// Copyright 2014 Google Inc. All Rights Reserved.
//
// Use of this source code is governed by a BSD-style license
// that can be found in the COPYING file in the root of the source
// tree. An additional intellectual property rights grant can be found
// in the file PATENTS. All contributing project authors may
// be found in the AUTHORS file in the root of the source tree.
// -----------------------------------------------------------------------------
//
// WebPPicture utils for colorspace conversion
//
// Author: Skal (pascal.massimino@gmail.com)
#include <assert.h>
#include <stdlib.h>
#include <math.h>
#include "./vp8enci.h"
#include "../utils/random.h"
#include "../utils/utils.h"
#include "../dsp/yuv.h"
// Uncomment to disable gamma-compression during RGB->U/V averaging
#define USE_GAMMA_COMPRESSION
// If defined, use table to compute x / alpha.
#define USE_INVERSE_ALPHA_TABLE
static const union {
uint32_t argb;
uint8_t bytes[4];
} test_endian = { 0xff000000u };
#define ALPHA_IS_LAST (test_endian.bytes[3] == 0xff)
//------------------------------------------------------------------------------
// Detection of non-trivial transparency
// Returns true if alpha[] has non-0xff values.
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.
}
alpha += y_step;
}
return 0;
}
// Checking for the presence of non-opaque alpha.
int WebPPictureHasTransparency(const WebPPicture* picture) {
if (picture == NULL) return 0;
if (!picture->use_argb) {
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;
}
}
return 0;
}
//------------------------------------------------------------------------------
// Code for gamma correction
#if defined(USE_GAMMA_COMPRESSION)
// gamma-compensates loss of resolution during chroma subsampling
#define kGamma 0.80 // for now we use a different gamma value than kGammaF
#define kGammaFix 12 // fixed-point precision for linear values
#define kGammaScale ((1 << kGammaFix) - 1)
#define kGammaTabFix 7 // fixed-point fractional bits precision
#define kGammaTabScale (1 << kGammaTabFix)
#define kGammaTabRounder (kGammaTabScale >> 1)
#define kGammaTabSize (1 << (kGammaFix - kGammaTabFix))
static int kLinearToGammaTab[kGammaTabSize + 1];
static uint16_t kGammaToLinearTab[256];
static volatile int kGammaTablesOk = 0;
static WEBP_TSAN_IGNORE_FUNCTION void InitGammaTables(void) {
if (!kGammaTablesOk) {
int v;
const double scale = (double)(1 << kGammaTabFix) / kGammaScale;
const double norm = 1. / 255.;
for (v = 0; v <= 255; ++v) {
kGammaToLinearTab[v] =
(uint16_t)(pow(norm * v, kGamma) * kGammaScale + .5);
}
for (v = 0; v <= kGammaTabSize; ++v) {
kLinearToGammaTab[v] = (int)(255. * pow(scale * v, 1. / kGamma) + .5);
}
kGammaTablesOk = 1;
}
}
static WEBP_INLINE uint32_t GammaToLinear(uint8_t v) {
return kGammaToLinearTab[v];
}
static WEBP_INLINE int Interpolate(int v) {
const int tab_pos = v >> (kGammaTabFix + 2); // integer part
const int x = v & ((kGammaTabScale << 2) - 1); // fractional part
const int v0 = kLinearToGammaTab[tab_pos];
const int v1 = kLinearToGammaTab[tab_pos + 1];
const int y = v1 * x + v0 * ((kGammaTabScale << 2) - x); // interpolate
assert(tab_pos + 1 < kGammaTabSize + 1);
return y;
}
// Convert a linear value 'v' to YUV_FIX+2 fixed-point precision
// U/V value, suitable for RGBToU/V calls.
static WEBP_INLINE int LinearToGamma(uint32_t base_value, int shift) {
const int y = Interpolate(base_value << shift); // final uplifted value
return (y + kGammaTabRounder) >> kGammaTabFix; // descale
}
#else
static WEBP_TSAN_IGNORE_FUNCTION void InitGammaTables(void) {}
static WEBP_INLINE uint32_t GammaToLinear(uint8_t v) { return v; }
static WEBP_INLINE int LinearToGamma(uint32_t base_value, int shift) {
return (int)(base_value << shift);
}
#endif // USE_GAMMA_COMPRESSION
//------------------------------------------------------------------------------
// RGB -> YUV conversion
static int RGBToY(int r, int g, int b, VP8Random* const rg) {
return (rg == NULL) ? VP8RGBToY(r, g, b, YUV_HALF)
: VP8RGBToY(r, g, b, VP8RandomBits(rg, YUV_FIX));
}
static int RGBToU(int r, int g, int b, VP8Random* const rg) {
return (rg == NULL) ? VP8RGBToU(r, g, b, YUV_HALF << 2)
: VP8RGBToU(r, g, b, VP8RandomBits(rg, YUV_FIX + 2));
}
static int RGBToV(int r, int g, int b, VP8Random* const rg) {
return (rg == NULL) ? VP8RGBToV(r, g, b, YUV_HALF << 2)
: VP8RGBToV(r, g, b, VP8RandomBits(rg, YUV_FIX + 2));
}
//------------------------------------------------------------------------------
// Smart RGB->YUV conversion
static const int kNumIterations = 6;
static const int kMinDimensionIterativeConversion = 4;
// We could use SFIX=0 and only uint8_t for fixed_y_t, but it produces some
// banding sometimes. Better use extra precision.
#define SFIX 2 // fixed-point precision of RGB and Y/W
typedef int16_t fixed_t; // signed type with extra SFIX precision for UV
typedef uint16_t fixed_y_t; // unsigned type with extra SFIX precision for W
#define SHALF (1 << SFIX >> 1)
#define MAX_Y_T ((256 << SFIX) - 1)
#define SROUNDER (1 << (YUV_FIX + SFIX - 1))
#if defined(USE_GAMMA_COMPRESSION)
// float variant of gamma-correction
// We use tables of different size and precision, along with a 'real-world'
// Gamma value close to ~2.
#define kGammaF 2.2
static float kGammaToLinearTabF[MAX_Y_T + 1]; // size scales with Y_FIX
static float kLinearToGammaTabF[kGammaTabSize + 2];
static volatile int kGammaTablesFOk = 0;
static WEBP_TSAN_IGNORE_FUNCTION void InitGammaTablesF(void) {
if (!kGammaTablesFOk) {
int v;
const double norm = 1. / MAX_Y_T;
const double scale = 1. / kGammaTabSize;
for (v = 0; v <= MAX_Y_T; ++v) {
kGammaToLinearTabF[v] = (float)pow(norm * v, kGammaF);
}
for (v = 0; v <= kGammaTabSize; ++v) {
kLinearToGammaTabF[v] = (float)(MAX_Y_T * pow(scale * v, 1. / kGammaF));
}
// to prevent small rounding errors to cause read-overflow:
kLinearToGammaTabF[kGammaTabSize + 1] = kLinearToGammaTabF[kGammaTabSize];
kGammaTablesFOk = 1;
}
}
static WEBP_INLINE float GammaToLinearF(int v) {
return kGammaToLinearTabF[v];
}
static WEBP_INLINE int LinearToGammaF(float value) {
const float v = value * kGammaTabSize;
const int tab_pos = (int)v;
const float x = v - (float)tab_pos; // fractional part
const float v0 = kLinearToGammaTabF[tab_pos + 0];
const float v1 = kLinearToGammaTabF[tab_pos + 1];
const float y = v1 * x + v0 * (1.f - x); // interpolate
return (int)(y + .5);
}
#else
static WEBP_TSAN_IGNORE_FUNCTION void InitGammaTablesF(void) {}
static WEBP_INLINE float GammaToLinearF(int v) {
const float norm = 1.f / MAX_Y_T;
return norm * v;
}
static WEBP_INLINE int LinearToGammaF(float value) {
return (int)(MAX_Y_T * value + .5);
}
#endif // USE_GAMMA_COMPRESSION
//------------------------------------------------------------------------------
static uint8_t clip_8b(fixed_t v) {
return (!(v & ~0xff)) ? (uint8_t)v : (v < 0) ? 0u : 255u;
}
static fixed_y_t clip_y(int y) {
return (!(y & ~MAX_Y_T)) ? (fixed_y_t)y : (y < 0) ? 0 : MAX_Y_T;
}
//------------------------------------------------------------------------------
static int RGBToGray(int r, int g, int b) {
const int luma = 19595 * r + 38470 * g + 7471 * b + YUV_HALF;
return (luma >> YUV_FIX);
}
static float RGBToGrayF(float r, float g, float b) {
return 0.299f * r + 0.587f * g + 0.114f * b;
}
static int ScaleDown(int a, int b, int c, int d) {
const float A = GammaToLinearF(a);
const float B = GammaToLinearF(b);
const float C = GammaToLinearF(c);
const float D = GammaToLinearF(d);
return LinearToGammaF(0.25f * (A + B + C + D));
}
static WEBP_INLINE void UpdateW(const fixed_y_t* src, fixed_y_t* dst, int len) {
while (len-- > 0) {
const float R = GammaToLinearF(src[0]);
const float G = GammaToLinearF(src[1]);
const float B = GammaToLinearF(src[2]);
const float Y = RGBToGrayF(R, G, B);
*dst++ = (fixed_y_t)LinearToGammaF(Y);
src += 3;
}
}
static int UpdateChroma(const fixed_y_t* src1,
const fixed_y_t* src2,
fixed_t* dst, fixed_y_t* tmp, int len) {
int diff = 0;
while (len--> 0) {
const int r = ScaleDown(src1[0], src1[3], src2[0], src2[3]);
const int g = ScaleDown(src1[1], src1[4], src2[1], src2[4]);
const int b = ScaleDown(src1[2], src1[5], src2[2], src2[5]);
const int W = RGBToGray(r, g, b);
const int r_avg = (src1[0] + src1[3] + src2[0] + src2[3] + 2) >> 2;
const int g_avg = (src1[1] + src1[4] + src2[1] + src2[4] + 2) >> 2;
const int b_avg = (src1[2] + src1[5] + src2[2] + src2[5] + 2) >> 2;
dst[0] = (fixed_t)(r - W);
dst[1] = (fixed_t)(g - W);
dst[2] = (fixed_t)(b - W);
dst += 3;
src1 += 6;
src2 += 6;
if (tmp != NULL) {
tmp[0] = tmp[1] = clip_y(W);
tmp += 2;
}
diff += abs(RGBToGray(r_avg, g_avg, b_avg) - W);
}
return diff;
}
//------------------------------------------------------------------------------
static WEBP_INLINE int Filter(const fixed_t* const A, const fixed_t* const B,
int rightwise) {
int v;
if (!rightwise) {
v = (A[0] * 9 + A[-3] * 3 + B[0] * 3 + B[-3]);
} else {
v = (A[0] * 9 + A[+3] * 3 + B[0] * 3 + B[+3]);
}
return (v + 8) >> 4;
}
static WEBP_INLINE int Filter2(int A, int B) { return (A * 3 + B + 2) >> 2; }
//------------------------------------------------------------------------------
static WEBP_INLINE fixed_y_t UpLift(uint8_t a) { // 8bit -> SFIX
return ((fixed_y_t)a << SFIX) | SHALF;
}
static void ImportOneRow(const uint8_t* const r_ptr,
const uint8_t* const g_ptr,
const uint8_t* const b_ptr,
int step,
int pic_width,
fixed_y_t* const dst) {
int i;
for (i = 0; i < pic_width; ++i) {
const int off = i * step;
dst[3 * i + 0] = UpLift(r_ptr[off]);
dst[3 * i + 1] = UpLift(g_ptr[off]);
dst[3 * i + 2] = UpLift(b_ptr[off]);
}
if (pic_width & 1) { // replicate rightmost pixel
memcpy(dst + 3 * pic_width, dst + 3 * (pic_width - 1), 3 * sizeof(*dst));
}
}
static void InterpolateTwoRows(const fixed_y_t* const best_y,
const fixed_t* const prev_uv,
const fixed_t* const cur_uv,
const fixed_t* const next_uv,
int w,
fixed_y_t* const out1,
fixed_y_t* const out2) {
int i, k;
{ // special boundary case for i==0
const int W0 = best_y[0];
const int W1 = best_y[w];
for (k = 0; k <= 2; ++k) {
out1[k] = clip_y(Filter2(cur_uv[k], prev_uv[k]) + W0);
out2[k] = clip_y(Filter2(cur_uv[k], next_uv[k]) + W1);
}
}
for (i = 1; i < w - 1; ++i) {
const int W0 = best_y[i + 0];
const int W1 = best_y[i + w];
const int off = 3 * (i >> 1);
for (k = 0; k <= 2; ++k) {
const int tmp0 = Filter(cur_uv + off + k, prev_uv + off + k, i & 1);
const int tmp1 = Filter(cur_uv + off + k, next_uv + off + k, i & 1);
out1[3 * i + k] = clip_y(tmp0 + W0);
out2[3 * i + k] = clip_y(tmp1 + W1);
}
}
{ // special boundary case for i == w - 1
const int W0 = best_y[i + 0];
const int W1 = best_y[i + w];
const int off = 3 * (i >> 1);
for (k = 0; k <= 2; ++k) {
out1[3 * i + k] = clip_y(Filter2(cur_uv[off + k], prev_uv[off + k]) + W0);
out2[3 * i + k] = clip_y(Filter2(cur_uv[off + k], next_uv[off + k]) + W1);
}
}
}
static WEBP_INLINE uint8_t ConvertRGBToY(int r, int g, int b) {
const int luma = 16839 * r + 33059 * g + 6420 * b + SROUNDER;
return clip_8b(16 + (luma >> (YUV_FIX + SFIX)));
}
static WEBP_INLINE uint8_t ConvertRGBToU(int r, int g, int b) {
const int u = -9719 * r - 19081 * g + 28800 * b + SROUNDER;
return clip_8b(128 + (u >> (YUV_FIX + SFIX)));
}
static WEBP_INLINE uint8_t ConvertRGBToV(int r, int g, int b) {
const int v = +28800 * r - 24116 * g - 4684 * b + SROUNDER;
return clip_8b(128 + (v >> (YUV_FIX + SFIX)));
}
static int ConvertWRGBToYUV(const fixed_y_t* const best_y,
const fixed_t* const best_uv,
WebPPicture* const picture) {
int i, j;
const int w = (picture->width + 1) & ~1;
const int h = (picture->height + 1) & ~1;
const int uv_w = w >> 1;
const int uv_h = h >> 1;
for (j = 0; j < picture->height; ++j) {
for (i = 0; i < picture->width; ++i) {
const int off = 3 * ((i >> 1) + (j >> 1) * uv_w);
const int off2 = i + j * picture->y_stride;
const int W = best_y[i + j * w];
const int r = best_uv[off + 0] + W;
const int g = best_uv[off + 1] + W;
const int b = best_uv[off + 2] + W;
picture->y[off2] = ConvertRGBToY(r, g, b);
}
}
for (j = 0; j < uv_h; ++j) {
uint8_t* const dst_u = picture->u + j * picture->uv_stride;
uint8_t* const dst_v = picture->v + j * picture->uv_stride;
for (i = 0; i < uv_w; ++i) {
const int off = 3 * (i + j * uv_w);
const int r = best_uv[off + 0];
const int g = best_uv[off + 1];
const int b = best_uv[off + 2];
dst_u[i] = ConvertRGBToU(r, g, b);
dst_v[i] = ConvertRGBToV(r, g, b);
}
}
return 1;
}
//------------------------------------------------------------------------------
// Main function
#define SAFE_ALLOC(W, H, T) ((T*)WebPSafeMalloc((W) * (H), sizeof(T)))
static int PreprocessARGB(const uint8_t* const r_ptr,
const uint8_t* const g_ptr,
const uint8_t* const b_ptr,
int step, int rgb_stride,
WebPPicture* const picture) {
// we expand the right/bottom border if needed
const int w = (picture->width + 1) & ~1;
const int h = (picture->height + 1) & ~1;
const int uv_w = w >> 1;
const int uv_h = h >> 1;
int i, j, iter;
// TODO(skal): allocate one big memory chunk. But for now, it's easier
// for valgrind debugging to have several chunks.
fixed_y_t* const tmp_buffer = SAFE_ALLOC(w * 3, 2, fixed_y_t); // scratch
fixed_y_t* const best_y = SAFE_ALLOC(w, h, fixed_y_t);
fixed_y_t* const target_y = SAFE_ALLOC(w, h, fixed_y_t);
fixed_y_t* const best_rgb_y = SAFE_ALLOC(w, 2, fixed_y_t);
fixed_t* const best_uv = SAFE_ALLOC(uv_w * 3, uv_h, fixed_t);
fixed_t* const target_uv = SAFE_ALLOC(uv_w * 3, uv_h, fixed_t);
fixed_t* const best_rgb_uv = SAFE_ALLOC(uv_w * 3, 1, fixed_t);
int ok;
int diff_sum = 0;
const int first_diff_threshold = (int)(2.5 * w * h);
const int min_improvement = 5; // stop if improvement is below this %
const int min_first_improvement = 80;
if (best_y == NULL || best_uv == NULL ||
target_y == NULL || target_uv == NULL ||
best_rgb_y == NULL || best_rgb_uv == NULL ||
tmp_buffer == NULL) {
ok = WebPEncodingSetError(picture, VP8_ENC_ERROR_OUT_OF_MEMORY);
goto End;
}
assert(picture->width >= kMinDimensionIterativeConversion);
assert(picture->height >= kMinDimensionIterativeConversion);
// Import RGB samples to W/RGB representation.
for (j = 0; j < picture->height; j += 2) {
const int is_last_row = (j == picture->height - 1);
fixed_y_t* const src1 = tmp_buffer;
fixed_y_t* const src2 = tmp_buffer + 3 * w;
const int off1 = j * rgb_stride;
const int off2 = off1 + rgb_stride;
const int uv_off = (j >> 1) * 3 * uv_w;
fixed_y_t* const dst_y = best_y + j * w;
// prepare two rows of input
ImportOneRow(r_ptr + off1, g_ptr + off1, b_ptr + off1,
step, picture->width, src1);
if (!is_last_row) {
ImportOneRow(r_ptr + off2, g_ptr + off2, b_ptr + off2,
step, picture->width, src2);
} else {
memcpy(src2, src1, 3 * w * sizeof(*src2));
}
UpdateW(src1, target_y + (j + 0) * w, w);
UpdateW(src2, target_y + (j + 1) * w, w);
diff_sum += UpdateChroma(src1, src2, target_uv + uv_off, dst_y, uv_w);
memcpy(best_uv + uv_off, target_uv + uv_off, 3 * uv_w * sizeof(*best_uv));
memcpy(dst_y + w, dst_y, w * sizeof(*dst_y));
}
// Iterate and resolve clipping conflicts.
for (iter = 0; iter < kNumIterations; ++iter) {
int k;
const fixed_t* cur_uv = best_uv;
const fixed_t* prev_uv = best_uv;
const int old_diff_sum = diff_sum;
diff_sum = 0;
for (j = 0; j < h; j += 2) {
fixed_y_t* const src1 = tmp_buffer;
fixed_y_t* const src2 = tmp_buffer + 3 * w;
{
const fixed_t* const next_uv = cur_uv + ((j < h - 2) ? 3 * uv_w : 0);
InterpolateTwoRows(best_y + j * w, prev_uv, cur_uv, next_uv,
w, src1, src2);
prev_uv = cur_uv;
cur_uv = next_uv;
}
UpdateW(src1, best_rgb_y + 0 * w, w);
UpdateW(src2, best_rgb_y + 1 * w, w);
diff_sum += UpdateChroma(src1, src2, best_rgb_uv, NULL, uv_w);
// update two rows of Y and one row of RGB
for (i = 0; i < 2 * w; ++i) {
const int off = i + j * w;
const int diff_y = target_y[off] - best_rgb_y[i];
const int new_y = (int)best_y[off] + diff_y;
best_y[off] = clip_y(new_y);
}
for (i = 0; i < uv_w; ++i) {
const int off = 3 * (i + (j >> 1) * uv_w);
int W;
for (k = 0; k <= 2; ++k) {
const int diff_uv = (int)target_uv[off + k] - best_rgb_uv[3 * i + k];
best_uv[off + k] += diff_uv;
}
W = RGBToGray(best_uv[off + 0], best_uv[off + 1], best_uv[off + 2]);
for (k = 0; k <= 2; ++k) {
best_uv[off + k] -= W;
}
}
}
// test exit condition
if (diff_sum > 0) {
const int improvement = 100 * abs(diff_sum - old_diff_sum) / diff_sum;
// Check if first iteration gave good result already, without a large
// jump of improvement (otherwise it means we need to try few extra
// iterations, just to be sure).
if (iter == 0 && diff_sum < first_diff_threshold &&
improvement < min_first_improvement) {
break;
}
// then, check if improvement is stalling.
if (improvement < min_improvement) {
break;
}
} else {
break;
}
}
// final reconstruction
ok = ConvertWRGBToYUV(best_y, best_uv, picture);
End:
WebPSafeFree(best_y);
WebPSafeFree(best_uv);
WebPSafeFree(target_y);
WebPSafeFree(target_uv);
WebPSafeFree(best_rgb_y);
WebPSafeFree(best_rgb_uv);
WebPSafeFree(tmp_buffer);
return ok;
}
#undef SAFE_ALLOC
//------------------------------------------------------------------------------
// "Fast" regular RGB->YUV
#define SUM4(ptr, step) LinearToGamma( \
GammaToLinear((ptr)[0]) + \
GammaToLinear((ptr)[(step)]) + \
GammaToLinear((ptr)[rgb_stride]) + \
GammaToLinear((ptr)[rgb_stride + (step)]), 0) \
#define SUM2(ptr) \
LinearToGamma(GammaToLinear((ptr)[0]) + GammaToLinear((ptr)[rgb_stride]), 1)
#define SUM2ALPHA(ptr) ((ptr)[0] + (ptr)[rgb_stride])
#define SUM4ALPHA(ptr) (SUM2ALPHA(ptr) + SUM2ALPHA((ptr) + 4))
#if defined(USE_INVERSE_ALPHA_TABLE)
static const int kAlphaFix = 19;
// Following table is (1 << kAlphaFix) / a. The (v * kInvAlpha[a]) >> kAlphaFix
// formula is then equal to v / a in most (99.6%) cases. Note that this table
// and constant are adjusted very tightly to fit 32b arithmetic.
// In particular, they use the fact that the operands for 'v / a' are actually
// derived as v = (a0.p0 + a1.p1 + a2.p2 + a3.p3) and a = a0 + a1 + a2 + a3
// with ai in [0..255] and pi in [0..1<<kGammaFix). The constraint to avoid
// overflow is: kGammaFix + kAlphaFix <= 31.
static const uint32_t kInvAlpha[4 * 0xff + 1] = {
0, /* alpha = 0 */
524288, 262144, 174762, 131072, 104857, 87381, 74898, 65536,
58254, 52428, 47662, 43690, 40329, 37449, 34952, 32768,
30840, 29127, 27594, 26214, 24966, 23831, 22795, 21845,
20971, 20164, 19418, 18724, 18078, 17476, 16912, 16384,
15887, 15420, 14979, 14563, 14169, 13797, 13443, 13107,
12787, 12483, 12192, 11915, 11650, 11397, 11155, 10922,
10699, 10485, 10280, 10082, 9892, 9709, 9532, 9362,
9198, 9039, 8886, 8738, 8594, 8456, 8322, 8192,
8065, 7943, 7825, 7710, 7598, 7489, 7384, 7281,
7182, 7084, 6990, 6898, 6808, 6721, 6636, 6553,
6472, 6393, 6316, 6241, 6168, 6096, 6026, 5957,
5890, 5825, 5761, 5698, 5637, 5577, 5518, 5461,
5405, 5349, 5295, 5242, 5190, 5140, 5090, 5041,
4993, 4946, 4899, 4854, 4809, 4766, 4723, 4681,
4639, 4599, 4559, 4519, 4481, 4443, 4405, 4369,
4332, 4297, 4262, 4228, 4194, 4161, 4128, 4096,
4064, 4032, 4002, 3971, 3942, 3912, 3883, 3855,
3826, 3799, 3771, 3744, 3718, 3692, 3666, 3640,
3615, 3591, 3566, 3542, 3518, 3495, 3472, 3449,
3426, 3404, 3382, 3360, 3339, 3318, 3297, 3276,
3256, 3236, 3216, 3196, 3177, 3158, 3139, 3120,
3102, 3084, 3066, 3048, 3030, 3013, 2995, 2978,
2962, 2945, 2928, 2912, 2896, 2880, 2864, 2849,
2833, 2818, 2803, 2788, 2774, 2759, 2744, 2730,
2716, 2702, 2688, 2674, 2661, 2647, 2634, 2621,
2608, 2595, 2582, 2570, 2557, 2545, 2532, 2520,
2508, 2496, 2484, 2473, 2461, 2449, 2438, 2427,
2416, 2404, 2394, 2383, 2372, 2361, 2351, 2340,
2330, 2319, 2309, 2299, 2289, 2279, 2269, 2259,
2250, 2240, 2231, 2221, 2212, 2202, 2193, 2184,
2175, 2166, 2157, 2148, 2139, 2131, 2122, 2114,
2105, 2097, 2088, 2080, 2072, 2064, 2056, 2048,
2040, 2032, 2024, 2016, 2008, 2001, 1993, 1985,
1978, 1971, 1963, 1956, 1949, 1941, 1934, 1927,
1920, 1913, 1906, 1899, 1892, 1885, 1879, 1872,
1865, 1859, 1852, 1846, 1839, 1833, 1826, 1820,
1814, 1807, 1801, 1795, 1789, 1783, 1777, 1771,
1765, 1759, 1753, 1747, 1741, 1736, 1730, 1724,
1718, 1713, 1707, 1702, 1696, 1691, 1685, 1680,
1675, 1669, 1664, 1659, 1653, 1648, 1643, 1638,
1633, 1628, 1623, 1618, 1613, 1608, 1603, 1598,
1593, 1588, 1583, 1579, 1574, 1569, 1565, 1560,
1555, 1551, 1546, 1542, 1537, 1533, 1528, 1524,
1519, 1515, 1510, 1506, 1502, 1497, 1493, 1489,
1485, 1481, 1476, 1472, 1468, 1464, 1460, 1456,
1452, 1448, 1444, 1440, 1436, 1432, 1428, 1424,
1420, 1416, 1413, 1409, 1405, 1401, 1398, 1394,
1390, 1387, 1383, 1379, 1376, 1372, 1368, 1365,
1361, 1358, 1354, 1351, 1347, 1344, 1340, 1337,
1334, 1330, 1327, 1323, 1320, 1317, 1314, 1310,
1307, 1304, 1300, 1297, 1294, 1291, 1288, 1285,
1281, 1278, 1275, 1272, 1269, 1266, 1263, 1260,
1257, 1254, 1251, 1248, 1245, 1242, 1239, 1236,
1233, 1230, 1227, 1224, 1222, 1219, 1216, 1213,
1210, 1208, 1205, 1202, 1199, 1197, 1194, 1191,
1188, 1186, 1183, 1180, 1178, 1175, 1172, 1170,
1167, 1165, 1162, 1159, 1157, 1154, 1152, 1149,
1147, 1144, 1142, 1139, 1137, 1134, 1132, 1129,
1127, 1125, 1122, 1120, 1117, 1115, 1113, 1110,
1108, 1106, 1103, 1101, 1099, 1096, 1094, 1092,
1089, 1087, 1085, 1083, 1081, 1078, 1076, 1074,
1072, 1069, 1067, 1065, 1063, 1061, 1059, 1057,
1054, 1052, 1050, 1048, 1046, 1044, 1042, 1040,
1038, 1036, 1034, 1032, 1030, 1028, 1026, 1024,
1022, 1020, 1018, 1016, 1014, 1012, 1010, 1008,
1006, 1004, 1002, 1000, 998, 996, 994, 992,
991, 989, 987, 985, 983, 981, 979, 978,
976, 974, 972, 970, 969, 967, 965, 963,
961, 960, 958, 956, 954, 953, 951, 949,
948, 946, 944, 942, 941, 939, 937, 936,
934, 932, 931, 929, 927, 926, 924, 923,
921, 919, 918, 916, 914, 913, 911, 910,
908, 907, 905, 903, 902, 900, 899, 897,
896, 894, 893, 891, 890, 888, 887, 885,
884, 882, 881, 879, 878, 876, 875, 873,
872, 870, 869, 868, 866, 865, 863, 862,
860, 859, 858, 856, 855, 853, 852, 851,
849, 848, 846, 845, 844, 842, 841, 840,
838, 837, 836, 834, 833, 832, 830, 829,
828, 826, 825, 824, 823, 821, 820, 819,
817, 816, 815, 814, 812, 811, 810, 809,
807, 806, 805, 804, 802, 801, 800, 799,
798, 796, 795, 794, 793, 791, 790, 789,
788, 787, 786, 784, 783, 782, 781, 780,
779, 777, 776, 775, 774, 773, 772, 771,
769, 768, 767, 766, 765, 764, 763, 762,
760, 759, 758, 757, 756, 755, 754, 753,
752, 751, 750, 748, 747, 746, 745, 744,
743, 742, 741, 740, 739, 738, 737, 736,
735, 734, 733, 732, 731, 730, 729, 728,
727, 726, 725, 724, 723, 722, 721, 720,
719, 718, 717, 716, 715, 714, 713, 712,
711, 710, 709, 708, 707, 706, 705, 704,
703, 702, 701, 700, 699, 699, 698, 697,
696, 695, 694, 693, 692, 691, 690, 689,
688, 688, 687, 686, 685, 684, 683, 682,
681, 680, 680, 679, 678, 677, 676, 675,
674, 673, 673, 672, 671, 670, 669, 668,
667, 667, 666, 665, 664, 663, 662, 661,
661, 660, 659, 658, 657, 657, 656, 655,
654, 653, 652, 652, 651, 650, 649, 648,
648, 647, 646, 645, 644, 644, 643, 642,
641, 640, 640, 639, 638, 637, 637, 636,
635, 634, 633, 633, 632, 631, 630, 630,
629, 628, 627, 627, 626, 625, 624, 624,
623, 622, 621, 621, 620, 619, 618, 618,
617, 616, 616, 615, 614, 613, 613, 612,
611, 611, 610, 609, 608, 608, 607, 606,
606, 605, 604, 604, 603, 602, 601, 601,
600, 599, 599, 598, 597, 597, 596, 595,
595, 594, 593, 593, 592, 591, 591, 590,
589, 589, 588, 587, 587, 586, 585, 585,
584, 583, 583, 582, 581, 581, 580, 579,
579, 578, 578, 577, 576, 576, 575, 574,
574, 573, 572, 572, 571, 571, 570, 569,
569, 568, 568, 567, 566, 566, 565, 564,
564, 563, 563, 562, 561, 561, 560, 560,
559, 558, 558, 557, 557, 556, 555, 555,
554, 554, 553, 553, 552, 551, 551, 550,
550, 549, 548, 548, 547, 547, 546, 546,
545, 544, 544, 543, 543, 542, 542, 541,
541, 540, 539, 539, 538, 538, 537, 537,
536, 536, 535, 534, 534, 533, 533, 532,
532, 531, 531, 530, 530, 529, 529, 528,
527, 527, 526, 526, 525, 525, 524, 524,
523, 523, 522, 522, 521, 521, 520, 520,
519, 519, 518, 518, 517, 517, 516, 516,
515, 515, 514, 514
};
// Note that LinearToGamma() expects the values to be premultiplied by 4,
// so we incorporate this factor 4 inside the DIVIDE_BY_ALPHA macro directly.
#define DIVIDE_BY_ALPHA(sum, a) (((sum) * kInvAlpha[(a)]) >> (kAlphaFix - 2))
#else
#define DIVIDE_BY_ALPHA(sum, a) (4 * (sum) / (a))
#endif // USE_INVERSE_ALPHA_TABLE
static WEBP_INLINE int LinearToGammaWeighted(const uint8_t* src,
const uint8_t* a_ptr,
uint32_t total_a, int step,
int rgb_stride) {
const uint32_t sum =
a_ptr[0] * GammaToLinear(src[0]) +
a_ptr[step] * GammaToLinear(src[step]) +
a_ptr[rgb_stride] * GammaToLinear(src[rgb_stride]) +
a_ptr[rgb_stride + step] * GammaToLinear(src[rgb_stride + step]);
assert(total_a > 0 && total_a <= 4 * 0xff);
#if defined(USE_INVERSE_ALPHA_TABLE)
assert((uint64_t)sum * kInvAlpha[total_a] < ((uint64_t)1 << 32));
#endif
return LinearToGamma(DIVIDE_BY_ALPHA(sum, total_a), 0);
}
static WEBP_INLINE void ConvertRowToY(const uint8_t* const r_ptr,
const uint8_t* const g_ptr,
const uint8_t* const b_ptr,
int step,
uint8_t* const dst_y,
int width,
VP8Random* const rg) {
int i, j;
for (i = 0, j = 0; i < width; i += 1, j += step) {
dst_y[i] = RGBToY(r_ptr[j], g_ptr[j], b_ptr[j], rg);
}
}
static WEBP_INLINE void AccumulateRGBA(const uint8_t* const r_ptr,
const uint8_t* const g_ptr,
const uint8_t* const b_ptr,
const uint8_t* const a_ptr,
int rgb_stride,
uint16_t* dst, int width) {
int i, j;
// we loop over 2x2 blocks and produce one R/G/B/A value for each.
for (i = 0, j = 0; i < (width >> 1); i += 1, j += 2 * 4, dst += 4) {
const uint32_t a = SUM4ALPHA(a_ptr + j);
int r, g, b;
if (a == 4 * 0xff || a == 0) {
r = SUM4(r_ptr + j, 4);
g = SUM4(g_ptr + j, 4);
b = SUM4(b_ptr + j, 4);
} else {
r = LinearToGammaWeighted(r_ptr + j, a_ptr + j, a, 4, rgb_stride);
g = LinearToGammaWeighted(g_ptr + j, a_ptr + j, a, 4, rgb_stride);
b = LinearToGammaWeighted(b_ptr + j, a_ptr + j, a, 4, rgb_stride);
}
dst[0] = r;
dst[1] = g;
dst[2] = b;
dst[3] = a;
}
if (width & 1) {
const uint32_t a = 2u * SUM2ALPHA(a_ptr + j);
int r, g, b;
if (a == 4 * 0xff || a == 0) {
r = SUM2(r_ptr + j);
g = SUM2(g_ptr + j);
b = SUM2(b_ptr + j);
} else {
r = LinearToGammaWeighted(r_ptr + j, a_ptr + j, a, 0, rgb_stride);
g = LinearToGammaWeighted(g_ptr + j, a_ptr + j, a, 0, rgb_stride);
b = LinearToGammaWeighted(b_ptr + j, a_ptr + j, a, 0, rgb_stride);
}
dst[0] = r;
dst[1] = g;
dst[2] = b;
dst[3] = a;
}
}
static WEBP_INLINE void AccumulateRGB(const uint8_t* const r_ptr,
const uint8_t* const g_ptr,
const uint8_t* const b_ptr,
int step, int rgb_stride,
uint16_t* dst, int width) {
int i, j;
for (i = 0, j = 0; i < (width >> 1); i += 1, j += 2 * step, dst += 4) {
dst[0] = SUM4(r_ptr + j, step);
dst[1] = SUM4(g_ptr + j, step);
dst[2] = SUM4(b_ptr + j, step);
}
if (width & 1) {
dst[0] = SUM2(r_ptr + j);
dst[1] = SUM2(g_ptr + j);
dst[2] = SUM2(b_ptr + j);
}
}
static WEBP_INLINE void ConvertRowsToUV(const uint16_t* rgb,
uint8_t* const dst_u,
uint8_t* const dst_v,
int width,
VP8Random* const rg) {
int i;
for (i = 0; i < width; i += 1, rgb += 4) {
const int r = rgb[0], g = rgb[1], b = rgb[2];
dst_u[i] = RGBToU(r, g, b, rg);
dst_v[i] = RGBToV(r, g, b, rg);
}
}
static int ImportYUVAFromRGBA(const uint8_t* const r_ptr,
const uint8_t* const g_ptr,
const uint8_t* const b_ptr,
const uint8_t* const a_ptr,
int step, // bytes per pixel
int rgb_stride, // bytes per scanline
float dithering,
int use_iterative_conversion,
WebPPicture* const picture) {
int y;
const int width = picture->width;
const int height = picture->height;
const int has_alpha = CheckNonOpaque(a_ptr, width, height, step, rgb_stride);
const int is_rgb = (r_ptr < b_ptr); // otherwise it's bgr
picture->colorspace = has_alpha ? WEBP_YUV420A : WEBP_YUV420;
picture->use_argb = 0;
// disable smart conversion if source is too small (overkill).
if (width < kMinDimensionIterativeConversion ||
height < kMinDimensionIterativeConversion) {
use_iterative_conversion = 0;
}
if (!WebPPictureAllocYUVA(picture, width, height)) {
return 0;
}
if (has_alpha) {
WebPInitAlphaProcessing();
assert(step == 4);
#if defined(USE_GAMMA_COMPRESSION) && defined(USE_INVERSE_ALPHA_TABLE)
assert(kAlphaFix + kGammaFix <= 31);
#endif
}
if (use_iterative_conversion) {
InitGammaTablesF();
if (!PreprocessARGB(r_ptr, g_ptr, b_ptr, step, rgb_stride, picture)) {
return 0;
}
if (has_alpha) {
WebPExtractAlpha(a_ptr, rgb_stride, width, height,
picture->a, picture->a_stride);
}
} else {
const int uv_width = (width + 1) >> 1;
int use_dsp = (step == 3); // use special function in this case
// temporary storage for accumulated R/G/B values during conversion to U/V
uint16_t* const tmp_rgb =
(uint16_t*)WebPSafeMalloc(4 * uv_width, sizeof(*tmp_rgb));
uint8_t* dst_y = picture->y;
uint8_t* dst_u = picture->u;
uint8_t* dst_v = picture->v;
uint8_t* dst_a = picture->a;
VP8Random base_rg;
VP8Random* rg = NULL;
if (dithering > 0.) {
VP8InitRandom(&base_rg, dithering);
rg = &base_rg;
use_dsp = 0; // can't use dsp in this case
}
WebPInitConvertARGBToYUV();
InitGammaTables();
if (tmp_rgb == NULL) return 0; // malloc error
// Downsample Y/U/V planes, two rows at a time
for (y = 0; y < (height >> 1); ++y) {
int rows_have_alpha = has_alpha;
const int off1 = (2 * y + 0) * rgb_stride;
const int off2 = (2 * y + 1) * rgb_stride;
if (use_dsp) {
if (is_rgb) {
WebPConvertRGB24ToY(r_ptr + off1, dst_y, width);
WebPConvertRGB24ToY(r_ptr + off2, dst_y + picture->y_stride, width);
} else {
WebPConvertBGR24ToY(b_ptr + off1, dst_y, width);
WebPConvertBGR24ToY(b_ptr + off2, dst_y + picture->y_stride, width);
}
} else {
ConvertRowToY(r_ptr + off1, g_ptr + off1, b_ptr + off1, step,
dst_y, width, rg);
ConvertRowToY(r_ptr + off2, g_ptr + off2, b_ptr + off2, step,
dst_y + picture->y_stride, width, rg);
}
dst_y += 2 * picture->y_stride;
if (has_alpha) {
rows_have_alpha &= !WebPExtractAlpha(a_ptr + off1, rgb_stride,
width, 2,
dst_a, picture->a_stride);
dst_a += 2 * picture->a_stride;
}
// Collect averaged R/G/B(/A)
if (!rows_have_alpha) {
AccumulateRGB(r_ptr + off1, g_ptr + off1, b_ptr + off1,
step, rgb_stride, tmp_rgb, width);
} else {
AccumulateRGBA(r_ptr + off1, g_ptr + off1, b_ptr + off1, a_ptr + off1,
rgb_stride, tmp_rgb, width);
}
// Convert to U/V
if (rg == NULL) {
WebPConvertRGBA32ToUV(tmp_rgb, dst_u, dst_v, uv_width);
} else {
ConvertRowsToUV(tmp_rgb, dst_u, dst_v, uv_width, rg);
}
dst_u += picture->uv_stride;
dst_v += picture->uv_stride;
}
if (height & 1) { // extra last row
const int off = 2 * y * rgb_stride;
int row_has_alpha = has_alpha;
if (use_dsp) {
if (r_ptr < b_ptr) {
WebPConvertRGB24ToY(r_ptr + off, dst_y, width);
} else {
WebPConvertBGR24ToY(b_ptr + off, dst_y, width);
}
} else {
ConvertRowToY(r_ptr + off, g_ptr + off, b_ptr + off, step,
dst_y, width, rg);
}
if (row_has_alpha) {
row_has_alpha &= !WebPExtractAlpha(a_ptr + off, 0, width, 1, dst_a, 0);
}
// Collect averaged R/G/B(/A)
if (!row_has_alpha) {
// Collect averaged R/G/B
AccumulateRGB(r_ptr + off, g_ptr + off, b_ptr + off,
step, /* rgb_stride = */ 0, tmp_rgb, width);
} else {
AccumulateRGBA(r_ptr + off, g_ptr + off, b_ptr + off, a_ptr + off,
/* rgb_stride = */ 0, tmp_rgb, width);
}
if (rg == NULL) {
WebPConvertRGBA32ToUV(tmp_rgb, dst_u, dst_v, uv_width);
} else {
ConvertRowsToUV(tmp_rgb, dst_u, dst_v, uv_width, rg);
}
}
WebPSafeFree(tmp_rgb);
}
return 1;
}
#undef SUM4
#undef SUM2
#undef SUM4ALPHA
#undef SUM2ALPHA
//------------------------------------------------------------------------------
// call for ARGB->YUVA conversion
static int PictureARGBToYUVA(WebPPicture* picture, WebPEncCSP colorspace,
float dithering, int use_iterative_conversion) {
if (picture == NULL) return 0;
if (picture->argb == NULL) {
return WebPEncodingSetError(picture, VP8_ENC_ERROR_NULL_PARAMETER);
} else if ((colorspace & WEBP_CSP_UV_MASK) != WEBP_YUV420) {
return WebPEncodingSetError(picture, VP8_ENC_ERROR_INVALID_CONFIGURATION);
} else {
const uint8_t* const argb = (const uint8_t*)picture->argb;
const uint8_t* const r = ALPHA_IS_LAST ? argb + 2 : argb + 1;
const uint8_t* const g = ALPHA_IS_LAST ? argb + 1 : argb + 2;
const uint8_t* const b = ALPHA_IS_LAST ? argb + 0 : argb + 3;
const uint8_t* const a = ALPHA_IS_LAST ? argb + 3 : argb + 0;
picture->colorspace = WEBP_YUV420;
return ImportYUVAFromRGBA(r, g, b, a, 4, 4 * picture->argb_stride,
dithering, use_iterative_conversion, picture);
}
}
int WebPPictureARGBToYUVADithered(WebPPicture* picture, WebPEncCSP colorspace,
float dithering) {
return PictureARGBToYUVA(picture, colorspace, dithering, 0);
}
int WebPPictureARGBToYUVA(WebPPicture* picture, WebPEncCSP colorspace) {
return PictureARGBToYUVA(picture, colorspace, 0.f, 0);
}
int WebPPictureSmartARGBToYUVA(WebPPicture* picture) {
return PictureARGBToYUVA(picture, WEBP_YUV420, 0.f, 1);
}
//------------------------------------------------------------------------------
// call for YUVA -> ARGB conversion
int WebPPictureYUVAToARGB(WebPPicture* picture) {
if (picture == NULL) return 0;
if (picture->y == NULL || picture->u == NULL || picture->v == NULL) {
return WebPEncodingSetError(picture, VP8_ENC_ERROR_NULL_PARAMETER);
}
if ((picture->colorspace & WEBP_CSP_ALPHA_BIT) && picture->a == NULL) {
return WebPEncodingSetError(picture, VP8_ENC_ERROR_NULL_PARAMETER);
}
if ((picture->colorspace & WEBP_CSP_UV_MASK) != WEBP_YUV420) {
return WebPEncodingSetError(picture, VP8_ENC_ERROR_INVALID_CONFIGURATION);
}
// Allocate a new argb buffer (discarding the previous one).
if (!WebPPictureAllocARGB(picture, picture->width, picture->height)) return 0;
picture->use_argb = 1;
// Convert
{
int y;
const int width = picture->width;
const int height = picture->height;
const int argb_stride = 4 * picture->argb_stride;
uint8_t* dst = (uint8_t*)picture->argb;
const uint8_t *cur_u = picture->u, *cur_v = picture->v, *cur_y = picture->y;
WebPUpsampleLinePairFunc upsample = WebPGetLinePairConverter(ALPHA_IS_LAST);
// First row, with replicated top samples.
upsample(cur_y, NULL, cur_u, cur_v, cur_u, cur_v, dst, NULL, width);
cur_y += picture->y_stride;
dst += argb_stride;
// Center rows.
for (y = 1; y + 1 < height; y += 2) {
const uint8_t* const top_u = cur_u;
const uint8_t* const top_v = cur_v;
cur_u += picture->uv_stride;
cur_v += picture->uv_stride;
upsample(cur_y, cur_y + picture->y_stride, top_u, top_v, cur_u, cur_v,
dst, dst + argb_stride, width);
cur_y += 2 * picture->y_stride;
dst += 2 * argb_stride;
}
// Last row (if needed), with replicated bottom samples.
if (height > 1 && !(height & 1)) {
upsample(cur_y, NULL, cur_u, cur_v, cur_u, cur_v, dst, NULL, width);
}
// Insert alpha values if needed, in replacement for the default 0xff ones.
if (picture->colorspace & WEBP_CSP_ALPHA_BIT) {
for (y = 0; y < height; ++y) {
uint32_t* const argb_dst = picture->argb + y * picture->argb_stride;
const uint8_t* const src = picture->a + y * picture->a_stride;
int x;
for (x = 0; x < width; ++x) {
argb_dst[x] = (argb_dst[x] & 0x00ffffffu) | ((uint32_t)src[x] << 24);
}
}
}
}
return 1;
}
//------------------------------------------------------------------------------
// automatic import / conversion
static int Import(WebPPicture* const picture,
const uint8_t* const rgb, int rgb_stride,
int step, int swap_rb, int import_alpha) {
int y;
const uint8_t* const r_ptr = rgb + (swap_rb ? 2 : 0);
const uint8_t* const g_ptr = rgb + 1;
const uint8_t* const b_ptr = rgb + (swap_rb ? 0 : 2);
const uint8_t* const a_ptr = import_alpha ? rgb + 3 : NULL;
const int width = picture->width;
const int height = picture->height;
if (!picture->use_argb) {
return ImportYUVAFromRGBA(r_ptr, g_ptr, b_ptr, a_ptr, step, rgb_stride,
0.f /* no dithering */, 0, picture);
}
if (!WebPPictureAlloc(picture)) return 0;
VP8EncDspARGBInit();
if (import_alpha) {
assert(step == 4);
for (y = 0; y < height; ++y) {
uint32_t* const dst = &picture->argb[y * picture->argb_stride];
const int offset = y * rgb_stride;
VP8PackARGB(a_ptr + offset, r_ptr + offset, g_ptr + offset,
b_ptr + offset, width, dst);
}
} else {
assert(step >= 3);
for (y = 0; y < height; ++y) {
uint32_t* const dst = &picture->argb[y * picture->argb_stride];
const int offset = y * rgb_stride;
VP8PackRGB(r_ptr + offset, g_ptr + offset, b_ptr + offset,
width, step, dst);
}
}
return 1;
}
// Public API
int WebPPictureImportRGB(WebPPicture* picture,
const uint8_t* rgb, int rgb_stride) {
return (picture != NULL) ? Import(picture, rgb, rgb_stride, 3, 0, 0) : 0;
}
int WebPPictureImportBGR(WebPPicture* picture,
const uint8_t* rgb, int rgb_stride) {
return (picture != NULL) ? Import(picture, rgb, rgb_stride, 3, 1, 0) : 0;
}
int WebPPictureImportRGBA(WebPPicture* picture,
const uint8_t* rgba, int rgba_stride) {
return (picture != NULL) ? Import(picture, rgba, rgba_stride, 4, 0, 1) : 0;
}
int WebPPictureImportBGRA(WebPPicture* picture,
const uint8_t* rgba, int rgba_stride) {
return (picture != NULL) ? Import(picture, rgba, rgba_stride, 4, 1, 1) : 0;
}
int WebPPictureImportRGBX(WebPPicture* picture,
const uint8_t* rgba, int rgba_stride) {
return (picture != NULL) ? Import(picture, rgba, rgba_stride, 4, 0, 0) : 0;
}
int WebPPictureImportBGRX(WebPPicture* picture,
const uint8_t* rgba, int rgba_stride) {
return (picture != NULL) ? Import(picture, rgba, rgba_stride, 4, 1, 0) : 0;
}
//------------------------------------------------------------------------------