ASP.NET实现图片压缩、添加文字或图片水印、指定位置裁剪等功能(附效果图)
这个类是ImageUtility
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。 
源代码：
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#region 图片水印操作
180
181 /**//// <summary>
182 /// 给图片添加图片水印
183 /// </summary>
184 /// <param name="inputStream">包含要源图片的流</param>
185 /// <param name="watermarkPath">水印图片的物理地址</param>
186 /// <param name="saveFilePath">目标图片的存储地址</param>
187 /// <param name="mp">水印位置</param>
188 public static void AddPicWatermarkAsJPG(Stream inputStream, string watermarkPath, string saveFilePath, MarkPosition mp)
189 {
190
191 Image image = Image.FromStream(inputStream);
192 Bitmap b = new Bitmap(image.Width, image.Height, PixelFormat.Format24bppRgb);
193 Graphics g = Graphics.FromImage(b);
194 g.Clear(Color.White);
195 g.SmoothingMode = SmoothingMode.HighQuality;
196 g.InterpolationMode = InterpolationMode.High;
197 g.DrawImage(image, 0, 0, image.Width, image.Height);
198
199 AddWatermarkImage(g, watermarkPath, mp, image.Width, image.Height);
200
201 try
202 {
203 CompressAsJPG(b, saveFilePath, 80);
204 }
205 catch { ;}
206 finally
207 {
208 b.Dispose();
209 image.Dispose();
210 }
211 }
212
213
214 /**//// <summary>
215 /// 给图片添加图片水印
216 /// </summary>
217 /// <param name="sourcePath">源图片的存储地址</param>
218 /// <param name="watermarkPath">水印图片的物理地址</param>
219 /// <param name="saveFilePath">目标图片的存储地址</param>
220 /// <param name="mp">水印位置</param>
221 public static void AddPicWatermarkAsJPG(string sourcePath, string watermarkPath, string saveFilePath, MarkPosition mp)
222 {
223 if (File.Exists(sourcePath))
224 {
225 using (StreamReader sr = new StreamReader(sourcePath))
226 {
227 AddPicWatermarkAsJPG(sr.BaseStream, watermarkPath, saveFilePath, mp);
228 }
229 }
230 }
231 /**//// <summary>
232 /// 给图片添加文字水印
233 /// </summary>
234 /// <param name="inputStream">包含要源图片的流</param>
235 /// <param name="text">水印文字</param>
236 /// <param name="saveFilePath">目标图片的存储地址</param>
237 /// <param name="mp">水印位置</param>
238 public static void AddTextWatermarkAsJPG(Stream inputStream, string text, string saveFilePath, MarkPosition mp)
239 {
240
241 Image image = Image.FromStream(inputStream);
242 Bitmap b = new Bitmap(image.Width, image.Height, PixelFormat.Format24bppRgb);
243 Graphics g = Graphics.FromImage(b);
244 g.Clear(Color.White);
245 g.SmoothingMode = SmoothingMode.HighQuality;
246 g.InterpolationMode = InterpolationMode.High;
247 g.DrawImage(image, 0, 0, image.Width, image.Height);
248
249 AddWatermarkText(g, text, mp, image.Width, image.Height);
250
251 try
252 {
253 CompressAsJPG(b, saveFilePath, 80);
254 }
255 catch { ;}
256 finally
257 {
258 b.Dispose();
259 image.Dispose();
260 }
261 }
262
263 /**//// <summary>
264 /// 给图片添加文字水印
265 /// </summary>
266 /// <param name="sourcePath">源图片的存储地址</param>
267 /// <param name="text">水印文字</param>
268 /// <param name="saveFilePath">目标图片的存储地址</param>
269 /// <param name="mp">水印位置</param>
270 public static void AddTextWatermarkAsJPG(string sourcePath, string text, string saveFilePath, MarkPosition mp)
271 {
272 if (File.Exists(sourcePath))
273 {
274 using (StreamReader sr = new StreamReader(sourcePath))
275 {
276 AddTextWatermarkAsJPG(sr.BaseStream, text, saveFilePath, mp);
277 }
278 }
279 }
280
281 /**//// <summary>
282 /// 添加文字水印
283 /// </summary>
284 /// <param name="picture">要加水印的原图像</param>
285 /// <param name="text">水印文字</param>
286 /// <param name="mp">添加的位置</param>
287 /// <param name="width">原图像的宽度</param>
288 /// <param name="height">原图像的高度</param>
289 private static void AddWatermarkText(Graphics picture, string text, MarkPosition mp, int width, int height)
290 {
291 int[] sizes = new int[] { 16, 14, 12, 10, 8, 6, 4 };
292 Font crFont = null;
293 SizeF crSize = new SizeF();
294 for (int i = 0; i < 7; i++)
295 {
296 crFont = new Font("Arial", sizes[i], FontStyle.Bold);
297 crSize = picture.MeasureString(text, crFont);
298
299 if ((ushort)crSize.Width < (ushort)width)
300 break;
301 }
302
303 float xpos = 0;
304 float ypos = 0;
305
306 switch (mp)
307 {
308 case MarkPosition.MP_Left_Top:
309 xpos = ((float)width * (float).01) + (crSize.Width / 2);
310 ypos = (float)height * (float).01;
311 break;
312 case MarkPosition.MP_Right_Top:
313 xpos = ((float)width * (float).99) - (crSize.Width / 2);
314 ypos = (float)height * (float).01;
315 break;
316 case MarkPosition.MP_Right_Bottom:
317 xpos = ((float)width * (float).99) - (crSize.Width / 2);
318 ypos = ((float)height * (float).99) - crSize.Height;
319 break;
320 case MarkPosition.MP_Left_Bottom:
321 xpos = ((float)width * (float).01) + (crSize.Width / 2);
322 ypos = ((float)height * (float).99) - crSize.Height;
323 break;
324 }
325
326 StringFormat StrFormat = new StringFormat();
327 StrFormat.Alignment = StringAlignment.Center;
328
329 SolidBrush semiTransBrush2 = new SolidBrush(Color.FromArgb(153, 0, 0, 0));
330 picture.DrawString(text, crFont, semiTransBrush2, xpos + 1, ypos + 1, StrFormat);
331
332 SolidBrush semiTransBrush = new SolidBrush(Color.FromArgb(153, 255, 255, 255));
333 picture.DrawString(text, crFont, semiTransBrush, xpos, ypos, StrFormat);
334
335 semiTransBrush2.Dispose();
336 semiTransBrush.Dispose();
337
338 }
339
340 /**//// <summary>
341 /// 添加图片水印
342 /// </summary>
343 /// <param name="picture">要加水印的原图像</param>
344 /// <param name="waterMarkPath">水印文件的物理地址</param>
345 /// <param name="mp">添加的位置</param>
346 /// <param name="width">原图像的宽度</param>
347 /// <param name="height">原图像的高度</param>
348 private static void AddWatermarkImage(Graphics picture, string waterMarkPath, MarkPosition mp, int width, int height)
349 {
350 Image watermark = new Bitmap(waterMarkPath);
351
352 ImageAttributes imageAttributes = new ImageAttributes();
353 ColorMap colorMap = new ColorMap();
354
355 colorMap.OldColor = Color.FromArgb(255, 0, 255, 0);
356 colorMap.NewColor = Color.FromArgb(0, 0, 0, 0);
357 ColorMap[] remapTable = { colorMap };
358
359 imageAttributes.SetRemapTable(remapTable, ColorAdjustType.Bitmap);
360
361 float[][] colorMatrixElements = {
362 new float[] {1.0f, 0.0f, 0.0f, 0.0f, 0.0f},
363 new float[] {0.0f, 1.0f, 0.0f, 0.0f, 0.0f},
364 new float[] {0.0f, 0.0f, 1.0f, 0.0f, 0.0f},
365 new float[] {0.0f, 0.0f, 0.0f, 0.3f, 0.0f},
366 new float[] {0.0f, 0.0f, 0.0f, 0.0f, 1.0f}
367 };
368
369 ColorMatrix colorMatrix = new ColorMatrix(colorMatrixElements);
370
371 imageAttributes.SetColorMatrix(colorMatrix, ColorMatrixFlag.Default, ColorAdjustType.Bitmap);
372
373 int xpos = 0;
374 int ypos = 0;
375 int WatermarkWidth = 0;
376 int WatermarkHeight = 0;
377 double bl = 1d;
378 if ((width > watermark.Width * 4) && (height > watermark.Height * 4))
379 {
380 bl = 1;
381 }
382 else if ((width > watermark.Width * 4) && (height < watermark.Height * 4))
383 {
384 bl = Convert.ToDouble(height / 4) / Convert.ToDouble(watermark.Height);
385
386 }
387 else
388
389 if ((width < watermark.Width * 4) && (height > watermark.Height * 4))
390 {
391 bl = Convert.ToDouble(width / 4) / Convert.ToDouble(watermark.Width);
392 }
393 else
394 {
395 if ((width * watermark.Height) > (height * watermark.Width))
396 {
397 bl = Convert.ToDouble(height / 4) / Convert.ToDouble(watermark.Height);
398
399 }
400 else
401 {
402 bl = Convert.ToDouble(width / 4) / Convert.ToDouble(watermark.Width);
403
404 }
405
406 }
407
408 WatermarkWidth = Convert.ToInt32(watermark.Width * bl);
409 WatermarkHeight = Convert.ToInt32(watermark.Height * bl);
410
411
412 switch (mp)
413 {
414 case MarkPosition.MP_Left_Top:
415 xpos = 10;
416 ypos = 10;
417 break;
418 case MarkPosition.MP_Right_Top:
419 xpos = width - WatermarkWidth - 10;
420 ypos = 10;
421 break;
422 case MarkPosition.MP_Right_Bottom:
423 xpos = width - WatermarkWidth - 10;
424 ypos = height - WatermarkHeight - 10;
425 break;
426 case MarkPosition.MP_Left_Bottom:
427 xpos = 10;
428 ypos = height - WatermarkHeight - 10;
429 break;
430 }
431
432 picture.DrawImage(watermark, new Rectangle(xpos, ypos, WatermarkWidth, WatermarkHeight), 0, 0, watermark.Width, watermark.Height, GraphicsUnit.Pixel, imageAttributes);
433
434
435 watermark.Dispose();
436 imageAttributes.Dispose();
437 }
438
439 /**//// <summary>
440 /// 水印的位置
441 /// </summary>
442 public enum MarkPosition
443 {
444 /**//// <summary>
445 /// 左上角
446 /// </summary>
447 MP_Left_Top,
448
449 /**//// <summary>
450 /// 左下角
451 /// </summary>
452 MP_Left_Bottom,
453
454 /**//// <summary>
455 /// 右上角
456 /// </summary>
457 MP_Right_Top,
458
459 /**//// <summary>
460 /// 右下角
461 /// </summary>
462 MP_Right_Bottom
463 }
464
465
466 #endregion
467
468 }
469}