Can you change one colour to another in an Bitmap image?

Question

For Bitmap, there is a MakeTransparent method, is there one similar for changing one color to another?

// This sets Color.White to          


        

Answer 1

Lifting the code from this answer:

public static class BitmapExtensions
{
    public static Bitmap ChangeColor(this Bitmap image, Color fromColor, Color toColor)
    {
        ImageAttributes attributes = new ImageAttributes();
        attributes.SetRemapTable(new ColorMap[]
        {
            new ColorMap()
            {
                OldColor = fromColor,
                NewColor = toColor,
            }
        }, ColorAdjustType.Bitmap);

        using (Graphics g = Graphics.FromImage(image))
        {
            g.DrawImage(
                image,
                new Rectangle(Point.Empty, image.Size),
                0, 0, image.Width, image.Height,
                GraphicsUnit.Pixel,
                attributes);
        }

        return image;
    }
}

While I haven't benchmarked it, this should be faster than any solution that's doing GetPixel/SetPixel in a loop. It's also a bit more straightforward.