RSS订阅前两天分别分享了ASP.NET上传文件和如何使用Photoshop制作半透明水印，今天把上传和添加水印结合起来，教大家ASP.NET上传图片并添加文字水印、图片水印的方法(含源代码)
添加文字水印
在水印文字的文本框内输入文字，上传图片，点击【上传图片并添加文字水印】按钮，即可在下方得到添加了文字水印后的图片
添加图片水印
事先准备水印图片watermark.png
放在指定目录内，然后上传图片，点击【上传图片并添加半透明的图片水印】按钮，即可得到添加图片水印后的图片 
源代码
该ASP.NET上传图片添加文字水印、图片水印的实例，包含三个主要文件：公共类文件 WatermarkPainter.cs、前台页面 watermark.aspx、后台C#代码 watermark.aspx.cs
公共类文件 WatermarkPainter.cs
using System.Drawing;
using System.Drawing.Imaging;
using System.IO;
using System.Text;
using System;
namespace Juice.Common.Drawing
{
/// <summary>
/// 图片水印绘制器
/// </summary>
public abstract class WatermarkPainter : IDisposable
{
/// <summary>
/// 构造函数
/// </summary>
/// <param name="rawImagePath"></param>
/// <param name="alpha"></param>
/// <param name="replaceRawImage"></param>
protected WatermarkPainter(string rawImagePath, int alpha, bool replaceRawImage)
{
ImageToBePainted = rawImagePath;
WatermarkAlpha = alpha;
ReplaceRawImage = replaceRawImage;
}
/// <summary>
/// 构造函数
/// </summary>
/// <param name="rawImagePath"></param>
/// <param name="alpha"></param>
protected WatermarkPainter(string rawImagePath, int alpha)
: this(rawImagePath, alpha, true)
{ }
/// <summary>
/// 为临时存储文件添加的后缀
/// </summary>
private string m_TempFileSuffix = ".juice.watermark.temp";
/// <summary>
/// 水印的透明度
/// </summary>
private int m_WatermarkAlpha;
/// <summary>
/// 水印透明度
/// </summary>
public int WatermarkAlpha
{
get
{
if (m_WatermarkAlpha > 255)
m_WatermarkAlpha = 255;
else if (m_WatermarkAlpha < 0)
m_WatermarkAlpha = 0;
return m_WatermarkAlpha;
}
set { m_WatermarkAlpha = value; }
}
private string m_ImageToBePainted;
/// <summary>
/// 添加水印的图片的物理路径
/// </summary>
public string ImageToBePainted
{
get { return m_ImageToBePainted; }
set { m_ImageToBePainted = value; }
}
private bool m_ReplaceRawImage;
/// <summary>
/// 是否用加了水印的图片替换原有的图片
/// </summary>
public bool ReplaceRawImage
{
get { return m_ReplaceRawImage; }
set { m_ReplaceRawImage = value; }
}
private string m_TempImagePath;
/// <summary>
/// 加了水印后的临时储存名称
/// </summary>
protected string TempImagePath
{
get
{
if (string.IsNullOrEmpty(this.m_TempImagePath))
{
StringBuilder s = new StringBuilder(ImageToBePainted);
s.Append(this.m_TempFileSuffix);
this.m_TempImagePath = s.ToString();
}
return m_TempImagePath;
}
set { m_TempImagePath = value; }
}
/// <summary>
/// 原始图像
/// </summary>
private Image m_RawImage;
/// <summary>
/// 为图片添加水印
/// </summary>
public void PaintWaterMark()
{
if (string.IsNullOrEmpty(ImageToBePainted))
return;
if (!System.IO.File.Exists(ImageToBePainted))
throw new FileNotFoundException(string.Format("file {0} not found.", ImageToBePainted));
bool succeed;
if (m_RawImage == null)
m_RawImage = Image.FromFile(ImageToBePainted);
///原始的图片
using (Bitmap newImage = new Bitmap(m_RawImage.Width, m_RawImage.Height))
{
///创建绘制图片的图面
using (Graphics g = Graphics.FromImage(newImage))
{
g.DrawImage(m_RawImage, 0, 0, m_RawImage.Width, m_RawImage.Height);
///开始绘制水印
succeed = AddWatermark(g, newImage);
}
if (succeed)
///将图片保存到临时的文件
newImage.Save(TempImagePath);
if (m_RawImage != null)
m_RawImage.Dispose();
}
if (succeed && ReplaceRawImage)
{
//删除原来的文件
if (System.IO.File.Exists(ImageToBePainted))
System.IO.File.Delete(ImageToBePainted);
FileInfo info = new FileInfo(TempImagePath);
if (info.Exists)
{
info.MoveTo(ImageToBePainted);
}
}
}
/// <summary>
/// 添加水印，继承类可以用来添加自己的水印
/// </summary>
/// <param name="graphics"></param>
/// <param name="newImage"></param>
/// <returns></returns>
protected abstract bool AddWatermark(Graphics graphics, Bitmap newImage);
#region IDisposable 成员
public virtual void Dispose()
{
}
#endregion
}
public sealed class TextWatermarkPainter : WatermarkPainter
{
/// <summary>
/// 构造函数
/// </summary>
/// <param name="rawImagePath"></param>
/// <param name="alpha"></param>
/// <param name="text"></param>
public TextWatermarkPainter(string rawImagePath, int alpha, string text)
: base(rawImagePath, alpha)
{
WatermarkText = text;
}
private Font m_Font;
/// <summary>
/// 水印文字的字体
/// </summary>
public Font Font
{
get
{
if (null == m_Font)
m_Font = new Font("Arial Black", 28, FontStyle.Bold, GraphicsUnit.Pixel);
return m_Font;
}
set { m_Font = value; }
}
private Color m_FontColor;
/// <summary>
/// 字体颜色
/// </summary>
public Color FontColor
{
get
{
if (m_FontColor == null)
m_FontColor = Color.DeepPink;
return m_FontColor;
}
set { m_FontColor = value; }
}
private string m_WatermarkText;
/// <summary>
/// 水印的文字
/// </summary>
public string WatermarkText
{
get { return m_WatermarkText; }
set { m_WatermarkText = value; }
}
/// <summary>
/// 实现添加水印的方法
/// </summary>
/// <param name="graphics"></param>
/// <param name="newImage"></param>
/// <returns></returns>
protected override bool AddWatermark(Graphics graphics, Bitmap newImage)
{
if (string.IsNullOrEmpty(WatermarkText))
return true;
using (SolidBrush brush = new SolidBrush(Color.FromArgb(WatermarkAlpha, FontColor.R, FontColor.G, FontColor.B)))
{
Font font;
///添加文字位置
PointF f = new PointF();
float totalWidth = Font.Size * WatermarkText.Length;
//f.X = newImage.Width - totalWidth - 100;
f.X = (newImage.Width - totalWidth+100)/2;
f.Y = (newImage.Height - Font.Height)/2;
// f.Y = newImage.Height/2;
if (f.X < 0)
{
///自动调整字体的大小
float width = newImage.Width / WatermarkText.Length;
font = new Font(Font.FontFamily, width, GraphicsUnit.Pixel);
}
else
font = Font;
graphics.DrawString(WatermarkText, font, brush, f);
}
return true;
}
#region IDisposable 成员
public override void Dispose()
{
Font.Dispose();
base.Dispose();
}
#endregion
}
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 (!System.IO.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;
int x = (newImage.Width - WatermarkImage.Width - 10)/2;
int y = (newImage.Height - WatermarkImage.Height)/2;
///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();
}
}
}前台页面 watermark.aspx
<%@ Page Language="C#" AutoEventWireup="true" CodeFile="watermark.aspx.cs" Inherits="demo_watermark" %> <!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>添加水印图片</title> </head> <body> <center> <form id="form1" runat="server"> <table width="550" style="text-align:left" > <tr style="text-align:left"> <td style="text-align:left" >水印文字:</td> <td colspan="3"><asp:TextBox ID="watermarkTextBox" runat="server" Width="220px"></asp:TextBox></td> </tr> <tr> <td>选择上传图片:</td> <td colspan="3"><asp:FileUpload ID="FileUpload1" runat="server" Width="300px" /></td> </tr> <tr> <td colspan="2"> <asp:Button ID="uploadFileBtn" runat="server" Text="上传图片并添加文字水印" onclick="uploadFileBtn_Click" /> </td> <td colspan="2"> <asp:Button ID="uploadAndAddImageBtn" runat="server" Text="上传图片并添加半透明的图片水印" onclick="uploadAndAddImageBtn_Click" /> </td> </tr> </table> <br />加了水印的图像如下： <hr/> <asp:Image ID="image" runat="server" /> </form> </center> </body> </html>
后台C#代码 watermark.aspx.cs
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 demo_watermark : 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("~/upload/{0}", FileUpload1.PostedFile.FileName));
///保存文件
FileUpload1.SaveAs(filePath);
///加水印
this.AddWatermark(filePath, this.watermarkTextBox.Text);
image.ImageUrl = string.Format("~/upload/{0}", 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.DeepPink;
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("~/upload/{0}", Server.HtmlEncode(FileUpload1.PostedFile.FileName)));
///保存文件
FileUpload1.SaveAs(filePath);
///加水印
this.AddImageWatermark(filePath);
image.ImageUrl = string.Format("~/upload/{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("~/demo/watermark.png")))
{
painter.PaintWaterMark();
}
}
}若在添加了文字水印后添加图片水印无变化，注意清理缓存。如有疑问，可致电postmaster@weisico.com学习交流
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