生成缩略图、为图片添加文字水印、图片水印的类

using System;
using System.Data;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;

/// <summary>
/// 生成缩略图、为图片添加文字水印、图片水印的类
/// </summary>
public class ThumNail
{
    public ThumNail()
    {
        //
        // TODO: Add constructor logic here
        //
    }
    /// <summary>
    /// 生成缩略图
    /// </summary>
    /// <param name="orginalImagePat"> 原图片地址 </param>
    /// <param name="thumNailPath"> 缩略图地址 </param>
    /// <param name="width"> 缩略图宽度 </param>
    /// <param name="height"> 缩略图高度 </param>
    /// <param name="model"> 生成缩略的模式 </param>
    public static void MakeThumNail( string originalImagePath, string thumNailPath, int width, int height, string model)
    {
        System.Drawing.Image originalImage = System.Drawing.Image.FromFile(originalImagePath);

        int thumWidth = width;      // 缩略图的宽度
        int thumHeight = height;    // 缩略图的高度

        int x = 0 ;
        int y = 0 ;

        int originalWidth = originalImage.Width;    // 原始图片的宽度
        int originalHeight = originalImage.Height;  // 原始图片的高度

        switch (model)
        {
            case " HW " :      // 指定高宽缩放,可能变形
                break ;
            case " W " :       // 指定宽度,高度按照比例缩放
                thumHeight = originalImage.Height * width / originalImage.Width;
                break ;
            case " H " :       // 指定高度,宽度按照等比例缩放
                thumWidth = originalImage.Width * height / originalImage.Height;
                break ;
            case " Cut " :
                if (( double )originalImage.Width / ( double )originalImage.Height > ( double )thumWidth / ( double )thumHeight)
                {
                    originalHeight = originalImage.Height;
                    originalWidth = originalImage.Height * thumWidth / thumHeight;
                    y = 0 ;
                    x = (originalImage.Width - originalWidth) / 2 ;
                }
                else
                {
                    originalWidth = originalImage.Width;
                    originalHeight = originalWidth * height / thumWidth;
                    x = 0 ;
                    y = (originalImage.Height - originalHeight) / 2 ;
                }
                break ;
            default :
                break ;
        }

        // 新建一个bmp图片
        System.Drawing.Image bitmap = new System.Drawing.Bitmap(thumWidth,thumHeight);

        // 新建一个画板
        System.Drawing.Graphics graphic = System.Drawing.Graphics.FromImage(bitmap);

        // 设置高质量查值法
        graphic.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High;

        // 设置高质量，低速度呈现平滑程度
        graphic.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;

        // 清空画布并以透明背景色填充
        graphic.Clear(System.Drawing.Color.Transparent);
       
        // 在指定位置并且按指定大小绘制原图片的指定部分
        graphic.DrawImage(originalImage, new System.Drawing.Rectangle( 0 , 0 , thumWidth, thumHeight), new System.Drawing.Rectangle(x, y, originalWidth, originalHeight), System.Drawing.GraphicsUnit.Pixel);

        try
        {
            bitmap.Save(thumNailPath, System.Drawing.Imaging.ImageFormat.Jpeg);
        }
        catch (Exception ex)
        {

            throw ex;
        }
        finally
        {
            originalImage.Dispose();
            bitmap.Dispose();
            graphic.Dispose();
        }

    }

    /// <summary>
    /// 在图片上添加文字水印
    /// </summary>
    /// <param name="path"> 要添加水印的图片路径 </param>
    /// <param name="syPath"> 生成的水印图片存放的位置 </param>
    public static void AddWaterWord( string path, string syPath)
    {
        string syWord = " http://www.hello36.cn " ;
        System.Drawing.Image image = System.Drawing.Image.FromFile(path);

        // 新建一个画板
        System.Drawing.Graphics graphic = System.Drawing.Graphics.FromImage(image);
        graphic.DrawImage(image, 0 , 0 ,image.Width,image.Height);

        // 设置字体
        System.Drawing.Font f = new System.Drawing.Font( " Verdana " , 60 );                           

        // 设置字体颜色
        System.Drawing.Brush b = new System.Drawing.SolidBrush(System.Drawing.Color.Green);

        graphic.DrawString(syWord, f, b, 35 , 35 );
        graphic.Dispose();

        // 保存文字水印图片
        image.Save(syPath);
        image.Dispose();

    }

    /// <summary>
    /// 在图片上添加图片水印
    /// </summary>
    /// <param name="path"> 原服务器上的图片路径 </param>
    /// <param name="syPicPath"> 水印图片的路径 </param>
    /// <param name="waterPicPath"> 生成的水印图片存放路径 </param>
    public static void AddWaterPic( string path, string syPicPath, string waterPicPath)
    {
        System.Drawing.Image image = System.Drawing.Image.FromFile(path);
        System.Drawing.Image waterImage = System.Drawing.Image.FromFile(syPicPath);
        System.Drawing.Graphics graphic = System.Drawing.Graphics.FromImage(image);
        graphic.DrawImage(waterImage, new System.Drawing.Rectangle(image.Width - waterImage.Width,image.Height - waterImage.Height,waterImage.Width,waterImage.Height), 0 , 0 ,waterImage.Width,waterImage.Height,System.Drawing.GraphicsUnit.Pixel);
        graphic.Dispose();

        image.Save(waterPicPath);
        image.Dispose();
    }

}