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[.net] Save an array of colors in BMP file

Started by atgroup Dec 29, 2010 at 12:07 PM 1 replies 2.9k views

Original Post

Dec 29, 2010 at 12:07 PM

Hello.

I want to save an array like this to a bitmap file:

string[] col = new string[1000];
col[0]="33,44,255";
col[1]="93,79,167";
col[2]="255,144,6";

I may have 10000 bytes or more, please help for source CODE.

using C#.net 2005, or newer.

thanks.

Ibasa

Jan 15, 2011 at 1:48 AM

Does the following help? There's no error checking in it but it should at least be a start.

//create a new bitmap, width*height should equal col.Length
 System.Drawing.Bitmap bitmap = new System.Drawing.Bitmap(width, height);
 
 //parse each color and return it in argb format
 int[] memory = col.Select(str => 
 {
 string[] rgb = str.Split(',');
 int red = int.Parse(rgb[0]);
 int green = int.Parse(rgb[1]);
 int blue = int.Parse(rgb[2]);
 return System.Drawing.Color.FromArgb(red, green,blue).ToArgb();
 }).ToArray();
 
 //lock the bitmap
 System.Drawing.Imaging.BitmapData data = bitmap.LockBits(
 new System.Drawing.Rectangle(0,0,bitmap.Width, bitmap.Height),
 System.Drawing.Imaging.ImageLockMode.WriteOnly,
 System.Drawing.Imaging.PixelFormat.Format32bppRgb);
 
 //write each scanline to the bitmap
 for(int scanline=0; scanline < bitmap.Height; ++scanline)
 {
 int offset = data.Stride * scanline;
 
 System.Runtime.InteropServices.Marshal.Copy(memory, scanline * bitmap.Width, data.Scan0 + offset, bitmap.Width * 4); 
 }
 
 bitmap.Save(path);

Say if there's any part you don't understand.

benryves

Jan 17, 2011 at 10:44 PM

A few points on the above code:

Once you have finished writing to the Bitmap you should Unlock it with bitmap.UnlockBits(data)
Similarly, you should Dispose the Bitmap when you're done. A using statement may help.
It produces a PNG, whereas the original poster asked for a BMP. Use bitmap.Save(path, ImageFormat.Bmp) to save as BMP.

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