Properly fill in memory in sampled RLE BMPs
Bug: oss-fuzz:11039
Previously, RLE BMPs were not initialized when they were incomplete,
with the thinking that they were fully initialized at the start of
decoding. While this is true during full decodes (onGetPixels), it is
not true of scanline decodes where we may start with a failing skip.
Remove incorrect comment about creating a sampler in SkBmpRLECodec.
Instead create the sampler when appropriate. Rather than make it
implement its own version of SkSampler::fill, which would look like the
other implementations, add a new virtual method to determine the width
and leave the common implementation to the caller.
Simplify SkCodec::fillIncompleteImage, which always does basically the
same thing.
Change-Id: I885ebb7a0fe5add2a4f59bce57d07d98e4dc1bdb
Reviewed-on: https://skia-review.googlesource.com/c/163484
Reviewed-by: Mike Klein <mtklein@google.com>
Commit-Queue: Leon Scroggins <scroggo@google.com>
diff --git a/src/codec/SkBmpRLECodec.cpp b/src/codec/SkBmpRLECodec.cpp
index 8fc0ea8..6690629 100644
--- a/src/codec/SkBmpRLECodec.cpp
+++ b/src/codec/SkBmpRLECodec.cpp
@@ -275,11 +275,10 @@
*/
int SkBmpRLECodec::decodeRows(const SkImageInfo& info, void* dst, size_t dstRowBytes,
const Options& opts) {
- const int width = this->dimensions().width();
int height = info.height();
// Account for sampling.
- SkImageInfo dstInfo = info.makeWH(get_scaled_dimension(width, fSampleX), height);
+ SkImageInfo dstInfo = info.makeWH(this->fillWidth(), height);
// Set the background as transparent. Then, if the RLE code skips pixels,
// the skipped pixels will be transparent.
@@ -538,6 +537,10 @@
SkASSERT(fCodec);
}
+ int fillWidth() const override {
+ return fCodec->fillWidth();
+ }
+
private:
int onSetSampleX(int sampleX) override {
return fCodec->setSampleX(sampleX);
@@ -547,20 +550,19 @@
SkBmpRLECodec* fCodec;
};
-SkSampler* SkBmpRLECodec::getSampler(bool /*createIfNecessary*/) {
- // We will always create an SkBmpRLESampler if one is requested.
- // This allows clients to always use the SkBmpRLESampler's
- // version of fill(), which does nothing since RLE decodes have
- // already filled pixel memory. This seems fine, since creating
- // an SkBmpRLESampler is pretty inexpensive.
- if (!fSampler) {
+SkSampler* SkBmpRLECodec::getSampler(bool createIfNecessary) {
+ if (!fSampler && createIfNecessary) {
fSampler.reset(new SkBmpRLESampler(this));
}
return fSampler.get();
}
-int SkBmpRLECodec::setSampleX(int sampleX){
+int SkBmpRLECodec::setSampleX(int sampleX) {
fSampleX = sampleX;
- return get_scaled_dimension(this->dimensions().width(), sampleX);
+ return this->fillWidth();
+}
+
+int SkBmpRLECodec::fillWidth() const {
+ return get_scaled_dimension(this->dimensions().width(), fSampleX);
}