Implemented onGetScanlines and onSkipScanlines for interlaced pngs
Modified DM tests to be faster when decoding interlaced pngs
BUG=skia:
Review URL: https://codereview.chromium.org/1194703002
diff --git a/dm/DMSrcSink.cpp b/dm/DMSrcSink.cpp
index 98f3ba4..51c79da 100644
--- a/dm/DMSrcSink.cpp
+++ b/dm/DMSrcSink.cpp
@@ -140,7 +140,7 @@
}
switch (fMode) {
- case kNormal_Mode:
+ case kNormal_Mode: {
switch (codec->getPixels(decodeInfo, bitmap.getPixels(), bitmap.rowBytes(), NULL,
colorPtr, colorCountPtr)) {
case SkImageGenerator::kSuccess:
@@ -156,23 +156,22 @@
}
canvas->drawBitmap(bitmap, 0, 0);
break;
+ }
case kScanline_Mode: {
SkScanlineDecoder* scanlineDecoder = codec->getScanlineDecoder(decodeInfo, NULL,
colorPtr, colorCountPtr);
if (NULL == scanlineDecoder) {
return Error::Nonfatal("Cannot use scanline decoder for all images");
}
- for (int y = 0; y < decodeInfo.height(); ++y) {
- const SkImageGenerator::Result result = scanlineDecoder->getScanlines(
- bitmap.getAddr(0, y), 1, 0);
- switch (result) {
- case SkImageGenerator::kSuccess:
- case SkImageGenerator::kIncompleteInput:
- break;
- default:
- return SkStringPrintf("%s failed after %d scanlines with error message %d",
- fPath.c_str(), y-1, (int) result);
- }
+ const SkImageGenerator::Result result = scanlineDecoder->getScanlines(
+ bitmap.getAddr(0, 0), decodeInfo.height(), bitmap.rowBytes());
+ switch (result) {
+ case SkImageGenerator::kSuccess:
+ case SkImageGenerator::kIncompleteInput:
+ break;
+ default:
+ return SkStringPrintf("%s failed with error message %d",
+ fPath.c_str(), (int) result);
}
canvas->drawBitmap(bitmap, 0, 0);
break;
@@ -207,8 +206,9 @@
return SkStringPrintf("Image(%s) is too large (%d x %d)\n", fPath.c_str(),
largestSubsetDecodeInfo.width(), largestSubsetDecodeInfo.height());
}
- char* line = SkNEW_ARRAY(char, decodeInfo.minRowBytes());
- SkAutoTDeleteArray<char> lineDeleter(line);
+ const size_t rowBytes = decodeInfo.minRowBytes();
+ char* buffer = SkNEW_ARRAY(char, largestSubsetDecodeInfo.height() * rowBytes);
+ SkAutoTDeleteArray<char> lineDeleter(buffer);
for (int col = 0; col < divisor; col++) {
//currentSubsetWidth may be larger than subsetWidth for rightmost subsets
const int currentSubsetWidth = (col + 1 == divisor) ?
@@ -247,21 +247,33 @@
bounds.setXYWH(0, 0, currentSubsetWidth, currentSubsetHeight);
SkAssertResult(largestSubsetBm.extractSubset(&subsetBm, bounds));
SkAutoLockPixels autlockSubsetBm(subsetBm, true);
- for (int subsetY = 0; subsetY < currentSubsetHeight; ++subsetY) {
- const SkImageGenerator::Result subsetResult =
- subsetScanlineDecoder->getScanlines(line, 1, 0);
- const size_t bpp = decodeInfo.bytesPerPixel();
- //copy section of line based on x value
- memcpy(subsetBm.getAddr(0, subsetY), line + x*bpp, currentSubsetWidth*bpp);
- switch (subsetResult) {
- case SkImageGenerator::kSuccess:
- case SkImageGenerator::kIncompleteInput:
- break;
- default:
- return SkStringPrintf("%s failed after %d scanlines with error"
- "message %d", fPath.c_str(), y-1, (int) subsetResult);
- }
+ const SkImageGenerator::Result subsetResult =
+ subsetScanlineDecoder->getScanlines(buffer, currentSubsetHeight, rowBytes);
+ switch (subsetResult) {
+ case SkImageGenerator::kSuccess:
+ case SkImageGenerator::kIncompleteInput:
+ break;
+ default:
+ return SkStringPrintf("%s failed with error message %d",
+ fPath.c_str(), (int) subsetResult);
}
+ const size_t bpp = decodeInfo.bytesPerPixel();
+ /*
+ * we copy all the lines at once becuase when calling getScanlines for
+ * interlaced pngs the entire image must be read regardless of the number
+ * of lines requested. Reading an interlaced png in a loop, line-by-line, would
+ * decode the entire image height times, which is very slow
+ * it is aknowledged that copying each line as you read it in a loop
+ * may be faster for other types of images. Since this is a correctness test
+ * that's okay.
+ */
+ char* bufferRow = buffer;
+ for (int subsetY = 0; subsetY < currentSubsetHeight; ++subsetY) {
+ memcpy(subsetBm.getAddr(0, subsetY), bufferRow + x*bpp,
+ currentSubsetWidth*bpp);
+ bufferRow += rowBytes;
+ }
+
canvas->drawBitmap(subsetBm, SkIntToScalar(x), SkIntToScalar(y));
}
}
@@ -341,6 +353,7 @@
}
}
canvas->drawBitmap(bitmap, 0, 0);
+ break;
}
}
return "";