请问如何将CBITMAP类上的位图保存到位图文件？
如上，另如何在保存之前设置位图的格式为黑白格式？ 问题点数：50、回复次数：1Top
1 楼wistaria（听风听雨）回复于 2002-08-02 10:33:55 得分 50
//try this
//lpfilename 为位图文件名
int SaveBitmapToFile(HBITMAP hbitmap , LPSTR lpfilename)
{
HDC hdc; //设备描述表
int ibits;
WORD wbitcount; //当前显示分辨率下每个像素所占字节数
//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
//定义文件，分配内存句柄，调色板句柄
HANDLE fh, hdib, hpal,holdpal=NULL;
//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 <= 16)
wbitcount = 16;
else if (ibits <= 24)
wbitcount = 24;
else
wbitcount = 32;
//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 ;
//为位图内容分配内存
hdib = GlobalAlloc(GHND,dwbmbitssize + dwpalettesize +
sizeof(BITMAPINFOHEADER));
lpbi = (LPBITMAPINFOHEADER)GlobalLock(hdib);
*lpbi = bi;
// 处理调色板
hpal = GetStockObject(DEFAULT_PALETTE);
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|
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;
}
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