使用位图数据直接绘图

使用位图数据直接绘图
StretchDIBits()函数
1:定义BYTE *m_date;
2:在按钮对应的函数中
void CBitmapDlg::OnButton1()
{
CFileDialog fl(true,"bmp","",OFN_HIDEREADONLY|OFN_OVERWRITEPROMPT,"位图文件|*bmp||");
if(fl.DoModal()==IDOK)
{
CString filename=fl.GetPathName();
CFile file;
file.Open(filename,CFile::modeReadWrite);
DWORD dwlen=file.GetLength();//获取文件长度
file.Seek(14,CFile::begin); //略过位图头文件
if(m_date)
{
delete[]m_date;
m_date=NULL;
}
m_date=new BYTE[dwlen-14];
file.Read(m_date,dwlen-14);//读取文件到缓冲区
file.Close();
OnPaint();

}
}
在OnPaint()中
else
{
if(m_date)
{
BYTE *pheader=m_date;
BITMAPINFO bitinfo;
memset(&bitinfo,0,sizeof(BITMAPINFO));
memcpy(&bitinfo,pheader,sizeof(BITMAPINFO));
int width=bitinfo.bmiHeader.biWidth;
int height=bitinfo.bmiHeader.biHeight;
pheader+=40;
StretchDIBits(GetDC->m_hDC,10,40,width,height,0,0,width,height,pheader,&bitinfo,DIB_RGB_COLORS,SRCCOPY);
}
CDialog::OnPaint();
}