Question

Im trying to generate a small square 32 by 32 pixels with a 10 by 10 squareish transparent gap in the middle.

This is what I have so far:

private Image CreatePicture(){     // Create a new Bitmap object, 32 x 32 pixels in size     Bitmap canvas = new Bitmap(32,32,System.Drawing.Imaging.PixelFormat.Format16bppRgb555);     for(int i=10;i<21;i++){         for(int p=10;p<21;p++){             canvas.SetPixel(i,p,Color.Lime);         }     }     canvas.MakeTransparent(Color.Lime);     // return the picture     return canvas; } 

Its a it rough and not going to be the final ‘optimized version’ its just a rough demo script. The problem is the returned image does not transparency instead its just a grey box :(.

Any help appreciated.

Michael

UPDATE: I have updated the script with the PixelFormat set to an Alpha RGB format which it actually accepts without erroring on runtime. Now though if I remove the ‘canvas.MakeTransparent(Color.Lime);’ line it shows a lime box in the middle with it it just shows a grey box the same colour as the grey background; so it seems as if transparency is being recognised just not implimenting the transparency!

private Bitmap CreatePicture(){     // Create a new Bitmap object, 50 x 50 pixels in size     Bitmap canvas = new Bitmap(82,82,System.Drawing.Imaging.PixelFormat.Format32bppArgb);      for(int i=10;i<71;i++){         for(int p=10;p<71;p++){             canvas.SetPixel(i,p,Color.Lime);         }     }     canvas.MakeTransparent(Color.Lime);     // return the picture     return canvas; } 

Answer 1

It depends on how your going to use or display the image. PNG and Gif are the two file formats that support transparency.

For the bitmap setting of transparency, i used:

Graphics.FromImage(bitmap).FillRectangle(Brushes.Transparent, …) to set the area I wanted as transparent, then I saved the file out as a PNG to get an image with transparency.

I also tried the MakeTransparent method and ran into problems and the Brushes.Transparent was the solution that worked for my situation.

Hope this gives you a direction to look into.

One last note, I create the Bitmap object with width and height only, I don’t specify the pixel format or whatever that’s called i.e. bitmap = New Bitmap(width, height);