C# Net 去除图片白边

using System.Drawing;

/// <summary>
        /// 裁剪图片（去掉百边）
        /// </summary>
        /// <param name="FilePath"></param>
        public static Bitmap CutImageWhitePart(string FilePath)
        {
            Bitmap bmp = new Bitmap(FilePath);
            //上左右下
            int top = 0,left = 0,right = bmp.Width,bottom = bmp.Height;

            //寻找最上面的标线,从左(0)到右，从上(0)到下
            for (int i = 0; i < bmp.Height; i++)//行
            {
                bool find = false;
                for (int j = 0; j < bmp.Width; j++)//列
                {
                    Color c = bmp.GetPixel(j,i);
                    if (!IsWhite(c))
                    {
                        top = i;
                        find = true;
                        break;
                    }
                }
                if (find)
                    break;
            }
            //寻找最左边的标线，从上（top位）到下，从左到右
            for (int i = 0; i < bmp.Width; i++)//列
            {
                bool find = false;
                for (int j = top; j < bmp.Height; j++)//行
                {
                    Color c = bmp.GetPixel(i,j);
                    if (!IsWhite(c))
                    {
                        left = i;
                        find = true;
                        break;
                    }
                }
                if (find)
                    break;
            }
            //寻找最下边标线，从下到上，从左到右
            for (int i = bmp.Height - 1; i >= 0; i--)//行
            {
                bool find = false;
                for (int j = left; j < bmp.Width; j++)//列
                {
                    Color c = bmp.GetPixel(j,i);
                    if (!IsWhite(c))
                    {
                        bottom = i;
                        find = true;
                        break;
                    }
                }
                if (find)
                    break;
            }
            //寻找最右边的标线，从上到下，从右往左
            for (int i = bmp.Width - 1; i >= 0; i--)//列
            {
                bool find = false;
                for (int j = 0; j <= bottom; j++)//行
                {
                    Color c = bmp.GetPixel(i,j);
                    if (!IsWhite(c))
                    {
                        right = i;
                        find = true;
                        break;
                    }
                }
                if (find)
                    break;
            }

            //克隆位图对象的一部分。
            Rectangle cloneRect = new Rectangle(left,top,right - left,bottom - top);
            Bitmap cloneBitmap = bmp.Clone(cloneRect,bmp.PixelFormat);
            bmp.Dispose();
            //cloneBitmap.Save(@"d:123.png",ImageFormat.Png);
            return cloneBitmap;
        }

        /// <summary>
        /// 判断是否白色和纯透明色（10点的容差）
        /// </summary>
        public static bool IsWhite(Color c)
        {
            //纯透明也是白色,RGB都为255为纯白
            if (c.A < 10 || (c.R > 245 && c.G > 245 && c.B > 245))
                return true;

            return false;
        }

            Bitmap bitmap = CutImageWhitePart(@"C:UsersPingDesktop2.png");
            bitmap.Save(@"d:123.png",ImageFormat.Png);