[C#] ASP.NET 上传图片添加半透明图片或者文字水印的方法(二)

visibility 862 event 2009-03-11 access_time 2 months ago language 中文
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[C#] ASP.NET 上传图片添加半透明图片或者文字水印的方法(二)

在上一篇文章中讲到了关于C#上传图片添加文字水印的方法,这个章节中则是添加半透明的图片水印的方法。

ImageWatermarkPainter

下面是ImageWatermarkPainter类的实现:

/* ***********************************************
* Author:           Raymond Tang
* Team:             Juice Sharing
* Created Time:     2009-3-11 20:53:14
* CopyRight:        Juice Sharing 团队版权所有 保留一切权利
* NameSpace:        Juice.Common.Drawing
* Class/Interface: ImageWatermarkPainter
* ***********************************************/
using System; using System.Text; using System.IO; using System.Drawing; using System.Drawing.Imaging;
namespace Juice.Common.Drawing {     /// <summary>     /// 图片水印绘制器     /// </summary>     public sealed class ImageWatermarkPainter : WatermarkPainter     {         /// <summary>         /// 构造函数         /// </summary>         /// <param name="rawImagePath"></param>         /// <param name="alpha"></param>         /// <param name="watermarkImage"></param>         public ImageWatermarkPainter(string rawImagePath, int alpha, string watermarkImage)             : base(rawImagePath, alpha)         {             WatermarkImagePath = watermarkImage;         }
        private string m_WatermarkImagePath;
        /// <summary>         /// 水印图片路径         /// </summary>         public string WatermarkImagePath         {             get { return m_WatermarkImagePath; }             set { m_WatermarkImagePath = value; }         }
        private Image m_WatermarkImage;         /// <summary>         /// 水印图片对象         /// </summary>         public Image WatermarkImage         {             get             {                 if (null == m_WatermarkImage)                     m_WatermarkImage = Image.FromFile(WatermarkImagePath);                 return m_WatermarkImage;             }         }
        /// <summary>         /// 添加水印         /// </summary>         /// <param name="graphics"></param>         /// <param name="newImage"></param>         /// <returns></returns>         protected override bool AddWatermark(Graphics graphics, Bitmap newImage)         {             if (string.IsNullOrEmpty(WatermarkImagePath))                 return false;             if (!File.Exists(WatermarkImagePath))                 throw new FileNotFoundException(string.Format("file {0} not found.", WatermarkImagePath));             if ((WatermarkImage.Width + 10) > newImage.Width || (WatermarkImage.Height + 10) > newImage.Height)                 return false;             using (ImageAttributes attributes = new ImageAttributes())             {                 float alpha = WatermarkAlpha / 255.0f;                 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, alpha, 0.0f},    new float[] {0.0f, 0.0f, 0.0f, 0.0f, 1.0f} };                 ColorMatrix colorMatrix = new ColorMatrix(colorMatrixElements);                 ///设置颜色调整矩阵                 attributes.SetColorMatrix(colorMatrix, ColorMatrixFlag.Default, ColorAdjustType.Bitmap);                 ///水印图片的位置,默认为右下角                 int x = newImage.Width - WatermarkImage.Width - 10;                 int y = newImage.Height - WatermarkImage.Height - 10;                 ///开始绘制水印                 graphics.DrawImage(WatermarkImage, new Rectangle(x, y, WatermarkImage.Width, WatermarkImage.Height), 0, 0, WatermarkImage.Width, WatermarkImage.Height, GraphicsUnit.Pixel, attributes);             }             return true;         }
        public override void Dispose()         {             if (null != WatermarkImage)                 WatermarkImage.Dispose();             base.Dispose();         }     } }

下面查看使用的方法:

default.aspx的内容如下:

<%@ Page Language="C#" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_Default" %>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> <html xmlns="http://www.w3.org/1999/xhtml"> <head runat="server">     <title>无标题页</title> </head> <body>     <form id="form1" runat="server">     <div>         水印文字:<asp:TextBox ID="watermarkTextBox" runat="server"></asp:TextBox><br />         选择上传图片:<asp:FileUpload ID="FileUpload1" runat="server" Width="189px" />         <br />         <asp:Button ID="uploadFileBtn" runat="server" Text="上传图片并且加文字水印"             onclick="uploadFileBtn_Click" />         <asp:Button ID="uploadAndAddImageBtn" runat="server" Text="上传图片并且添加半透明的图片水印"             onclick="uploadAndAddImageBtn_Click" />         <br />加了水印的图像如下:         <asp:Image ID="image" runat="server" />     </div>     </form> </body> </html>

default.aspx.cs的内容如下:

using System;
using System.Configuration;
using System.Data;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.HtmlControls;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using Juice.Common.Drawing;
using System.Web.Hosting;
public partial class _Default : System.Web.UI.Page {     protected void Page_Load(object sender, EventArgs e)     {
    }     protected void uploadFileBtn_Click(object sender, EventArgs e)     {         if (string.IsNullOrEmpty(this.watermarkTextBox.Text))             return;         if (FileUpload1.HasFile)         {             string contentType = FileUpload1.PostedFile.ContentType;             if (contentType.StartsWith("image/"))             {                 string filePath = Server.MapPath(string.Format("~/{0}", Server.HtmlEncode(FileUpload1.PostedFile.FileName)));                 ///保存文件                 FileUpload1.SaveAs(filePath);                 ///加水印                 this.AddWatermark(filePath, this.watermarkTextBox.Text);                 image.ImageUrl = string.Format("~/{0}", Server.HtmlEncode(FileUpload1.PostedFile.FileName));             }         }     }
    /// <summary>     /// 添加水印     /// </summary>     /// <param name="filePath"></param>     /// <param name="watermaterText"></param>     private void AddWatermark(string filePath, string watermaterText)     {         using (TextWatermarkPainter painter = new TextWatermarkPainter(filePath, 80, watermaterText))         {             painter.FontColor = System.Drawing.Color.DarkGreen;             painter.PaintWaterMark();         }
    }
    protected void uploadAndAddImageBtn_Click(object sender, EventArgs e)     {         if (FileUpload1.HasFile)         {             string contentType = FileUpload1.PostedFile.ContentType;             if (contentType.StartsWith("image/"))             {                 string filePath = Server.MapPath(string.Format("~/{0}", Server.HtmlEncode(FileUpload1.PostedFile.FileName)));                 ///保存文件                 FileUpload1.SaveAs(filePath);                 ///加水印                 this.AddImageWatermark(filePath);                 image.ImageUrl = string.Format("~/{0}", Server.HtmlEncode(FileUpload1.PostedFile.FileName));             }         }     }
    /// <summary>     /// 添加图片水印     /// </summary>     /// <param name="filePath"></param>     private void AddImageWatermark(string filePath)     {         using (WatermarkPainter painter = new ImageWatermarkPainter(filePath, 180, Server.MapPath("~/watermark.gif")))         {             painter.PaintWaterMark();         }     }
}

其显示效果如下:

点击“上传图片并且添加半透明的图片水印”按钮后效果如下:

上图中右下角的绿色的标志则是水印,需要说明的是:

WatermarkPainter painter = new ImageWatermarkPainter(filePath, 180, Server.MapPath("~/watermark.gif"))) 这个地方就是创建水印绘制器的实例,且为图片水印绘制器,透明度为180(介于0-255之间),水印图片的地址是~/watermark.gif.

好了关于上传图片添加水印的方法就这些了,大家可以修改使得类更加的灵活和完善,如果以上有错误也请大家指教。

info Last modified by Raymond 2 months ago copyright This page is subject to Site terms.
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