【分享】截取屏幕指定区域保存为BMP文件

阿杰

1. HBITMAP CopyScreenToBitmap(LPRECT lpRect)
   
2. {
   
3. //屏幕和内存设备描述表
   
4. HDC hSrcDC, hMemDC;
   
5. //位图句柄
   
6. HBITMAP hBitmap, hOldBitmap;
   
7. //选定区域坐标
   
8. int nX, nY, nX2, nY2;
   
9. //位图宽度和高度
   
10. int nWidth, nHeight;
    
11. //屏幕分辨率
    
12. int xScrn, yScrn;
    
13. //确保选定区域不为空矩形
    
14. if(IsRectEmpty(lpRect))
    
15.    return NULL;
    
16. //为屏幕创建设备描述表
    
17. hSrcDC = CreateDC("DISPLAY", NULL, NULL, NULL);
    
18. //为屏幕设备描述表创建兼容的内存设备描述表
    
19. hMemDC = CreateCompatibleDC(hSrcDC);
    
20. //获得选定区域坐标
    
21. nX ＝ lpRect->left;
    
22. nY = lpRect->top;
    
23. nX2 = lpRect->right;
    
24. nY2 = lpRect->bottom;
    
25. //获得屏幕分辨率
    
26. xScrn = GetDeviceCaps(hSrcDC, HORZRES);
    
27. yScrn = GetDeviceCaps(hSrcDC, VERTRES);
    
28. //确保选定区域是可见的
    
29. if(nX<0)
    
30.    nX = 0;
    
31. if(nY<0)
    
32.    nY = 0;
    
33. if(nX2>xScrn)
    
34.    nX2 = xScrn;
    
35. if(nY2>yScrn)
    
36.    nY2 = yScrn;
    
37. nWidth = nX2 - nX;
    
38. nHeight = nY2 - nY;
    
39. //创建一个与屏幕设备描述表兼容的位图
    
40. hBitmap = CreateCompatibleBitmap(hSrcDC, nWidth, nHeight);
    
41. //把新位图选到内存设备描述表中
    
42. hOldBitmap = (HBITMAP)SelectObject(hMemDC, hBitmap);
    
43. //把屏幕设备描述表拷贝到内存设备描述表中
    
44. BitBlt(hMemDC, 0, 0, nWidth, nHeight, hSrcDC, nX, nY, SRCCOPY);
    
45. //得到屏幕位图的句柄
    
46. hBitmap = (HBITMAP)SelectObject(hMemDC, hOldBitmap);
    
47. //清除
    
48. DeleteDC(hSrcDC);
    
49. DeleteDC(hMemDC);
    
50. //返回位置句柄
    
51. }
    
52. */
    
53. HBITMAP CopyScreenToBitmap(int x1, int x2, int y1, int y2)
    
54. {
    
55. //屏幕和内存设备描述表
    
56. HDC hSrcDC, hMemDC;
    
57. //位图句柄
    
58. HBITMAP hBitmap, hOldBitmap;
    
59. //选定区域坐标
    
60. int nX, nY, nX2, nY2;
    
61. //位图宽度和高度
    
62. int nWidth, nHeight;
    
63. //屏幕分辨率
    
64. int xScrn, yScrn;
    
65. /*
    
66. //确保选定区域不为空矩形
    
67. if(IsRectEmpty(lpRect))
    
68.    return NULL;*/
    
69. //为屏幕创建设备描述表
    
70. hSrcDC = CreateDC("DISPLAY", NULL, NULL, NULL);
    
71. //为屏幕设备描述表创建兼容的内存设备描述表
    
72. hMemDC = CreateCompatibleDC(hSrcDC);
    
73. //获得选定区域坐标
    
74. nX = x1;
    
75. nY = y1;
    
76. nX2 = x2;
    
77. nY2 = y2;
    
78. //获得屏幕分辨率
    
79. xScrn = GetDeviceCaps(hSrcDC, HORZRES);
    
80. yScrn = GetDeviceCaps(hSrcDC, VERTRES);
    
81. //确保选定区域是可见的
    
82. if(nX<0)
    
83.    nX = 0;
    
84. if(nY<0)
    
85.    nY = 0;
    
86. if(nX2>xScrn)
    
87.    nX2 = xScrn;
    
88. if(nY2>yScrn)
    
89.    nY2 = yScrn;
    
90. nWidth = nX2 - nX;
    
91. nHeight = nY2 - nY;
    
92. //创建一个与屏幕设备描述表兼容的位图
    
93. hBitmap = CreateCompatibleBitmap(hSrcDC, nWidth, nHeight);
    
94. //把新位图选到内存设备描述表中
    
95. hOldBitmap = (HBITMAP)SelectObject(hMemDC, hBitmap);
    
96. //把屏幕设备描述表拷贝到内存设备描述表中
    
97. BitBlt(hMemDC, 0, 0, nWidth, nHeight, hSrcDC, nX, nY, SRCCOPY);
    
98. //得到屏幕位图的句柄
    
99. hBitmap = (HBITMAP)SelectObject(hMemDC, hOldBitmap);
    
100. //清除
     
101. DeleteDC(hSrcDC);
     
102. DeleteDC(hMemDC);
     
103. //返回位置句柄
     
104. return hBitmap;
     
105. }
     
106. BOOL SaveCapturedBitmap(HBITMAP hBitmap, CString FileName)
     
107. {
     
108. if(hBitmap==NULL || FileName.IsEmpty())
     
109. {
     
110.      AfxMessageBox("参数错误");
     
111.    return false;
     
112. }
     
113. HDC hDC;
     
114. //当前分辨率下每象素所占字节数
     
115. int iBits;
     
116. //位图中每象素所占字节数
     
117. WORD wBitCount;
     
118. //定义调色板大小， 位图中像素字节大小 ，位图文件大小 ， 写入文件字节数
     
119. DWORD dwPaletteSize=0, dwBmBitsSize=0, dwDIBSize=0, dwWritten=0;
     
120. //位图属性结构
     
121. BITMAP Bitmap;
     
122. //位图文件头结构
     
123. BITMAPFILEHEADER bmfHdr;
     
124. //位图信息头结构
     
125. BITMAPINFOHEADER bi;
     
126. //指向位图信息头结构
     
127. LPBITMAPINFOHEADER lpbi;
     
128. //定义文件，分配内存句柄，调色板句柄
     
129. HANDLE fh, hDib, hPal,hOldPal=NULL;
     
130. 
     
131. //计算位图文件每个像素所占字节数
     
132. hDC = CreateDC("DISPLAY", NULL, NULL, NULL);
     
133. iBits = GetDeviceCaps(hDC, BITSPIXEL) * GetDeviceCaps(hDC, PLANES);
     
134. DeleteDC(hDC);
     
135. if (iBits <= 1) wBitCount = 1;
     
136. else if (iBits <= 4) wBitCount = 4;
     
137. else if (iBits <= 8) wBitCount = 8;
     
138. else      wBitCount = 24;
     
139. 
     
140. GetObject(hBitmap, sizeof(Bitmap), (LPSTR)&Bitmap);
     
141. bi.biSize   = sizeof(BITMAPINFOHEADER);
     
142. bi.biWidth   = Bitmap.bmWidth;
     
143. bi.biHeight   = Bitmap.bmHeight;
     
144. bi.biPlanes   = 1;
     
145. bi.biBitCount = wBitCount;
     
146. bi.biCompression = BI_RGB;
     
147. bi.biSizeImage = 0;
     
148. bi.biXPelsPerMeter = 0;
     
149. bi.biYPelsPerMeter = 0;
     
150. bi.biClrImportant = 0;
     
151. bi.biClrUsed = 0;
     
152. 
     
153. dwBmBitsSize = ((Bitmap.bmWidth * wBitCount + 31) / 32) * 4 * Bitmap.bmHeight;
     
154. 
     
155. //为位图内容分配内存
     
156. hDib = GlobalAlloc(GHND,dwBmBitsSize + dwPaletteSize + sizeof(BITMAPINFOHEADER));
     
157. lpbi = (LPBITMAPINFOHEADER)GlobalLock(hDib);
     
158. *lpbi = bi;
     
159. // 处理调色板
     
160. hPal = GetStockObject(DEFAULT_PALETTE);
     
161. if (hPal)
     
162. {
     
163.    hDC = ::GetDC(NULL);
     
164.    hOldPal = ::SelectPalette(hDC, (HPALETTE)hPal, FALSE);
     
165.    RealizePalette(hDC);
     
166. }
     
167. // 获取该调色板下新的像素值
     
168. GetDIBits(hDC, hBitmap, 0, (UINT) Bitmap.bmHeight, (LPSTR)lpbi + sizeof(BITMAPINFOHEADER)
     
169.     +dwPaletteSize, (BITMAPINFO *)lpbi, DIB_RGB_COLORS);
     
170. 
     
171. //恢复调色板
     
172. if (hOldPal)
     
173. {
     
174.    ::SelectPalette(hDC, (HPALETTE)hOldPal, TRUE);
     
175.    RealizePalette(hDC);
     
176.    ::ReleaseDC(NULL, hDC);
     
177. }
     
178. //创建位图文件
     
179. fh = CreateFile(FileName, GENERIC_WRITE,0, NULL, CREATE_ALWAYS,
     
180.    FILE_ATTRIBUTE_NORMAL | FILE_FLAG_SEQUENTIAL_SCAN, NULL);
     
181. 
     
182. if (fh == INVALID_HANDLE_VALUE) return FALSE;
     
183. 
     
184. // 设置位图文件头
     
185. bmfHdr.bfType = 0x4D42; // "BM"
     
186. dwDIBSize = sizeof(BITMAPFILEHEADER) + sizeof(BITMAPINFOHEADER) + dwPaletteSize + dwBmBitsSize;
     
187. bmfHdr.bfSize = dwDIBSize;
     
188. bmfHdr.bfReserved1 = 0;
     
189. bmfHdr.bfReserved2 = 0;
     
190. bmfHdr.bfOffBits = (DWORD)sizeof(BITMAPFILEHEADER) + (DWORD)sizeof(BITMAPINFOHEADER) + dwPaletteSize;
     
191. // 写入位图文件头
     
192. WriteFile(fh, (LPSTR)&bmfHdr, sizeof(BITMAPFILEHEADER), &dwWritten, NULL);
     
193. // 写入位图文件其余内容
     
194. WriteFile(fh, (LPSTR)lpbi, dwDIBSize, &dwWritten, NULL);
     
195. //清除
     
196. GlobalUnlock(hDib);
     
197. GlobalFree(hDib);
     
198. CloseHandle(fh);
     
199. return TRUE;
     
200. }
     
201. int main()
     
202. {
     
203. HBITMAP hCaptureBitmap = CopyScreenToBitmap(100, 700, 100, 700);
     
204. SaveCapturedBitmap(hCaptureBitmap, "Hello.bmp");
     
205. return 0;
     
206. }

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REF：http://weiyuweizhi.blog.163.com/ ... 332120091493344277/

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