         !SkXfermode::IsMode(paint.getXfermode(), SkXfermode::kSrcOver_Mode))
     {
         return true;
     }
     return false;
 }