c#图片添加水印

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今天讲一个上传图片添加水印的方法,直接上代码吧

protected void Button1_Click(object sender, EventArgs e)
{
int location = Convert.ToInt32(this.DropDownList1.SelectedValue);//获取水印放置位置

//判断FileUpload里是否有文件地址
if (FileUpload1.HasFile)
{
if ((FileUpload1.PostedFile.ContentType == "image/pjpeg") || (FileUpload1.PostedFile.ContentType == "image/jpeg") || (FileUpload1.PostedFile.ContentType == "image/gif") || (FileUpload1.PostedFile.ContentType == "image/bmp") || (FileUpload1.PostedFile.ContentType == "image/x-png") || (FileUpload1.PostedFile.ContentType == "image/png"))//获取客户端发送的文件的MIME内容类型
{
//上传文件总大小
int fileLength = 0;
fileLength = fileLength + FileUpload1.PostedFile.ContentLength;
//大小不能超过maxLengthk
int maxLength = 2048;
int sysLength = maxLength * 1024;
if (fileLength > sysLength)
{
Response.Write("<script>alert(''''该图片大小超过2M限制'''')</script>");
}
else
{
string[] strSpil = FileUpload1.FileName.Split(''''.'''');//将此地址用.号进行分割(img/1.jpg)
string strEnd = strSpil[strSpil.Length - 1].ToLower();//得到后面的("jpg", "gif", "bmp", "png","jpeg","JPG","GIF","BMP","PNG","JPEG")
string[] strPic = new string[] { "jpg", "gif", "bmp", "png", "jpeg", "JPG", "GIF", "BMP", "PNG", "JPEG" };//定义一个数组里面放文件格式
List<string> arry = new List<string>();
arry.AddRange(strPic); //定义一个可变数组，用于放文件格式
if (arry.Contains(strEnd))//判断这个数组中是否有（"jpg", "gif", "bmp", "png","jpeg","JPG","GIF","BMP","PNG","JPEG"）
{
Random rand = new Random();//定义一个随机数，为了防止你要上传得图片重名
string strName = DateTime.Now.ToString("yyyymmmddhhss") + rand.Next(100, 9999).ToString();//得到不同得名字
string strPointEnd = "." + strEnd;
string strFile = Server.MapPath("~/upfile");//获取其相对地址
FileUpload1.SaveAs(strFile + "/" + strName + strPointEnd);//保存原始图片
string src = strFile + "/" + strName + strPointEnd;

//进行水印添加处理--------------------------------------------
//水印图片
string shuiyin = "~/watermark/logo.png";
//加载文件
System.Drawing.Image Cover;
Cover = System.Drawing.Image.FromFile(src);
//加载水印文件
System.Drawing.Image water = System.Drawing.Image.FromFile(Request.MapPath(shuiyin));
//创建画布
System.Drawing.Graphics g = System.Drawing.Graphics.FromImage(Cover);
if (location == 1)//左上方
{
//在image上绘制水印
g.DrawImage(water, new Rectangle(0, 0, water.Width, water.Height), 0, 0, water.Width, water.Height, GraphicsUnit.Pixel);
}
else if (location == 2)//左下方
{
//在image上绘制水印
g.DrawImage(water, new Rectangle(0, Cover.Height - water.Height, water.Width, water.Height), 0, 0, water.Width, water.Height, GraphicsUnit.Pixel);
}
else if (location == 3)//右上方
{
//在image上绘制水印
g.DrawImage(water, new Rectangle(Cover.Width - water.Width, 0, water.Width, water.Height), 0, 0, water.Width, water.Height, GraphicsUnit.Pixel);
}
else if (location == 4)//右下方
{
//在image上绘制水印
g.DrawImage(water, new Rectangle(Cover.Width - water.Width, Cover.Height - water.Height, water.Width, water.Height), 0, 0, water.Width, water.Height, GraphicsUnit.Pixel);
}
else if (location == 5)//正中间
{
//在image上绘制水印
g.DrawImage(water, new Rectangle((Cover.Width - water.Width) / 2, (Cover.Height - water.Height) / 2, water.Width, water.Height), 0, 0, water.Width, water.Height, GraphicsUnit.Pixel);
}
else
{
//在image上绘制水印
g.DrawImage(water, new Rectangle(Cover.Width - water.Width, Cover.Height - water.Height, water.Width, water.Height), 0, 0, water.Width, water.Height, GraphicsUnit.Pixel);
}
//释放画布
g.Dispose();
//释放水印图片
water.Dispose();
Cover.Save(HttpContext.Current.Server.MapPath("~/upfile/") + strName+"s"+ "." + strEnd);//保存打过水印的图片
Cover.Dispose();
string src1 = "upfile/" + strName + "s" + "." + strEnd;
Response.Write("<a href="+src1+">点击查看水印图片</a>");
}
else
{
Response.Write("<script>alert(''''该图片格式不能上传！'''')</script>");
}
}
}
else
{
Response.Write("<script>alert(''''该图片格式不能上传！'''')</script>");
}
}
else
{
Response.Write("<script>alert(''''请选择图片路径！'''')</script>");
}
}