Advanced MFC Programming

Chapter 9. Font
Variables m_nSelIndexBgnOld and m_nSelIndexEndOld are used to remember the old selection indices,
functions GetSelIndexBgnOld() and GetSelIndexEndOld() are used to obtain their values outside class
CGDIDoc. Because we also need to know the value of m_nCaretIndex when updating the client window,
another function GetCaretIndex() is also added for retrieving its value.
Old selection:
Old selection:
New selection:
New selection:
Difference:
Difference:
Selected area
Area needs to be updated
Figure 9-5. Text selection and window update
The value of m_nSelIndexEndOld is initialized in the constructor:
……
CGDIDoc::CGDIDoc()
{
}
m_nSelIndexEndOld=-1;
In the sample, some macros are defined as follows to indicate different updating situations when
function CDocument::UpdateAllViews(…) is called:
#define HINT_DELCHAR_AFTER 100
#define HINT_DELCHAR_BEFORE 101
#define HINT_DELETE_SELECTION 102
#define HINT_PASTE 103
#define HINT_SELECTION 104
#define HINT_UNSELECTION 105
#define HINT_INPUT 106
Calling Function CDocument::UpdateAllViews(…)
We must modify all the function calls to CDocument::UpdateAllViews(…). The following shows the
modifications made to function CGDIDoc::SetCaret(…):
Old Version:
……
void CGDIDoc::SetCaret(CPoint point)
{
}
if(m_nSelIndexBgn == -1)m_nSelIndexBgn=m_nCaretIndex;
else
{
m_nSelIndexEnd=m_nCaretIndex;
UpdateAllViews(NULL);
}
GetCGDIView()->RedrawCaret();
New Version:
274