FloatPixMapRef FPMCreateWithPNGCustom(png_voidp ioPtr, png_rw_ptr readDataFn, FPMGammaFactor desiredGamma, FPMPNGErrorHandler errorHandler)
{
png_structp png = NULL;
png_infop pngInfo = NULL;
png_infop pngEndInfo = NULL;
FloatPixMapRef result = NULL;
png_uint_32 i, width, height, rowBytes;
int depth, colorType;
png_bytepp rows = NULL;
void *data = NULL;
png = png_create_read_struct(PNG_LIBPNG_VER_STRING, errorHandler, PNGError, PNGWarning);
if (png == NULL) goto FAIL;
pngInfo = png_create_info_struct(png);
if (pngInfo == NULL) goto FAIL;
pngEndInfo = png_create_info_struct(png);
if (pngEndInfo == NULL) goto FAIL;
if (setjmp(png_jmpbuf(png)))
{
// libpng will jump here on error.
goto FAIL;
}
png_set_read_fn(png, ioPtr, readDataFn);
png_read_info(png, pngInfo);
if (!png_get_IHDR(png, pngInfo, &width, &height, &depth, &colorType, NULL, NULL, NULL)) goto FAIL;
#if __LITTLE_ENDIAN__
if (depth == 16) png_set_swap(png);
#endif
if (depth <= 8 && !(colorType & PNG_COLOR_MASK_ALPHA))
{
png_set_filler(png, 0xFF, PNG_FILLER_AFTER);
}
png_set_gray_to_rgb(png);
if (depth < 8)
{
png_set_packing(png);
png_set_expand(png);
}
png_read_update_info(png, pngInfo);
rowBytes = png_get_rowbytes(png, pngInfo);
rows = malloc(sizeof *rows * height);
data = malloc(rowBytes * height);
if (rows == NULL || data == NULL) goto FAIL;
// Set up row pointers.
for (i = 0; i < height; i++)
{
rows[i] = (png_bytep)data + i * rowBytes;
}
png_read_image(png, rows);
png_read_end(png, pngEndInfo);
free(rows);
result = ConvertPNGData(data, width, height, rowBytes, png_get_bit_depth(png, pngInfo), png_get_color_type(png, pngInfo));
if (result != NULL)
{
double invGamma = 1.0/kFPMGammaSRGB;
png_get_gAMA(png, pngInfo, &invGamma);
FPMApplyGamma(result, 1.0/invGamma, desiredGamma, png_get_bit_depth(png, pngInfo) == 16 ? 65536 : 256);
}
png_destroy_read_struct(&png, &pngInfo, &pngEndInfo);
free(data);
return result;
FAIL:
FPMRelease(&result);
if (png != NULL) png_destroy_read_struct(&png, &pngInfo, &pngEndInfo);
free(rows);
free(data);
return NULL;
}
FloatPixMapRef FPMCreateWithPNGCustom(png_voidp ioPtr, png_rw_ptr readDataFn, FPMGammaFactor desiredGamma, FPMPNGErrorHandler errorHandler, FPMPNGProgressHandler progressHandler, void *callbackContext)
{
png_structp png = NULL;
png_infop pngInfo = NULL;
png_infop pngEndInfo = NULL;
FloatPixMapRef result = NULL;
png_uint_32 i, width, height, rowBytes;
int depth, colorType;
void *data = NULL;
ErrorInfo errInfo = { errorHandler, callbackContext };
png = png_create_read_struct(PNG_LIBPNG_VER_STRING, &errInfo, PNGError, PNGWarning);
if (png == NULL) goto FAIL;
pngInfo = png_create_info_struct(png);
if (pngInfo == NULL) goto FAIL;
pngEndInfo = png_create_info_struct(png);
if (pngEndInfo == NULL) goto FAIL;
if (setjmp(png_jmpbuf(png)))
{
// libpng will jump here on error.
goto FAIL;
}
png_set_read_fn(png, ioPtr, readDataFn);
png_read_info(png, pngInfo);
if (!png_get_IHDR(png, pngInfo, &width, &height, &depth, &colorType, NULL, NULL, NULL)) goto FAIL;
#if FPM_LITTLE_ENDIAN
if (depth == 16) png_set_swap(png);
#endif
if (depth <= 8 && !(colorType & PNG_COLOR_MASK_ALPHA))
{
png_set_filler(png, 0xFF, PNG_FILLER_AFTER);
}
png_set_gray_to_rgb(png);
if (depth < 8)
{
png_set_packing(png);
png_set_expand(png);
}
if (colorType & PNG_COLOR_MASK_PALETTE)
{
png_set_palette_to_rgb(png);
}
png_read_update_info(png, pngInfo);
rowBytes = png_get_rowbytes(png, pngInfo);
data = malloc(rowBytes * height);
if (data == NULL) goto FAIL;
// Set up row pointers.
for (i = 0; i < height; i++)
{
png_read_row(png, (png_bytep)data + i * rowBytes, NULL);
if (progressHandler) progressHandler((float)(i + 1) / (float)height, callbackContext);
}
png_read_end(png, pngEndInfo);
result = ConvertPNGData(data, width, height, rowBytes, png_get_bit_depth(png, pngInfo), png_get_color_type(png, pngInfo));
if (result != NULL)
{
double invGamma = 1.0/kFPMGammaSRGB;
png_get_gAMA(png, pngInfo, &invGamma);
FPMApplyGamma(result, 1.0/invGamma, desiredGamma, png_get_bit_depth(png, pngInfo) == 16 ? 65536 : 256);
}
else
{
if (errorHandler != NULL) errorHandler("Could not convert PNG data to native representation.", true, callbackContext);
}
png_destroy_read_struct(&png, &pngInfo, &pngEndInfo);
free(data);
return result;
FAIL:
FPMRelease(&result);
if (png != NULL) png_destroy_read_struct(&png, &pngInfo, &pngEndInfo);
free(data);
return NULL;
}
