Make SkAndroidCodec support bmp

src/codec/SkSampledCodec.cpp

Index: src/codec/SkSampledCodec.cpp
diff --git a/src/codec/SkSampledCodec.cpp b/src/codec/SkSampledCodec.cpp
index d5fbd0fa520615a4a750674ea792bb199b7bdfb9..bb7b067ce2946a13a097e76138021d109cc731e5 100644
--- a/src/codec/SkSampledCodec.cpp
+++ b/src/codec/SkSampledCodec.cpp
@@ -226,6 +226,45 @@ SkCodec::Result SkSampledCodec::sampledDecode(const SkImageInfo& info, void* pix
             }
             return SkCodec::kSuccess;
         }
+        case SkCodec::kBottomUp_SkScanlineOrder: {
+            // Note that this mode does not support subsetting.
+            SkASSERT(0 == subsetY && nativeSize.height() == subsetHeight);
+            SkCodec::Result result = SkCodec::kSuccess;
+            int y;
+            for (y = 0; y < nativeSize.height(); y++) {
+                int srcY = fCodec->nextScanline();
+                if (is_coord_necessary(srcY, sampleY, dstHeight)) {
+                    void* pixelPtr = SkTAddOffset<void>(pixels,
+                            rowBytes * get_dst_coord(srcY, sampleY));
+                    if (1 != fCodec->getScanlines(pixelPtr, 1, rowBytes)) {
+                        result = SkCodec::kIncompleteInput;

[scroggo, 2015/11/17 15:33:17]

This might be 6 of one, half a dozen of the other, but I think the following
might be a little simpler (it at least eliminates a variable):

if (1 != fCodec->getScanlines(...)) {
  break;
}
...
if (!fCodec->skipScanlines(1)) {
  break;
}

if (nativeSize.height() == y) {
  return SkCodec::kSuccess;
}

// fill uninitialized memory
return SkCodec::kIncompleteInput;

[msarett, 2015/11/17 16:06:24]

I think this approach makes things a little clearer.  I've changed this.

+                        break;
+                    }
+                } else {
+                    if (!fCodec->skipScanlines(1)) {
+                        result = SkCodec::kIncompleteInput;
+                        break;
+                    }
+                }
+            }
+
+            // We handle filling uninitialized memory here instead of using fCodec.
+            // fCodec does not know that we are sampling.
+            if (SkCodec::kIncompleteInput == result) {
+                const uint32_t fillValue = fCodec->getFillValue(info.colorType(),
+                        info.alphaType());
+                for (; y < nativeSize.height(); y++) {
+                    int srcY = fCodec->outputScanline(y);
+                    if (is_coord_necessary(srcY, sampleY, dstHeight)) {
+                        void* pixelPtr = SkTAddOffset<void>(pixels,
+                                rowBytes * get_dst_coord(srcY, sampleY));
+                        SkSampler::Fill(info.makeWH(info.width(), 1), pixelPtr, rowBytes, fillValue,
+                                options.fZeroInitialized);
+                    }
+                }
+            }
+            return result;
+        }
         case SkCodec::kNone_SkScanlineOrder: {
             const int linesNeeded = subsetHeight - samplingOffsetY;
             SkAutoMalloc storage(linesNeeded * rowBytes);