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); }