mfc动态显示图片

Posted 2021-01-22 rixiang

参考：https://blog.csdn.net/pudongdong/article/details/69396600

 

之前写过win32动态显示图片的博客，这次用到了mfc。原理是一样的。

 

OnInitDialog函数初始化

BOOL CXxxDlg::OnInitDialog()
{
    CDialog::OnInitDialog();
    if (m_bmp.m_hObject != NULL)
        m_bmp.DeleteObject();
    /*载入图片*/
    HBITMAP hbmp = (HBITMAP)::LoadImage(AfxGetInstanceHandle(),L"initPic.bmp", IMAGE_BITMAP, 0, 0, LR_CREATEDIBSECTION | LR_LOADFROMFILE);
    if (hbmp == NULL)
        return FALSE;
    /*取得加载的BMP的信息*/
    m_bmp.Attach(hbmp);
    DIBSECTION ds;
    BITMAPINFOHEADER &bminfo = ds.dsBmih;
    m_bmp.GetObject(sizeof(ds), &ds);
    int cx = bminfo.biWidth; 
    int cy = bminfo.biHeight; 
    /*得到了图像的宽度和高度后,对图像大小进行适应,即调整控件的大小,让它正好显示一张图片*/
    CRect rect;
    GetDlgItem(IDC_PIC_ZONE)->GetWindowRect(&rect);
    ScreenToClient(&rect);
    /*调整大小*/
    GetDlgItem(IDC_PIC_ZONE)->MoveWindow(rect.left, rect.top, cx, cy, true);
    return TRUE; 
}

 

OnPaint具体画图。

IDC_PIC_ZONE为picture control控件。

void CXxxDlg::OnPaint()
{
    if (m_bmp.m_hObject != NULL)
        m_bmp.DeleteObject();
    /*重新载入图片，因为可能刷新*/
    HBITMAP hbmp = (HBITMAP)::LoadImage(AfxGetInstanceHandle(), L"initPic.bmp", IMAGE_BITMAP, 0, 0, LR_CREATEDIBSECTION | LR_LOADFROMFILE);
    if (hbmp == NULL)
        return;
    /*取得加载的BMP的信息*/
    m_bmp.Attach(hbmp);
    DIBSECTION ds;
    BITMAPINFOHEADER &bminfo = ds.dsBmih;
    m_bmp.GetObject(sizeof(ds), &ds);
    /*若用此句,得到的是对话框的DC,图片将被绘制在对话框上*/
    //CPaintDC dc(this);    
    /*用此句,得到picture控件的DC,图像将被绘制在控件上  */
    CPaintDC dc(GetDlgItem(IDC_PIC_ZONE));
    /*若用此两句,得到的是屏幕的DC,图片将被绘制在屏幕上*/
    //  CDC dc;
    //  dc.m_hDC=::GetDC(NULL);  
    CRect rcclient;
    GetDlgItem(IDC_PIC_ZONE)->GetClientRect(&rcclient);
    CDC memdc;
    memdc.CreateCompatibleDC(&dc);
    CBitmap bitmap;
    bitmap.CreateCompatibleBitmap(&dc, rcclient.Width(), rcclient.Height());
    memdc.SelectObject(&bitmap);
    CWnd::DefWindowProc(WM_PAINT, (WPARAM)memdc.m_hDC, 0);
    CDC maskdc;
    maskdc.CreateCompatibleDC(&dc);
    CBitmap maskbitmap;
    maskbitmap.CreateBitmap(rcclient.Width(), rcclient.Height(), 1, 1, NULL);
    maskdc.SelectObject(&maskbitmap);
    maskdc.BitBlt(0, 0, rcclient.Width(), rcclient.Height(), &memdc,
        rcclient.left, rcclient.top, SRCCOPY);
    CBrush brush;
    brush.CreatePatternBrush(&m_bmp);
    dc.FillRect(rcclient, &brush);
    dc.BitBlt(rcclient.left, rcclient.top, rcclient.Width(), rcclient.Height(),
        &memdc, rcclient.left, rcclient.top, SRCPAINT);
    brush.DeleteObject();
}

 

 

注意，要想程序运行到OnPaint方法，需要在BEGIN_MESSAGE_MAP注册ON_WM_PAINT()

 

效果：