C# 剪裁图片

        /// <summary>
        /// 剪裁图片
        /// </summary>
        /// <param name="src">原图片</param>
        /// <param name="left">左坐标</param>
        /// <param name="top">顶部坐标</param>
        /// <param name="right">右坐标</param>
        /// <param name="bottom">底部坐标</param>
        /// <returns>剪裁后的图片</returns>
        public Image CutImage(Image src, int left, int top, int right, int bottom)
        {
            Bitmap srcBitmap = new Bitmap(src);
            int width = right - left;
            int height = bottom - top;
            Bitmap destBitmap = new Bitmap(width, height);
            using (Graphics g = Graphics.FromImage(destBitmap))
            {
                g.Clear(Color.Transparent);

                //设置画布的描绘质量         
                g.CompositingQuality = System.Drawing.Drawing2D.CompositingQuality.HighQuality;
                g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
                g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.HighQualityBicubic;
                g.DrawImage(srcBitmap, new Rectangle(0, 0, width, height), left, top, width, height, GraphicsUnit.Pixel);
            }

            return destBitmap;
        }