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gif2webp: Allow single-frame animations

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Some single-frame GIF images have a canvas larger than the frame rectangle. For
such images, we retain the ANMF, ANIM and VP8X chunks in the output WebP file.
This ensures that the full canvas width/height and frame offsets are retained.

Change-Id: I3ebae4893f953984de4072fda0938411de787a29
This commit is contained in:
Urvang Joshi 2014-07-10 15:21:05 -07:00
parent 46fd44c104
commit bb4fc051bf
1 changed files with 10 additions and 6 deletions
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16
src/mux/muxedit.c
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@ -585,9 +585,9 @@ static WebPMuxError MuxCleanup(WebPMux* const mux) {
int num_fragments; int num_fragments;
int num_anim_chunks; int num_anim_chunks;
// If we have an image with single fragment or frame, convert it to a // If we have an image with a single fragment or frame, and its rectangle
// non-animated non-fragmented image (to avoid writing FRGM/ANMF chunk // covers the whole canvas, convert it to a non-animated non-fragmented image
// unnecessarily). // (to avoid writing FRGM/ANMF chunk unnecessarily).
WebPMuxError err = WebPMuxNumChunks(mux, kChunks[IDX_ANMF].id, &num_frames); WebPMuxError err = WebPMuxNumChunks(mux, kChunks[IDX_ANMF].id, &num_frames);
if (err != WEBP_MUX_OK) return err; if (err != WEBP_MUX_OK) return err;
err = WebPMuxNumChunks(mux, kChunks[IDX_FRGM].id, &num_fragments); err = WebPMuxNumChunks(mux, kChunks[IDX_FRGM].id, &num_fragments);
@ -596,14 +596,18 @@ static WebPMuxError MuxCleanup(WebPMux* const mux) {
WebPMuxImage* frame_frag; WebPMuxImage* frame_frag;
err = MuxImageGetNth((const WebPMuxImage**)&mux->images_, 1, &frame_frag); err = MuxImageGetNth((const WebPMuxImage**)&mux->images_, 1, &frame_frag);
assert(err == WEBP_MUX_OK); // We know that one frame/fragment does exist. assert(err == WEBP_MUX_OK); // We know that one frame/fragment does exist.
if (frame_frag->header_ != NULL) { assert(frame_frag != NULL);
if (frame_frag->header_ != NULL &&
((mux->canvas_width_ == 0 && mux->canvas_height_ == 0) ||
(frame_frag->width_ == mux->canvas_width_ &&
frame_frag->height_ == mux->canvas_height_))) {
assert(frame_frag->header_->tag_ == kChunks[IDX_ANMF].tag || assert(frame_frag->header_->tag_ == kChunks[IDX_ANMF].tag ||
frame_frag->header_->tag_ == kChunks[IDX_FRGM].tag); frame_frag->header_->tag_ == kChunks[IDX_FRGM].tag);
ChunkDelete(frame_frag->header_); // Removes ANMF/FRGM chunk. ChunkDelete(frame_frag->header_); // Removes ANMF/FRGM chunk.
frame_frag->header_ = NULL; frame_frag->header_ = NULL;
num_frames = 0;
num_fragments = 0;
} }
num_frames = 0;
num_fragments = 0;
} }
// Remove ANIM chunk if this is a non-animated image. // Remove ANIM chunk if this is a non-animated image.
err = WebPMuxNumChunks(mux, kChunks[IDX_ANIM].id, &num_anim_chunks); err = WebPMuxNumChunks(mux, kChunks[IDX_ANIM].id, &num_anim_chunks);