1 public class ImageDraw
2 {
3 public Image NewBitmap(int w, int h, float dpix, float dpiy)
4 {
5 var rt = new Bitmap(w, h);
6 rt.SetResolution(dpix, dpiy);
7 return rt;
8 }
9
10 /// <summary> 得到图像的指定区域.
11 /// </summary>
12 /// <param name="source"></param>
13 /// <param name="rect"></param>
14 /// <returns></returns>
15 public Image GetImageRect(Image source, Rectangle rect)
16 {
17 var rt = NewBitmap(rect.Width, rect.Height, source.HorizontalResolution, source.VerticalResolution);
18 Graphics gh = Graphics.FromImage(rt);
19 gh.DrawImage(source, 0, 0, rect, GraphicsUnit.Pixel);
20 gh.Save();
21 gh.Dispose();
22 return rt;
23 }
24
25 /// <summary> 拉伸图像.
26 /// </summary>
27 /// <param name="source"></param>
28 /// <param name="newSize"></param>
29 /// <returns></returns>
30 public Image GetStretchImage(Image source, Size newSize)
31 {
32 var w = source.Width;
33 var h = source.Height;
34
35 var rt = NewBitmap(newSize.Width, newSize.Height, source.HorizontalResolution, source.VerticalResolution);
36 var gh = Graphics.FromImage(rt);
37
38 gh.DrawImage(source, new Rectangle(0, 0, newSize.Width, newSize.Height), new Rectangle(0, 0, w, h), GraphicsUnit.Pixel);
39
40 gh.Save();
41 gh.Dispose();
42
43 return rt;
44 }
45
46 /// <summary> 拉伸图像至合适大小,并保持纵横比..
47 /// </summary>
48 /// <param name="source"></param>
49 /// <param name="newSize"></param>
50 /// <returns></returns>
51 public Image GetAdaptiveImage(Image source, Size newSize)
52 {
53 var sw = source.Width;
54 var sh = source.Height;
55 var tw = newSize.Width;
56 var th = newSize.Height;
57
58 double wb = sw * 1.0 / tw;
59 double hb = sh * 1.0 / th;
60
61 //计算目标图像宽高.
62 if (wb > hb)
63 {
64 //取宽度作为标准
65 th = (int)(sh / wb);
66 }
67 else
68 {
69 tw = (int)(sw / hb);
70 }
71
72 //生成图像
73 return GetStretchImage(source, new Size(tw, th));
74 }
75
76 /// <summary> 剪裁图像至合适大小.
77 /// </summary>
78 /// <param name="image"></param>
79 /// <param name="size"></param>
80 /// <returns></returns>
81 public Image GetFillImage(Image source, Size newSize)
82 {
83 var sw = source.Width;
84 var sh = source.Height;
85 var tw = newSize.Width;
86 var th = newSize.Height;
87
88 double wb = sw * 1.0 / tw;
89 double hb = sh * 1.0 / th;
90
91 Image rt;
92 Graphics gh;
93
94 //计算目标图像宽高.
95 if (wb > hb)
96 {
97 th = sh;
98 tw = (int)(tw * hb);
99
100 rt = NewBitmap(newSize.Width, newSize.Height, source.HorizontalResolution, source.VerticalResolution);
101 gh = Graphics.FromImage(rt);
102
103 gh.DrawImage(source, new Rectangle(new Point(0, 0), newSize), new Rectangle(new Point((sw - tw) / 2, 0), new Size(tw, th)), GraphicsUnit.Pixel);
104 gh.Dispose();
105
106 return rt;
107 }
108 else
109 {
110 //计算出原图中要裁剪的尺寸.
111 tw = sw;
112 th = (int)(th * wb);
113
114 rt = NewBitmap(newSize.Width, newSize.Height, source.HorizontalResolution, source.VerticalResolution);
115 gh = Graphics.FromImage(rt);
116
117 gh.DrawImage(source, new Rectangle(0, 0, 100, 100), new Rectangle(30, 30, 100, 100), GraphicsUnit.Pixel);
118
119 gh.DrawImage(source, new Rectangle(new Point(0, 0), newSize), new Rectangle(new Point(0, (sh - th) / 2), new Size(tw, th)), GraphicsUnit.Pixel);
120 gh.Dispose();
121
122 return rt;
123 }
124 }
125
126 /// <summary> 获取图像数据
127 /// </summary>
128 /// <param name="img"></param>
129 /// <returns></returns>
130 public byte[] GetImageData(Image img)
131 {
132 //将图像转化为32位位图 ( 24位计算色差有些麻烦.^^ 32位,则直接转换为整数.)
133 var bmp = new Bitmap(img.Width, img.Height, PixelFormat.Format32bppPArgb);
134
135 bmp.SetResolution(img.HorizontalResolution, img.VerticalResolution);
136
137 var gh = Graphics.FromImage(bmp);
138
139 gh.DrawImageUnscaled(img, 0, 0);
140
141 gh.Save();
142
143 img = bmp;
144
145 gh.Dispose();
146
147 var ms = new MemoryStream(img.Width * img.Height * 4 + 2048);
148
149 img.Save(ms, ImageFormat.Bmp);
150 ms.Flush();
151 ms.Position = 0;
152 var data = new byte[ms.Length];
153 ms.Read(data, 0, data.Length);
154 ms.Close();
155 return data;
156 }
157
158 /// <summary> 保存图片 貌似是0 - 100
159 /// </summary>
160 /// <param name="lm"></param>
161 /// <param name="p"></param>
162 /// <param name="fn"> </param>
163 /// <param name="quality"> </param>
164 public void SaveImageToJpeg(Image lm, string fn, int quality)
165 {
166 System.IO.Directory.CreateDirectory(Path.GetDirectoryName(fn));
167
168 var sm = new FileStream(fn, FileMode.Create);
169 SaveImageToJpeg(lm, sm, quality);
170 sm.Close();
171 }
172
173 public void SaveImageToJpeg(Image lm, Stream stream, int quality)
174 {
175 if (quality == 0)
176 {
177 quality = 80;
178 }
179
180 var jgpEncoder = System.Drawing.Imaging.ImageCodecInfo.GetImageDecoders().First(j => j.FormatID == ImageFormat.Jpeg.Guid);
181
182 //参数数组
183 var myEncoderParameters = new System.Drawing.Imaging.EncoderParameters(1);
184
185 //质量
186 var myEncoder = System.Drawing.Imaging.Encoder.Quality;
187
188 //质量包含参数
189 //EncoderParameters paramList = Image.FromFile("c:\\http_imgload.jpg").GetEncoderParameterList(jgpEncoder.Clsid);
190
191 var myEncoderParameter = new System.Drawing.Imaging.EncoderParameter(myEncoder, (Int64)quality);
192
193 myEncoderParameters.Param[0] = myEncoderParameter;
194
195 lm.Save(stream, jgpEncoder, myEncoderParameters);
196 stream.Flush();
197 }
198 }
