Add SkEncodedInfo to report properties of encoded image data
All this does is build an SkEncodedInfo for each codec, and
then convert it to an SkImageInfo.
In future steps I intend to:
(1) Use SkEncodedInfo in place of SrcConfig in SkSwizzler.
(2) Support more conversions in SkSwizzler (non-native
BGRA/RGBA, 16-bit components, float, fixed point)
(3) Investigate optimizing conversions from encoded data
to linear color spaces.
BUG=skia:4133
GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1820073002
Committed: https://skia.googlesource.com/skia/+/f682d9ad70d690a343bc15e26ef321d86770be41
Review URL: https://codereview.chromium.org/1820073002
diff --git a/src/codec/SkWebpCodec.cpp b/src/codec/SkWebpCodec.cpp
index 77af8e5..e40c3f2 100644
--- a/src/codec/SkWebpCodec.cpp
+++ b/src/codec/SkWebpCodec.cpp
@@ -31,7 +31,7 @@
// Parse headers of RIFF container, and check for valid Webp (VP8) content.
// NOTE: This calls peek instead of read, since onGetPixels will need these
// bytes again.
-static bool webp_parse_header(SkStream* stream, SkImageInfo* info) {
+static bool webp_parse_header(SkStream* stream, int* width, int* height, SkEncodedInfo* info) {
unsigned char buffer[WEBP_VP8_HEADER_SIZE];
SkASSERT(WEBP_VP8_HEADER_SIZE <= SkCodec::MinBufferedBytesNeeded());
@@ -62,22 +62,55 @@
}
if (info) {
- // FIXME: Is N32 the right type?
- // Is unpremul the right type? Clients of SkCodec may assume it's the
- // best type, when Skia currently cannot draw unpremul (and raster is faster
- // with premul).
- *info = SkImageInfo::Make(features.width, features.height, kN32_SkColorType,
- SkToBool(features.has_alpha) ? kUnpremul_SkAlphaType
- : kOpaque_SkAlphaType);
+ SkEncodedInfo::Color color;
+ SkEncodedInfo::Alpha alpha;
+ switch (features.format) {
+ case 0:
+ // This indicates a "mixed" format. We would see this for
+ // animated webps or for webps encoded in multiple fragments.
+ // I believe that this is a rare case.
+ // We could also guess kYUV here, but I think it makes more
+ // sense to guess kBGRA which is likely closer to the final
+ // output. Otherwise, we might end up converting
+ // BGRA->YUVA->BGRA.
+ color = SkEncodedInfo::kBGRA_Color;
+ alpha = SkEncodedInfo::kUnpremul_Alpha;
+ break;
+ case 1:
+ // This is the lossy format (YUV).
+ if (SkToBool(features.has_alpha)) {
+ color = SkEncodedInfo::kYUVA_Color;
+ alpha = SkEncodedInfo::kUnpremul_Alpha;
+ } else {
+ color = SkEncodedInfo::kYUV_Color;
+ alpha = SkEncodedInfo::kOpaque_Alpha;
+ }
+ break;
+ case 2:
+ // This is the lossless format (BGRA).
+ // FIXME: Should we check the has_alpha flag here? It looks
+ // like the image is encoded with an alpha channel
+ // regardless of whether or not the alpha flag is set.
+ color = SkEncodedInfo::kBGRA_Color;
+ alpha = SkEncodedInfo::kUnpremul_Alpha;
+ break;
+ default:
+ return false;
+ }
+
+ *width = features.width;
+ *height = features.height;
+ *info = SkEncodedInfo::Make(color, alpha, 8);
}
return true;
}
SkCodec* SkWebpCodec::NewFromStream(SkStream* stream) {
SkAutoTDelete<SkStream> streamDeleter(stream);
- SkImageInfo info;
- if (webp_parse_header(stream, &info)) {
- return new SkWebpCodec(info, streamDeleter.release());
+ int width, height;
+ SkEncodedInfo info;
+ if (webp_parse_header(stream, &width, &height, &info)) {
+ return new SkWebpCodec(width, height, info, streamDeleter.release());
}
return nullptr;
}
@@ -252,7 +285,7 @@
}
}
-SkWebpCodec::SkWebpCodec(const SkImageInfo& info, SkStream* stream)
+SkWebpCodec::SkWebpCodec(int width, int height, const SkEncodedInfo& info, SkStream* stream)
// The spec says an unmarked image is sRGB, so we return that space here.
// TODO: Add support for parsing ICC profiles from webps.
- : INHERITED(info, stream, SkColorSpace::NewNamed(SkColorSpace::kSRGB_Named)) {}
+ : INHERITED(width, height, info, stream, SkColorSpace::NewNamed(SkColorSpace::kSRGB_Named)) {}