// Cleans up 'mux' by removing any unnecessary chunks.
static WebPMuxError MuxCleanup(WebPMux* const mux) {
int num_frames;
int num_fragments;
int num_anim_chunks;
// If we have an image with single fragment or frame, convert it to a
// non-animated non-fragmented image (to avoid writing FRGM/ANMF chunk
// unnecessarily).
WebPMuxError err = WebPMuxNumChunks(mux, kChunks[IDX_ANMF].id, &num_frames);
if (err != WEBP_MUX_OK) return err;
err = WebPMuxNumChunks(mux, kChunks[IDX_FRGM].id, &num_fragments);
if (err != WEBP_MUX_OK) return err;
if (num_frames == 1 || num_fragments == 1) {
WebPMuxImage* frame_frag;
err = MuxImageGetNth((const WebPMuxImage**)&mux->images_, 1, &frame_frag);
assert(err == WEBP_MUX_OK); // We know that one frame/fragment does exist.
if (frame_frag->header_ != NULL) {
assert(frame_frag->header_->tag_ == kChunks[IDX_ANMF].tag ||
frame_frag->header_->tag_ == kChunks[IDX_FRGM].tag);
ChunkDelete(frame_frag->header_); // Removes ANMF/FRGM chunk.
frame_frag->header_ = NULL;
}
num_frames = 0;
num_fragments = 0;
}
// Remove ANIM chunk if this is a non-animated image.
err = WebPMuxNumChunks(mux, kChunks[IDX_ANIM].id, &num_anim_chunks);
if (err != WEBP_MUX_OK) return err;
if (num_anim_chunks >= 1 && num_frames == 0) {
err = MuxDeleteAllNamedData(mux, kChunks[IDX_ANIM].tag);
if (err != WEBP_MUX_OK) return err;
}
return WEBP_MUX_OK;
}
// Cleans up 'mux' by removing any unnecessary chunks.
static WebPMuxError MuxCleanup(WebPMux* const mux) {
int num_frames;
int num_anim_chunks;
// If we have an image with a single frame, and its rectangle
// covers the whole canvas, convert it to a non-animated image
// (to avoid writing ANMF chunk unnecessarily).
WebPMuxError err = WebPMuxNumChunks(mux, kChunks[IDX_ANMF].id, &num_frames);
if (err != WEBP_MUX_OK) return err;
if (num_frames == 1) {
WebPMuxImage* frame = NULL;
err = MuxImageGetNth((const WebPMuxImage**)&mux->images_, 1, &frame);
assert(err == WEBP_MUX_OK); // We know that one frame does exist.
assert(frame != NULL);
if (frame->header_ != NULL &&
((mux->canvas_width_ == 0 && mux->canvas_height_ == 0) ||
(frame->width_ == mux->canvas_width_ &&
frame->height_ == mux->canvas_height_))) {
assert(frame->header_->tag_ == kChunks[IDX_ANMF].tag);
ChunkDelete(frame->header_); // Removes ANMF chunk.
frame->header_ = NULL;
num_frames = 0;
}
}
// Remove ANIM chunk if this is a non-animated image.
err = WebPMuxNumChunks(mux, kChunks[IDX_ANIM].id, &num_anim_chunks);
if (err != WEBP_MUX_OK) return err;
if (num_anim_chunks >= 1 && num_frames == 0) {
err = MuxDeleteAllNamedData(mux, kChunks[IDX_ANIM].tag);
if (err != WEBP_MUX_OK) return err;
}
return WEBP_MUX_OK;
}
WebPMuxError WebPMuxGetFrame(
const WebPMux* mux, uint32_t nth, WebPMuxFrameInfo* frame) {
WebPMuxError err;
WebPMuxImage* wpi;
// Sanity checks.
if (mux == NULL || frame == NULL) {
return WEBP_MUX_INVALID_ARGUMENT;
}
// Get the nth WebPMuxImage.
err = MuxImageGetNth((const WebPMuxImage**)&mux->images_, nth, &wpi);
if (err != WEBP_MUX_OK) return err;
// Get frame info.
if (wpi->header_ == NULL) {
return MuxGetImageInternal(wpi, frame);
} else {
return MuxGetFrameFragmentInternal(wpi, frame);
}
}
