C# 簡單一鍵影像灰階化

利用GetPixel與SetPixel達到簡易的圖片灰階化處理。

開啟圖檔

private void btnOpen_Click(object sender, EventArgs e)
{
    OpenFileDialog openFileDialog = new OpenFileDialog();
    openFileDialog.Filter = "JPG(*.jpg)|*.jpg|" + "BMP(*.BMP)|*.bmp|" + "GIF(*.GIT)|*.gif|" + "所有檔案|*.*";
    if (openFileDialog.ShowDialog() == DialogResult.OK)
    {
        pictureBox1.Width = Image.FromFile(openFileDialog.FileName).Width;
        pictureBox1.Height = Image.FromFile(openFileDialog.FileName).Height;
        pictureBox1.Image = Image.FromFile(openFileDialog.FileName);
    }
}

灰階化

private void btnGray_Click(object sender, EventArgs e)
{
    //前提利用OpenFileDialog將影像放到pictureBox1
    try
    {
        //並宣告bm1為Bitmap
        Bitmap bm1 = (Bitmap)pictureBox1.Image;
        //宣告寬及高
        int w1 = pictureBox1.Image.Width;
        int h1 = pictureBox1.Image.Width;
        int x;
        int y;
        //掃影像每一個pixel並做處理
        for (y = 0; y <= h1 - 1; y++)
        {
            for (x = 0; x <= w1 - 1; x++)
            {
                Color c1 = bm1.GetPixel(x, y);
                int r1 = c1.R;
                int g1 = c1.G;
                int b1 = c1.B;
                int avg1 = (r1 + g1 + b1) / 3;
                bm1.SetPixel(x, y, Color.FromArgb(avg1, avg1,avg1));
            }
        }
        //處理完後放回pictureBox1
        pictureBox1.Image = bm1;
    }
 
    catch (Exception ex)
    {
        MessageBox.Show(ex.Message);
    }
}

Sample SourceCode：
Download



Reference：

日向俊二、陳亦苓 譯，”Visual Basic 2005 功能索引式參考手冊”