HWND hDesktop = ::GetDesktopWindow();
HDC hDC = ::GetDC(hDesktop);
HDC hMemDC = ::CreateCompatibleDC(hDC);
::GetWindowRect(hDesktop,&rect);
int cx,cy;
cx = rect.right - rect.left;
cy = rect.bottom - rect.top;
HBITMAP hBitmap = ::CreateCompatibleBitmap(hDC,cx,cy);
HGDIOBJ hOldObject = ::SelectObject(hMemDC,m_hBitmap);
::BitBlt(hMemDC,0,0,cx,cy,hDC,rect.left,rect.top,SRCCOPY);
::SelectObject(hMemDC,hOldObject);
::DeleteObject(hMemDC);
::ReleaseDC(hDesktop,hDC);
hBitmap里就是截下来的图像
------------------------------------------------------------
dysxq() ,如何保存hBitmap成位图呢？？？
----------------------------------------------------------------------
LPTSTR CRemoteC::CopyScreenToBitmap(LPRECT lpRect)
{
HDC hScrDC, hMemDC; // 屏幕和内存设备描述表
HBITMAP hBitmap,hOldBitmap; // 位图句柄
int nX, nY, nX2, nY2; // 选定区域坐标
int nWidth, nHeight; // 位图宽度和高度
int xScrn, yScrn; // 屏幕分辨率
// 确保选定区域不为空矩形
if (IsRectEmpty(lpRect)) return NULL;
//为屏幕创建设备描述表
hScrDC = CreateDC("DISPLAY", NULL, NULL, NULL);
//为屏幕设备描述表创建兼容的内存设备描述表
hMemDC = CreateCompatibleDC(hScrDC);
// 获得选定区域坐标
nX = lpRect-> left;
nY = lpRect-> top;
nX2 = lpRect-> right;
nY2 = lpRect-> bottom;
// 获得屏幕分辨率
xScrn = GetDeviceCaps(hScrDC, HORZRES);
yScrn = GetDeviceCaps(hScrDC, VERTRES);
//确保选定区域是可见的
if (nX < 0) nX = 0;
if (nY < 0) nY = 0;
if (nX2 > xScrn) nX2 = xScrn;
if (nY2 > yScrn) nY2 = yScrn;
nWidth = nX2 - nX;
nHeight = nY2 - nY;
// 创建一个与屏幕设备描述表兼容的位图
int *temp=new int(m_szResolution.Find("*"));
char *pWidth=new char[10];
char *pHeight=new char[10];
strcpy(pWidth,m_szResolution.Mid(0,*temp));
strcpy(pHeight,m_szResolution.Mid(*temp+1));
delete temp;
int nDestResWidth=atoi(pWidth);
int nDestResHeight=atoi(pHeight);
delete pWidth;
delete pHeight;
hBitmap = CreateCompatibleBitmap(hScrDC, nDestResWidth, nDestResHeight);
// 把新位图选到内存设备描述表中
hOldBitmap=(HBITMAP)::SelectObject(hMemDC, hBitmap);
// 把屏幕设备描述表拷贝到内存设备描述表中
StretchBlt(hMemDC, 0, 0, nDestResWidth, nDestResHeight,hScrDC, nX, nY,nWidth,nHeight,SRCCOPY);
//得到屏幕位图的句柄
hBitmap =(HBITMAP) ::SelectObject(hMemDC, hOldBitmap);
//清除
DeleteDC(hScrDC);
DeleteDC(hMemDC);
char tmppath[MAX_PATH];
char *tmpname=new char[MAX_PATH];
GetTempPath(MAX_PATH,tmppath);
GetTempFileName(tmppath,"AnyServer",0,tmpname);//获得一个唯一的临时文件名
SaveBitmapToFile(hBitmap,tmpname);
return tmpname;
}
int CRemoteC::SaveBitmapToFile(HBITMAP hBitmap, LPSTR lpFileName)
{
//我们也可以把屏幕内容以位图格式存到磁盘文件上.
//lpFileName 为位图文件名
HDC hDC; //设备描述表
int iBits; //当前显示分辨率下每个像素所占字节数
WORD wBitCount; //位图中每个像素所占字节数
//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
DWORD dwPaletteSize=0,
dwBmBitsSize,
dwDIBSize, dwWritten;
BITMAP Bitmap; //位图属性结构
BITMAPFILEHEADER bmfHdr; //位图文件头结构
BITMAPINFOHEADER bi; //位图信息头结构
LPBITMAPINFOHEADER lpbi; //指向位图信息头结构
HANDLE fh, hDib, hPal,hOldPal=NULL;
//定义文件，分配内存句柄，调色板句柄
//计算位图文件每个像素所占字节数
hDC = CreateDC("DISPLAY",NULL,NULL,NULL);
iBits = GetDeviceCaps(hDC, BITSPIXEL)*GetDeviceCaps(hDC, PLANES);
DeleteDC(hDC);
if (iBits < = 1)
wBitCount = 1;
else if (iBits < = 4)
wBitCount = 4;
else if (iBits < = 8)
wBitCount = 8;
else if (iBits < = 32)
wBitCount = 24;
//计算调色板大小
if (wBitCount < = 8)
dwPaletteSize = (1 < < wBitCount) *
sizeof(RGBQUAD);
//设置位图信息头结构
GetObject(hBitmap, sizeof(BITMAP), (LPSTR)& Bitmap);
bi.biSize = sizeof(BITMAPINFOHEADER);
bi.biWidth = Bitmap.bmWidth;
bi.biHeight = Bitmap.bmHeight;
bi.biPlanes = 1;
bi.biBitCount = wBitCount;
bi.biCompression = BI_RGB;
bi.biSizeImage = 0;
bi.biXPelsPerMeter = 0;
bi.biYPelsPerMeter = 0;
bi.biClrUsed = 0;
bi.biClrImportant = 0;
dwBmBitsSize = ((Bitmap.bmWidth*wBitCount+31)/32)* 4*Bitmap.bmHeight ;
hDib = GlobalAlloc(GHND,dwBmBitsSize+dwPaletteSize+sizeof(BITMAPINFOHEADER));//为位图内容分配内存
lpbi = (LPBITMAPINFOHEADER)GlobalLock(hDib);
*lpbi = bi;
hPal=(HPALETTE)::GetStockObject(DEFAULT_PALETTE);// 处理调色板
if (hPal)
{
hDC = GetDC(NULL);
hOldPal = SelectPalette(hDC,(HPALETTE)hPal, FALSE);
RealizePalette(hDC);
}
// 获取该调色板下新的像素值
GetDIBits(hDC, hBitmap, 0, (UINT) Bitmap.bmHeight,
(LPSTR)lpbi + sizeof(BITMAPINFOHEADER)
+dwPaletteSize,
(BITMAPINFO *)
lpbi, DIB_RGB_COLORS);
//恢复调色板
if (hOldPal)
{
SelectPalette(hDC,(HPALETTE) hOldPal, TRUE);
RealizePalette(hDC);
ReleaseDC(NULL, hDC);
}
//创建位图文件
fh = CreateFile(lpFileName, GENERIC_WRITE,0, NULL, CREATE_ALWAYS,
FILE_ATTRIBUTE_NORMAL& brvbar;FILE_FLAG_SEQUENTIAL_SCAN, NULL);
if (fh == INVALID_HANDLE_VALUE)
return FALSE;
// 设置位图文件头
bmfHdr.bfType = 0x4D42; // "BM"
dwDIBSize = sizeof(BITMAPFILEHEADER)+sizeof(BITMAPINFOHEADER)
+ dwPaletteSize + dwBmBitsSize;
bmfHdr.bfSize = dwDIBSize;
bmfHdr.bfReserved1 = 0;
bmfHdr.bfReserved2 = 0;
bmfHdr.bfOffBits = (DWORD)sizeof
(BITMAPFILEHEADER)
+ (DWORD)sizeof(BITMAPINFOHEADER)
+ dwPaletteSize;
// 写入位图文件头
WriteFile(fh, (LPSTR)& bmfHdr, sizeof
(BITMAPFILEHEADER), & dwWritten, NULL);
// 写入位图文件其余内容
WriteFile(fh, (LPSTR)lpbi, dwDIBSize,
& dwWritten, NULL);
//清除
GlobalUnlock(hDib);
GlobalFree(hDib);
CloseHandle(fh);
return TRUE;
}
首先我们要确定屏幕截取的
区域,
用LPRECT结构来定义.可以截取一个窗口,或整个屏幕.以下代码把选定的屏幕区域
拷贝到
位图中.
HBITMAP CopyScreenToBitmap(LPRECT lpRect)
//lpRect 代表选定区域
{
HDC hScrDC, hMemDC;
// 屏幕和内存设备描述表
HBITMAP hBitmap, hOldBitmap;
// 位图句柄
int nX, nY, nX2, nY2;
// 选定区域坐标
int nWidth, nHeight;
// 位图宽度和高度
int xScrn, yScrn;
// 屏幕分辨率
// 确保选定区域不为空矩形
if (IsRectEmpty(lpRect))
return NULL;
//为屏幕创建设备描述表
hScrDC = CreateDC("DISPLAY", NULL, NULL, NULL);
//为屏幕设备描述表创建兼容的内存设备描述表
hMemDC = CreateCompatibleDC(hScrDC);
// 获得选定区域坐标
nX = lpRect- >left;
nY = lpRect- >top;
nX2 = lpRect- >right;
nY2 = lpRect- >bottom;
// 获得屏幕分辨率
xScrn = GetDeviceCaps(hScrDC, HORZRES);
yScrn = GetDeviceCaps(hScrDC, VERTRES);
//确保选定区域是可见的
if (nX < 0)
nX = 0;
if (nY < 0)
nY = 0;
if (nX2 > xScrn)
nX2 = xScrn;
if (nY2 > yScrn)
nY2 = yScrn;
nWidth = nX2 - nX;
nHeight = nY2 - nY;
// 创建一个与屏幕设备描述表兼容的位图
hBitmap = CreateCompatibleBitmap
(hScrDC, nWidth, nHeight);
// 把新位图选到内存设备描述表中
hOldBitmap = SelectObject(hMemDC, hBitmap);
// 把屏幕设备描述表拷贝到内存设备描述表中
BitBlt(hMemDC, 0, 0, nWidth, nHeight,
hScrDC, nX, nY, SRCCOPY);
//得到屏幕位图的句柄
hBitmap = SelectObject(hMemDC, hOldBitmap);
//清除
DeleteDC(hScrDC);
DeleteDC(hMemDC);
// 返回位图句柄
return hBitmap;
}
得到屏幕位图句柄以后,我们
可以把屏幕位图显示在窗口中
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