dany/libwebp
1
0
Fork 0
mirror of https://github.com/webmproject/libwebp.git synced 2025-07-16 13:59:51 +02:00
Code Issues Actions Packages Projects Releases Wiki Activity

Add a WebPExtractAlpha function to dsp

Browse Source 
This is the opposite of WebPDispatchAlpha

+ Implement the SSE2 version

(cherry picked from commit cddd334050)

Conflicts:
	src/dsp/alpha_processing_sse2.c

Change-Id: I0c297309255f508c5261da8aad01f7e57f924d6c
This commit is contained in:
Pascal Massimino
2014-09-15 08:11:36 +02:00
committed by James Zern
parent e407b5d516
commit 9102a7b63d
7 changed files with 119 additions and 0 deletions
Download Patch File Download Diff File Expand all files Collapse all files

31
src/dsp/alpha_processing.c
View File

@ -284,15 +284,46 @@ static void ApplyAlphaMultiply_16b(uint8_t* rgba4444,
#endif
}
static int ExtractAlpha(const uint8_t* argb, int argb_stride,
int width, int height,
uint8_t* alpha, int alpha_stride) {
uint8_t alpha_mask = 0xff;
int i, j;
for (j = 0; j < height; ++j) {
for (i = 0; i < width; ++i) {
const uint8_t alpha_value = argb[4 * i];
alpha[i] = alpha_value;
alpha_mask &= alpha_value;
}
argb += argb_stride;
alpha += alpha_stride;
}
return (alpha_mask == 0xff);
}
void (*WebPApplyAlphaMultiply)(uint8_t*, int, int, int, int);
void (*WebPApplyAlphaMultiply4444)(uint8_t*, int, int, int);
int (*WebPExtractAlpha)(const uint8_t*, int, int, int, uint8_t*, int);
//------------------------------------------------------------------------------
// Init function
extern void WebPInitAlphaProcessingSSE2(void);
void WebPInitAlphaProcessing(void) {
WebPMultARGBRow = MultARGBRow;
WebPMultRow = MultRow;
WebPApplyAlphaMultiply = ApplyAlphaMultiply;
WebPApplyAlphaMultiply4444 = ApplyAlphaMultiply_16b;
WebPExtractAlpha = ExtractAlpha;
// If defined, use CPUInfo() to overwrite some pointers with faster versions.
if (VP8GetCPUInfo != NULL) {
#if defined(WEBP_USE_SSE2)
if (VP8GetCPUInfo(kSSE2)) {
WebPInitAlphaProcessingSSE2();
}
#endif
}
}