public static bool TryGenerate(IPdfImage image, out byte[] bytes)
{
bytes = null;
var hasValidDetails = image.ColorSpaceDetails != null &&
!(image.ColorSpaceDetails is UnsupportedColorSpaceDetails);
var actualColorSpace = hasValidDetails ? image.ColorSpaceDetails.BaseType : image.ColorSpace;
var isColorSpaceSupported =
actualColorSpace == ColorSpace.DeviceGray || actualColorSpace == ColorSpace.DeviceRGB ||
actualColorSpace == ColorSpace.DeviceCMYK || actualColorSpace == ColorSpace.CalGray ||
actualColorSpace == ColorSpace.CalRGB;
if (!isColorSpaceSupported || !image.TryGetBytes(out var bytesPure))
{
return(false);
}
try
{
bytesPure = ColorSpaceDetailsByteConverter.Convert(image.ColorSpaceDetails, bytesPure,
image.BitsPerComponent, image.WidthInSamples, image.HeightInSamples);
var numberOfComponents =
actualColorSpace == ColorSpace.DeviceCMYK ? 4 :
actualColorSpace == ColorSpace.DeviceRGB ? 3 :
actualColorSpace == ColorSpace.CalRGB ? 3 : 1;
var is3Byte = numberOfComponents == 3;
var builder = PngBuilder.Create(image.WidthInSamples, image.HeightInSamples, false);
var requiredSize = (image.WidthInSamples * image.HeightInSamples * numberOfComponents);
var actualSize = bytesPure.Count;
var isCorrectlySized = bytesPure.Count == requiredSize ||
// Spec, p. 37: "...error if the stream contains too much data, with the exception that
// there may be an extra end-of-line marker..."
(actualSize == requiredSize + 1 && bytesPure[actualSize - 1] == ReadHelper.AsciiLineFeed) ||
(actualSize == requiredSize + 1 && bytesPure[actualSize - 1] == ReadHelper.AsciiCarriageReturn) ||
// The combination of a CARRIAGE RETURN followed immediately by a LINE FEED is treated as one EOL marker.
(actualSize == requiredSize + 2 &&
bytesPure[actualSize - 2] == ReadHelper.AsciiCarriageReturn &&
bytesPure[actualSize - 1] == ReadHelper.AsciiLineFeed);
if (!isCorrectlySized)
{
return(false);
}
var i = 0;
for (var col = 0; col < image.HeightInSamples; col++)
{
for (var row = 0; row < image.WidthInSamples; row++)
{
if (actualColorSpace == ColorSpace.DeviceCMYK)
{
/*
* Where CMYK in 0..1
* R = 255 × (1-C) × (1-K)
* G = 255 × (1-M) × (1-K)
* B = 255 × (1-Y) × (1-K)
*/
var c = (bytesPure[i++] / 255d);
var m = (bytesPure[i++] / 255d);
var y = (bytesPure[i++] / 255d);
var k = (bytesPure[i++] / 255d);
var r = (byte)(255 * (1 - c) * (1 - k));
var g = (byte)(255 * (1 - m) * (1 - k));
var b = (byte)(255 * (1 - y) * (1 - k));
builder.SetPixel(r, g, b, row, col);
}
else if (is3Byte)
{
builder.SetPixel(bytesPure[i++], bytesPure[i++], bytesPure[i++], row, col);
}
else
{
var pixel = bytesPure[i++];
builder.SetPixel(pixel, pixel, pixel, row, col);
}
}
}
bytes = builder.Save();
return(true);
}
catch
{
// ignored.
}
return(false);
}
public static bool TryGenerate(IPdfImage image, out byte[] bytes)
{
bytes = null;
var hasValidDetails = image.ColorSpaceDetails != null &&
!(image.ColorSpaceDetails is UnsupportedColorSpaceDetails);
var actualColorSpace = hasValidDetails ? image.ColorSpaceDetails.BaseType : image.ColorSpace;
var isColorSpaceSupported =
actualColorSpace == ColorSpace.DeviceGray || actualColorSpace == ColorSpace.DeviceRGB ||
actualColorSpace == ColorSpace.DeviceCMYK;
if (!isColorSpaceSupported || !image.TryGetBytes(out var bytesPure))
{
return(false);
}
try
{
bytesPure = ColorSpaceDetailsByteConverter.Convert(image.ColorSpaceDetails, bytesPure,
image.BitsPerComponent, image.WidthInSamples, image.HeightInSamples);
var numberOfComponents = actualColorSpace == ColorSpace.DeviceCMYK ? 4 : actualColorSpace == ColorSpace.DeviceRGB ? 3 : 1;
var is3Byte = numberOfComponents == 3;
var builder = PngBuilder.Create(image.WidthInSamples, image.HeightInSamples, false);
var isCorrectlySized = bytesPure.Count == (image.WidthInSamples * image.HeightInSamples * numberOfComponents);
if (!isCorrectlySized)
{
return(false);
}
var i = 0;
for (var col = 0; col < image.HeightInSamples; col++)
{
for (var row = 0; row < image.WidthInSamples; row++)
{
if (actualColorSpace == ColorSpace.DeviceCMYK)
{
/*
* Where CMYK in 0..1
* R = 255 × (1-C) × (1-K)
* G = 255 × (1-M) × (1-K)
* B = 255 × (1-Y) × (1-K)
*/
var c = (bytesPure[i++] / 255d);
var m = (bytesPure[i++] / 255d);
var y = (bytesPure[i++] / 255d);
var k = (bytesPure[i++] / 255d);
var r = (byte)(255 * (1 - c) * (1 - k));
var g = (byte)(255 * (1 - m) * (1 - k));
var b = (byte)(255 * (1 - y) * (1 - k));
builder.SetPixel(r, g, b, row, col);
}
else if (is3Byte)
{
builder.SetPixel(bytesPure[i++], bytesPure[i++], bytesPure[i++], row, col);
}
else
{
var pixel = bytesPure[i++];
builder.SetPixel(pixel, pixel, pixel, row, col);
}
}
}
bytes = builder.Save();
return(true);
}
catch
{
// ignored.
}
return(false);
}
