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ClassiCube/src/Bitmap.c
Shinovon 47679d1788 Merge remote-tracking branch 'origin/master' into symbian_squashed 
# Conflicts:
#	src/Builder.c
2025-05-20 19:28:34 +05:00

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#include "Bitmap.h"
#include "Platform.h"
#include "ExtMath.h"
#include "Deflate.h"
#include "Logger.h"
#include "Stream.h"
#include "Errors.h"
#include "Utils.h"
#include "Funcs.h"
BitmapCol BitmapColor_Offset(BitmapCol color, int rBy, int gBy, int bBy) {
int r, g, b;
r = BitmapCol_R(color) + rBy; Math_Clamp(r, 0, 255);
g = BitmapCol_G(color) + gBy; Math_Clamp(g, 0, 255);
b = BitmapCol_B(color) + bBy; Math_Clamp(b, 0, 255);
return BitmapColor_RGB(r, g, b);
}
BitmapCol BitmapColor_Scale(BitmapCol a, float t) {
cc_uint8 R = (cc_uint8)(BitmapCol_R(a) * t);
cc_uint8 G = (cc_uint8)(BitmapCol_G(a) * t);
cc_uint8 B = (cc_uint8)(BitmapCol_B(a) * t);
return (a & BITMAPCOLOR_A_MASK) | BitmapColor_R_Bits(R) | BitmapColor_G_Bits(G) | BitmapColor_B_Bits(B);
}
void Bitmap_UNSAFE_CopyBlock(int srcX, int srcY, int dstX, int dstY,
struct Bitmap* src, struct Bitmap* dst, int size) {
int x, y;
for (y = 0; y < size; y++) {
BitmapCol* srcRow = Bitmap_GetRow(src, srcY + y) + srcX;
BitmapCol* dstRow = Bitmap_GetRow(dst, dstY + y) + dstX;
for (x = 0; x < size; x++) { dstRow[x] = srcRow[x]; }
}
}
void Bitmap_Allocate(struct Bitmap* bmp, int width, int height) {
bmp->width = width; bmp->height = height;
bmp->scan0 = (BitmapCol*)Mem_Alloc(width * height, BITMAPCOLOR_SIZE, "bitmap data");
}
void Bitmap_TryAllocate(struct Bitmap* bmp, int width, int height) {
bmp->width = width; bmp->height = height;
bmp->scan0 = (BitmapCol*)Mem_TryAlloc(width * height, BITMAPCOLOR_SIZE);
}
void Bitmap_Scale(struct Bitmap* dst, struct Bitmap* src,
int srcX, int srcY, int srcWidth, int srcHeight) {
BitmapCol* dstRow;
BitmapCol* srcRow;
int x, y, width, height;
width = dst->width;
height = dst->height;
for (y = 0; y < height; y++) {
srcRow = Bitmap_GetRow(src, srcY + (y * srcHeight / height));
dstRow = Bitmap_GetRow(dst, y);
for (x = 0; x < width; x++) {
dstRow[x] = srcRow[srcX + (x * srcWidth / width)];
}
}
}
/*########################################################################################################################*
*------------------------------------------------------PNG decoder--------------------------------------------------------*
*#########################################################################################################################*/
#define PNG_IHDR_SIZE 13
#define PNG_PALETTE 256
#define PNG_FourCC(a, b, c, d) (((cc_uint32)a << 24) | ((cc_uint32)b << 16) | ((cc_uint32)c << 8) | (cc_uint32)d)
enum PngColor {
PNG_COLOR_GRAYSCALE = 0, PNG_COLOR_RGB = 2, PNG_COLOR_INDEXED = 3,
PNG_COLOR_GRAYSCALE_A = 4, PNG_COLOR_RGB_A = 6
};
enum PngFilter {
PNG_FILTER_NONE, PNG_FILTER_SUB, PNG_FILTER_UP, PNG_FILTER_AVERAGE, PNG_FILTER_PAETH
};
typedef void (*Png_RowExpander)(int width, BitmapCol* palette, cc_uint8* src, BitmapCol* dst);
static const cc_uint8 pngSig[PNG_SIG_SIZE] = { 137, 80, 78, 71, 13, 10, 26, 10 };
/* 5.2 PNG signature */
cc_bool Png_Detect(const cc_uint8* data, cc_uint32 len) {
return len >= PNG_SIG_SIZE && Mem_Equal(data, pngSig, PNG_SIG_SIZE);
}
/* 9 Filtering */
/* 13.9 Filtering */
static void Png_ReconstructFirst(cc_uint8 type, cc_uint8 bytesPerPixel, cc_uint8* line, cc_uint32 lineLen) {
/* First scanline is a special case, where all values in prior array are 0 */
cc_uint32 i, j;
switch (type) {
case PNG_FILTER_SUB:
for (i = bytesPerPixel, j = 0; i < lineLen; i++, j++) {
line[i] += line[j];
}
return;
case PNG_FILTER_AVERAGE:
for (i = bytesPerPixel, j = 0; i < lineLen; i++, j++) {
line[i] += (line[j] >> 1);
}
return;
case PNG_FILTER_PAETH:
for (i = bytesPerPixel, j = 0; i < lineLen; i++, j++) {
line[i] += line[j];
}
return;
}
}
static void Png_Reconstruct(cc_uint8 type, cc_uint8 bytesPerPixel, cc_uint8* line, cc_uint8* prior, cc_uint32 lineLen) {
cc_uint32 i, j;
switch (type) {
case PNG_FILTER_SUB:
for (i = bytesPerPixel, j = 0; i < lineLen; i++, j++) {
line[i] += line[j];
}
return;
case PNG_FILTER_UP:
for (i = 0; i < lineLen; i++) {
line[i] += prior[i];
}
return;
case PNG_FILTER_AVERAGE:
for (i = 0; i < bytesPerPixel; i++) {
line[i] += (prior[i] >> 1);
}
for (j = 0; i < lineLen; i++, j++) {
line[i] += ((prior[i] + line[j]) >> 1);
}
return;
case PNG_FILTER_PAETH:
/* TODO: verify this is right */
for (i = 0; i < bytesPerPixel; i++) {
line[i] += prior[i];
}
for (j = 0; i < lineLen; i++, j++) {
cc_uint8 a = line[j], b = prior[i], c = prior[j];
int p = a + b - c;
int pa = Math_AbsI(p - a);
int pb = Math_AbsI(p - b);
int pc = Math_AbsI(p - c);
if (pa <= pb && pa <= pc) { line[i] += a; }
else if (pb <= pc) { line[i] += b; }
else { line[i] += c; }
}
return;
}
}
#define Bitmap_Set(dst, r,g,b,a) dst = BitmapCol_Make(r, g, b, a);
/* 7.2 Scanlines */
#define PNG_Do_Grayscale(dstI, src, scale) rgb = (src) * scale; Bitmap_Set(dst[dstI], rgb, rgb, rgb, 255);
#define PNG_Do_Grayscale_8() rgb = src[0]; Bitmap_Set(*dst, rgb, rgb, rgb, 255); dst--; src -= 1;
#define PNG_Do_Grayscale_A__8() rgb = src[0]; Bitmap_Set(*dst, rgb, rgb, rgb, src[1]); dst--; src -= 2;
#define PNG_Do_RGB__8() Bitmap_Set(*dst, src[0], src[1], src[2], 255); dst--; src -= 3;
#define PNG_Do_RGB_A__8() Bitmap_Set(*dst, src[0], src[1], src[2], src[3]); dst++; src += 4;
#define PNG_Do_Palette__8() *dst-- = palette[*src--];
#define PNG_Mask_1(i) (7 - (i & 7))
#define PNG_Mask_2(i) ((3 - (i & 3)) * 2)
#define PNG_Mask_4(i) ((1 - (i & 1)) * 4)
#define PNG_Get__1(i) ((src[i >> 3] >> PNG_Mask_1(i)) & 0x01)
#define PNG_Get__2(i) ((src[i >> 2] >> PNG_Mask_2(i)) & 0x03)
#define PNG_Get__4(i) ((src[i >> 1] >> PNG_Mask_4(i)) & 0x0F)
static void Png_Expand_GRAYSCALE_1(int width, BitmapCol* palette, cc_uint8* src, BitmapCol* dst) {
int i; cc_uint8 rgb; /* NOTE: not optimised*/
for (i = width - 1; i >= 0; i--) { PNG_Do_Grayscale(i, PNG_Get__1(i), 255); }
}
static void Png_Expand_GRAYSCALE_2(int width, BitmapCol* palette, cc_uint8* src, BitmapCol* dst) {
int i; cc_uint8 rgb; /* NOTE: not optimised */
for (i = width - 1; i >= 0; i--) { PNG_Do_Grayscale(i, PNG_Get__2(i), 85); }
}
static void Png_Expand_GRAYSCALE_4(int width, BitmapCol* palette, cc_uint8* src, BitmapCol* dst) {
int i; cc_uint8 rgb;
for (i = width - 1; i >= 0; i--) { PNG_Do_Grayscale(i, PNG_Get__4(i), 17); }
}
static void Png_Expand_GRAYSCALE_8(int width, BitmapCol* palette, cc_uint8* src, BitmapCol* dst) {
cc_uint8 rgb;
src += (width - 1);
dst += (width - 1);
for (; width >= 4; width -= 4) {
PNG_Do_Grayscale_8(); PNG_Do_Grayscale_8();
PNG_Do_Grayscale_8(); PNG_Do_Grayscale_8();
}
for (; width > 0; width--) { PNG_Do_Grayscale_8(); }
}
static void Png_Expand_RGB_8(int width, BitmapCol* palette, cc_uint8* src, BitmapCol* dst) {
src += (width - 1) * 3;
dst += (width - 1);
for (; width >= 4; width -= 4) {
PNG_Do_RGB__8(); PNG_Do_RGB__8();
PNG_Do_RGB__8(); PNG_Do_RGB__8();
}
for (; width > 0; width--) { PNG_Do_RGB__8(); }
}
static void Png_Expand_INDEXED_1(int width, BitmapCol* palette, cc_uint8* src, BitmapCol* dst) {
int i; /* NOTE: not optimised */
for (i = width - 1; i >= 0; i--) { dst[i] = palette[PNG_Get__1(i)]; }
}
static void Png_Expand_INDEXED_2(int width, BitmapCol* palette, cc_uint8* src, BitmapCol* dst) {
int i; /* NOTE: not optimised */
for (i = width - 1; i >= 0; i--) { dst[i] = palette[PNG_Get__2(i)]; }
}
static void Png_Expand_INDEXED_4(int width, BitmapCol* palette, cc_uint8* src, BitmapCol* dst) {
int i; /* NOTE: not optimised */
for (i = width - 1; i >= 0; i--) { dst[i] = palette[PNG_Get__4(i)]; }
}
static void Png_Expand_INDEXED_8(int width, BitmapCol* palette, cc_uint8* src, BitmapCol* dst) {
src += (width - 1) * 1;
dst += (width - 1);
for (; width >= 4; width -= 4) {
PNG_Do_Palette__8(); PNG_Do_Palette__8();
PNG_Do_Palette__8(); PNG_Do_Palette__8();
}
for (; width > 0; width--) { PNG_Do_Palette__8(); }
}
static void Png_Expand_GRAYSCALE_A_8(int width, BitmapCol* palette, cc_uint8* src, BitmapCol* dst) {
cc_uint8 rgb;
src += (width - 1) * 2;
dst += (width - 1);
for (; width >= 4; width -= 4) {
PNG_Do_Grayscale_A__8(); PNG_Do_Grayscale_A__8();
PNG_Do_Grayscale_A__8(); PNG_Do_Grayscale_A__8();
}
for (; width > 0; width--) { PNG_Do_Grayscale_A__8(); }
}
static void Png_Expand_RGB_A_8(int width, BitmapCol* palette, cc_uint8* src, BitmapCol* dst) {
/* Processed in forward order */
for (; width >= 4; width -= 4) {
PNG_Do_RGB_A__8(); PNG_Do_RGB_A__8();
PNG_Do_RGB_A__8(); PNG_Do_RGB_A__8();
}
for (; width > 0; width--) { PNG_Do_RGB_A__8(); }
}
static Png_RowExpander Png_GetExpander(cc_uint8 col, cc_uint8 bitsPerSample) {
switch (col) {
case PNG_COLOR_GRAYSCALE:
switch (bitsPerSample) {
case 1: return Png_Expand_GRAYSCALE_1;
case 2: return Png_Expand_GRAYSCALE_2;
case 4: return Png_Expand_GRAYSCALE_4;
case 8: return Png_Expand_GRAYSCALE_8;
}
return NULL;
case PNG_COLOR_RGB:
switch (bitsPerSample) {
case 8: return Png_Expand_RGB_8;
}
return NULL;
case PNG_COLOR_INDEXED:
switch (bitsPerSample) {
case 1: return Png_Expand_INDEXED_1;
case 2: return Png_Expand_INDEXED_2;
case 4: return Png_Expand_INDEXED_4;
case 8: return Png_Expand_INDEXED_8;
}
return NULL;
case PNG_COLOR_GRAYSCALE_A:
switch (bitsPerSample) {
case 8: return Png_Expand_GRAYSCALE_A_8;
}
return NULL;
case PNG_COLOR_RGB_A:
switch (bitsPerSample) {
case 8: return Png_Expand_RGB_A_8;
}
return NULL;
}
return NULL;
}
/* Sets alpha to 0 for any pixels in the bitmap whose RGB is same as colorspace */
static void ComputeTransparency(struct Bitmap* bmp, BitmapCol col) {
BitmapCol trnsRGB = col & BITMAPCOLOR_RGB_MASK;
int x, y, width = bmp->width, height = bmp->height;
for (y = 0; y < height; y++) {
BitmapCol* row = Bitmap_GetRow(bmp, y);
for (x = 0; x < width; x++) {
BitmapCol rgb = row[x] & BITMAPCOLOR_RGB_MASK;
row[x] = (rgb == trnsRGB) ? trnsRGB : row[x];
}
}
}
static BitmapCol ExpandRGB(cc_uint8 bitsPerSample, int r, int g, int b) {
switch (bitsPerSample) {
case 1:
r *= 255; g *= 255; b *= 255; break;
case 2:
r *= 85; g *= 85; b *= 85; break;
case 4:
r *= 17; g *= 17; b *= 17; break;
}
return BitmapCol_Make(r, g, b, 0);
}
#ifdef CC_BUILD_32X
cc_result Png_Decode(struct Bitmap* bmp, struct Stream* stream) {
return ERR_NOT_SUPPORTED;
}
#else
cc_result Png_Decode(struct Bitmap* bmp, struct Stream* stream) {
cc_uint8 tmp[64];
cc_uint32 dataSize, fourCC;
cc_result res;
/* header variables */
static const cc_uint8 samplesPerPixel[] = { 1, 0, 3, 1, 2, 0, 4 };
cc_uint8 colorspace, bitsPerSample, bytesPerPixel = 0;
Png_RowExpander rowExpander = NULL;
cc_uint32 scanlineSize = 0, scanlineBytes = 0;
/* palette data */
BitmapCol trnsColor;
BitmapCol palette[PNG_PALETTE];
cc_uint32 i;
/* idat state */
cc_uint32 available = 0, rowY = 0;
cc_uint8 buffer[PNG_PALETTE * 3];
cc_uint32 read, bufferIdx = 0;
cc_uint32 left, bufferLen = 0;
int curY;
/* idat decompressor */
#if CC_BUILD_MAXSTACK <= (50 * 1024)
void* mem = TempMem_Alloc(sizeof(struct InflateState));
struct InflateState* inflate = (struct InflateState*)mem;
#else
struct InflateState _inflate;
struct InflateState* inflate = &_inflate;
#endif
struct Stream compStream, datStream;
struct ZLibHeader zlibHeader;
cc_uint8* data = NULL;
bmp->width = 0; bmp->height = 0;
bmp->scan0 = NULL;
res = Stream_Read(stream, tmp, PNG_SIG_SIZE);
if (res) return res;
if (!Png_Detect(tmp, PNG_SIG_SIZE)) return PNG_ERR_INVALID_SIG;
colorspace = 0xFF; /* Unknown colour space */
trnsColor = BITMAPCOLOR_BLACK;
for (i = 0; i < PNG_PALETTE; i++) { palette[i] = BITMAPCOLOR_BLACK; }
Inflate_MakeStream2(&compStream, inflate, stream);
ZLibHeader_Init(&zlibHeader);
for (;;) {
res = Stream_Read(stream, tmp, 8);
if (res) return res;
dataSize = Stream_GetU32_BE(tmp + 0);
fourCC = Stream_GetU32_BE(tmp + 4);
switch (fourCC) {
/* 11.2.2 IHDR Image header */
case PNG_FourCC('I','H','D','R'): {
if (dataSize != PNG_IHDR_SIZE) return PNG_ERR_INVALID_HDR_SIZE;
res = Stream_Read(stream, tmp, PNG_IHDR_SIZE);
if (res) return res;
bmp->width = (int)Stream_GetU32_BE(tmp + 0);
bmp->height = (int)Stream_GetU32_BE(tmp + 4);
if (bmp->width < 0 || bmp->width > PNG_MAX_DIMS) return PNG_ERR_TOO_WIDE;
if (bmp->height < 0 || bmp->height > PNG_MAX_DIMS) return PNG_ERR_TOO_TALL;
bitsPerSample = tmp[8]; colorspace = tmp[9];
if (bitsPerSample == 16) return PNG_ERR_16BITSAMPLES;
rowExpander = Png_GetExpander(colorspace, bitsPerSample);
if (!rowExpander) return PNG_ERR_INVALID_COL_BPP;
if (tmp[10] != 0) return PNG_ERR_COMP_METHOD;
if (tmp[11] != 0) return PNG_ERR_FILTER;
if (tmp[12] != 0) return PNG_ERR_INTERLACED;
bytesPerPixel = ((samplesPerPixel[colorspace] * bitsPerSample) + 7) >> 3;
scanlineSize = ((samplesPerPixel[colorspace] * bitsPerSample * bmp->width) + 7) >> 3;
scanlineBytes = scanlineSize + 1; /* Add 1 byte for filter byte of each scanline */
data = (cc_uint8*)Mem_TryAlloc(bmp->height, max(scanlineBytes, bmp->width * 4));
bmp->scan0 = (BitmapCol*)data;
if (!bmp->scan0) return ERR_OUT_OF_MEMORY;
bufferLen = bmp->height * scanlineBytes;
} break;
/* 11.2.3 PLTE Palette */
case PNG_FourCC('P','L','T','E'): {
if (dataSize > PNG_PALETTE * 3) return PNG_ERR_PAL_SIZE;
if ((dataSize % 3) != 0) return PNG_ERR_PAL_SIZE;
res = Stream_Read(stream, buffer, dataSize);
if (res) return res;
for (i = 0; i < dataSize; i += 3) {
palette[i / 3] &= BITMAPCOLOR_A_MASK; /* set RGB to 0 */
palette[i / 3] |= BitmapColor_R_Bits(buffer[i ]);
palette[i / 3] |= BitmapColor_G_Bits(buffer[i + 1]);
palette[i / 3] |= BitmapColor_B_Bits(buffer[i + 2]);
}
} break;
/* 11.3.2.1 tRNS Transparency */
case PNG_FourCC('t','R','N','S'): {
if (colorspace == PNG_COLOR_GRAYSCALE) {
if (dataSize != 2) return PNG_ERR_TRANS_COUNT;
res = Stream_Read(stream, buffer, dataSize);
if (res) return res;
/* RGB is always two bytes */
trnsColor = ExpandRGB(bitsPerSample, buffer[1], buffer[1], buffer[1]);
} else if (colorspace == PNG_COLOR_INDEXED) {
if (dataSize > PNG_PALETTE) return PNG_ERR_TRANS_COUNT;
res = Stream_Read(stream, buffer, dataSize);
if (res) return res;
/* set alpha component of palette */
for (i = 0; i < dataSize; i++) {
palette[i] &= BITMAPCOLOR_RGB_MASK; /* set A to 0 */
palette[i] |= BitmapColor_A_Bits(buffer[i]);
}
} else if (colorspace == PNG_COLOR_RGB) {
if (dataSize != 6) return PNG_ERR_TRANS_COUNT;
res = Stream_Read(stream, buffer, dataSize);
if (res) return res;
/* R,G,B are always two bytes */
trnsColor = ExpandRGB(bitsPerSample, buffer[1], buffer[3], buffer[5]);
} else {
return PNG_ERR_TRANS_INVALID;
}
} break;
/* 11.2.4 IDAT Image data */
case PNG_FourCC('I','D','A','T'): {
Stream_ReadonlyPortion(&datStream, stream, dataSize);
inflate->Source = &datStream;
/* TODO: This assumes zlib header will be in 1 IDAT chunk */
while (!zlibHeader.done) {
if ((res = ZLibHeader_Read(&datStream, &zlibHeader))) return res;
}
if (!bmp->scan0) return PNG_ERR_NO_DATA;
if (rowY >= bmp->height) break;
left = bufferLen - bufferIdx;
res = compStream.Read(&compStream, &data[bufferIdx], left, &read);
if (res) return res;
if (!read) break;
available += read;
bufferIdx += read;
/* Process all of the scanline(s) that have been fully decompressed */
/* NOTE: Need to check height too, in case IDAT is corrupted and has extra data */
for (; available >= scanlineBytes && rowY < bmp->height; rowY++, available -= scanlineBytes) {
cc_uint8* scanline = &data[rowY * scanlineBytes];
if (scanline[0] > PNG_FILTER_PAETH) return PNG_ERR_INVALID_SCANLINE;
if (rowY == 0) {
/* First row, prior is assumed as 0 */
Png_ReconstructFirst(scanline[0], bytesPerPixel, &scanline[1], scanlineSize);
} else {
cc_uint8* prior = &data[(rowY - 1) * scanlineBytes];
Png_Reconstruct(scanline[0], bytesPerPixel, &scanline[1], &prior[1], scanlineSize);
/* With the RGBA colourspace, each scanline is (1 + width*4) bytes wide */
/* Therefore once a row has been reconstructed, the prior row can be converted */
/* immediately into the destination colour format */
if (colorspace == PNG_COLOR_RGB_A) {
/* Prior line is no longer needed and can be overwritten now */
rowExpander(bmp->width, palette, &prior[1], Bitmap_GetRow(bmp, rowY - 1));
}
}
/* Current line is also no longer needed and can be overwritten now */
if (colorspace == PNG_COLOR_RGB_A && rowY == bmp->height - 1) {
rowExpander(bmp->width, palette, &scanline[1], Bitmap_GetRow(bmp, rowY));
}
}
/* Check if image fully decoded or not */
if (bufferIdx != bufferLen) break;
/* With other colourspaces, the length of a scanline might be less than the width of a 32 bpp image row */
/* Therefore image expansion can only be done after all the rows have been reconstructed, and must */
/* be done backwards to avoid overwriting any source data that has yet to be processed */
/* This is slightly slower, but the majority of images ClassiCube encounters are RGBA anyways */
if (colorspace != PNG_COLOR_RGB_A) {
for (curY = bmp->height - 1; curY >= 0; curY--) {
cc_uint8* scanline = &data[curY * scanlineBytes];
rowExpander(bmp->width, palette, &scanline[1], Bitmap_GetRow(bmp, curY));
}
}
if (!BitmapCol_A(trnsColor)) ComputeTransparency(bmp, trnsColor);
return 0;
} break;
/* 11.2.5 IEND Image trailer */
case PNG_FourCC('I','E','N','D'):
/* Reading all image data should be handled by above if in the IDAT chunk */
/* If we reached here, it means not all of the image data was read */
return PNG_ERR_REACHED_IEND;
default:
if ((res = stream->Skip(stream, dataSize))) return res;
break;
}
if ((res = stream->Skip(stream, 4))) return res; /* Skip CRC32 */
}
}
#endif
/*########################################################################################################################*
*------------------------------------------------------PNG encoder--------------------------------------------------------*
*#########################################################################################################################*/
#ifdef CC_BUILD_FILESYSTEM
static void Png_Filter(cc_uint8 filter, const cc_uint8* cur, const cc_uint8* prior, cc_uint8* best, int lineLen, int bpp) {
/* 3 bytes per pixel constant */
cc_uint8 a, b, c;
int i, p, pa, pb, pc;
switch (filter) {
case PNG_FILTER_SUB:
for (i = 0; i < bpp; i++) { best[i] = cur[i]; }
for (; i < lineLen; i++) {
best[i] = cur[i] - cur[i - bpp];
}
break;
case PNG_FILTER_UP:
for (i = 0; i < lineLen; i++) {
best[i] = cur[i] - prior[i];
}
break;
case PNG_FILTER_AVERAGE:
for (i = 0; i < bpp; i++) { best[i] = cur[i] - (prior[i] >> 1); }
for (; i < lineLen; i++) {
best[i] = cur[i] - ((prior[i] + cur[i - bpp]) >> 1);
}
break;
case PNG_FILTER_PAETH:
for (i = 0; i < bpp; i++) { best[i] = cur[i] - prior[i]; }
for (; i < lineLen; i++) {
a = cur[i - bpp]; b = prior[i]; c = prior[i - bpp];
p = a + b - c;
pa = Math_AbsI(p - a);
pb = Math_AbsI(p - b);
pc = Math_AbsI(p - c);
if (pa <= pb && pa <= pc) { best[i] = cur[i] - a; }
else if (pb <= pc) { best[i] = cur[i] - b; }
else { best[i] = cur[i] - c; }
}
break;
}
}
static void Png_MakeRow(const BitmapCol* src, cc_uint8* dst, int lineLen, cc_bool alpha) {
cc_uint8* end = dst + lineLen;
BitmapCol col; /* if we use *src, register gets reloaded each time */
if (alpha) {
for (; dst < end; src++, dst += 4) {
col = *src;
dst[0] = BitmapCol_R(col); dst[1] = BitmapCol_G(col);
dst[2] = BitmapCol_B(col); dst[3] = BitmapCol_A(col);
}
} else {
for (; dst < end; src++, dst += 3) {
col = *src;
dst[0] = BitmapCol_R(col); dst[1] = BitmapCol_G(col);
dst[2] = BitmapCol_B(col);
}
}
}
static void Png_EncodeRow(const cc_uint8* cur, const cc_uint8* prior, cc_uint8* best, int lineLen, cc_bool alpha) {
cc_uint8* dst;
int bestFilter = PNG_FILTER_SUB;
int bestEstimate = Int32_MaxValue;
int x, filter, estimate;
dst = best + 1;
/* NOTE: Waste of time trying the PNG_NONE filter */
for (filter = PNG_FILTER_SUB; filter <= PNG_FILTER_PAETH; filter++) {
Png_Filter(filter, cur, prior, dst, lineLen, alpha ? 4 : 3);
/* Estimate how well this filtered line will compress, based on */
/* smallest sum of magnitude of each byte (signed) in the line */
/* (see note in PNG specification, 12.8 "Filter selection" ) */
estimate = 0;
for (x = 0; x < lineLen; x++) {
estimate += Math_AbsI((cc_int8)dst[x]);
}
if (estimate > bestEstimate) continue;
bestEstimate = estimate;
bestFilter = filter;
}
/* The bytes in dst are from last filter run (paeth) */
/* However, we want dst to be bytes from the best filter */
if (bestFilter != PNG_FILTER_PAETH) {
Png_Filter(bestFilter, cur, prior, dst, lineLen, alpha ? 4 : 3);
}
best[0] = bestFilter;
}
static BitmapCol* DefaultGetRow(struct Bitmap* bmp, int y, void* ctx) { return Bitmap_GetRow(bmp, y); }
static cc_result Png_EncodeCore(struct Bitmap* bmp, struct Stream* stream, cc_uint8* buffer,
Png_RowGetter getRow, cc_bool alpha, void* ctx) {
cc_uint8 tmp[32];
cc_uint8* prevLine = buffer;
cc_uint8* curLine = buffer + (bmp->width * 4) * 1;
cc_uint8* bestLine = buffer + (bmp->width * 4) * 2;
#if CC_BUILD_MAXSTACK <= (50 * 1024)
struct ZLibState* zlState = (struct ZLibState*)Mem_TryAlloc(1, sizeof(struct ZLibState));
#else
struct ZLibState _zlState;
struct ZLibState* zlState = &_zlState;
#endif
struct Stream chunk, zlStream;
cc_uint32 stream_end, stream_beg;
int y, lineSize;
cc_result res;
/* stream may not start at 0 (e.g. when making default.zip) */
if ((res = stream->Position(stream, &stream_beg))) return res;
if (!getRow) getRow = DefaultGetRow;
if ((res = Stream_Write(stream, pngSig, PNG_SIG_SIZE))) return res;
Stream_WriteonlyCrc32(&chunk, stream);
/* Write header chunk */
Stream_SetU32_BE(&tmp[0], PNG_IHDR_SIZE);
Stream_SetU32_BE(&tmp[4], PNG_FourCC('I','H','D','R'));
{
Stream_SetU32_BE(&tmp[8], bmp->width);
Stream_SetU32_BE(&tmp[12], bmp->height);
tmp[16] = 8; /* bits per sample */
tmp[17] = alpha ? PNG_COLOR_RGB_A : PNG_COLOR_RGB;
tmp[18] = 0; /* DEFLATE compression method */
tmp[19] = 0; /* ADAPTIVE filter method */
tmp[20] = 0; /* Not using interlacing */
}
Stream_SetU32_BE(&tmp[21], Utils_CRC32(&tmp[4], 17));
/* Write PNG body */
Stream_SetU32_BE(&tmp[25], 0); /* size of IDAT, filled in later */
if ((res = Stream_Write(stream, tmp, 29))) return res;
Stream_SetU32_BE(&tmp[0], PNG_FourCC('I','D','A','T'));
if ((res = Stream_Write(&chunk, tmp, 4))) return res;
ZLib_MakeStream(&zlStream, zlState, &chunk);
lineSize = bmp->width * (alpha ? 4 : 3);
Mem_Set(prevLine, 0, lineSize);
for (y = 0; y < bmp->height; y++) {
BitmapCol* src = getRow(bmp, y, ctx);
cc_uint8* prev = (y & 1) == 0 ? prevLine : curLine;
cc_uint8* cur = (y & 1) == 0 ? curLine : prevLine;
Png_MakeRow(src, cur, lineSize, alpha);
Png_EncodeRow(cur, prev, bestLine, lineSize, alpha);
/* +1 for filter byte */
if ((res = Stream_Write(&zlStream, bestLine, lineSize + 1))) return res;
}
if ((res = zlStream.Close(&zlStream))) return res;
Stream_SetU32_BE(&tmp[0], chunk.meta.crc32.crc32 ^ 0xFFFFFFFFUL);
/* Write end chunk */
Stream_SetU32_BE(&tmp[4], 0);
Stream_SetU32_BE(&tmp[8], PNG_FourCC('I','E','N','D'));
Stream_SetU32_BE(&tmp[12], 0xAE426082UL); /* CRC32 of IEND */
if ((res = Stream_Write(stream, tmp, 16))) return res;
/* Come back to fixup size of data in data chunk */
if ((res = stream->Position(stream, &stream_end))) return res;
if ((res = stream->Seek(stream, stream_beg + 33))) return res;
Stream_SetU32_BE(&tmp[0], (stream_end - stream_beg) - 57);
if ((res = Stream_Write(stream, tmp, 4))) return res;
return stream->Seek(stream, stream_end);
}
cc_result Png_Encode(struct Bitmap* bmp, struct Stream* stream,
Png_RowGetter getRow, cc_bool alpha, void* ctx) {
cc_result res;
/* Add 1 for scanline filter type byter */
cc_uint8* buffer = (cc_uint8*)Mem_TryAlloc(3, bmp->width * 4 + 1);
if (!buffer) return ERR_NOT_SUPPORTED;
res = Png_EncodeCore(bmp, stream, buffer, getRow, alpha, ctx);
Mem_Free(buffer);
return res;
}
#else
/* No point including encoding code when can't save screenshots anyways */
cc_result Png_Encode(struct Bitmap* bmp, struct Stream* stream,
Png_RowGetter getRow, cc_bool alpha, void* ctx) {
return ERR_NOT_SUPPORTED;
}
#endif
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