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Mux: Allow only some frames/tiles to have alpha.

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And related const fixes.

Change-Id: I79f6f1b9f8c6faac8cc4ef24b58edff6d90de045
This commit is contained in:
Urvang Joshi
2012-06-29 17:16:08 +05:30
parent 3ba81bbe8b
commit 97649c8f6b
4 changed files with 17 additions and 26 deletions
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5
src/mux/muxedit.c
View File

@ -613,9 +613,8 @@ static WebPMuxError CreateVP8XChunk(WebPMux* const mux) {
}
}
if (images->alpha_ != NULL && images->alpha_->data_.bytes_ != NULL) {
// This is an image with alpha channel.
flags |= ALPHA_FLAG;
if (MuxImageCount(images, WEBP_CHUNK_ALPHA) > 0) {
flags |= ALPHA_FLAG; // Some images have an alpha channel.
}
if (flags == 0) {

12
src/mux/muxi.h
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@ -194,7 +194,7 @@ WebPMuxImage* MuxImageDelete(WebPMuxImage* const wpi);
void MuxImageDeleteAll(WebPMuxImage** const wpi_list);
// Count number of images matching the given tag id in the 'wpi_list'.
int MuxImageCount(WebPMuxImage* const wpi_list, WebPChunkId id);
int MuxImageCount(const WebPMuxImage* wpi_list, WebPChunkId id);
// Check if given ID corresponds to an image related chunk.
static WEBP_INLINE int IsWPI(WebPChunkId id) {
@ -208,14 +208,14 @@ static WEBP_INLINE int IsWPI(WebPChunkId id) {
}
// Get a reference to appropriate chunk list within an image given chunk tag.
static WEBP_INLINE WebPChunk** MuxImageGetListFromId(WebPMuxImage* wpi,
WebPChunkId id) {
static WEBP_INLINE WebPChunk** MuxImageGetListFromId(
const WebPMuxImage* const wpi, WebPChunkId id) {
assert(wpi != NULL);
switch (id) {
case WEBP_CHUNK_FRAME:
case WEBP_CHUNK_TILE: return &wpi->header_;
case WEBP_CHUNK_ALPHA: return &wpi->alpha_;
case WEBP_CHUNK_IMAGE: return &wpi->img_;
case WEBP_CHUNK_TILE: return (WebPChunk**)&wpi->header_;
case WEBP_CHUNK_ALPHA: return (WebPChunk**)&wpi->alpha_;
case WEBP_CHUNK_IMAGE: return (WebPChunk**)&wpi->img_;
default: return NULL;
}
}

11
src/mux/muxinternal.c
View File

@ -262,9 +262,9 @@ WebPMuxImage* MuxImageRelease(WebPMuxImage* const wpi) {
//------------------------------------------------------------------------------
// MuxImage search methods.
int MuxImageCount(WebPMuxImage* const wpi_list, WebPChunkId id) {
int MuxImageCount(const WebPMuxImage* wpi_list, WebPChunkId id) {
int count = 0;
WebPMuxImage* current;
const WebPMuxImage* current;
for (current = wpi_list; current != NULL; current = current->next_) {
const WebPChunk* const wpi_chunk = *MuxImageGetListFromId(current, id);
if (wpi_chunk != NULL) {
@ -558,13 +558,6 @@ WebPMuxError MuxValidate(const WebPMux* const mux) {
} else {
err = ValidateChunk(mux, IDX_ALPHA, ALPHA_FLAG, flags, -1, &num_alpha);
if (err != WEBP_MUX_OK) return err;
// num_images & num_alpha_chunks are consistent.
if (num_alpha > 0 && num_alpha != num_images) {
// Note that "num_alpha > 0" is the correct test but "flags && ALPHA_FLAG"
// is NOT, because ALPHA_FLAG is based on first image only.
return WEBP_MUX_INVALID_ARGUMENT;
}
}
// num_tiles & num_images are consistent.