Fill incomplete images in SkCodec parent class

tools/SkBitmapRegionCanvas.cpp

 /*
  * Copyright 2015 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #include "SkBitmapRegionCanvas.h"
 #include "SkCanvas.h"
 #include "SkScanlineDecoder.h"
+#include "SkSwizzler.h"
 
 SkBitmapRegionCanvas::SkBitmapRegionCanvas(SkScanlineDecoder* decoder)
     : INHERITED(decoder->getInfo().width(), decoder->getInfo().height())
     , fDecoder(decoder)
 {}
 
 /*
  * Chooses the correct image subset offsets and dimensions for the partial decode.
  */
 static inline void set_subset_region(int inputOffset, int inputDimension,
@@ skipping 101 matching lines @@
 
     // Allocate a bitmap for the unscaled decode
     SkBitmap tmp;
     SkImageInfo tmpInfo = decodeInfo.makeWH(this->width(), imageSubsetHeight);
     if (!tmp.tryAllocPixels(tmpInfo)) {
         SkDebugf("Error: Could not allocate pixels.\n");
         return nullptr;
     }
 
     // Skip the unneeded rows
-    if (SkCodec::kSuccess != fDecoder->skipScanlines(imageSubsetY)) {
+    if ((uint32_t) imageSubsetY != fDecoder->skipScanlines(imageSubsetY)) {
         SkDebugf("Error: Failed to skip scanlines.\n");
         return nullptr;
     }
 
     // Decode the necessary rows
-    SkCodec::Result result = fDecoder->getScanlines(tmp.getAddr(0, 0), imageSubsetHeight,
-            tmp.rowBytes());
-    switch (result) {
-        case SkCodec::kSuccess:
-        case SkCodec::kIncompleteInput:
-            break;
-        default:
-            SkDebugf("Error: Failed to get scanlines.\n");
-            return nullptr;
+    uint32_t lines = fDecoder->getScanlines(tmp.getAddr(0, 0), imageSubsetHeight, tmp.rowBytes());
+    if (lines != (uint32_t) imageSubsetHeight) {
+        const SkImageInfo fillInfo = tmpInfo.makeWH(tmpInfo.width(), imageSubsetHeight - lines);
+        const uint32_t fillValue = fDecoder->getFillValue(fillInfo);
+        SkSwizzler::Fill(tmp.getAddr(0, lines), fillInfo, tmp.rowBytes(), fillValue,
+                SkCodec::kNo_ZeroInitialized);
     }
 
     // Calculate the size of the output
     const int outWidth = get_scaled_dimension(inputWidth, sampleSize);
     const int outHeight = get_scaled_dimension(inputHeight, sampleSize);
 
     // Initialize the destination bitmap
     SkAutoTDelete<SkBitmap> bitmap(new SkBitmap());
     SkImageInfo dstInfo = decodeInfo.makeWH(outWidth, outHeight);
     if (!bitmap->tryAllocPixels(dstInfo)) {
@@ skipping 23 matching lines @@
             (SkScalar) get_scaled_dimension(imageSubsetWidth, sampleSize),
             (SkScalar) get_scaled_dimension(imageSubsetHeight, sampleSize));
     SkPaint paint;
     // Overwrite the dst with the src pixels
     paint.setXfermodeMode(SkXfermode::kSrc_Mode);
     // TODO (msarett): Test multiple filter qualities.  kNone is the default.
     canvas.drawBitmapRect(tmp, src, dst, &paint);
 
     return bitmap.detach();
 }