图片等比例截取

    private static bool ThumbnailCallback()
    {
        return false;
    }
    //****************************************************************************
    //设置高质量插值法
    //g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High;
    //设置高质量,低速度呈现平滑程度
    //g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;
    //清空画布并以透明背景色填充
    //g.Clear(Color.Transparent);
    //****************************************************************************
    /// <summary>
    /// 图片智能截取
    /// </summary>
    /// <returns></returns>
    public static bool IntellectiveCut(string srcPath, string destPath, double  width, double  height)
    {
        System.Drawing.Image img = new Bitmap(srcPath);
        //生成图片大小必需小于原图
        if (width > img.Width || height > img.Height)
            return false;
        //删除的高度，与宽度
        double  cutWidth, cutHeight;
        cutWidth =(img.Width * height/ img.Height -width); //宽度切割,高度缩放
        cutHeight = (img.Height * width /img.Width-height);//高度切割,宽度缩放
        byte flag=0;//0 截高，1 截宽
        flag =(byte)( cutHeight < cutWidth ? 0 : 1);
        if (cutWidth >= 0 && cutHeight < 0)
            flag = 1;
        if (cutHeight >= 0 && cutWidth < 0)
            flag = 0;
        //System.Drawing.Image.GetThumbnailImageAbort myCallback=new System.Drawing.Image.GetThumbnailImageAbort(ThumbnailCallback);
        System.Drawing.Image thumImg;
        if (flag == 0)
            thumImg = new Bitmap(img,(int)width, (int)height + (int)cutHeight); //img.GetThumbnailImage((int)width, (int)height + (int)cutHeight, myCallback, IntPtr.Zero);
        else
            thumImg = new Bitmap(img,(int)width + (int)cutWidth, (int)height);// img.GetThumbnailImage((int)width + (int)cutWidth, (int)height, myCallback, IntPtr.Zero);
        System.Drawing.Bitmap destImg = new Bitmap((int)width, (int)height);
        Graphics g = Graphics.FromImage(destImg);
        Rectangle rect = new Rectangle(0, 0, (int)width,(int) height);
        g.DrawImage(thumImg, rect, rect, GraphicsUnit.Pixel);
        g.Save();
        destImg.Save(destPath,ImageFormat.Jpeg);
        thumImg.Dispose();
        img.Dispose();
        destImg.Dispose();
        return true;

    }