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Simplify the gif2webp tool: move the optimization details to util

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Specifically:
- Merge OptimizeAndEncodeFrame with WebPFrameCacheAddFrame: they use the same
  if-else structure.
- Move maintenance of 'prev_canvas' and 'curr_canvas' to util.
- Move ReduceTransparency() and FlattenPixels() calls to SetFrame(): This is in
  preparation for the next patch: which will try try lossless encoding for
  each frame, even when '-lossy' option is given.
- Make most methods static inside util.

No changes to output expected.

Change-Id: I1f65af25246665508cb20f0f6e338f9aaba9367b
This commit is contained in:
Urvang Joshi
2013-10-14 14:39:46 -07:00
parent cb22155201
commit 38efdc2e9c
3 changed files with 399 additions and 421 deletions
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89
examples/gif2webp_util.h
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@ -22,6 +22,21 @@
extern "C" {
#endif
//------------------------------------------------------------------------------
// Helper utilities.
#define WEBP_UTIL_TRANSPARENT_COLOR 0x00ffffff
struct WebPPicture;
typedef struct {
int x_offset, y_offset, width, height;
} WebPFrameRect;
// Clear pixels in 'picture' within given 'rect' to transparent color.
void WebPUtilClearPic(struct WebPPicture* const picture,
const WebPFrameRect* const rect);
//------------------------------------------------------------------------------
// Frame cache.
@ -30,23 +45,20 @@ typedef struct WebPFrameCache WebPFrameCache;
// Given the minimum distance between key frames 'kmin' and maximum distance
// between key frames 'kmax', returns an appropriately allocated cache object.
// Use WebPFrameCacheDelete() to deallocate the 'cache'.
WebPFrameCache* WebPFrameCacheNew(size_t kmin, size_t kmax);
WebPFrameCache* WebPFrameCacheNew(int width, int height,
size_t kmin, size_t kmax);
// Release all the frame data from 'cache' and free 'cache'.
void WebPFrameCacheDelete(WebPFrameCache* const cache);
// Add encoded frame in the cache. 'sub_frame_info' and 'sub_frame_pic' are used
// to encode the frame rectangle, while 'key_frame_info' and 'key_frame_pic' are
// used to encode the key frame. Either 'sub_frame_pic' (and 'sub_frame_info')
// or 'key_frame_pic' (and 'key_frame_info') can be NULL; in which case the
// corresponding variant will be omitted.
// Returns true on success.
// Given an image described by 'frame', 'info' and 'orig_rect', optimize it for
// WebP, encode it and add it to 'cache'.
// This takes care of frame disposal too, according to 'info->dispose_method'.
int WebPFrameCacheAddFrame(WebPFrameCache* const cache,
const WebPConfig* const config,
const WebPMuxFrameInfo* const sub_frame_info,
WebPPicture* const sub_frame_pic,
const WebPMuxFrameInfo* const key_frame_info,
WebPPicture* const key_frame_pic);
const WebPFrameRect* const orig_rect,
WebPPicture* const frame,
WebPMuxFrameInfo* const info);
// Flush the *ready* frames from cache and add them to 'mux'. If 'verbose' is
// true, prints the information about these frames.
@ -57,61 +69,6 @@ WebPMuxError WebPFrameCacheFlush(WebPFrameCache* const cache, int verbose,
WebPMuxError WebPFrameCacheFlushAll(WebPFrameCache* const cache, int verbose,
WebPMux* const mux);
// Returns true if subsequent call to WebPFrameCacheAddFrame() should
// incorporate a potential keyframe.
int WebPFrameCacheShouldTryKeyFrame(const WebPFrameCache* const cache);
//------------------------------------------------------------------------------
// Frame rectangle and related utilities.
#define TRANSPARENT_COLOR 0x00ffffff
typedef struct {
int x_offset, y_offset, width, height;
} WebPFrameRect;
struct WebPPicture;
// Clear pixels in 'picture' within given 'rect' to transparent color.
void WebPUtilClearPic(struct WebPPicture* const picture,
const WebPFrameRect* const rect);
// Copy pixels from 'src' to 'dst' honoring strides. 'src' and 'dst' are assumed
// to be already allocated.
void WebPUtilCopyPixels(const struct WebPPicture* const src,
WebPPicture* const dst);
// Given 'src' picture and its frame rectangle 'rect', blend it into 'dst'.
void WebPUtilBlendPixels(const struct WebPPicture* const src,
const WebPFrameRect* const src_rect,
struct WebPPicture* const dst);
// Replace transparent pixels within 'dst_rect' of 'dst' by those in the 'src'.
void WebPUtilReduceTransparency(const struct WebPPicture* const src,
const WebPFrameRect* const dst_rect,
struct WebPPicture* const dst);
// Replace similar blocks of pixels by a 'see-through' transparent block
// with uniform average color.
void WebPUtilFlattenSimilarBlocks(const WebPPicture* const src,
const WebPFrameRect* const rect,
WebPPicture* const dst);
//------------------------------------------------------------------------------
// Key frame related.
// Returns true if 'curr' frame with frame rectangle 'curr_rect' is a key frame,
// that is, it can be decoded independently of 'prev' canvas.
int WebPUtilIsKeyFrame(const WebPPicture* const curr,
const WebPFrameRect* const curr_rect,
const WebPPicture* const prev);
// Given 'prev' frame and current frame rectangle 'rect', convert 'curr' frame
// to a key frame.
void WebPUtilConvertToKeyFrame(const WebPPicture* const prev,
WebPFrameRect* const rect,
WebPPicture* const curr);
//------------------------------------------------------------------------------
#if defined(__cplusplus) || defined(c_plusplus)