Advanced MFC Programming

Chapter 9. Font
}
dlg.m_bBgdStyle=m_bTransparentBgd;
if(dlg.DoModal() == IDOK)
{
lf.lfOrientation=lf.lfEscapement=dlg.m_lEsp;
m_bTransparentBgd=dlg.m_bBgdStyle;
if(m_fontDraw.GetSafeHandle() != NULL)m_fontDraw.DeleteObject();
ASSERT(m_fontDraw.CreateFontIndirect(&lf));
UpdateAllViews(NULL);
}
First function CFont::GetLogFont(…) is called to retrieve the information of the current font, which is
then stored in a LOGFONT type object. Before the dialog box is invoked, its members CStyleDlg::m_lEsp
and CStyleDlg::m_bBgdStyle are initialized so that the current font’s escapement angle and background
style will be displayed in the dialog box. After function CDialog::DoModal() is called, the new value of
CStyleDlg::m_lEsp is stored back to members lfEscapement and lfOrientation of structure LOGFONT,
and the new value of CStyleDlg::m_bBgdStyle is stored to variable CGDIDoc::m_bTransparentBgd. Then
the old font is deleted and the new font is created. Finally, function CGDIDoc::UpdateAllViews(…) is called
to update the client window.
When we call function CDocument::UpdateAllViews(…), the associated view’s member function
OnDraw(…) will be called automatically. So we need to modify this function to display the font specified by
variable CGDIDoc::m_fontDraw. The following is the implementation of function CGDIView::OnDraw():
void CGDIView::OnDraw(CDC* pDC)
{
CFont *ptrFt;
CFont *ptrFtOld;
CRect rect;
LOGFONT logFont;
}
CGDIDoc* pDoc=GetDocument();
ASSERT_VALID(pDoc);
ptrFt=pDoc->GetCurrentFont();
ASSERT(ptrFt != NULL);
if(ptrFt->GetSafeHandle() != NULL)
{
ptrFt->GetLogFont(&logFont);
ptrFtOld=pDC->SelectObject(ptrFt);
pDC->SetTextColor(pDoc->GetFontColor());
pDC->SetBkMode(pDoc->GetBgdStyle() ? TRANSPARENT:OPAQUE);
pDC->SetBkColor((~pDoc->GetFontColor())&0x00FFFFFF);
}
GetClientRect(rect);
pDC->TextOut(rect.Width()/4, rect.Height()/4, logFont.lfFaceName);
if(ptrFt->GetSafeHandle() != NULL)pDC->SelectObject(ptrFtOld);
First, function CGDIDoc::GetCurrentFont() is called to retrieve the currently selected font from the
document, then function CFont::GetLogFont(…) is called to retrieve the information of this font (the face
name of the font will be used as the output string). Next, the font is selected into the target DC. Also,
CGDIDoc::GetFontColor() is called to retrieve the current font color, and CDC::SetTextColor(…) is called
to set the text foreground color. Then, CGDIDoc::GetBgdStyle(…) is called to see if the text should be
drawn with an opaque or transparent background, and CDC::SetBkMode(…) is called to set the background
style. Next, the text background color is set to the inverse of the foreground color by calling function
CDC::SetBkColor(…) (If text background style is transparent, this operation has no effect). Finally, function
CDC::TextOut(…) is called to display font’s face name in the client window, and the font is selected out of
the DC.
The default font displayed in the client window should be “System”, which is not a True Type font. To
see how a text can be displayed with different escapement angles, we need to choose a True Type font such
as “Arial”. Please note that the unit of the escapement angle is on tenth of a degree, so if we want to display
the text vertically, escapement angle should be set to 900.
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