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Merge branch 'stbiw_update_jpeg' of https://github.com/DanielGibson/stb into work2

This commit is contained in:
Sean Barrett 2020-02-02 10:01:04 -08:00
parent 1586318a00 15516199e5
commit 454da539a2
1 changed files with 75 additions and 32 deletions
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89
stb_image_write.h
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@ -1271,26 +1271,30 @@ static void stbiw__jpg_calcBits(int val, unsigned short bits[2]) {
bits[0] = val & ((1<<bits[1])-1);
}
static int stbiw__jpg_processDU(stbi__write_context *s, int *bitBuf, int *bitCnt, float *CDU, float *fdtbl, int DC, const unsigned short HTDC[256][2], const unsigned short HTAC[256][2]) {
static int stbiw__jpg_processDU(stbi__write_context *s, int *bitBuf, int *bitCnt, float *CDU, int du_stride, float *fdtbl, int DC, const unsigned short HTDC[256][2], const unsigned short HTAC[256][2]) {
const unsigned short EOB[2] = { HTAC[0x00][0], HTAC[0x00][1] };
const unsigned short M16zeroes[2] = { HTAC[0xF0][0], HTAC[0xF0][1] };
int dataOff, i, diff, end0pos;
int dataOff, i, j, n, diff, end0pos, x, y;
int DU[64];
// DCT rows
for(dataOff=0; dataOff<64; dataOff+=8) {
for(dataOff=0, n=du_stride*8; dataOff<n; dataOff+=du_stride) {
stbiw__jpg_DCT(&CDU[dataOff], &CDU[dataOff+1], &CDU[dataOff+2], &CDU[dataOff+3], &CDU[dataOff+4], &CDU[dataOff+5], &CDU[dataOff+6], &CDU[dataOff+7]);
}
// DCT columns
for(dataOff=0; dataOff<8; ++dataOff) {
stbiw__jpg_DCT(&CDU[dataOff], &CDU[dataOff+8], &CDU[dataOff+16], &CDU[dataOff+24], &CDU[dataOff+32], &CDU[dataOff+40], &CDU[dataOff+48], &CDU[dataOff+56]);
stbiw__jpg_DCT(&CDU[dataOff], &CDU[dataOff+du_stride], &CDU[dataOff+du_stride*2], &CDU[dataOff+du_stride*3], &CDU[dataOff+du_stride*4],
&CDU[dataOff+du_stride*5], &CDU[dataOff+du_stride*6], &CDU[dataOff+du_stride*7]);
}
// Quantize/descale/zigzag the coefficients
for(i=0; i<64; ++i) {
float v = CDU[i]*fdtbl[i];
// DU[stbiw__jpg_ZigZag[i]] = (int)(v < 0 ? ceilf(v - 0.5f) : floorf(v + 0.5f));
for(y = 0, j=0; y < 8; ++y) {
for(x = 0; x < 8; ++x,++j) {
i = y*du_stride+x;
float v = CDU[i]*fdtbl[j];
// DU[stbiw__jpg_ZigZag[j]] = (int)(v < 0 ? ceilf(v - 0.5f) : floorf(v + 0.5f));
// ceilf() and floorf() are C99, not C89, but I /think/ they're not needed here anyway?
DU[stbiw__jpg_ZigZag[i]] = (int)(v < 0 ? v - 0.5f : v + 0.5f);
DU[stbiw__jpg_ZigZag[j]] = (int)(v < 0 ? v - 0.5f : v + 0.5f);
}
}
// Encode DC
@ -1408,7 +1412,7 @@ static int stbi_write_jpg_core(stbi__write_context *s, int width, int height, in
static const float aasf[] = { 1.0f * 2.828427125f, 1.387039845f * 2.828427125f, 1.306562965f * 2.828427125f, 1.175875602f * 2.828427125f,
1.0f * 2.828427125f, 0.785694958f * 2.828427125f, 0.541196100f * 2.828427125f, 0.275899379f * 2.828427125f };
int row, col, i, k;
int row, col, i, k, subsample;
float fdtbl_Y[64], fdtbl_UV[64];
unsigned char YTable[64], UVTable[64];
@ -1417,6 +1421,7 @@ static int stbi_write_jpg_core(stbi__write_context *s, int width, int height, in
}
quality = quality ? quality : 90;
subsample = quality <= 90 ? 1 : 0;
quality = quality < 1 ? 1 : quality > 100 ? 100 : quality;
quality = quality < 50 ? 5000 / quality : 200 - quality * 2;
@ -1439,7 +1444,7 @@ static int stbi_write_jpg_core(stbi__write_context *s, int width, int height, in
static const unsigned char head0[] = { 0xFF,0xD8,0xFF,0xE0,0,0x10,'J','F','I','F',0,1,1,0,0,1,0,1,0,0,0xFF,0xDB,0,0x84,0 };
static const unsigned char head2[] = { 0xFF,0xDA,0,0xC,3,1,0,2,0x11,3,0x11,0,0x3F,0 };
const unsigned char head1[] = { 0xFF,0xC0,0,0x11,8,(unsigned char)(height>>8),STBIW_UCHAR(height),(unsigned char)(width>>8),STBIW_UCHAR(width),
3,1,0x11,0,2,0x11,1,3,0x11,1,0xFF,0xC4,0x01,0xA2,0 };
3,1,(unsigned char)(subsample?0x22:0x11),0,2,0x11,1,3,0x11,1,0xFF,0xC4,0x01,0xA2,0 };
s->func(s->context, (void*)head0, sizeof(head0));
s->func(s->context, (void*)YTable, sizeof(YTable));
stbiw__putc(s, 1);
@ -1462,36 +1467,74 @@ static int stbi_write_jpg_core(stbi__write_context *s, int width, int height, in
// Encode 8x8 macroblocks
{
static const unsigned short fillBits[] = {0x7F, 7};
const unsigned char *imageData = (const unsigned char *)data;
int DCY=0, DCU=0, DCV=0;
int bitBuf=0, bitCnt=0;
// comp == 2 is grey+alpha (alpha is ignored)
int ofsG = comp > 2 ? 1 : 0, ofsB = comp > 2 ? 2 : 0;
const unsigned char *dataR = (const unsigned char *)data;
const unsigned char *dataG = dataR + ofsG;
const unsigned char *dataB = dataR + ofsB;
int x, y, pos;
if(subsample) {
for(y = 0; y < height; y += 16) {
for(x = 0; x < width; x += 16) {
float Y[256], U[256], V[256];
for(row = y, pos = 0; row < y+16; ++row) {
// row >= height => use last input row
int clamped_row = (row < height) ? row : height - 1;
int base_p = (stbi__flip_vertically_on_write ? (height-1-clamped_row) : clamped_row)*width*comp;
for(col = x; col < x+16; ++col, ++pos) {
// if col >= width => use pixel from last input column
int p = base_p + ((col < width) ? col : (width-1))*comp;
float r = dataR[p], g = dataG[p], b = dataB[p];
Y[pos]= +0.29900f*r + 0.58700f*g + 0.11400f*b - 128;
U[pos]= -0.16874f*r - 0.33126f*g + 0.50000f*b;
V[pos]= +0.50000f*r - 0.41869f*g - 0.08131f*b;
}
}
DCY = stbiw__jpg_processDU(s, &bitBuf, &bitCnt, Y+0, 16, fdtbl_Y, DCY, YDC_HT, YAC_HT);
DCY = stbiw__jpg_processDU(s, &bitBuf, &bitCnt, Y+8, 16, fdtbl_Y, DCY, YDC_HT, YAC_HT);
DCY = stbiw__jpg_processDU(s, &bitBuf, &bitCnt, Y+128, 16, fdtbl_Y, DCY, YDC_HT, YAC_HT);
DCY = stbiw__jpg_processDU(s, &bitBuf, &bitCnt, Y+136, 16, fdtbl_Y, DCY, YDC_HT, YAC_HT);
// subsample U,V
{
float subU[64], subV[64];
int yy, xx;
for(yy = 0, pos = 0; yy < 8; ++yy) {
for(xx = 0; xx < 8; ++xx, ++pos) {
int j = yy*32+xx*2;
subU[pos] = (U[j+0] + U[j+1] + U[j+16] + U[j+17]) * 0.25f;
subV[pos] = (V[j+0] + V[j+1] + V[j+16] + V[j+17]) * 0.25f;
}
}
DCU = stbiw__jpg_processDU(s, &bitBuf, &bitCnt, subU, 8, fdtbl_UV, DCU, UVDC_HT, UVAC_HT);
DCV = stbiw__jpg_processDU(s, &bitBuf, &bitCnt, subV, 8, fdtbl_UV, DCV, UVDC_HT, UVAC_HT);
}
}
}
} else {
for(y = 0; y < height; y += 8) {
for(x = 0; x < width; x += 8) {
float YDU[64], UDU[64], VDU[64];
float Y[64], U[64], V[64];
for(row = y, pos = 0; row < y+8; ++row) {
// row >= height => use last input row
int clamped_row = (row < height) ? row : height - 1;
int base_p = (stbi__flip_vertically_on_write ? (height-1-clamped_row) : clamped_row)*width*comp;
for(col = x; col < x+8; ++col, ++pos) {
float r, g, b;
// if col >= width => use pixel from last input column
int p = base_p + ((col < width) ? col : (width-1))*comp;
r = imageData[p+0];
g = imageData[p+ofsG];
b = imageData[p+ofsB];
YDU[pos]=+0.29900f*r+0.58700f*g+0.11400f*b-128;
UDU[pos]=-0.16874f*r-0.33126f*g+0.50000f*b;
VDU[pos]=+0.50000f*r-0.41869f*g-0.08131f*b;
float r = dataR[p], g = dataG[p], b = dataB[p];
Y[pos]= +0.29900f*r + 0.58700f*g + 0.11400f*b - 128;
U[pos]= -0.16874f*r - 0.33126f*g + 0.50000f*b;
V[pos]= +0.50000f*r - 0.41869f*g - 0.08131f*b;
}
}
DCY = stbiw__jpg_processDU(s, &bitBuf, &bitCnt, YDU, fdtbl_Y, DCY, YDC_HT, YAC_HT);
DCU = stbiw__jpg_processDU(s, &bitBuf, &bitCnt, UDU, fdtbl_UV, DCU, UVDC_HT, UVAC_HT);
DCV = stbiw__jpg_processDU(s, &bitBuf, &bitCnt, VDU, fdtbl_UV, DCV, UVDC_HT, UVAC_HT);
DCY = stbiw__jpg_processDU(s, &bitBuf, &bitCnt, Y, 8, fdtbl_Y, DCY, YDC_HT, YAC_HT);
DCU = stbiw__jpg_processDU(s, &bitBuf, &bitCnt, U, 8, fdtbl_UV, DCU, UVDC_HT, UVAC_HT);
DCV = stbiw__jpg_processDU(s, &bitBuf, &bitCnt, V, 8, fdtbl_UV, DCV, UVDC_HT, UVAC_HT);
}
}
}