[C#] ASP.NET 上传图片添加半透明图片或者文字水印的方法(二)
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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 3 years ago
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