Asp.net，C#给图片加上水印效果

下面的代码中，加文字水印和加图片水印的代码不能共存，为了方便显示才写在一块的

private void Btn_Upload_Click(object sender, System.EventArgs e)

{

if(UploadFile.PostedFile.FileName.Trim()!="")

{

//上传文件

string extension = Path.GetExtension(UploadFile.PostedFile.FileName).ToUpper();

string fileName = DateTime.Now.ToString("yyyyMMddhhmmss");

string path = Server.MapPath(".") + "/UploadFile/" + fileName + extension;

UploadFile.PostedFile.SaveAs(path);

//加文字水印，注意，这里的代码和以下加图片水印的代码不能共存

System.Drawing.Image image = System.Drawing.Image.FromFile(path);

Graphics g = Graphics.FromImage(image);

g.DrawImage(image, 0, 0, image.Width, image.Height);

Font f = new Font("Verdana", 32);

Brush b = new SolidBrush(Color.White);

string addText = AddText.Value.Trim();

g.DrawString(addText, f, b, 10, 10);

g.Dispose();

//加图片水印

System.Drawing.Image image = System.Drawing.Image.FromFile(path);

System.Drawing.Image copyImage = System.Drawing.Image.FromFile( Server.MapPath(".") + "/Alex.gif");

Graphics g = Graphics.FromImage(image);

g.DrawImage(copyImage, new Rectangle(image.Width-copyImage.Width, image.Height-copyImage.Height, copyImage.Width, copyImage.Height), 0, 0, copyImage.Width, copyImage.Height, GraphicsUnit.Pixel);

g.Dispose();

//保存加水印过后的图片,删除原始图片

string newPath = Server.MapPath(".") + "/UploadFile/" + fileName + "_new" + extension;

image.Save(newPath);

image.Dispose();

if(File.Exists(path))

{

File.Delete(path);

}

Response.Redirect(newPath);

}

}