Fill incomplete images in SkCodec parent class
Rather than implementing some sort of "fill" in every
SkCodec subclass for incomplete images, let's make the
parent class handle this situation.
This includes an API change to SkCodec.h
SkCodec::getScanlines() now returns the number of lines it
read successfully, rather than an SkCodec::Result enum.
getScanlines() most often fails on an incomplete input, in
which case it is useful to know how many lines were
successfully decoded - this provides more information than
kIncomplete vs kSuccess. We do lose information when the
API is used improperly, as we are no longer able to return
kInvalidParameter or kScanlineNotStarted.
Known Issues:
Does not work for incomplete fFrameIsSubset gifs.
Does not work for incomplete icos.
BUG=skia:
Review URL: https://codereview.chromium.org/1332053002
diff --git a/dm/DMSrcSink.cpp b/dm/DMSrcSink.cpp
index 2ea115b..88371a8 100644
--- a/dm/DMSrcSink.cpp
+++ b/dm/DMSrcSink.cpp
@@ -28,6 +28,8 @@
#include "SkStream.h"
#include "SkTLogic.h"
#include "SkXMLWriter.h"
+#include "SkScaledCodec.h"
+#include "SkSwizzler.h"
DEFINE_bool(multiPage, false, "For document-type backends, render the source"
" into multiple pages");
@@ -340,36 +342,30 @@
return Error::Nonfatal("Could not start scanline decoder");
}
- SkCodec::Result result = SkCodec::kUnimplemented;
+ void* dst = bitmap.getAddr(0, 0);
+ size_t rowBytes = bitmap.rowBytes();
+ uint32_t height = decodeInfo.height();
switch (codec->getScanlineOrder()) {
case SkCodec::kTopDown_SkScanlineOrder:
case SkCodec::kBottomUp_SkScanlineOrder:
case SkCodec::kNone_SkScanlineOrder:
- result = codec->getScanlines(bitmap.getAddr(0, 0),
- decodeInfo.height(), bitmap.rowBytes());
+ // We do not need to check the return value. On an incomplete
+ // image, memory will be filled with a default value.
+ codec->getScanlines(dst, height, rowBytes);
break;
case SkCodec::kOutOfOrder_SkScanlineOrder: {
for (int y = 0; y < decodeInfo.height(); y++) {
- int dstY = codec->nextScanline();
+ int dstY = codec->outputScanline(y);
void* dstPtr = bitmap.getAddr(0, dstY);
- result = codec->getScanlines(dstPtr, 1, bitmap.rowBytes());
- if (SkCodec::kSuccess != result && SkCodec::kIncompleteInput != result) {
- return SkStringPrintf("%s failed with error message %d",
- fPath.c_str(), (int) result);
- }
+ // We complete the loop, even if this call begins to fail
+ // due to an incomplete image. This ensures any uninitialized
+ // memory will be filled with the proper value.
+ codec->getScanlines(dstPtr, 1, bitmap.rowBytes());
}
break;
}
}
- switch (result) {
- case SkCodec::kSuccess:
- case SkCodec::kIncompleteInput:
- break;
- default:
- return SkStringPrintf("%s failed with error message %d",
- fPath.c_str(), (int) result);
- }
canvas->drawBitmap(bitmap, 0, 0);
break;
}
@@ -429,41 +425,21 @@
return "Error scanline decoder is nullptr";
}
}
- //skip to first line of subset
- const SkCodec::Result skipResult = codec->skipScanlines(y);
- switch (skipResult) {
- case SkCodec::kSuccess:
- case SkCodec::kIncompleteInput:
- break;
- default:
- return SkStringPrintf("%s failed after attempting to skip %d scanlines"
- "with error message %d", fPath.c_str(), y, (int) skipResult);
- }
+ // Skip to the first line of subset. We ignore the result value here.
+ // If the skip value fails, this will indicate an incomplete image.
+ // This means that the call to getScanlines() will also fail, but it
+ // will fill the buffer with a default value, so we can still draw the
+ // image.
+ codec->skipScanlines(y);
+
//create and set size of subsetBm
SkBitmap subsetBm;
SkIRect bounds = SkIRect::MakeWH(currentSubsetWidth, currentSubsetHeight);
SkAssertResult(largestSubsetBm.extractSubset(&subsetBm, bounds));
SkAutoLockPixels autlockSubsetBm(subsetBm, true);
- const SkCodec::Result subsetResult =
- codec->getScanlines(buffer, currentSubsetHeight, rowBytes);
- switch (subsetResult) {
- case SkCodec::kSuccess:
- case SkCodec::kIncompleteInput:
- break;
- default:
- return SkStringPrintf("%s failed with error message %d",
- fPath.c_str(), (int) subsetResult);
- }
+ codec->getScanlines(buffer, currentSubsetHeight, rowBytes);
+
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,
@@ -493,31 +469,17 @@
// to run this test for image types that do not have this scanline ordering.
return Error::Nonfatal("Could not start top-down scanline decoder");
}
+
for (int i = 0; i < numStripes; i += 2) {
// Skip a stripe
const int linesToSkip = SkTMin(stripeHeight, height - i * stripeHeight);
- SkCodec::Result result = codec->skipScanlines(linesToSkip);
- switch (result) {
- case SkCodec::kSuccess:
- case SkCodec::kIncompleteInput:
- break;
- default:
- return SkStringPrintf("Cannot skip scanlines for %s.", fPath.c_str());
- }
+ codec->skipScanlines(linesToSkip);
// Read a stripe
const int startY = (i + 1) * stripeHeight;
const int linesToRead = SkTMin(stripeHeight, height - startY);
if (linesToRead > 0) {
- result = codec->getScanlines(bitmap.getAddr(0, startY),
- linesToRead, bitmap.rowBytes());
- switch (result) {
- case SkCodec::kSuccess:
- case SkCodec::kIncompleteInput:
- break;
- default:
- return SkStringPrintf("Cannot get scanlines for %s.", fPath.c_str());
- }
+ codec->getScanlines(bitmap.getAddr(0, startY), linesToRead, bitmap.rowBytes());
}
}
@@ -531,27 +493,12 @@
// Read a stripe
const int startY = i * stripeHeight;
const int linesToRead = SkTMin(stripeHeight, height - startY);
- SkCodec::Result result = codec->getScanlines(bitmap.getAddr(0, startY),
- linesToRead, bitmap.rowBytes());
- switch (result) {
- case SkCodec::kSuccess:
- case SkCodec::kIncompleteInput:
- break;
- default:
- return SkStringPrintf("Cannot get scanlines for %s.", fPath.c_str());
- }
+ codec->getScanlines(bitmap.getAddr(0, startY), linesToRead, bitmap.rowBytes());
// Skip a stripe
const int linesToSkip = SkTMin(stripeHeight, height - (i + 1) * stripeHeight);
if (linesToSkip > 0) {
- result = codec->skipScanlines(linesToSkip);
- switch (result) {
- case SkCodec::kSuccess:
- case SkCodec::kIncompleteInput:
- break;
- default:
- return SkStringPrintf("Cannot skip scanlines for %s.", fPath.c_str());
- }
+ codec->skipScanlines(linesToSkip);
}
}
canvas->drawBitmap(bitmap, 0, 0);
@@ -592,8 +539,9 @@
// And scale
// FIXME: Should we have a version of getScaledDimensions that takes a subset
// into account?
- decodeInfo = decodeInfo.makeWH(SkScalarRoundToInt(preScaleW * fScale),
- SkScalarRoundToInt(preScaleH * fScale));
+ decodeInfo = decodeInfo.makeWH(
+ SkTMax(1, SkScalarRoundToInt(preScaleW * fScale)),
+ SkTMax(1, SkScalarRoundToInt(preScaleH * fScale)));
size_t rowBytes = decodeInfo.minRowBytes();
if (!subsetBm.installPixels(decodeInfo, pixels, rowBytes, colorTable.get(),
nullptr, nullptr)) {