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POFind CMYK counts in bitmap pixels
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  1. POFind CMYK counts in bitmap pixels
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    copied!<ol> <li>RGB bitmap to CMYK?</li> <li>Count the CMYK to read the colour depth?</li> </ol> <p>or</p> <ol> <li>Count RGB values(done), not convert RGB --> CMYK using ICC profile</li> </ol> <p>How to find the percentage of CMYK in bitmap. Similar to Ghostscript API. I can't use this in my program because it is not managed and doesn't support for parallel processing. I have done this using RGB <a href="https://stackoverflow.com/q/18757027/1834352">(as per this)</a> , but for printer friendliness need this in CMYK.</p> <pre><code> public static bool IsCMYK(System.Drawing.Image image) { var flags = (ImageFlags)image.Flags; if (flags.HasFlag(ImageFlags.ColorSpaceCmyk) || flags.HasFlag(ImageFlags.ColorSpaceYcck)) { return true; } const int PixelFormat32bppCMYK = (15 | (32 &lt;&lt; 8)); return (int)image.PixelFormat == PixelFormat32bppCMYK; } public void ImagemagicTool(Bitmap bi) { ImageMagick.MagickImage img = new MagickImage(bi); string str= img.ColorSpace.ToString(); } public ImageColorFormat GetColorFormat(Bitmap bitmap) { const int pixelFormatIndexed = 0x00010000; const int pixelFormat32bppCMYK = 0x200F; const int pixelFormat16bppGrayScale = (4 | (16 &lt;&lt; 8)); // Check image flags var flags = (ImageFlags)bitmap.Flags; if (flags.HasFlag(ImageFlags.ColorSpaceCmyk) || flags.HasFlag(ImageFlags.ColorSpaceYcck)) { return ImageColorFormat.Cmyk; } else if (flags.HasFlag(ImageFlags.ColorSpaceGray)) { return ImageColorFormat.Grayscale; } // Check pixel format var pixelFormat = (int)bitmap.PixelFormat; if (pixelFormat == pixelFormat32bppCMYK) { return ImageColorFormat.Cmyk; } else if ((pixelFormat &amp; pixelFormatIndexed) != 0) { return ImageColorFormat.Indexed; } else if (pixelFormat == pixelFormat16bppGrayScale) { return ImageColorFormat.Grayscale; } // Default to RGB return ImageColorFormat.Rgb; } </code></pre> <p>*Update: Looks I have to separate the layers CMYK and then find the percentage of the each C,M,Y &amp; K.How do I do that in bitmap stream? This might be complex, for simpler approach Finding RGB and then Convert RGB to CMYK based on ICC US webcotedSWOP v2 .ICC...</p> <p>Just trying with the above mentioned, appreciate to put me in right direction</p> <hr> <p>Now I have got the CMYK propotionate values for RGB in bitmap, but not sure about the desired result in percentage, is there any upper limit for CMYK? </p> <pre><code>public static CMYK RGBtoCMYK(int red, int green, int blue) { double c = (double)(255 - red) / 255; double m = (double)(255 - green) / 255; double y = (double)(255 - blue) / 255; double min = (double)Math.Min(c, Math.Min(m, y)); if (min == 1.0) { return new CMYK(0, 0, 0, 1); } else { return new CMYK((c - min) / (1 - min), (m - min) / (1 - min), (y - min) / (1 - min), min); } } public class CMYK { public double Cyan { get; set; } public double Magenta { get; set; } public double Yellow { get; set; } public double Black { get; set; } public CMYK() { } public CMYK(double cyan, double magenta, double yellow,double black) { Cyan = cyan; Magenta = magenta; Yellow = yellow; Black = black; } } public static void GetRGBlock(Bitmap bmp) { System.Drawing.Rectangle rect = new System.Drawing.Rectangle(0, 0, bmp.Width, bmp.Height); System.Drawing.Imaging.BitmapData bmpData = bmp.LockBits(rect, System.Drawing.Imaging.ImageLockMode.ReadOnly, System.Drawing.Imaging.PixelFormat.Format24bppRgb); IntPtr ptr = bmpData.Scan0; List&lt;System.Drawing.Color&gt; cols = new List&lt;System.Drawing.Color&gt;(); int bytes = Math.Abs(bmpData.Stride) * bmp.Height; byte[] rgbValues = new byte[bytes]; System.Runtime.InteropServices.Marshal.Copy(ptr, rgbValues, 0, bytes); int x = 0; int y = 0; int dx = 0; int l = 0; for (y = 0; y &lt;= rect.Height - 1; y++) { l = y * bmpData.Stride; //calulate line based on stride for (x = 0; x &lt;= rect.Width - 1; x++) { dx = l + x * 3; //3 for RGB, 4 for ARGB, notice l is used as offset cols.Add(System.Drawing.Color.FromArgb(rgbValues[dx + 2], rgbValues[dx + 1], rgbValues[dx])); } } List&lt;CMYK&gt; cmykcols = new List&lt;CMYK&gt;(); foreach (var item in cols) cmykcols.Add(RGBtoCMYK(item.R, item.G, item.B)); bmp.UnlockBits(bmpData); bmp.Dispose(); } </code></pre>
 

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