HBITMAP CopyScreenToBitmap(LPRECT lpRect)
//lpRect 代表選定區域
{
HDC hScrDC, hMemDC;
// 屏幕和內存設備描述表
HBITMAP hBitmap, hOldBitmap;
// 位圖句柄
int nX, nY, nX2, nY2;
// 選定區域座標
int nWidth, nHeight;
// 位圖寬度和高度
int xScrn, yScrn;
// 屏幕分辨率
// 確保選定區域不爲空矩形
if (IsRectEmpty(lpRect))
return NULL;
//爲屏幕創建設備描述表
hScrDC = CreateDC("DISPLAY", NULL, NULL, NULL);
//爲屏幕設備描述表創建兼容的內存設備描述表
hMemDC = CreateCompatibleDC(hScrDC);
// 獲得選定區域座標
nX = lpRect->left;
nY = lpRect->top;
nX2 = lpRect->right;
nY2 = lpRect->bottom;
// 獲得屏幕分辨率
xScrn = GetDeviceCaps(hScrDC, HORZRES);
yScrn = GetDeviceCaps(hScrDC, VERTRES);
//確保選定區域是可見的
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;
// 創建一個與屏幕設備描述表兼容的位圖
hBitmap = CreateCompatibleBitmap
(hScrDC, nWidth, nHeight);
// 把新位圖選到內存設備描述表中
hOldBitmap = (HBITMAP)SelectObject(hMemDC, hBitmap);
// 把屏幕設備描述表拷貝到內存設備描述表中
BitBlt(hMemDC, 0, 0, nWidth, nHeight,
hScrDC, nX, nY, SRCCOPY);
//得到屏幕位圖的句柄
hBitmap = (HBITMAP)SelectObject(hMemDC, hOldBitmap);//這個時候可以把得到的句柄交給savebitmaptofile保存到文件,我在這裏繼續偷懶寫
//清除
BITMAPINFOHEADER bih;
bih.biSize =sizeof(BITMAPINFOHEADER);
bih.biWidth =800;
bih.biHeight = 600;
bih.biPlanes = 1;
bih.biBitCount= 8;//8bit bitmap
bih.biCompression = BI_RGB;
bih.biSizeImage = 0;
bih.biXPelsPerMeter =0;
bih.biYPelsPerMeter = 0;
bih.biClrUsed = 0;
bih.biClrImportant = 0;
DWORD dwBmBitsSize=800*600*8/8;
HANDLE hDib=GlobalAlloc(GHND,dwBmBitsSize+256*sizeof(RGBQUAD)+sizeof(BITMAPINFOHEADER));//分配內存,GlobalAlloc分配內存能夠和dll程序共享分配的內存(可以由非c++編譯的dll釋放),malloc的話只能有c++自己知道怎麼釋放
//分配的內容包括 BITMAPINFOHEADER + PALETTE(調色板) + 位圖內容
LPVOID ptr=(LPVOID)GlobalLock(hDib);
*(BITMAPINFOHEADER*)ptr=bih;//保存那個BITMAPINFOHEADER到我們分配的內存
HDC xdc=GetDC(NULL);
//HPALETTE hPal= (HPALETTE)GetStockObject(DEFAULT_PALETTE);
//HPALETTE hOldPal=(HPALETTE)SelectPalette(xdc,hPal,FALSE);
//RealizePalette(xdc);
if(!GetDIBits(hScrDC,hBitmap,0,600,
(LPSTR)ptr+sizeof(BITMAPINFOHEADER)+256*sizeof(RGBQUAD),
(BITMAPINFO *)ptr,
DIB_RGB_COLORS))
//參數說明 從哪個dc(一定要有正確的PALETTE) ,位圖句柄,從哪一行(scanline),保存多少行,保存位圖內容的地方,一個保存BITMAPINFO結構(GetDIBits會幫我們完善該死的PALETTE),顏色的表示方式,要得到bmp就一定要DIB_RGB_COLORS
{
return hBitmap;//如果GetDIBits 返回0那就失敗了……
}
HANDLE fh = CreateFile("c://b.bmp", GENERIC_WRITE,
0, NULL, CREATE_ALWAYS,
FILE_ATTRIBUTE_NORMAL | FILE_FLAG_SEQUENTIAL_SCAN,
NULL);
if (fh == INVALID_HANDLE_VALUE)
return FALSE;
// 設置位圖文件頭
BITMAPFILEHEADER bmfHdr;
bmfHdr.bfType = 0x4D42; // "BM"
DWORD dwDIBSize = sizeof(BITMAPFILEHEADER)
+ sizeof(BITMAPINFOHEADER)
+ 256*sizeof(RGBQUAD) + dwBmBitsSize;
bmfHdr.bfSize = dwDIBSize;
bmfHdr.bfReserved1 = 0;
bmfHdr.bfReserved2 = 0;
bmfHdr.bfOffBits = (DWORD)sizeof
(BITMAPFILEHEADER)
+ (DWORD)sizeof(BITMAPINFOHEADER)
+ 256*sizeof(RGBQUAD);
// 寫入位圖文件頭
DWORD dwWritten;
WriteFile(fh, (LPSTR)&bmfHdr, sizeof
(BITMAPFILEHEADER), &dwWritten, NULL);
// 寫入位圖文件其餘內容
WriteFile(fh, (LPSTR)ptr, dwDIBSize,
&dwWritten, NULL);
DeleteDC(hScrDC);
DeleteDC(hMemDC);
// 返回位圖句柄
return hBitmap;
}
int SaveBitmapToFile(HBITMAP hBitmap ,
LPSTR lpFileName) //hBitmap 爲剛纔的屏幕位圖句柄
{ //lpFileName 爲位圖文件名
HDC hDC;
//設備描述表
int iBits;
//當前顯示分辨率下每個像素所佔字節數
WORD wBitCount;
//位圖中每個像素所佔字節數
//定義調色板大小, 位圖中像素字節大小 ,
//位圖文件大小 , 寫入文件字節數
DWORD dwPaletteSize=0,
dwBmBitsSize,
dwDIBSize, dwWritten;
BITMAP Bitmap;
//位圖屬性結構
BITMAPFILEHEADER bmfHdr;
//位圖文件頭結構
BITMAPINFOHEADER bi;
//位圖信息頭結構
LPBITMAPINFOHEADER lpbi;
//指向位圖信息頭結構
HANDLE fh, hDib;
HPALETTE hPal,hOldPal=NULL;
//定義文件,分配內存句柄,調色板句柄
//計算位圖文件每個像素所佔字節數
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
wBitCount = 24;
//計算調色板大小
wBitCount=8;
if (wBitCount <= 8)
dwPaletteSize = (1 << wBitCount) *
sizeof(RGBQUAD);
//設置位圖信息頭結構
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 ;
//爲位圖內容分配內存
hDib = GlobalAlloc(GHND,dwBmBitsSize+
dwPaletteSize+sizeof(BITMAPINFOHEADER));
lpbi = (LPBITMAPINFOHEADER)GlobalLock(hDib);
*lpbi = bi;
// 處理調色板
hPal = (HPALETTE)GetStockObject(DEFAULT_PALETTE);
if (hPal)
{
hDC = GetDC(NULL);
hOldPal = SelectPalette(hDC, hPal, FALSE);
RealizePalette(hDC);
}
// 獲取該調色板下新的像素值
GetDIBits(hDC, hBitmap, 0, (UINT) Bitmap.bmHeight,
(LPSTR)lpbi + sizeof(BITMAPINFOHEADER)
+dwPaletteSize,
(BITMAPINFO *)lpbi,
DIB_RGB_COLORS);
//恢復調色板
if (hOldPal)
{
SelectPalette(hDC, hOldPal, TRUE);
RealizePalette(hDC);
ReleaseDC(NULL, hDC);
}
//創建位圖文件
fh = CreateFile(lpFileName, GENERIC_WRITE,
0, NULL, CREATE_ALWAYS,
FILE_ATTRIBUTE_NORMAL | FILE_FLAG_SEQUENTIAL_SCAN
, NULL);
if (fh == INVALID_HANDLE_VALUE)
return FALSE;
// 設置位圖文件頭
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;
// 寫入位圖文件頭
WriteFile(fh, (LPSTR)&bmfHdr, sizeof
(BITMAPFILEHEADER), &dwWritten, NULL);
// 寫入位圖文件其餘內容
WriteFile(fh, (LPSTR)lpbi, dwDIBSize,
&dwWritten, NULL);
//清除
GlobalUnlock(hDib);
GlobalFree(hDib);
CloseHandle(fh);
}
//我也是半懂不懂的狀態..