.ashx 加水印 为什么有的图片能加成功，有的不成功呀！

[sailei1]

<%@ WebHandler Language="C#" Class="WaterHandler" %>

using System;
using System.Web;
using System.Drawing;
using System.IO;
public class WaterHandler : IHttpHandler {

public void ProcessRequest (HttpContext context) {

string waterPath = "~/images/WaterLogo.jpg";
string defaultPath = "~/images/logo.jpg";
string path = context.Server.MapPath( context.Request.QueryString["pic"].ToString());
Image image = null;
if (File.Exists(path))
{
//try
//{
image = Image.FromFile(path);
Image water = Image.FromFile(context.Server.MapPath(waterPath));
Graphics g = Graphics.FromImage(image);//在这报错
g.DrawImage(water, new Rectangle(image.Width - water.Width, image.Height - water.Height, water.Width, water.Height), 0, 0, water.Width, water.Height, GraphicsUnit.Pixel);
//}
//catch (Exception)
//{

// image = Image.FromFile(context.Server.MapPath(defaultPath));
//}
}
else {
image = Image.FromFile(context.Server.MapPath(defaultPath));
}
context.Response.ContentType = "image/jpeg";
image.Save(context.Response.OutputStream, System.Drawing.Imaging.ImageFormat.Jpeg);
}

public bool IsReusable {
get {
return false;
}
}

}
这是改路径的方法

public string water(object o) {
return "~/WaterHandler.ashx?pic=" + o.ToString() ;
}

希望 csdn 上 高手们，指点一下迷津！QQ861072515

[sailei1]

不用 catch 就报错

[正在加载昵称]

DiscuzNT开源项目里有加水印代码，建议楼主参考一下

public void AddImageSignPic(Image img, string filename, string watermarkFilename, int watermarkStatus, int quality, int watermarkTransparency)
        {
            Graphics g = Graphics.FromImage(img);
            //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;
            Image watermark = new Bitmap(watermarkFilename);

            if (watermark.Height >= img.Height || watermark.Width >= img.Width)
                return;

            ImageAttributes imageAttributes = new ImageAttributes();
            ColorMap colorMap = new ColorMap();

            colorMap.OldColor = Color.FromArgb(255, 0, 255, 0);
            colorMap.NewColor = Color.FromArgb(0, 0, 0, 0);
            ColorMap[] remapTable = { colorMap };

            imageAttributes.SetRemapTable(remapTable, ColorAdjustType.Bitmap);

            float transparency = 0.5F;
            if (watermarkTransparency >= 1 && watermarkTransparency <= 10)
                transparency = (watermarkTransparency / 10.0F);


            float[][] colorMatrixElements = {
												new float[] {1.0f,  0.0f,  0.0f,  0.0f, 0.0f},
												new float[] {0.0f,  1.0f,  0.0f,  0.0f, 0.0f},
												new float[] {0.0f,  0.0f,  1.0f,  0.0f, 0.0f},
												new float[] {0.0f,  0.0f,  0.0f,  transparency, 0.0f},
												new float[] {0.0f,  0.0f,  0.0f,  0.0f, 1.0f}
											};

            ColorMatrix colorMatrix = new ColorMatrix(colorMatrixElements);

            imageAttributes.SetColorMatrix(colorMatrix, ColorMatrixFlag.Default, ColorAdjustType.Bitmap);

            int xpos = 0;
            int ypos = 0;

            switch (watermarkStatus)
            {
                case 1:
                    xpos = (int)(img.Width * (float).01);
                    ypos = (int)(img.Height * (float).01);
                    break;
                case 2:
                    xpos = (int)((img.Width * (float).50) - (watermark.Width / 2));
                    ypos = (int)(img.Height * (float).01);
                    break;
                case 3:
                    xpos = (int)((img.Width * (float).99) - (watermark.Width));
                    ypos = (int)(img.Height * (float).01);
                    break;
                case 4:
                    xpos = (int)(img.Width * (float).01);
                    ypos = (int)((img.Height * (float).50) - (watermark.Height / 2));
                    break;
                case 5:
                    xpos = (int)((img.Width * (float).50) - (watermark.Width / 2));
                    ypos = (int)((img.Height * (float).50) - (watermark.Height / 2));
                    break;
                case 6:
                    xpos = (int)((img.Width * (float).99) - (watermark.Width));
                    ypos = (int)((img.Height * (float).50) - (watermark.Height / 2));
                    break;
                case 7:
                    xpos = (int)(img.Width * (float).01);
                    ypos = (int)((img.Height * (float).99) - watermark.Height);
                    break;
                case 8:
                    xpos = (int)((img.Width * (float).50) - (watermark.Width / 2));
                    ypos = (int)((img.Height * (float).99) - watermark.Height);
                    break;
                case 9:
                    xpos = (int)((img.Width * (float).99) - (watermark.Width));
                    ypos = (int)((img.Height * (float).99) - watermark.Height);
                    break;
            }

            g.DrawImage(watermark, new Rectangle(xpos, ypos, watermark.Width, watermark.Height), 0, 0, watermark.Width, watermark.Height, GraphicsUnit.Pixel, imageAttributes);

            ImageCodecInfo[] codecs = ImageCodecInfo.GetImageEncoders();
            ImageCodecInfo ici = null;
            foreach (ImageCodecInfo codec in codecs)
            {
                if (codec.MimeType.IndexOf("jpeg") > -1)
                    ici = codec;
            }
            EncoderParameters encoderParams = new EncoderParameters();
            long[] qualityParam = new long[1];
            if (quality < 0 || quality > 100)
                quality = 80;

            qualityParam[0] = quality;

            EncoderParameter encoderParam = new EncoderParameter(System.Drawing.Imaging.Encoder.Quality, qualityParam);
            encoderParams.Param[0] = encoderParam;

            //if (ici != null)
            //    img.Save(filename, ici, encoderParams);
            //else
            //    img.Save(filename);
            if (ici != null)
                img.Save(filename.Substring(0, filename.LastIndexOf('\\') + 1) + "#" + filename.Substring(filename.LastIndexOf('\\') + 1, filename.Length - 1 - filename.LastIndexOf('\\')), ici, encoderParams);
            else
                img.Save(filename.Substring(0, filename.LastIndexOf('\\') + 1) + "#" + filename.Substring(filename.LastIndexOf('\\') + 1, filename.Length - 1 - filename.LastIndexOf('\\')));

            g.Dispose();
            img.Dispose();
            watermark.Dispose();
            imageAttributes.Dispose();
        }

[Teng_s2000]

catch中获取文件了啊

不用try看是不是报路径的错误 啊

[sailei1]

路径没错 ，问教员 教员说是图片的错误！ 我有点怀疑 所以发帖问问

[wuhuabucai]

具体什么错误呢

[xinshouno7]

web.config中也需要设置吧
<!--针对图片的文件夹进行处理-->
<location path="image">
<system.web>
<httpHandlers>
<!--对jpg文件添加水印-->

<add verb="*" path="*.jpg" type="WaterHandler"/>
<add verb="*" path="*.bmp" type="WaterHandler"/>
</httpHandlers>
</system.web>
</location>