.net - 如何确定winforms中给定颜色的禁用颜色？

Question

Windows 窗体具有方便的 ControlPaint.DrawImageDisabled 以在灰显、禁用状态下绘制彩色图像。对于给定的颜色，有没有办法确定禁用的颜色是什么（就好像它是由 DrawImageDisabled 绘制的一样）？

Answer 1

Reflector 告诉我们，这是创建使用的 ColorMatrix 的代码：

// In class-level declarations in ColorPaint
private static ImageAttributes disabledImageAttr;

// In the actual implementation method for DrawImageDisabled
    if (disabledImageAttr == null)
    {
        float[][] newColorMatrix = new float[5][];
        newColorMatrix[0] = new float[] { 0.2125f, 0.2125f, 0.2125f, 0f, 0f };
        newColorMatrix[1] = new float[] { 0.2577f, 0.2577f, 0.2577f, 0f, 0f };
        newColorMatrix[2] = new float[] { 0.0361f, 0.0361f, 0.0361f, 0f, 0f };
        float[] numArray2 = new float[5];
        numArray2[3] = 1f;
        newColorMatrix[3] = numArray2;
        newColorMatrix[4] = new float[] { 0.38f, 0.38f, 0.38f, 0f, 1f };
        ColorMatrix matrix = new ColorMatrix(newColorMatrix);
        disabledImageAttr = new ImageAttributes();
        disabledImageAttr.ClearColorKey();
        disabledImageAttr.SetColorMatrix(matrix);
    }

// To draw the image itself
using (Bitmap bitmap = new Bitmap(image.Width, image.Height))
{
    using (Graphics graphics2 = Graphics.FromImage(bitmap))
    {
        graphics2.DrawImage(image, new Rectangle(0, 0, size.Width, size.Height), 0, 0, size.Width, size.Height, GraphicsUnit.Pixel, disabledImageAttr);
    }
    graphics.DrawImageUnscaled(bitmap, imageBounds);
    return;
}