C#实现缩放和剪裁图片的方法示例

using System;using System.Collections.Generic;using System.Text;using System.Drawing;using System.Drawing.Drawing2D;using System.Drawing.Imaging;namespace Project{  class ImageOperation  {    /// <summary>    /// Resize图片    /// </summary>    /// <param name="bmp">原始Bitmap </param>    /// <param name="newW">新的宽度</param>    /// <param name="newH">新的高度</param>    /// <param name="Mode">保留着，暂时未用</param>    /// <returns>处理以后的图片</returns>    public static Bitmap ResizeImage(Bitmap bmp, int newW, int newH, int Mode)    {      try      {        Bitmap b = new Bitmap(newW, newH);        Graphics g = Graphics.FromImage(b);        // 插值算法的质量        g.InterpolationMode = InterpolationMode.HighQualityBicubic;        g.DrawImage(bmp, new Rectangle(0, 0, newW, newH), new Rectangle(0, 0, bmp.Width, bmp.Height), GraphicsUnit.Pixel);        g.Dispose();        return b;      }      catch      {        return null;      }    }    /// <summary>    /// 剪裁 -- 用GDI+    /// </summary>    /// <param name="b">原始Bitmap</param>    /// <param name="StartX">开始坐标X</param>    /// <param name="StartY">开始坐标Y</param>    /// <param name="iWidth">宽度</param>    /// <param name="iHeight">高度</param>    /// <returns>剪裁后的Bitmap</returns>    public static Bitmap Cut(Bitmap b, int StartX, int StartY, int iWidth, int iHeight)    {      if (b == null)      {        return null;      }      int w = b.Width;      int h = b.Height;      if (StartX >= w || StartY >= h)      {        return null;      }      if (StartX + iWidth > w)      {        iWidth = w - StartX;      }      if (StartY + iHeight > h)      {        iHeight = h - StartY;      }      try      {        Bitmap bmpOut = new Bitmap(iWidth, iHeight, PixelFormat.Format24bppRgb);        Graphics g = Graphics.FromImage(bmpOut);        g.DrawImage(b, new Rectangle(0, 0, iWidth, iHeight), new Rectangle(StartX, StartY, iWidth, iHeight), GraphicsUnit.Pixel);        g.Dispose();        return bmpOut;      }      catch      {        return null;      }    }  }}