Advanced MFC Programming

Chapter 6. Dialog Box
int ::GetSystemMetrics(int nIndex);
Possible Value of nIndex
Meaning
SM_CXBORDER, SM_CYBORDER Width and height of the window border
SM_CXCURSOR, SM_CYCURSOR Width and height of the cursor
SM_CXDLGFRAME, SM_CYDLGFRAME Width and height of the non-resizable dialog box frame
SM_CXFULLSCREEN,
Width and height of the desktop screen
SM_CYFULLSCREEN
SM_CXICON, SM_CYICON Width and height of the icon (usually 32×32)
SM_CXSMICON, SM_CYSMICON Width and height of the small icon (usually 16×16)
SM_CYCAPTION
Height of the caption area
In the sample, the maximized size of the dialog is set to 1/4 of the desk top screen size. When the
application is first maximized, it will be positioned at top-left corner (0, 0).
The dialog box’s initial size is set in function CDialog::OnInitDialog():
……
BOOL CDBDlg::OnInitDialog()
{
RECT rect;
rect.left=0;
rect.top=0;
rect.right=MIN_X_SIZE;
rect.bottom=MIN_Y_SIZE;
MapDialogRect(&rect);
rect.right+=50;
rect.bottom+=50;
MoveWindow(&rect);
CenterWindow();
}
return TRUE;
The dialog box’s initial size is a little bigger than its minimum tracking size.
The above sizes are not unique to dialog boxes. In fact, any window has the above sizes, and can be
customized with the same method.
6.5 Customizing Dialog Box Background
Background Drawing
Generally all dialog boxes have a gray background. Sometimes it is more desirable to change dialog
box’s background to a custom color, or, we may want to paint the background using a repeated pattern. To
customize a dialog box’s background, we need to handle message WM_ERASEBKGND, and draw the custom
background after receiving this message. All classes that are derived from CWnd will inherit function
CWnd::OnEraseBkgnd(…), which has the following format:
BOOL CWnd::OnEraseBkgnd(CDC *pDC)
{
}
Here, pointer pDC can be used to draw anything on the target window. For example, we can create
solid brush and paint the background with a custom color, or we can create pattern brush, and paint the
background with certain pattern. Of course, bitmap can also be used here: we can draw our own bitmap
repeatedly until all of the dialog box area is covered by the bitmap patterns.
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