高手求救,存储位图出错

[sparrow429]

我是05的,用MFC,想要存储位图,请各位帮我看看代码

void CTraceWindowView::OnTestTest1()
{
// TODO: Add your command handler code here
CRect rc;
HBITMAP Bmp;
Bmp=CopyScreenToBitmap(&rc);
CFileDialog dlg(false,L"*.bmp",NULL,NULL,L"*.BMP|*.BMP||");
if(dlg.DoModal()==IDOK)
{
SaveBitmapToFile(Bmp,dlg.GetPathName());
//PostQuitMessage(0);
}


bool CTraceWindowView::SaveBitmapToFile(HBITMAP hBitmap, LPCTSTR lpFileName)
{
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(L"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 <= 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));
//这里出错.无法为位图分配内存
if(hDib == NULL)
{
MessageBox(NULL,L"错误", MB_OK);
return false;
}
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;


}

HBITMAP CTraceWindowView::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;
if (IsRectEmpty(lpRect))
return NULL;
//为屏幕创建设备描述表
hScrDC = CreateDC(L"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 = (HBITMAP)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=(HBITMAP)SelectObject(hMemDC, hOldBitmap);
//清除
DeleteDC(hScrDC);
DeleteDC(hMemDC);
// 返回位图句柄

return HBITMAP();
}
我知道是无法为位图分配内存这里出错,但是不知道怎么改,各位大哥多多援手啊!!

[sparrow429]

我顶,,来人啊

[whycom]

看看错误信息是什么？？

[whycom]

代码太长，没仔细看
hDib = GlobalAlloc(GHND, dwBmBitsSize + dwPaletteSize + sizeof(BITMAPINFOHEADER));
//这里出错.无法为位图分配内存
if(hDib == NULL)
{
LPVOID lpMsgBuf;
FormatMessage(
FORMAT_MESSAGE_ALLOCATE_BUFFER |
FORMAT_MESSAGE_FROM_SYSTEM |
FORMAT_MESSAGE_IGNORE_INSERTS,
NULL,
GetLastError(),
MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), // Default language
(LPTSTR) &lpMsgBuf,
0,
NULL )
AfxMessageBox( lpMsgBuf );
return ;

}

[sparrow429]

请问楼上的这么写有什么用呢?hDib得出来的值还是0x00000000(我的理解是没有分配内存),你这么改这个值又不会改变..

[sparrow429]

自己顶,怎么没人啊??

[sparrow429]

跳出错误是在*lpbi = bi;这里,就是说内存什么的...