Advanced MFC Programming

Chapter 3. Splitter Window
In the above functions, parameters row and col are used to identify a pane with specified row and
column indices, cyIdeal and cxIdeal are the ideal size of a pane, cyMin and cxMin indicate minimum size
of it.
When the splitter window is being displayed, each pane’s dimension is decided from its ideal size.
According to the current size of the frame window, some panes may be set to their ideal sizes, but some
may not (This depends on how much space is left for that pane). In any case, a pane’s actual size should not
be smaller than its minimum size. This is why we need both ideal size and minimum size to set a row or
column’s dimension.
The number of rows and columns a splitter window currently has can be obtained by calling other two
member functions of CSplitterWnd:
int CSplitterWnd::GetRowCount();
int CSplitterWnd::GetColumnCount();
After we call function CSplitterWnd::SetColumnInfo(…) or CSplitterWnd::SetRowInfo(…), the old
layout will not change until we call function CSplitterWnd::RecalcLayout() to update the splitter
window. The system will re-calculate the layout for each pane according to their new sizes (both ideal size
and minimum size), and the split bar will be moved to a new position according to the new layout.
Overriding CSplitterWnd::DeleteRow(…) and CSplitterWnd::
DeleteColumn(…)
Sample 3.3\Spw is based on sample 3.2\Spw. In the new sample, the behavior of the split bar is
modified: if the user double clicks on it, it will move a small step downward (for horizontal split bar) or
rightward (for vertical split bar). A pane will be deleted after it reaches its minimum size.
In the sample application, first a new class MCSplitterWnd is derived from class CSplitterWnd:
class MCSplitterWnd : public CSplitterWnd
{
public:
void DeleteRow(int);
void DeleteColumn(int);
};
The class does nothing but overriding two functions. The implementation of function MCSplitterWnd
::DeleteRow(…) is listed as follows:
void MCSplitterWnd::DeleteRow(int rowDelete)
{
int nNumRows;
nNumRows=GetRowCount();
if(nNumRows < 2)
{
CSplitterWnd::DeleteRow(rowDelete);
}
else
{
int nCyCur, nCyMin;
GetRowInfo(0, nCyCur, nCyMin);
nCyCur+=ONE_STEP_MOVE;
SetRowInfo(0, nCyCur, nCyMin);
GetRowInfo(1, nCyCur, nCyMin);
nCyCur-=ONE_STEP_MOVE;
if(nCyCur < nCyMin)
{
CSplitterWnd::DeleteRow(rowDelete);
}
else
{
SetRowInfo(1, nCyCur, nCyMin);
63