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Util: Add missing PNG read functions

This commit is contained in:
Vicki Pfau 2018-09-12 19:27:23 -07:00
parent cc2362aea9
commit 4f312a0998
2 changed files with 77 additions and 0 deletions
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2
include/mgba-util/png-io.h
View File

@ -42,6 +42,8 @@ png_structp PNGReadOpen(struct VFile* source, unsigned offset);
bool PNGInstallChunkHandler(png_structp png, void* context, ChunkHandler handler, const char* chunkName);
bool PNGReadHeader(png_structp png, png_infop info);
bool PNGReadPixels(png_structp png, png_infop info, void* pixels, unsigned width, unsigned height, unsigned stride);
bool PNGReadPixelsA(png_structp png, png_infop info, void* pixels, unsigned width, unsigned height, unsigned stride);
bool PNGReadPixels8(png_structp png, png_infop info, void* pixels, unsigned width, unsigned height, unsigned stride);
bool PNGIgnorePixels(png_structp png, png_infop info);
bool PNGReadFooter(png_structp png, png_infop end);
void PNGReadClose(png_structp png, png_infop info, png_infop end);

75
src/util/png-io.c
View File

@ -323,6 +323,81 @@ bool PNGReadPixels(png_structp png, png_infop info, void* pixels, unsigned width
return true;
}
bool PNGReadPixelsA(png_structp png, png_infop info, void* pixels, unsigned width, unsigned height, unsigned stride) {
if (setjmp(png_jmpbuf(png))) {
return false;
}
uint8_t* pixelData = pixels;
unsigned pngHeight = png_get_image_height(png, info);
if (height < pngHeight) {
pngHeight = height;
}
unsigned pngWidth = png_get_image_width(png, info);
if (width < pngWidth) {
pngWidth = width;
}
unsigned i;
png_bytep row = malloc(png_get_rowbytes(png, info));
for (i = 0; i < pngHeight; ++i) {
png_read_row(png, row, 0);
unsigned x;
for (x = 0; x < pngWidth; ++x) {
#ifdef COLOR_16_BIT
uint16_t c = row[x * 4 + 2] >> 3;
#ifdef COLOR_5_6_5
c |= (row[x * 4 + 1] << 3) & 0x7E0;
c |= (row[x * 4] << 8) & 0xF800;
#else
c |= (row[x * 4 + 1] << 2) & 0x3E0;
c |= (row[x * 4] << 7) & 0x7C00;
#endif
((uint16_t*) pixelData)[stride * i + x] = c;
#else
#if __BIG_ENDIAN__
pixelData[stride * i * 4 + x * 4 + 3] = row[x * 4];
pixelData[stride * i * 4 + x * 4 + 2] = row[x * 4 + 1];
pixelData[stride * i * 4 + x * 4 + 1] = row[x * 4 + 2];
pixelData[stride * i * 4 + x * 4] = row[x * 4 + 3];
#else
pixelData[stride * i * 4 + x * 4] = row[x * 4];
pixelData[stride * i * 4 + x * 4 + 1] = row[x * 4 + 1];
pixelData[stride * i * 4 + x * 4 + 2] = row[x * 4 + 2];
pixelData[stride * i * 4 + x * 4 + 3] = row[x * 4 + 3];
#endif
#endif
}
}
free(row);
return true;
}
bool PNGReadPixels8(png_structp png, png_infop info, void* pixels, unsigned width, unsigned height, unsigned stride) {
if (setjmp(png_jmpbuf(png))) {
return false;
}
uint8_t* pixelData = pixels;
unsigned pngHeight = png_get_image_height(png, info);
if (height < pngHeight) {
pngHeight = height;
}
unsigned pngWidth = png_get_image_width(png, info);
if (width < pngWidth) {
pngWidth = width;
}
unsigned i;
for (i = 0; i < pngHeight; ++i) {
png_read_row(png, &pixelData[stride * i], 0);
}
return true;
}
bool PNGReadFooter(png_structp png, png_infop end) {
if (setjmp(png_jmpbuf(png))) {
return false;