如何在不丢失透明度的情况下将PNG图像转换为灰度C# [英] How to convert a PNG image to grayscale and without losing the transparency C#

问题描述

我想将透明的png图像转换为灰度而不丢失其透明度.

I want to convert a transparent png image to greyscale without losing its transparency.

问题是我正在使用的算法将透明部分转换为黑色，某些带有黑色字符的图片将不会显示.给你个主意.

The problem is the algorithm that I am using in is converting the transparent part into Black, which some picture with black character wouldn't be shown. To give you an idea.

此处显示原始图片:

看看当我通过算法时会发生什么.

算法:

       public static void ToWhiteBlack(Bitmap original)
    {
        try
        {

            for (var i = 0; i < original.Width; i++)
            {
                for (var j = 0; j < original.Height; j++)
                {
                    var originalColor = original.GetPixel(i, j);
                    var grayScale = (int) ((originalColor.R*0.3) + (originalColor.G*0.59) + (originalColor.B*0.11));
                    var corEmEscalaDeCinza = Color.FromArgb(grayScale, grayScale, grayScale);
                    original.SetPixel(i, j, corEmEscalaDeCinza);
                }
            }
        }
        catch
        {

        }

    }

推荐答案

您需要传递原始颜色的alpha值以获取透明度.请注意，如果您也将通过部分透明的像素.

You need to pass the alpha value of the original color to get the transparency. Note that if you have partially transparent pixels that will be passed as well.

var corEmEscalaDeCinza = Color.FromArgb(originalColor.A, grayScale, grayScale, grayScale);

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