C#中调整图像大小的步骤详解

string path = Server.MapPath("~/Images");
System.Drawing.Image img = System.Drawing.Image.FromFile(string.Concat(path,"/3904.jpg"));

Bitmap b = new Bitmap(img);

private static System.Drawing.Image resizeImage(System.Drawing.Image imgToResize, Size size)
{
    //获取图片宽度
    int sourceWidth = imgToResize.Width;
    //获取图片高度
    int sourceHeight = imgToResize.Height;
  
    float nPercent = 0;
    float nPercentW = 0;
    float nPercentH = 0;
    //计算宽度的缩放比例
    nPercentW = ((float)size.Width / (float)sourceWidth);
    //计算高度的缩放比例
    nPercentH = ((float)size.Height / (float)sourceHeight);      
  
    if (nPercentH < nPercentW)
        nPercent = nPercentH;
    else
     nPercent = nPercentW;
     //期望的宽度
     int destWidth = (int)(sourceWidth * nPercent);
     //期望的高度
     int destHeight = (int)(sourceHeight * nPercent);
  
     Bitmap b = new Bitmap(destWidth, destHeight);
     Graphics g = Graphics.FromImage((System.Drawing.Image)b);
     g.InterpolationMode = InterpolationMode.HighQualityBicubic;
     //绘制图像
     g.DrawImage(imgToResize, 0, 0, destWidth, destHeight);
     g.Dispose();
     return (System.Drawing.Image)b;
}

System.Drawing. Image i = resizeImage(b, new Size(100, 100));