FloatPixMapRef FPMCopySub(FloatPixMapRef pm, FPMRect rect)
{
FloatPixMapRef sub = FPMCreateSub(pm, rect);
FloatPixMapRef result = FPMCopy(sub);
FPMRelease(&sub);
return result;
}
bool FPMWritePNGCustom(FloatPixMapRef srcPM, png_voidp ioPtr, png_rw_ptr writeDataFn, png_flush_ptr flushDataFn, FPMWritePNGFlags options, FPMGammaFactor sourceGamma, FPMGammaFactor fileGamma, FPMPNGErrorHandler errorHandler)
{
if (srcPM != NULL)
{
bool success = false;
png_structp png = NULL;
png_infop pngInfo = NULL;
FloatPixMapRef pm = NULL;
// Prepare data.
FPMDimension width = FPMGetWidth(srcPM);
FPMDimension height = FPMGetHeight(srcPM);
if (width > UINT32_MAX || height > UINT32_MAX)
{
if (errorHandler != NULL) errorHandler("image is too large for PNG format.", true);
return false;
}
pm = FPMCopy(srcPM);
if (pm == NULL) return false;
unsigned steps = (options & kFPMWritePNG16BPC) ? 0x10000 : 0x100;
FPMApplyGamma(pm, sourceGamma, fileGamma, steps);
FPMQuantize(pm, 0.0f, 1.0f, 0.0f, steps - 1, steps, (options & kFPMQuantizeDither & kFPMQuantizeJitter) | kFMPQuantizeClip | kFMPQuantizeAlpha);
png = png_create_write_struct(PNG_LIBPNG_VER_STRING, errorHandler, PNGError, PNGWarning);
if (png == NULL) goto FAIL;
pngInfo = png_create_info_struct(png);
if (pngInfo == NULL) goto FAIL;
if (setjmp(png_jmpbuf(png)))
{
// libpng will jump here on error.
goto FAIL;
}
png_set_write_fn(png, ioPtr, writeDataFn, flushDataFn);
png_set_IHDR(png, pngInfo, width, height, (options & kFPMWritePNG16BPC) ? 16 : 8,PNG_COLOR_TYPE_RGB_ALPHA, PNG_INTERLACE_NONE, PNG_COMPRESSION_TYPE_DEFAULT, PNG_FILTER_TYPE_DEFAULT);
if (fileGamma == kFPMGammaSRGB)
{
png_set_sRGB_gAMA_and_cHRM(png, pngInfo, PNG_sRGB_INTENT_PERCEPTUAL);
}
else
{
png_set_gAMA(png, pngInfo, fileGamma);
}
/* Select function used to transform a row of data to PNG-friendly
format. NOTE: these work in place,and overwrite the data in pm,
which is OK since we copied it.
*/
RowTransformer transformer = NULL;
if (options & kFPMWritePNG16BPC)
{
transformer = TransformRow16;
}
else
{
transformer = TransformRow8;
}
png_write_info(png, pngInfo);
size_t i;
size_t rowOffset = FPMGetRowByteCount(pm);
png_bytep row = (png_bytep)FPMGetBufferPointer(pm);
for (i = 0; i < height; i++)
{
transformer(row, width);
png_write_row(png, row);
row += rowOffset;
}
png_write_end(png, pngInfo);
success = true;
FAIL:
if (png != NULL) png_destroy_write_struct(&png, &pngInfo);
FPMRelease(&pm);
return success;
}
else
{
return false;
}
}
