Advanced MFC Programming

Chapter 6. Dialog Box
}
brush=(HBRUSH)::GetStockObject(GRAY_BRUSH);
break;
}
case CTLCOLOR_MSGBOX:
{
brush=(HBRUSH)::GetStockObject(LTGRAY_BRUSH);
break;
}
case CTLCOLOR_SCROLLBAR:
{
brush=(HBRUSH)::GetStockObject(GRAY_BRUSH);
break;
}
default: brush=CDialog::OnCtlColor(pDC, pWnd, nCtlColor);
}
return brush;
Stock Objects
In the above implementation, the background of different controls is painted using different brushes:
the button and static control have a transparent background; the background of the list box and scroll bar is
painted with a gray brush; the background of the message box is painted with a light gray brush. Here, all
the brushes are obtained through calling function ::GetStockObject(…) rather than being created by
ourselves.
In Windows, there are a lot of predefined stock objects that can be used. These objects include
brushes, pens, fonts and palette. The predefined brushes include white brush, black brush, gray brush, light
gray brush, dark gray brush, and null (hollow) brush. Function ::GetStockObject(…) will return a GDI
object handle (a brush handle in our sample). If we attach the returned handle to a GDI object, we must
detach it instead of deleting the object when it is no longer useful.
Text Foreground and Background
Now the edit box, static control and list box all have transparent background. But these controls also
contain text. Since a character also has both foreground and background areas (Figure 6-4), if we don’t set
the text’s drawing mode, its background area may be drawn with an undesirable color (Figure 6-5).
A
Foreground
color
Background color
Figure 6-4. Foreground and background color of a character
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