1、通過點(diǎn)擊瀏覽按鈕選擇BMP圖像文件
點(diǎn)擊瀏覽按鈕打開文件對(duì)話框選擇BMP圖像文件，得到文件所在的路徑目錄。
關(guān)鍵代碼如下：
void CShowBMPDlg::OnButtonSelectiamge()
...{
char szFilter[] = "BMP Files (*.bmp)|*.bmp|All Files (*.*)|*.*||";
CFileDialog dlg( TRUE,"BMP",NULL,OFN_HIDEREADONLY | OFN_OVERWRITEPROMPT,szFilter );
if(dlg.DoModal() == IDOK)
...{
strPathName = dlg.GetPathName();
LoadShowBMPFile(strPathName);
m_hBitmap = BufferToHBITMAP();
Invalidate();
}
}
通過得到的BMP圖像文件路徑目錄，加載BMP圖像文件到內(nèi)存中。
關(guān)鍵代碼如下：
BOOL CShowBMPDlg::LoadShowBMPFile(const char *pPathname)
...{
CFile file;
if( !file.Open( pPathname, CFile::modeRead) )
return FALSE;
DWORD m_nFileLen;
m_nFileLen = file.GetLength();
m_pBMPBuffer = new char[m_nFileLen + 1];
if(!m_pBMPBuffer)
return FALSE;
if(file.Read(m_pBMPBuffer,m_nFileLen) != m_nFileLen)
return FALSE;
return TRUE;
}
將內(nèi)存中的BMP文件內(nèi)容轉(zhuǎn)換成位圖句柄。
關(guān)鍵代碼如下：
HBITMAP CShowBMPDlg::BufferToHBITMAP()
...{
HBITMAP hShowBMP;
LPSTR hDIB,lpBuffer = m_pBMPBuffer;
LPVOID lpDIBBits;
BITMAPFILEHEADER bmfHeader;
DWORD bmfHeaderLen;
bmfHeaderLen = sizeof(bmfHeader);
strncpy((LPSTR)&bmfHeader,(LPSTR)lpBuffer,bmfHeaderLen);
if (bmfHeader.bfType != (*(WORD*)"BM")) return NULL;
hDIB = lpBuffer + bmfHeaderLen;
BITMAPINFOHEADER &bmiHeader = *(LPBITMAPINFOHEADER)hDIB ;
BITMAPINFO &bmInfo = *(LPBITMAPINFO)hDIB ;
m_bmW = bmiHeader.biWidth;
m_bmH = bmiHeader.biHeight;
lpDIBBits=(lpBuffer)+((BITMAPFILEHEADER *)lpBuffer)->bfOffBits;
CClientDC dc(this);
hShowBMP = CreateDIBitmap(dc.m_hDC,&bmiHeader,CBM_INIT,lpDIBBits,&bmInfo,DIB_RGB_COLORS);
return hShowBMP;
}
雙緩沖實(shí)現(xiàn)BMP位圖顯示在屏幕上。
關(guān)鍵代碼如下：
void CShowBMPDlg::DrawImage(int x, int y, CDC *pDC)
...{
HBITMAP OldBitmap;
CDC MemDC;
MemDC.CreateCompatibleDC(pDC);
OldBitmap=(HBITMAP)MemDC.SelectObject(m_hBitmap);
CBitmap* pBitmap = CBitmap::FromHandle(m_hBitmap);
if(m_bmW == 0 || m_bmH == 0)
return ;
CRect rect;
GetClientRect(&rect);
/**//*str.Format("%d %d", rect.Width(),rect.Height());
MessageBox(str);*/
pDC->BitBlt(x,y,rect.Width(),rect.Height(),&MemDC,0,0,SRCCOPY);
GetRGB(MemDC);
MemDC.SelectObject(OldBitmap);
}
