Q149407: HOWTO: How to Display a Bitmap in a CStatusBar Pane
Article: Q149407
Product(s): Microsoft C Compiler
Version(s): winnt:1.0,2.0,2.1,2.2,4.0,4.1
Operating System(s):
Keyword(s): kbBitmap kbMFC kbStatBar KbUIDesign kbVC kbGrpDSMFCATL kbMFCCtrlBar
Last Modified: 30-JUL-2001
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The information in this article applies to:
- The Microsoft Foundation Classes (MFC), used with:
- Microsoft Visual C++ for Windows, 16-bit edition, versions 1.0, 1.5, 1.51, 1.52
- Microsoft Visual C++, 32-bit Editions, versions 1.0, 2.0, 2.1, 2.2, 4.0, 4.1
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SUMMARY
=======
The standard status bar in an MFC application easily allows the application to
display its status. Sometimes it is a good idea to display the status using
bitmaps or other graphic entities. MFC's CStatusBar class directly supports
displaying text, but not graphics, in its panes. This article shows by example
how to display a bitmap in a CStatusBar pane.
MORE INFORMATION
================
It is not very difficult to display a bitmap in a status bar pane. The code at
the end of this article will let you display a bitmap in pane 1 of the status
bar. Put the code in a Default AppWizard application, and add a new pane to the
status bar before the standard panes. Please refer to online documentation for
CStatusBar for information on how to add a pane to the status bar.
With Visual C++ 4.0 and later, MFC's CStatusBar uses the status window common
control. In earlier versions, CStatusBar was implemented in MFC. Hence the code
required for displaying bitmap in a CStatusBar pane is different.
You can add the sample code to an application built with an earlier version of
Visual C++ (a version previous to 4.0), and then recompile the application using
Visual C++ 4.0 without modifying the code. If you are using Visual C++ 4.0 or
later, you need not add code between the
#if _MFC_VER < 0x400
...
#endif
directives.
Step-by-Step Example and Sample Code
------------------------------------
1. Derive a class from CStatusBar (for example, CMyStatusBar), and use this
class instead of CStatusBar in CMainFrame.
2. Add the following member functions to the class definition in the .h file:
class CMyStatusBar : public CStatusBar
{
...
#if _MFC_VER < 0x400
virtual void DoPaint(CDC* pDC);
#endif
#if _MFC_VER >= 0x400
virtual void DrawItem(LPDRAWITEMSTRUCT lpDrawItemStruct);
#endif
...
}
3. Add the following code for the functions in the .cpp file:
#if _MFC_VER < 0x400
void CMyStatusBar::DoPaint(CDC* pDC)
{
CRect rect;
GetItemRect(1, &rect); // get pane rect
pDC->ExcludeClipRect(&rect); // exclude pane rect from paint
CStatusBar::DoPaint(pDC); // paint remainder of status bar
CRgn paneRgn;
paneRgn.CreateRectRgnIndirect(rect);
pDC->SelectClipRgn(&paneRgn); // set clip region to pane rect
CBitmap* pBitmap = /* pointer to current CBitmap */;
CDC srcDC; // select current bitmap into a compatible CDC
srcDC.CreateCompatibleDC(NULL);
CBitmap* pOldBitmap = srcDC.SelectObject(pBitmap);
pDC->BitBlt(rect.left, rect.top, rect.Width(), rect.Height(),
&srcDC, 0, 0, SRCCOPY); // BitBlt to pane rect
srcDC.SelectObject(pOldBitmap);
}
#endif
#if _MFC_VER >= 0x400
void CMyStatusBar::DrawItem(LPDRAWITEMSTRUCT lpDrawItemStruct)
{
switch(lpDrawItemStruct->itemID)
{
case 1:
// Attach to a CDC object
CDC dc;
dc.Attach(lpDrawItemStruct->hDC);
// Get the pane rectangle and calculate text coordinates
CRect rect(&lpDrawItemStruct->rcItem);
CBitmap* pBitmap = /* pointer to current CBitmap */;
CDC srcDC; // select current bitmap into a compatible CDC
srcDC.CreateCompatibleDC(NULL);
CBitmap* pOldBitmap = srcDC.SelectObject(pBitmap);
dc.BitBlt(rect.left, rect.top, rect.Width(), rect.Height(),
&srcDC, 0, 0, SRCCOPY); // BitBlt to pane rect
srcDC.SelectObject(pOldBitmap);
// Detach from the CDC object, otherwise the hDC will be
// destroyed when the CDC object goes out of scope
dc.Detach();
return;
}
CStatusBar::DrawItem(lpDrawItemStruct);
}
#endif
4. Add the following code to CMainFrame::OnCreate().
int CMainFrame::OnCreate(LPCREATESTRUCT lpCreateStruct)
{
...
if (!m_wndStatusBar.Create(this) ||
!m_wndStatusBar.SetIndicators(indicators,
sizeof(indicators)/sizeof(UINT)))
TRACE0("Failed to create status bar\n");
return -1; // fail to create
}
// Add the following code
#if _MFC_VER >= 0x400
UINT nID, nStyle;
int cxWidth;
m_wndStatusBar.GetPaneInfo(1, nID, nStyle, cxWidth);
m_wndStatusBar.SetPaneInfo(1, nID, nStyle | SBT_OWNERDRAW,
cxWidth);
#endif
...
}
REFERENCES
==========
Visual C++ Books Online and the Windows SDK docuemntation.
Additional query words: kbinf 1.00 1.50 1.51 1.52 2.00 2.10 2.20 2.50 2.51 2.52 3.00 3.10 3.20 4.00 4.10
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Keywords : kbBitmap kbMFC kbStatBar KbUIDesign kbVC kbGrpDSMFCATL kbMFCCtrlBar
Technology : kbAudDeveloper kbMFC
Version : winnt:1.0,2.0,2.1,2.2,4.0,4.1
Issue type : kbhowto
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