Util: Add alpha versions of PNG functions

This commit is contained in:
Vicki Pfau 2017-09-23 12:33:36 -07:00
parent 507d033a97
commit 697c1cfa9d
2 changed files with 60 additions and 11 deletions

View File

@ -26,9 +26,11 @@ enum {
png_structp PNGWriteOpen(struct VFile* source);
png_infop PNGWriteHeader(png_structp png, unsigned width, unsigned height);
png_infop PNGWriteHeaderA(png_structp png, unsigned width, unsigned height);
png_infop PNGWriteHeader8(png_structp png, unsigned width, unsigned height);
bool PNGWritePalette(png_structp png, png_infop info, const uint32_t* palette, unsigned entries);
bool PNGWritePixels(png_structp png, unsigned width, unsigned height, unsigned stride, const void* pixels);
bool PNGWritePixelsA(png_structp png, unsigned width, unsigned height, unsigned stride, const void* pixels);
bool PNGWritePixels8(png_structp png, unsigned width, unsigned height, unsigned stride, const void* pixels);
bool PNGWriteCustomChunk(png_structp png, const char* name, size_t size, void* data);
void PNGWriteClose(png_structp png, png_infop info);

View File

@ -38,7 +38,7 @@ png_structp PNGWriteOpen(struct VFile* source) {
return png;
}
png_infop PNGWriteHeader(png_structp png, unsigned width, unsigned height) {
static png_infop _pngWriteHeader(png_structp png, unsigned width, unsigned height, int type) {
png_infop info = png_create_info_struct(png);
if (!info) {
return 0;
@ -46,21 +46,21 @@ png_infop PNGWriteHeader(png_structp png, unsigned width, unsigned height) {
if (setjmp(png_jmpbuf(png))) {
return 0;
}
png_set_IHDR(png, info, width, height, 8, PNG_COLOR_TYPE_RGB, PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
png_set_IHDR(png, info, width, height, 8, type, PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
png_write_info(png, info);
return info;
}
png_infop PNGWriteHeader(png_structp png, unsigned width, unsigned height) {
return _pngWriteHeader(png, width, height, PNG_COLOR_TYPE_RGB);
}
png_infop PNGWriteHeaderA(png_structp png, unsigned width, unsigned height) {
return _pngWriteHeader(png, width, height, PNG_COLOR_TYPE_RGB_ALPHA);
}
png_infop PNGWriteHeader8(png_structp png, unsigned width, unsigned height) {
png_infop info = png_create_info_struct(png);
if (!info) {
return 0;
}
if (setjmp(png_jmpbuf(png))) {
return 0;
}
png_set_IHDR(png, info, width, height, 8, PNG_COLOR_TYPE_PALETTE, PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_BASE, PNG_FILTER_TYPE_BASE);
return info;
return _pngWriteHeader(png, width, height, PNG_COLOR_TYPE_PALETTE);
}
bool PNGWritePalette(png_structp png, png_infop info, const uint32_t* palette, unsigned entries) {
@ -128,6 +128,53 @@ bool PNGWritePixels(png_structp png, unsigned width, unsigned height, unsigned s
return true;
}
bool PNGWritePixelsA(png_structp png, unsigned width, unsigned height, unsigned stride, const void* pixels) {
png_bytep row = malloc(sizeof(png_byte) * width * 4);
if (!row) {
return false;
}
const png_byte* pixelData = pixels;
if (setjmp(png_jmpbuf(png))) {
free(row);
return false;
}
unsigned i;
for (i = 0; i < height; ++i) {
unsigned x;
for (x = 0; x < width; ++x) {
#ifdef COLOR_16_BIT
uint16_t c = ((uint16_t*) pixelData)[stride * i + x];
#ifdef COLOR_5_6_5
row[x * 4] = (c >> 8) & 0xF8;
row[x * 4 + 1] = (c >> 3) & 0xFC;
row[x * 4 + 2] = (c << 3) & 0xF8;
row[x * 4 + 3] = 0xFF;
#else
row[x * 4] = (c >> 7) & 0xF8;
row[x * 4 + 1] = (c >> 2) & 0xF8;
row[x * 4 + 2] = (c << 3) & 0xF8;
row[x * 4 + 3] = (c >> 15) * 0xFF;
#endif
#else
#ifdef __BIG_ENDIAN__
row[x * 4] = pixelData[stride * i * 4 + x * 4 + 3];
row[x * 4 + 1] = pixelData[stride * i * 4 + x * 4 + 2];
row[x * 4 + 2] = pixelData[stride * i * 4 + x * 4 + 1];
row[x * 4 + 3] = pixelData[stride * i * 4 + x * 4];
#else
row[x * 4] = pixelData[stride * i * 4 + x * 4];
row[x * 4 + 1] = pixelData[stride * i * 4 + x * 4 + 1];
row[x * 4 + 2] = pixelData[stride * i * 4 + x * 4 + 2];
row[x * 4 + 3] = pixelData[stride * i * 4 + x * 4 + 3];
#endif
#endif
}
png_write_row(png, row);
}
free(row);
return true;
}
bool PNGWritePixels8(png_structp png, unsigned width, unsigned height, unsigned stride, const void* pixels) {
UNUSED(width);
const png_byte* pixelData = pixels;