.NET图片操作类，包含图片格式转换、图片缩放、 文字水印、图片水印、路径转换
using System;
using System.Collections.Generic;
using System.Text;
using System.IO;
using System.Drawing.Imaging;
using System.Drawing;
using System.Web;
namespace ZC.Utils
{
public static class ImageHelper
{
#region 图片格式转换
/// <summary>
/// 图片格式转换
/// </summary>
/// <param name="OriFilename">原始文件相对路径</param>
/// <param name="DesiredFilename">生成目标文件相对路径</param>
/// <returns></returns>
/// JPG采用的是有损压缩所以JPG图像有可能会降低图像清晰度，而像素是不会降低的
/// GIF采用的是无损压缩所以GIF图像是不会降低原图图像清晰度和像素的，但是GIF格式只支持256色图像。
public static bool ConvertImage(string OriFilename, string DesiredFilename)
{
string extname = DesiredFilename.Substring(DesiredFilename.LastIndexOf('.')+1).ToLower();
ImageFormat DesiredFormat;
//根据扩张名，指定ImageFormat
switch (extname)
{
case "bmp":
DesiredFormat = ImageFormat.Bmp;
break;
case "gif":
DesiredFormat = ImageFormat.Gif;
break;
case "jpeg":
DesiredFormat = ImageFormat.Jpeg;
break;
case "ico":
DesiredFormat = ImageFormat.Icon;
break;
case "png":
DesiredFormat = ImageFormat.Png;
break;
default:
DesiredFormat = ImageFormat.Jpeg;
break;
}
try
{
System.Drawing.Image imgFile = System.Drawing.Image.FromFile(WebPathTran(OriFilename));
imgFile.Save(WebPathTran(DesiredFilename), DesiredFormat);
return true;
}
catch
{
return false;
}
}
#endregion
#region 图片缩放
/// <summary>
/// 图片固定大小缩放
/// </summary>
/// <param name="OriFileName">源文件相对地址</param>
/// <param name="DesiredFilename">目标文件相对地址</param>
/// <param name="IntWidth">目标文件宽</param>
/// <param name="IntHeight">目标文件高</param>
/// <param name="imageFormat">图片文件格式</param>
public static bool ChangeImageSize(string OriFileName, string DesiredFilename, int IntWidth, int IntHeight, ImageFormat imageFormat)
{
string SourceFileNameStr =WebPathTran(OriFileName); //来源图片名称路径
string TransferFileNameStr = WebPathTran(DesiredFilename); //目的图片名称路径
FileStream myOutput =null;
try
{
System.Drawing.Image.GetThumbnailImageAbort myAbort = new System.Drawing.Image.GetThumbnailImageAbort(imageAbort);
Image SourceImage = System.Drawing.Image.FromFile(OriFileName);//来源图片定义
Image TargetImage = SourceImage.GetThumbnailImage(IntWidth, IntHeight, myAbort, IntPtr.Zero); //目的图片定义
//将TargetFileNameStr的图片放宽为IntWidth，高为IntHeight
myOutput = new FileStream(TransferFileNameStr, FileMode.Create, FileAccess.Write, FileShare.Write);
TargetImage.Save(myOutput, imageFormat);
myOutput.Close();
return true;
}
catch
{
myOutput.Close();
return false;
}
}
private static bool imageAbort()
{
return false;
}
#endregion
#region 文字水印
/// <summary>
/// 文字水印
/// </summary>
/// <param name="wtext">水印文字</param>
/// <param name="source">原图片物理文件名</param>
/// <param name="target">生成图片物理文件名</param>
public static bool ImageWaterText(string wtext,string source, string target)
{
bool resFlag = false;
Image image = Image.FromFile(source);
Graphics graphics = Graphics.FromImage(image);
try
{
graphics.DrawImage(image, 0, 0, image.Width, image.Height);
Font font = new System.Drawing.Font("Verdana", 60);
Brush brush = new System.Drawing.SolidBrush(System.Drawing.Color.Green);
graphics.DrawString(wtext, font, brush, 35, 35);
image.Save(target);
resFlag = true;
}
catch (Exception)
{
throw;
}
finally
{
graphics.Dispose();
image.Dispose();
}
return resFlag;
}
#endregion
#region 图片水印
/// <summary>
/// 在图片上生成图片水印
/// </summary>
/// <param name="Path">原服务器图片路径</param>
/// <param name="Path_syp">生成的带图片水印的图片路径</param>
/// <param name="Path_sypf">水印图片路径</param>
public static bool ImageWaterPic(string source, string target, string waterPicSource)
{
bool resFlag = false;
Image sourceimage = Image.FromFile(source);
Graphics sourcegraphics = Graphics.FromImage(sourceimage);
Image waterPicSourceImage = Image.FromFile(waterPicSource);
try
{
sourcegraphics.DrawImage(waterPicSourceImage, new System.Drawing.Rectangle(sourceimage.Width - waterPicSourceImage.Width, sourceimage.Height - waterPicSourceImage.Height, waterPicSourceImage.Width, waterPicSourceImage.Height), 0, 0, waterPicSourceImage.Width, waterPicSourceImage.Height, GraphicsUnit.Pixel);
sourceimage.Save(target);
}
catch (Exception)
{
throw;
}
finally
{
sourcegraphics.Dispose();
sourceimage.Dispose();
waterPicSourceImage.Dispose();
}
return resFlag;
}
#endregion
#region 路径转换
/// <summary>
/// 路径转换（转换成绝对路径）
/// </summary>
/// <param name="path"></param>
/// <returns></returns>
private static string WebPathTran(string path)
{
try
{
return HttpContext.Current.Server.MapPath(path);
}
catch
{
return path;
}
}
#endregion
}
}