c# - 设置 BMP/JPG 文件的像素颜色

Question

我正在尝试为图像的给定像素设置颜色。这是代码片段

        Bitmap myBitmap = new Bitmap(@"c:\file.bmp");

        for (int Xcount = 0; Xcount < myBitmap.Width; Xcount++)
        {
            for (int Ycount = 0; Ycount < myBitmap.Height; Ycount++)
            {
                myBitmap.SetPixel(Xcount, Ycount, Color.Black);
            }
        }

每次我得到以下异常:

Unhandled Exception: System.InvalidOperationException: SetPixel is not supported for images with indexed pixel formats.

bmp 和 jpg 文件都会抛出异常。

Answer 1

您必须将图像从索引转换为非索引。试试这个代码来转换它:

    public Bitmap CreateNonIndexedImage(Image src)
    {
        Bitmap newBmp = new Bitmap(src.Width, src.Height, System.Drawing.Imaging.PixelFormat.Format32bppArgb);

        using (Graphics gfx = Graphics.FromImage(newBmp)) {
            gfx.DrawImage(src, 0, 0);
        }

        return newBmp;
    }