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Add example code snippet for demux API

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Change-Id: I4e9f32d030dd7f184e1cedf5b37f6f640ba4845e
This commit is contained in:
Urvang Joshi
2013-02-22 14:16:48 -08:00
parent 5f557f3c1b
commit 38a91e990b
1 changed files with 35 additions and 2 deletions
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37
src/webp/demux.h
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@@ -8,7 +8,39 @@
// Demux API. // Demux API.
// Enables extraction of image and extended format data from WebP files. // Enables extraction of image and extended format data from WebP files.
// TODO(urvang): Add an example code snippet (similar to mux.h). // Code Example: Demuxing WebP data to extract all the frames, ICC profile
// and EXIF/XMP metadata.
//
// WebPDemuxer* demux = WebPDemux(&webp_data);
//
// uint32_t width = WebPDemuxGetI(demux, WEBP_FF_CANVAS_WIDTH);
// uint32_t height = WebPDemuxGetI(demux, WEBP_FF_CANVAS_HEIGHT);
// // ... (Get information about the features present in the WebP file).
// uint32_t flags = WebPDemuxGetI(demux, WEBP_FF_FORMAT_FLAGS);
//
// // ... (Iterate over all frames).
// WebPIterator iter;
// if (WebPDemuxGetFrame(demux, 1, &iter)) {
// do {
// // ... (Consume 'iter'; e.g. Decode 'iter.fragment' with WebPDecode(),
// // ... and get other frame properties like width, height, offsets etc.
// // ... see 'struct WebPIterator' below for more info).
// } while (WebPDemuxNextFrame(&iter));
// WebPDemuxReleaseIterator(&iter);
// }
//
// // ... (Extract metadata).
// WebPChunkIterator chunk_iter;
// if (flags & ICCP_FLAG) WebPDemuxGetChunk(demux, "ICCP", 1, &chunk_iter);
// // ... (Consume the ICC profile in 'chunk_iter.chunk').
// WebPDemuxReleaseChunkIterator(&chunk_iter);
// if (flags & EXIF_FLAG) WebPDemuxGetChunk(demux, "EXIF", 1, &chunk_iter);
// // ... (Consume the EXIF metadata in 'chunk_iter.chunk').
// WebPDemuxReleaseChunkIterator(&chunk_iter);
// if (flags & XMP_FLAG) WebPDemuxGetChunk(demux, "XMP ", 1, &chunk_iter);
// // ... (Consume the XMP metadata in 'chunk_iter.chunk').
// WebPDemuxReleaseChunkIterator(&chunk_iter);
// WebPDemuxDelete(demux);
#ifndef WEBP_WEBP_DEMUX_H_ #ifndef WEBP_WEBP_DEMUX_H_
#define WEBP_WEBP_DEMUX_H_ #define WEBP_WEBP_DEMUX_H_
@@ -120,7 +152,8 @@ WEBP_EXTERN(int) WebPDemuxPrevFrame(WebPIterator* iter);
WEBP_EXTERN(int) WebPDemuxSelectFragment(WebPIterator* iter, int fragment_num); WEBP_EXTERN(int) WebPDemuxSelectFragment(WebPIterator* iter, int fragment_num);
// Releases any memory associated with 'iter'. // Releases any memory associated with 'iter'.
// Must be called before destroying the associated WebPDemuxer with // Must be called before any subsequent calls to WebPDemuxGetChunk() on the same
// iter. Also, must be called before destroying the associated WebPDemuxer with
// WebPDemuxDelete(). // WebPDemuxDelete().
WEBP_EXTERN(void) WebPDemuxReleaseIterator(WebPIterator* iter); WEBP_EXTERN(void) WebPDemuxReleaseIterator(WebPIterator* iter);