【IT168技术文档】在web程序开发中，相信很多同行们都碰到过图片压缩，生成缩略图的操作，比如产品的图片，会员的照片等等功能。
为了满足此类操作今天给大家介绍ImageUtility类，该类几乎实现了常规网站开发图片处理的功能，比如按大小生成缩略图，指定位置和大小裁剪，以前给图片添加 文字或图片水印等。此外此类生成的文件格式均为.jpg格式，如果想要.GIF或PNG的透明效果的朋友，就不要再向下看了。
老样子，先上图：
所有详细的介绍在代里的注释里已经标识的很清楚了，在此不在多说。
代码：
1using System;
2using System.Collections.Generic;
3using System.Text;
4using System.Drawing;
5using System.Drawing.Drawing2D;
6using System.Drawing.Imaging;
7using System.IO;
8
9namespace Loskiv.Utility
10{
11 /// <summary>
12 /// 名称：图片处理常用操作类
13 /// 作者：loskiv
14 /// 创建时间：2009-07-07
15 /// </summary>
16 public class ImageUtility
17 {
18
19 /// <summary>
20 /// 获取指定mimeType的ImageCodecInfo
21 /// </summary>
22 private static ImageCodecInfo GetImageCodecInfo(string mimeType)
23 {
24 ImageCodecInfo[] CodecInfo = ImageCodecInfo.GetImageEncoders();
25 foreach (ImageCodecInfo ici in CodecInfo)
26 {
27 if (ici.MimeType == mimeType) return ici;
28 }
29 return null;
30 }
31
32 /// <summary>
33 /// 获取inputStream中的Bitmap对象
34 /// </summary>
35 public static Bitmap GetBitmapFromStream(Stream inputStream)
36 {
37 Bitmap bitmap = new Bitmap(inputStream);
38 return bitmap;
39 }
40
41 /// <summary>
42 /// 将Bitmap对象压缩为JPG图片类型
43 /// </summary>
44 /// </summary>
45 /// <param name="bmp">源bitmap对象</param>
46 /// <param name="saveFilePath">目标图片的存储地址</param>
47 /// <param name="quality">压缩质量，越大照片越清晰，推荐80</param>
48 public static void CompressAsJPG(Bitmap bmp, string saveFilePath, int quality)
49 {
50 EncoderParameter p = new EncoderParameter(System.Drawing.Imaging.Encoder.Quality, quality); ;
51 EncoderParameters ps = new EncoderParameters(1);
52 ps.Param[0] = p;
53 bmp.Save(saveFilePath, GetImageCodecInfo("image/jpeg"), ps);
54 bmp.Dispose();
55 }
56
57 /// <summary>
58 /// 将inputStream中的对象压缩为JPG图片类型
59 /// </summary>
60 /// <param name="inputStream">源Stream对象</param>
61 /// <param name="saveFilePath">目标图片的存储地址</param>
62 /// <param name="quality">压缩质量，越大照片越清晰，推荐80</param>
63 public static void CompressAsJPG(Stream inputStream, string saveFilePath, int quality)
64 {
65 Bitmap bmp = GetBitmapFromStream(inputStream);
66 CompressAsJPG(bmp, saveFilePath, quality);
67 }
68
69
70 /// <summary>
71 /// 生成缩略图（JPG 格式）
72 /// </summary>
73 /// <param name="inputStream">包含图片的Stream</param>
74 /// <param name="saveFilePath">目标图片的存储地址</param>
75 /// <param name="width">缩略图的宽</param>
76 /// <param name="height">缩略图的高</param>
77 public static void ThumbAsJPG(Stream inputStream, string saveFilePath, int width, int height)
78 {
79 Image image = Image.FromStream(inputStream);
80 if (image.Width == width && image.Height == height)
81 {
82 CompressAsJPG(inputStream, saveFilePath, 80);
83 }
84 int tWidth, tHeight, tLeft, tTop;
85 double fScale = (double)height / (double)width;
86 if (((double)image.Width * fScale) > (double)image.Height)
87 {
88 tWidth = width;
89 tHeight = (int)((double)image.Height * (double)tWidth / (double)image.Width);
90 tLeft = 0;
91 tTop = (height - tHeight) / 2;
92 }
93 else
94 {
95 tHeight = height;
96 tWidth = (int)((double)image.Width * (double)tHeight / (double)image.Height);
97 tLeft = (width - tWidth) / 2;
98 tTop = 0;
99 }
100 if (tLeft < 0) tLeft = 0;
101 if (tTop < 0) tTop = 0;
102
103 Bitmap bitmap = new Bitmap(width, height, PixelFormat.Format32bppArgb);
104 Graphics graphics = Graphics.FromImage(bitmap);
105
106 //可以在这里设置填充背景颜色
107 graphics.Clear(Color.White);
108 graphics.DrawImage(image, new Rectangle(tLeft, tTop, tWidth, tHeight));
109 image.Dispose();
110 try
111 {
112 CompressAsJPG(bitmap, saveFilePath, 80);
113 }
114 catch
115 {
116 ;
117 }
118 finally
119 {
120 bitmap.Dispose();
121 graphics.Dispose();
122 }
123 }
124
125 /// <summary>
126 /// 将Bitmap对象裁剪为指定JPG文件
127 /// </summary>
128 /// <param name="bmp">源bmp对象</param>
129 /// <param name="saveFilePath">目标图片的存储地址</param>
130 /// <param name="x">开始坐标x，单位：像素</param>
131 /// <param name="y">开始坐标y，单位：像素</param>
132 /// <param name="width">宽度：像素</param>
133 /// <param name="height">高度：像素</param>
134 public static void CutAsJPG(Bitmap bmp, string saveFilePath, int x, int y, int width, int height)
135 {
136 int bmpW = bmp.Width;
137 int bmpH = bmp.Height;
138
139 if (x >= bmpW || y >= bmpH)
140 {
141 CompressAsJPG(bmp, saveFilePath, 80);
142 return;
143 }
144
145 if (x + width > bmpW)
146 {
147 width = bmpW - x;
148 }
149
150 if (y + height > bmpH)
151 {
152 height = bmpH - y;
153 }
154
155 Bitmap bmpOut = new Bitmap(width, height, PixelFormat.Format24bppRgb);
156 Graphics g = Graphics.FromImage(bmpOut);
157 g.DrawImage(bmp, new Rectangle(0, 0, width, height), new Rectangle(x, y, width, height), GraphicsUnit.Pixel);
158 g.Dispose();
159 bmp.Dispose();
160 CompressAsJPG(bmpOut, saveFilePath, 80);
161 }
162
163 /// <summary>
164 /// 将Stream中的对象裁剪为指定JPG文件
165 /// </summary>
166 /// <param name="inputStream">源bmp对象</param>
167 /// <param name="saveFilePath">目标图片的存储地址</param>
168 /// <param name="x">开始坐标x，单位：像素</param>
169 /// <param name="y">开始坐标y，单位：像素</param>
170 /// <param name="width">宽度：像素</param>
171 /// <param name="height">高度：像素</param>
172 public static void CutAsJPG(Stream inputStream, string saveFilePath, int x, int y, int width, int height)
173 {
174 Bitmap bmp = GetBitmapFromStream(inputStream);
175 CutAsJPG(bmp, saveFilePath, x, y, width, height);
176 }
177
178
179 图片水印操作
467
468 }
469}
470
