Make SkCodec more flexible about its required frame
SkCodec sets fRequiredFrame to be the earliest possible frame that a
given frame can depend on. e.g.
- Frame A fills the screen, Keep
- Frame B does not cover A, Keep
- Frame C covers B but not A, and is opaque
Frame C can depend on either A or B. SkCodec already reports that C
depends on A. This CL allows a client of SkCodec to use either A or
B to create C.
Also expose the DisposalMethod. Since any frame between A and C can
be used to create C except for DisposePrevious frames, the client
needs to be able to know the disposal method so they do not try to
use such a frame to create C.
Further, the disposal method can be used to give the client a better
idea whether they will continue to need a frame. (e.g. if frame i is
DisposePrevious and depends on i-1, the client may not want to steal
i-1 to create i, since i+1 may also depend on i-1.)
TODO: Share code for decoding prior frames between GIF and WEBP
Change-Id: I91a5ae22ba3d8dfbe0bde833fa67ae3da0d81ed6
Reviewed-on: https://skia-review.googlesource.com/13722
Reviewed-by: Mike Reed <reed@google.com>
Reviewed-by: Chris Blume <cblume@chromium.org>
Reviewed-by: Matt Sarett <msarett@google.com>
Commit-Queue: Leon Scroggins <scroggo@google.com>
diff --git a/src/codec/SkWebpCodec.cpp b/src/codec/SkWebpCodec.cpp
index 21d45da..f702a3a 100644
--- a/src/codec/SkWebpCodec.cpp
+++ b/src/codec/SkWebpCodec.cpp
@@ -7,6 +7,8 @@
#include "SkBitmap.h"
#include "SkCanvas.h"
+#include "SkCodecAnimation.h"
+#include "SkCodecAnimationPriv.h"
#include "SkCodecPriv.h"
#include "SkColorSpaceXform.h"
#include "SkRasterPipeline.h"
@@ -253,8 +255,8 @@
Frame* frame = fFrameHolder.appendNewFrame(iter.has_alpha);
frame->setXYWH(iter.x_offset, iter.y_offset, iter.width, iter.height);
frame->setDisposalMethod(iter.dispose_method == WEBP_MUX_DISPOSE_BACKGROUND ?
- SkCodecAnimation::RestoreBGColor_DisposalMethod :
- SkCodecAnimation::Keep_DisposalMethod);
+ SkCodecAnimation::DisposalMethod::kRestoreBGColor :
+ SkCodecAnimation::DisposalMethod::kKeep);
frame->setDuration(iter.duration);
if (WEBP_MUX_BLEND != iter.blend_method) {
frame->setBlend(SkCodecAnimation::Blend::kBG);
@@ -292,6 +294,7 @@
// animated image.
frameInfo->fFullyReceived = true;
frameInfo->fAlphaType = alpha_type(frame->hasAlpha());
+ frameInfo->fDisposalMethod = frame->getDisposalMethod();
}
return true;
@@ -437,9 +440,15 @@
SkSampler::Fill(dstInfo, dst, rowBytes, 0, options.fZeroInitialized);
}
} else {
- if (!options.fHasPriorFrame) {
+ // FIXME: Share with GIF
+ if (options.fPriorFrame != kNone) {
+ if (options.fPriorFrame < requiredFrame || options.fPriorFrame >= index) {
+ return kInvalidParameters;
+ }
+ } else {
Options prevFrameOpts(options);
prevFrameOpts.fFrameIndex = requiredFrame;
+ prevFrameOpts.fPriorFrame = kNone;
const auto result = this->getPixels(dstInfo, dst, rowBytes, &prevFrameOpts,
nullptr, nullptr);
switch (result) {
@@ -452,16 +461,20 @@
}
}
- // Dispose bg color
- const Frame* priorFrame = fFrameHolder.frame(requiredFrame);
- if (priorFrame->getDisposalMethod() == SkCodecAnimation::RestoreBGColor_DisposalMethod) {
- // FIXME: If we add support for scaling/subsets, this rectangle needs to be adjusted.
- const auto priorRect = priorFrame->frameRect();
- const auto info = dstInfo.makeWH(priorRect.width(), priorRect.height());
- const size_t bpp = SkColorTypeBytesPerPixel(dstInfo.colorType());
- const size_t offset = priorRect.x() * bpp + priorRect.y() * rowBytes;
- auto* eraseDst = SkTAddOffset<void>(dst, offset);
- SkSampler::Fill(info, eraseDst, rowBytes, 0, kNo_ZeroInitialized);
+ if (options.fPriorFrame == requiredFrame || options.fPriorFrame == kNone) {
+ // Dispose bg color
+ const Frame* priorFrame = fFrameHolder.frame(requiredFrame);
+ if (priorFrame->getDisposalMethod()
+ == SkCodecAnimation::DisposalMethod::kRestoreBGColor) {
+ // FIXME: If we add support for scaling/subsets, this rectangle needs to be
+ // adjusted.
+ const auto priorRect = priorFrame->frameRect();
+ const auto info = dstInfo.makeWH(priorRect.width(), priorRect.height());
+ const size_t bpp = SkColorTypeBytesPerPixel(dstInfo.colorType());
+ const size_t offset = priorRect.x() * bpp + priorRect.y() * rowBytes;
+ auto* eraseDst = SkTAddOffset<void>(dst, offset);
+ SkSampler::Fill(info, eraseDst, rowBytes, 0, kNo_ZeroInitialized);
+ }
}
}