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introduce WebPHasAlpha8b and WebPHasAlpha32b

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Rewrote WebPPictureHasTransparency() to use them (even for argb).
This is 10% faster, for some reasons.

SSE2 version should be straightforward.
Removes a TODO.

Change-Id: I7ad5848fc5e355e2df505dbcd5a0f42fb6cbab41
This commit is contained in:
Pascal Massimino 2017-11-16 06:59:52 -08:00
parent 80285d97ad
commit 44a0ee3fa7
3 changed files with 38 additions and 15 deletions
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21
src/dsp/alpha_processing.c
View File

@ -346,6 +346,19 @@ static void ExtractGreen_C(const uint32_t* argb, uint8_t* alpha, int size) {
}
#endif // !WEBP_NEON_OMIT_C_CODE
//------------------------------------------------------------------------------
static int HasAlpha8b_C(const uint8_t* src, int length) {
while (length-- > 0) if (*src++ != 0xff) return 1;
return 0;
}
static int HasAlpha32b_C(const uint8_t* src, int length) {
int x;
for (x = 0; length-- > 0; x += 4) if (src[x] != 0xff) return 1;
return 0;
}
//------------------------------------------------------------------------------
// Simple channel manipulations.
@ -371,6 +384,9 @@ void (*WebPExtractGreen)(const uint32_t* argb, uint8_t* alpha, int size);
void (*WebPPackRGB)(const uint8_t* r, const uint8_t* g, const uint8_t* b,
int len, int step, uint32_t* out);
int (*WebPHasAlpha8b)(const uint8_t* src, int length);
int (*WebPHasAlpha32b)(const uint8_t* src, int length);
//------------------------------------------------------------------------------
// Init function
@ -398,6 +414,9 @@ WEBP_TSAN_IGNORE_FUNCTION void WebPInitAlphaProcessing(void) {
WebPExtractGreen = ExtractGreen_C;
#endif
WebPHasAlpha8b = HasAlpha8b_C;
WebPHasAlpha32b = HasAlpha32b_C;
// If defined, use CPUInfo() to overwrite some pointers with faster versions.
if (VP8GetCPUInfo != NULL) {
#if defined(WEBP_USE_SSE2)
@ -433,6 +452,8 @@ WEBP_TSAN_IGNORE_FUNCTION void WebPInitAlphaProcessing(void) {
assert(WebPExtractAlpha != NULL);
assert(WebPExtractGreen != NULL);
assert(WebPPackRGB != NULL);
assert(WebPHasAlpha8b != NULL);
assert(WebPHasAlpha32b != NULL);
alpha_processing_last_cpuinfo_used = VP8GetCPUInfo;
}

5
src/dsp/dsp.h
View File

@ -578,6 +578,11 @@ void WebPMultARGBRow_C(uint32_t* const ptr, int width, int inverse);
extern void (*WebPPackRGB)(const uint8_t* r, const uint8_t* g, const uint8_t* b,
int len, int step, uint32_t* out);
// This function returns true if src[i] contains a value different from 0xff.
extern int (*WebPHasAlpha8b)(const uint8_t* src, int length);
// This function returns true if src[4*i] contains a value different from 0xff.
extern int (*WebPHasAlpha32b)(const uint8_t* src, int length);
// To be called first before using the above.
void WebPInitAlphaProcessing(void);

27
src/enc/picture_csp_enc.c
View File

@ -41,12 +41,15 @@ static const union {
static int CheckNonOpaque(const uint8_t* alpha, int width, int height,
int x_step, int y_step) {
if (alpha == NULL) return 0;
while (height-- > 0) {
int x;
for (x = 0; x < width * x_step; x += x_step) {
if (alpha[x] != 0xff) return 1; // TODO(skal): check 4/8 bytes at a time.
WebPInitAlphaProcessing();
if (x_step == 1) {
for (; height-- > 0; alpha += y_step) {
if (WebPHasAlpha8b(alpha, width)) return 1;
}
} else {
for (; height-- > 0; alpha += y_step) {
if (WebPHasAlpha32b(alpha, width)) return 1;
}
alpha += y_step;
}
return 0;
}
@ -58,15 +61,10 @@ int WebPPictureHasTransparency(const WebPPicture* picture) {
return CheckNonOpaque(picture->a, picture->width, picture->height,
1, picture->a_stride);
} else {
int x, y;
const uint32_t* argb = picture->argb;
if (argb == NULL) return 0;
for (y = 0; y < picture->height; ++y) {
for (x = 0; x < picture->width; ++x) {
if (argb[x] < 0xff000000u) return 1; // test any alpha values != 0xff
}
argb += picture->argb_stride;
}
const int alpha_offset = ALPHA_IS_LAST ? 3 : 0;
return CheckNonOpaque((const uint8_t*)picture->argb + alpha_offset,
picture->width, picture->height,
4, picture->argb_stride * sizeof(*picture->argb));
}
return 0;
}
@ -858,7 +856,6 @@ static int ImportYUVAFromRGBA(const uint8_t* r_ptr,
return 0;
}
if (has_alpha) {
WebPInitAlphaProcessing();
assert(step == 4);
#if defined(USE_GAMMA_COMPRESSION) && defined(USE_INVERSE_ALPHA_TABLE)
assert(kAlphaFix + kGammaFix <= 31);