给图片打水印问题

Question

提供一个图片的地址，然后你把这个图片打上水印。
要求：可以自己设置水印的透明度，以及水印的位置。

Answer 1

 MakeThumbnail(xx, xx, 100, 100, "Cut");     // 生成缩略图方法

Answer 2

http://www.svnhost.cn/Article/?k=%E5%9B%BE

Answer 3

    /// <summary>
    /// 生成水印，源代码来自网上，修改了几个bug
    /// </summary>
    /// <param name="sourceFile">底图</param>
    /// <param name="waterMarkFile">水印图</param>
    /// <param name="saveFile">要保存的文件</param>
    /// <param name="local">位置：左上(1)、左下(2)、右上(3)、右下(4)、居中(5)</param>
    /// <param name="alpha">透明度(1-100)</param>
    public void DrawImages(string sourceFile, string saveFile, int local, int alpha)
    {
        //原图
        System.Drawing.Image m_image = System.Drawing.Image.FromFile(sourceFile);
        Bitmap sImage = new Bitmap(m_image);
        m_image.Dispose();
        int sWidth = sImage.Width;
        int sHeight = sImage.Height;        //水印图
        string m_locallogo;
        if (sWidth > 200 && sHeight > 50)
        {
            m_locallogo = Server.MapPath("/upload_picture/img_logo.gif");
        }
        else
        {
            m_locallogo = Server.MapPath("/upload_picture/img_logo_small.gif");
        }        Bitmap wImage = new Bitmap(m_locallogo);
        int wWidth = wImage.Width;
        int wHeight = wImage.Height;        //make Graphics.
        Graphics g = Graphics.FromImage(sImage);
        int x; //临时变量
        int y; //监时变量
        int x1 = 0; //原图和水印图的宽度差,即开始绘图的X位置
        int y1 = 0; //原图和水印图的高度差,即开始绘图的Y位置
        int w = 0; //生成的水印图的宽度,即结束绘图的X位置
        int h = 0; //生成的水印图的高度,即结束绘图的Y位置
        int al; //alpha
        int rl; //Red
        int gl; //Green
        int bl; //Blue        //校验透明度
        al = alpha;        if (sWidth > wWidth && sHeight > wHeight) //如果源图比水印图大
        {
            switch (local)
            {
                case 1: //左上
                    x1 = 0;
                    y1 = 0;
                    break;
                case 2: //左下
                    x1 = 0;
                    if ((sHeight - wHeight) > 0) //源图比水印图高
                        y1 = sHeight - wHeight;
                    else
                        y1 = sWidth;
                    break;
                case 3: //右上
                    y1 = 0;
                    if ((sWidth - wWidth) > 0) // 源图比水印图宽
                        x1 = sWidth - wWidth;
                    else
                        x1 = sWidth;
                    break;
                case 4: //右下
                    //计算高度
                    if ((sHeight - wHeight) > 0) //源图比水印图高
                        y1 = sHeight - wHeight;
                    else
                        y1 = sWidth;
                    //计算宽度
                    if ((sWidth - wWidth) > 0) // 源图比水印图宽
                        x1 = sWidth - wWidth;
                    else
                        x1 = sWidth;
                    break;
                case 5: //居中
                    //计算高度
                    if ((sHeight - wHeight) > 0) //源图比水印图高
                        y1 = (sHeight - wHeight) / 2;
                    else
                        y1 = sWidth;
                    //计算宽度
                    if ((sWidth - wWidth) > 0) // 源图比水印图宽
                        x1 = (sWidth - wWidth) / 2;
                    else
                        x1 = sWidth;
                    break;
            }
            if ((sHeight - wHeight) > 0)
                h = wHeight;
            else
                h = sHeight;
            if ((sWidth - wWidth) > 0)
                w = wWidth;
            else
                w = sWidth;
        }
        else //源图比水印图小
        {
            x1 = 0;
            y1 = 0;
            w = sWidth;
            h = sHeight;
        }        //开始绘图
        for (x = 1; x < w; x++)
        {
            for (y = 1; y < h; y++)
            {
                try
                {
                    rl = wImage.GetPixel(x, y).R;
                    gl = wImage.GetPixel(x, y).G;
                    bl = wImage.GetPixel(x, y).B;
                }
                catch
                {
                    continue;
                }                if (!(rl == 255 && gl == 255 && bl == 255))
                {
                    if (rl + 25 < 255)
                        rl += 25;
                    if (gl + 25 < 255)
                        gl += 25;
                    if (bl + 25 < 255)
                        bl += 25;                    g.DrawEllipse(new Pen(new SolidBrush(Color.FromArgb(al, rl, gl, bl))), x1 + x, y1 + y, 1, 1);
                }
                else
                {
                    g.DrawEllipse(new Pen(new SolidBrush(Color.FromArgb(0, rl, gl, bl))), x1 + x, y1 + y, 1, 1);
                }
            }
        }
        g.Save();
        g.Dispose();
        wImage.Dispose();        sImage.Save(saveFile);
        sImage.Dispose();
    }

Answer 4

http://www.svnhost.cn/Article/Detail-14.shtml这片文章好像少2个类啊

Answer 5

用GDI+贴图上去就是了，很简单的，买本专门讲GDI+的书看看吧。

Answer 6

看一下Handler,两种方式,一种需要修改所有图片的路径,一种需要在WebConfig中配置一下即可