看了清清月儿的这篇文章让自己受益匪浅，但是觉得还有一些问题。上传图片后还有原来的图片文件存在，觉得这样很不爽，调用file类的delete方法删除原来没有生成水印的图片另外自己又加了一个限制图片大小的函数
1.最简单的单文件上传(没花头)
效果图：
说明：这是最基本的文件上传，在asp.net1.x中没有这个FileUpload控件，只有html的上传控件，那时候要把html控件转化为服务器控件，很不好用。其实所有文件上传的美丽效果都是从这个FileUpload控件衍生，第一个例子虽然简单却是根本。
后台代码：
using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
public partial class _Default : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
}
protected void bt_upload_Click(object sender, EventArgs e)
{
try
{
if (FileUpload1.PostedFile.FileName == "")
{
this.lb_info.Text = "请选择文件！";
}
else
{
string filepath = FileUpload1.PostedFile.FileName;
string filename = filepath.Substring(filepath.LastIndexOf("//") + 1);
string serverpath = Server.MapPath("images/") + filename;
FileUpload1.PostedFile.SaveAs(serverpath);
this.lb_info.Text = "上传成功！";
}
}
catch (Exception ex)
{
this.lb_info.Text = "上传发生错误！原因是：" + ex.ToString();
}
}
}
前台代码：
<table style="width: 343px">
<tr>
<td style="width: 100px">
单文件上传</td>
<td style="width: 100px">
</td>
</tr>
<tr>
<td style="width: 100px">
<asp:FileUpload ID="FileUpload1" runat="server" Width="475px" />
</td>
<td style="width: 100px">
<asp:Button ID="bt_upload" runat="server" OnClick="bt_upload_Click" Text="上传" /></td>
</tr>
<tr>
<td style="width: 100px; height: 21px;">
<asp:Label ID="lb_info" runat="server" ForeColor="Red" Width="183px"></asp:Label></td>
<td style="width: 100px; height: 21px">
</td>
</tr>
</table>
2.多文件上传
效果图：
后台代码：
using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
public partial class _Default : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
}
protected void bt_upload_Click(object sender, EventArgs e)
{
if ((FileUpload1.PostedFile.FileName == "" && FileUpload2.PostedFile.FileName == "")&&FileUpload3.PostedFile.FileName == "")
{
this.lb_info.Text = "请选择文件！";
}
else
{
HttpFileCollection myfiles = Request.Files;
for (int i = 0; i < myfiles.Count; i++)
{
HttpPostedFile mypost = myfiles[i];
try
{
if (mypost.ContentLength > 0)
{
string filepath = mypost.FileName;
string filename = filepath.Substring(filepath.LastIndexOf("//") + 1);
string serverpath = Server.MapPath("images/") + filename;
mypost.SaveAs(serverpath);
this.lb_info.Text = "上传成功！";
}
}
catch (Exception error)
{
this.lb_info.Text = "上传发生错误！原因：" + error.ToString();
}
}
}
}
}
前台代码：
<%@ 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>多文件上传 清清月儿http://blog.csdn.net/21aspnet/</title>
</head>
<body>
<form id="form1" runat="server">
<div>
<table style="width: 343px">
<tr>
<td style="width: 100px">
多文件上传</td>
<td style="width: 100px">
</td>
</tr>
<tr>
<td style="width: 100px">
<asp:FileUpload ID="FileUpload1" runat="server" Width="475px" />
</td>
<td style="width: 100px">
</td>
</tr>
<tr>
<td style="width: 100px">
<asp:FileUpload ID="FileUpload2" runat="server" Width="475px" /></td>
<td style="width: 100px">
</td>
</tr>
<tr>
<td style="width: 100px">
<asp:FileUpload ID="FileUpload3" runat="server" Width="475px" /></td>
<td style="width: 100px">
</td>
</tr>
<tr>
<td style="width: 100px">
<asp:Button ID="bt_upload" runat="server" OnClick="bt_upload_Click" Text="一起上传" />
<asp:Label ID="lb_info" runat="server" ForeColor="Red" Width="183px"></asp:Label></td>
<td style="width: 100px">
</td>
</tr>
</table>
</div>
</form>
</body>
</html>
3.客户端检查上传文件类型(以上传图片为例)
效果图：
后台代码和1.最简单的单文件上传一样；
前台代码：
<%@ 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>清清月儿 http://blog.csdn.net/21aspnet</title>
<script language="javascript">
function Check_FileType()
{
var str=document.getElementById("FileUpload1").value;
var pos = str.lastIndexOf(".");
var lastname = str.substring(pos,str.length)
if (lastname.toLowerCase()!=".jpg" && lastname.toLowerCase()!=".gif")
{
alert("您上传的文件类型为"+lastname+"，图片必须为.jpg,.gif类型");
return false;
}
else
{
return true;
}
}
</script>
</head>
<body>
<form id="form1" runat="server">
<div>
<table style="width: 343px">
<tr>
<td style="width: 104px">
文件上传判断</td>
<td style="width: 100px">
</td>
</tr>
<tr>
<td style="width: 104px">
<asp:FileUpload ID="FileUpload1" runat="server" Width="400px" />
</td>
<td style="width: 100px">
<asp:Button ID="bt_upload" runat="server" OnClick="bt_upload_Click" Text="上传" OnClientClick="return Check_FileType()"/></td>
</tr>
<tr>
<td style="width: 104px; height: 21px;">
<asp:Label ID="lb_info" runat="server" ForeColor="Red" Width="183px"></asp:Label></td>
<td style="width: 100px; height: 21px">
</td>
</tr>
</table>
</div>
</form>
</body>
</html>
说明：点击上传时先触发客户端事件Check_FileType；
4.服务器端检查上传文件类型(以上传图片为例)
效果图：
后台代码：
using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
public partial class _Default : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
}
protected void bt_upload_Click(object sender, EventArgs e)
{
try
{
if (FileUpload1.PostedFile.FileName == "")
{
this.lb_info.Text = "请选择文件！";
}
else
{
string filepath = FileUpload1.PostedFile.FileName;
if (IsAllowedExtension(FileUpload1) == true)
{
string filename = filepath.Substring(filepath.LastIndexOf("//") + 1);
string serverpath = Server.MapPath("images/") + filename;
FileUpload1.PostedFile.SaveAs(serverpath);
this.lb_info.Text = "上传成功！";
}
else
{
this.lb_info.Text = "请上传图片";
}
}
}
catch (Exception error)
{
this.lb_info.Text = "上传发生错误！原因：" + error.ToString();
}
}
public static bool IsAllowedExtension(FileUpload hifile)
{
string strOldFilePath = "", strExtension = "";
string[] arrExtension = { ".gif", ".jpg", ".jpeg", ".bmp", ".png" };
if (hifile.PostedFile.FileName != string.Empty)
{
strOldFilePath = hifile.PostedFile.FileName;
strExtension = strOldFilePath.Substring(strOldFilePath.LastIndexOf("."));
for (int i = 0; i < arrExtension.Length; i++)
{
if (strExtension.Equals(arrExtension[i]))
{
return true;
}
}
}
return false;
}
}
5.服务器端检查上传文件类型(可以检测真正文件名)
其实方法4并不好，因为用户可以把XXX.txt伪装为XXX.jpg。
效果图：
后台代码：
using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
public partial class _Default : System.Web.UI.Page
{
//清清月儿 http://blog.csdn.net/21aspnet
protected void Page_Load(object sender, EventArgs e)
{
}
protected void bt_upload_Click(object sender, EventArgs e)
{
try
{
if (FileUpload1.PostedFile.FileName == "")
{
this.lb_info.Text = "请选择文件！";
}
else
{
string filepath = FileUpload1.PostedFile.FileName;
if (IsAllowedExtension(FileUpload1) == true)
{
string filename = filepath.Substring(filepath.LastIndexOf("//") + 1);
string serverpath = Server.MapPath("images/") + filename;
FileUpload1.PostedFile.SaveAs(serverpath);
this.lb_info.Text = "上传成功！";
}
else
{
this.lb_info.Text = "请上传图片";
}
}
}
catch (Exception error)
{
this.lb_info.Text = "上传发生错误！原因：" + error.ToString();
}
}
public static bool IsAllowedExtension(FileUpload hifile)
{
System.IO.FileStream fs = new System.IO.FileStream(hifile.PostedFile.FileName, System.IO.FileMode.Open, System.IO.FileAccess.Read);
System.IO.BinaryReader r = new System.IO.BinaryReader(fs);
string fileclass = "";
byte buffer;
try
{
buffer = r.ReadByte();
fileclass = buffer.ToString();
buffer = r.ReadByte();
fileclass += buffer.ToString();
}
catch
{
}
r.Close();
fs.Close();
if (fileclass == "255216" || fileclass == "7173")//说明255216是jpg;7173是gif;6677是BMP,13780是PNG;7790是exe,8297是rar
{
return true;
}
else
{
return false;
}
}
}
6.上传文件文件名唯一性处理(时间戳+SessionID)
效果图：
说明：年月日时分秒+临时session+原文件名 如果大家怕还会重复可以加GUID
后台代码：
try
{
if (FileUpload1.PostedFile.FileName == "")
{
this.lb_info.Text = "请选择文件！";
}
else
{
string filepath = FileUpload1.PostedFile.FileName;
string filename = filepath.Substring(filepath.LastIndexOf("//") + 1);
string serverpath = Server.MapPath("images/") + System.DateTime.Now.ToString("yyy-MM-dd-hh-mm-ss") + Session.SessionID + filename;
FileUpload1.PostedFile.SaveAs(serverpath);
this.lb_info.Text = "上传成功！";
}
}
catch (Exception error)
{
this.lb_info.Text = "上传发生错误！原因：" + error.ToString();
}
注：GUID的方法：Guid myGuid=Guid.NewGuid();
7.上传图片生成等比例缩略图
效果图：
缩略图代码：
ImageThumbnail.cs
using System;
using System.IO;
using System.Drawing;
using System.Drawing.Imaging;
public class ImageThumbnail
{
public Image ResourceImage;
private int ImageWidth;
private int ImageHeight;
public string ErrorMessage;
public ImageThumbnail(string ImageFileName)
{
ResourceImage = Image.FromFile(ImageFileName);
ErrorMessage = "";
}
public bool ThumbnailCallback()
{
return false;
}
// 方法1，按大小
public bool ReducedImage(int Width, int Height, string targetFilePath)
{
try
{
Image ReducedImage;
Image.GetThumbnailImageAbort callb = new Image.GetThumbnailImageAbort(ThumbnailCallback);
ReducedImage = ResourceImage.GetThumbnailImage(Width, Height, callb, IntPtr.Zero);
ReducedImage.Save(@targetFilePath, ImageFormat.Jpeg);
ReducedImage.Dispose();
return true;
}
catch (Exception e)
{
ErrorMessage = e.Message;
return false;
}
}
// 方法2，按百分比 缩小60% Percent为0.6 targetFilePath为目标路径
public bool ReducedImage(double Percent, string targetFilePath)
{
try
{
Image ReducedImage;
Image.GetThumbnailImageAbort callb = new Image.GetThumbnailImageAbort(ThumbnailCallback);
ImageWidth = Convert.ToInt32(ResourceImage.Width * Percent);
ImageHeight = (ResourceImage.Height)*ImageWidth/ ResourceImage.Width;//等比例缩放
ReducedImage = ResourceImage.GetThumbnailImage(ImageWidth, ImageHeight, callb, IntPtr.Zero);
ReducedImage.Save(@targetFilePath, ImageFormat.Jpeg);
ReducedImage.Dispose();
return true;
}
catch (Exception e)
{
ErrorMessage = e.Message;
return false;
}
}
}
后台代码：
using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
public partial class _Default : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
}
protected void bt_upload_Click(object sender, EventArgs e)
{
try
{
if (FileUpload1.PostedFile.FileName == "")
{
this.lb_info.Text = "请选择文件！";
}
else
{
string filepath = FileUpload1.PostedFile.FileName;
string filename = filepath.Substring(filepath.LastIndexOf("//") + 1);
string serverpath1 = Server.MapPath("images/") + filename;
string serverpath2 = Server.MapPath("images/") + System.DateTime.Now.ToString("yyy-MM-dd-hh-mm-ss") + Session.SessionID + filename;
FileUpload1.PostedFile.SaveAs(serverpath1);
ImageThumbnail img = new ImageThumbnail(filepath);
img.ReducedImage(0.4, serverpath2);//0.4表示缩小40%
this.lb_info.Text = "上传成功！";
}
}
catch (Exception error)
{
this.lb_info.Text = "上传发生错误！原因：" + error.ToString();
}
}
}
8.上传图片加水印(文字水印，图片水印，文字+图片水印)
效果图：
原图
水印
给图片加水印以后（注意右上角+正下方）
代码：
DrawImg.cs 出自http://www.codeproject.com/csharp/watermark.asp
using System;
using System.Drawing;
using System.Drawing.Imaging;
using System.Drawing.Drawing2D;
public class DrawImg
{
private string WorkingDirectory = string.Empty ; //路径
private string ImageName = string.Empty; //被处理的图片
private string ImageWater = string.Empty; //水印图片
private string FontString = string.Empty; //水印文字
enum DealType{NONE,WaterImage,WaterFont,DoubleDo}; //枚举命令
private DealType dealtype;
public DrawImg()
{}
public string PublicWorkingDirectory
{
get
{
return WorkingDirectory;
}
set
{
WorkingDirectory = value;
}
}
public string PublicImageName
{
get
{
return ImageName;
}
set
{
ImageName = value;
}
}
public string PublicImageWater
{
get
{
return ImageWater;
}
set //设置了水印图片的话说明是要水印图片效果的
{
dealtype = DealType.WaterImage;
ImageWater = value;
}
}
public string PublicFontString
{
get
{
return FontString;
}
set //设置了水印文字的话说明是要水印文字效果的
{
dealtype = DealType.WaterFont;
FontString = value;
}
}
public void DealImage()
{
IsDouble();
switch( dealtype )
{
case DealType.WaterFont: WriteFont(); break;
case DealType.WaterImage: WriteImg(); break;
case DealType.DoubleDo: WriteFontAndImg(); break;
}
}
private void IsDouble()
{
if(ImageWater+""!="" && FontString+""!="")
{
dealtype = DealType.DoubleDo;
}
}
private void WriteFont()
{
//set a working directory
//string WorkingDirectory = @"C:/Watermark_src/WaterPic";
//define a string of text to use as the Copyright message
//string Copyright = "Copyright ?2002 - AP Photo/David Zalubowski";
//create a image object containing the photograph to watermark
Image imgPhoto = Image.FromFile(WorkingDirectory + ImageName);
int phWidth = imgPhoto.Width;
int phHeight = imgPhoto.Height;
//create a Bitmap the Size of the original photograph
Bitmap bmPhoto = new Bitmap(phWidth, phHeight, PixelFormat.Format24bppRgb);
bmPhoto.SetResolution(imgPhoto.HorizontalResolution, imgPhoto.VerticalResolution);
//load the Bitmap into a Graphics object
Graphics grPhoto = Graphics.FromImage(bmPhoto);
//------------------------------------------------------------
//Step #1 - Insert Copyright message
//------------------------------------------------------------
//Set the rendering quality for this Graphics object
grPhoto.SmoothingMode = SmoothingMode.AntiAlias;
//Draws the photo Image object at original size to the graphics object.
grPhoto.DrawImage(
imgPhoto, // Photo Image object
new Rectangle(0, 0, phWidth, phHeight), // Rectangle structure
0, // x-coordinate of the portion of the source image to draw.
0, // y-coordinate of the portion of the source image to draw.
phWidth, // Width of the portion of the source image to draw.
phHeight, // Height of the portion of the source image to draw.
GraphicsUnit.Pixel); // Units of measure
//-------------------------------------------------------
//to maximize the size of the Copyright message we will
//test multiple Font sizes to determine the largest posible
//font we can use for the width of the Photograph
//define an array of point sizes you would like to consider as possiblities
//-------------------------------------------------------
int[] sizes = new int[]{16,14,12,10,8,6,4};
Font crFont = null;
SizeF crSize = new SizeF();
//Loop through the defined sizes checking the length of the Copyright string
//If its length in pixles is less then the image width choose this Font size.
for (int i=0 ;i<7; i++)
{
//set a Font object to Arial (i)pt, Bold
//crFont = new Font("arial", sizes[i], FontStyle.Bold);
crFont = new Font("arial",sizes[i],FontStyle.Bold);
//Measure the Copyright string in this Font
crSize = grPhoto.MeasureString(FontString, crFont);
if((ushort)crSize.Width < (ushort)phWidth)
break;
}
//Since all photographs will have varying heights, determine a
//position 5% from the bottom of the image
int yPixlesFromBottom = (int)(phHeight *.05);
//Now that we have a point size use the Copyrights string height
//to determine a y-coordinate to draw the string of the photograph
float yPosFromBottom = ((phHeight - yPixlesFromBottom)-(crSize.Height/2));
//Determine its x-coordinate by calculating the center of the width of the image
float xCenterOfImg = (phWidth/2);
//Define the text layout by setting the text alignment to centered
StringFormat StrFormat = new StringFormat();
StrFormat.Alignment = StringAlignment.Center;
//define a Brush which is semi trasparent black (Alpha set to 153)
SolidBrush semiTransBrush2 = new SolidBrush(Color.FromArgb(153, 0, 0, 0));
//Draw the Copyright string
grPhoto.DrawString(FontString, //string of text
crFont, //font
semiTransBrush2, //Brush
new PointF(xCenterOfImg+1,yPosFromBottom+1), //Position
StrFormat);
//define a Brush which is semi trasparent white (Alpha set to 153)
SolidBrush semiTransBrush = new SolidBrush(Color.FromArgb(153, 255, 255, 255));
//Draw the Copyright string a second time to create a shadow effect
//Make sure to move this text 1 pixel to the right and down 1 pixel
grPhoto.DrawString(FontString, //string of text
crFont, //font
semiTransBrush, //Brush
new PointF(xCenterOfImg,yPosFromBottom), //Position
StrFormat);
imgPhoto = bmPhoto;
grPhoto.Dispose();
//save new image to file system.
imgPhoto.Save(WorkingDirectory + ImageName + "_finally.jpg", ImageFormat.Jpeg);
imgPhoto.Dispose();
//Text alignment
}
private void WriteImg()
{
//set a working directory
//string WorkingDirectory = @"C:/Watermark_src/WaterPic";
//create a image object containing the photograph to watermark
Image imgPhoto = Image.FromFile(WorkingDirectory + ImageName);
int phWidth = imgPhoto.Width;
int phHeight = imgPhoto.Height;
//create a Bitmap the Size of the original photograph
Bitmap bmPhoto = new Bitmap(phWidth, phHeight, PixelFormat.Format24bppRgb);
bmPhoto.SetResolution(imgPhoto.HorizontalResolution, imgPhoto.VerticalResolution);
//load the Bitmap into a Graphics object
Graphics grPhoto = Graphics.FromImage(bmPhoto);
//create a image object containing the watermark
Image imgWatermark = new Bitmap(WorkingDirectory + ImageWater);
int wmWidth = imgWatermark.Width;
int wmHeight = imgWatermark.Height;
//Set the rendering quality for this Graphics object
grPhoto.SmoothingMode = SmoothingMode.AntiAlias;
//Draws the photo Image object at original size to the graphics object.
grPhoto.DrawImage(
imgPhoto, // Photo Image object
new Rectangle(0, 0, phWidth, phHeight), // Rectangle structure
0, // x-coordinate of the portion of the source image to draw.
0, // y-coordinate of the portion of the source image to draw.
phWidth, // Width of the portion of the source image to draw.
phHeight, // Height of the portion of the source image to draw.
GraphicsUnit.Pixel); // Units of measure
//------------------------------------------------------------
//Step #2 - Insert Watermark image
//------------------------------------------------------------
//Create a Bitmap based on the previously modified photograph Bitmap
Bitmap bmWatermark = new Bitmap(bmPhoto);
bmWatermark.SetResolution(imgPhoto.HorizontalResolution, imgPhoto.VerticalResolution);
//Load this Bitmap into a new Graphic Object
Graphics grWatermark = Graphics.FromImage(bmWatermark);
//To achieve a transulcent watermark we will apply (2) color
//manipulations by defineing a ImageAttributes object and
//seting (2) of its properties.
ImageAttributes imageAttributes = new ImageAttributes();
//The first step in manipulating the watermark image is to replace
//the background color with one that is trasparent (Alpha=0, R=0, G=0, B=0)
//to do this we will use a Colormap and use this to define a RemapTable
ColorMap colorMap = new ColorMap();
//My watermark was defined with a background of 100% Green this will
//be the color we search for and replace with transparency
colorMap.OldColor = Color.FromArgb(255, 0, 255, 0);
colorMap.NewColor = Color.FromArgb(0, 0, 0, 0);
ColorMap[] remapTable = {colorMap};
imageAttributes.SetRemapTable(remapTable, ColorAdjustType.Bitmap);
//The second color manipulation is used to change the opacity of the
//watermark. This is done by applying a 5x5 matrix that contains the
//coordinates for the RGBA space. By setting the 3rd row and 3rd column
//to 0.3f we achive a level of opacity
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, 0.3f, 0.0f},
new float[] {0.0f, 0.0f, 0.0f, 0.0f, 1.0f}};
ColorMatrix wmColorMatrix = new ColorMatrix(colorMatrixElements);
imageAttributes.SetColorMatrix(wmColorMatrix, ColorMatrixFlag.Default,
ColorAdjustType.Bitmap);
//For this example we will place the watermark in the upper right
//hand corner of the photograph. offset down 10 pixels and to the
//left 10 pixles
int xPosOfWm = ((phWidth - wmWidth)-10);
int yPosOfWm = 10;
grWatermark.DrawImage(imgWatermark,
new Rectangle(xPosOfWm,yPosOfWm,wmWidth,wmHeight), //Set the detination Position
0, // x-coordinate of the portion of the source image to draw.
0, // y-coordinate of the portion of the source image to draw.
wmWidth, // Watermark Width
wmHeight, // Watermark Height
GraphicsUnit.Pixel, // Unit of measurment
imageAttributes); //ImageAttributes Object
//Replace the original photgraphs bitmap with the new Bitmap
imgPhoto = bmWatermark;
grPhoto.Dispose();
grWatermark.Dispose();
//save new image to file system.
imgPhoto.Save(WorkingDirectory + ImageName +"_finally.jpg", ImageFormat.Jpeg);
imgPhoto.Dispose();
imgWatermark.Dispose();
}
private void WriteFontAndImg()
{
//create a image object containing the photograph to watermark
Image imgPhoto = Image.FromFile(WorkingDirectory + ImageName);
int phWidth = imgPhoto.Width;
int phHeight = imgPhoto.Height;
//create a Bitmap the Size of the original photograph
Bitmap bmPhoto = new Bitmap(phWidth, phHeight, PixelFormat.Format24bppRgb);
bmPhoto.SetResolution(imgPhoto.HorizontalResolution, imgPhoto.VerticalResolution);
//load the Bitmap into a Graphics object
Graphics grPhoto = Graphics.FromImage(bmPhoto);
//create a image object containing the watermark
Image imgWatermark = new Bitmap(WorkingDirectory + ImageWater);
int wmWidth = imgWatermark.Width;
int wmHeight = imgWatermark.Height;
//------------------------------------------------------------
//Step #1 - Insert Copyright message
//------------------------------------------------------------
//Set the rendering quality for this Graphics object
grPhoto.SmoothingMode = SmoothingMode.AntiAlias;
//Draws the photo Image object at original size to the graphics object.
grPhoto.DrawImage(
imgPhoto, // Photo Image object
new Rectangle(0, 0, phWidth, phHeight), // Rectangle structure
0, // x-coordinate of the portion of the source image to draw.
0, // y-coordinate of the portion of the source image to draw.
phWidth, // Width of the portion of the source image to draw.
phHeight, // Height of the portion of the source image to draw.
GraphicsUnit.Pixel); // Units of measure
//-------------------------------------------------------
//to maximize the size of the Copyright message we will
//test multiple Font sizes to determine the largest posible
//font we can use for the width of the Photograph
//define an array of point sizes you would like to consider as possiblities
//-------------------------------------------------------
int[] sizes = new int[]{16,14,12,10,8,6,4};//这里可以修改文字
Font crFont = null;
SizeF crSize = new SizeF();
//Loop through the defined sizes checking the length of the Copyright string
//If its length in pixles is less then the image width choose this Font size.
for (int i=0 ;i<7; i++)
{
//set a Font object to Arial (i)pt, Bold
crFont = new Font("arial", sizes[i], FontStyle.Bold);
//Measure the Copyright string in this Font
crSize = grPhoto.MeasureString(FontString, crFont);
if((ushort)crSize.Width < (ushort)phWidth)
break;
}
//Since all photographs will have varying heights, determine a
//position 5% from the bottom of the image
int yPixlesFromBottom = (int)(phHeight *.05);
//Now that we have a point size use the Copyrights string height
//to determine a y-coordinate to draw the string of the photograph
float yPosFromBottom = ((phHeight - yPixlesFromBottom)-(crSize.Height/2));
//Determine its x-coordinate by calculating the center of the width of the image
float xCenterOfImg = (phWidth/2);
//Define the text layout by setting the text alignment to centered
StringFormat StrFormat = new StringFormat();
StrFormat.Alignment = StringAlignment.Center;
//define a Brush which is semi trasparent black (Alpha set to 153)
SolidBrush semiTransBrush2 = new SolidBrush(Color.FromArgb(153, 0, 0, 0));
//Draw the Copyright string
grPhoto.DrawString(FontString, //string of text
crFont, //font
semiTransBrush2, //Brush
new PointF(xCenterOfImg+1,yPosFromBottom+1), //Position
StrFormat);
//define a Brush which is semi trasparent white (Alpha set to 153)
SolidBrush semiTransBrush = new SolidBrush(Color.FromArgb(153, 255, 255, 255));
//Draw the Copyright string a second time to create a shadow effect
//Make sure to move this text 1 pixel to the right and down 1 pixel
grPhoto.DrawString(FontString, //string of text
crFont, //font
semiTransBrush, //Brush
new PointF(xCenterOfImg,yPosFromBottom), //Position
StrFormat); //Text alignment
//------------------------------------------------------------
//Step #2 - Insert Watermark image
//------------------------------------------------------------
//Create a Bitmap based on the previously modified photograph Bitmap
Bitmap bmWatermark = new Bitmap(bmPhoto);
bmWatermark.SetResolution(imgPhoto.HorizontalResolution, imgPhoto.VerticalResolution);
//Load this Bitmap into a new Graphic Object
Graphics grWatermark = Graphics.FromImage(bmWatermark);
//To achieve a transulcent watermark we will apply (2) color
//manipulations by defineing a ImageAttributes object and
//seting (2) of its properties.
ImageAttributes imageAttributes = new ImageAttributes();
//The first step in manipulating the watermark image is to replace
//the background color with one that is trasparent (Alpha=0, R=0, G=0, B=0)
//to do this we will use a Colormap and use this to define a RemapTable
ColorMap colorMap = new ColorMap();
//My watermark was defined with a background of 100% Green this will
//be the color we search for and replace with transparency
colorMap.OldColor = Color.FromArgb(255, 0, 255, 0);
colorMap.NewColor = Color.FromArgb(0, 0, 0, 0);
ColorMap[] remapTable = {colorMap};
imageAttributes.SetRemapTable(remapTable, ColorAdjustType.Bitmap);
//The second color manipulation is used to change the opacity of the
//watermark. This is done by applying a 5x5 matrix that contains the
//coordinates for the RGBA space. By setting the 3rd row and 3rd column
//to 0.3f we achive a level of opacity
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, 0.3f, 0.0f},
new float[] {0.0f, 0.0f, 0.0f, 0.0f, 1.0f}};
ColorMatrix wmColorMatrix = new ColorMatrix(colorMatrixElements);
imageAttributes.SetColorMatrix(wmColorMatrix, ColorMatrixFlag.Default,
ColorAdjustType.Bitmap);
//For this example we will place the watermark in the upper right
//hand corner of the photograph. offset down 10 pixels and to the
//left 10 pixles
int xPosOfWm = ((phWidth - wmWidth)-10);
int yPosOfWm = 10;
grWatermark.DrawImage(imgWatermark,
new Rectangle(xPosOfWm,yPosOfWm,wmWidth,wmHeight), //Set the detination Position
0, // x-coordinate of the portion of the source image to draw.
0, // y-coordinate of the portion of the source image to draw.
wmWidth, // Watermark Width
wmHeight, // Watermark Height
GraphicsUnit.Pixel, // Unit of measurment
imageAttributes); //ImageAttributes Object
//Replace the original photgraphs bitmap with the new Bitmap
imgPhoto = bmWatermark;
grPhoto.Dispose();
grWatermark.Dispose();
//save new image to file system.
imgPhoto.Save(WorkingDirectory + ImageName +"_finally.jpg", ImageFormat.Jpeg);
imgPhoto.Dispose();
imgWatermark.Dispose();
}
}
//水印图片加水印文字
// ReDrawImg img = new ReDrawImg();
// img .PublicWorkingDirectory = @"C:/Watermark_src/WaterPic/";
// img .PublicImageName = "watermark_photo.jpg";
// img .PublicImageWater = "watermark.bmp";
// img .PublicFontString = "清清月儿";
// img .DealImage();
//水印文字
ReDrawImg img = new ReDrawImg();
img .PublicWorkingDirectory = @"C:/Watermark_src/WaterPic/";
img .PublicImageName = "watermark_photo.jpg";
img .PublicFontString = @"清清月儿";
img .DealImage();
//水印图片
// ReDrawImg img = new ReDrawImg();
// img .PublicWorkingDirectory = @"C:/Watermark_src/WaterPic/";
// img .PublicImageName = "watermark_photo.jpg";
// img .PublicImageWater = "watermark.bmp";
// img .DealImage();
后台代码：
using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
public partial class _Default : System.Web.UI.Page
{
protected void Page_Load(object sender, EventArgs e)
{
}
protected void bt_upload_Click(object sender, EventArgs e)
{
try
{
if (FileUpload1.PostedFile.FileName == "")
{
this.lb_info.Text = "请选择文件！";
}
else
{
string filepath = FileUpload1.PostedFile.FileName;
string filename = filepath.Substring(filepath.LastIndexOf("//") + 1);
HttpPostedFile UpFile = FileUpload1.PostedFile;//获取上传图片对象
int filelength = UpFile.ContentLength;//获取上传图片的大小（字节大小）
if (CheckBytes(filelength)==true)
{
// string serverpath1 = Server.MapPath("images/") + filename;
string serverpath2 = Server.MapPath("images/") + System.DateTime.Now.ToString("yyy-MM-dd-hh-mm-ss") + Session.SessionID + filename;
string newname = System.DateTime.Now.ToString("yyy-MM-dd-hh-mm-ss") + Session.SessionID + filename;//上传到指定文件夹后的图片的新名称 FileUpload1.PostedFile.SaveAs(serverpath2);
//ImageThumbnail img = new ImageThumbnail(filepath);
//img.ReducedImage(0.4, serverpath2);
DrawImg img = new DrawImg();
img.PublicWorkingDirectory = Server.MapPath("images/");
// img.PublicImageName = filename;//作者的例子是上传图片已经存在要上传到的文件夹里
img.PublicImageName =newname;//自己要上传的文件一般不会存在要上传到的文件夹里。这里获取上传成功后的图片文件名称。
img.PublicFontString = "http://blog.csdn.net/21aspnet";
img.PublicImageWater = "yyy.jpg";
img.DealImage();
this.lb_info.Text = "上传成功！";
GC.Collect();//释放进程，否则删不掉图片文件
File.Delete(serverpath);
}
else
{
this.lb_info.Text = "图片大小不能大于2M！";
}
}
}
catch (Exception error)
{
this.lb_info.Text = "上传发生错误！原因：" + error.ToString();
}
}
public bool CheckBytes(int FileLength)//限制图片大小
{
bool Result = true;
int Length = 2097152;//2M
if (FileLength > Length)
{
Result = false;
}
return Result;
}
}
原帖地址：http://blog.csdn.net/21aspnet/archive/2007/04/01/1548696.aspx