+// helper function used in CalcMin() to sum up the sizes of non-hidden items
+static int SumArraySizes(const wxArrayInt& sizes, int gap)
+{
+ // Sum total minimum size, including gaps between rows/columns.
+ // -1 is used as a magic number meaning empty row/column.
+ int total = 0;
+
+ const size_t count = sizes.size();
+ for ( size_t n = 0; n < count; n++ )
+ {
+ if ( sizes[n] != -1 )
+ {
+ if ( total )
+ total += gap; // separate from the previous column
+
+ total += sizes[n];
+ }
+ }
+
+ return total;
+}
+
+void wxFlexGridSizer::FindWidthsAndHeights(int nrows, int ncols)
+{
+ // We have to recalculate the sizes in case the item minimum size has
+ // changed since the previous layout, or the item has been hidden using
+ // wxSizer::Show(). If all the items in a row/column are hidden, the final
+ // dimension of the row/column will be -1, indicating that the column
+ // itself is hidden.
+ m_rowHeights.assign(nrows, -1);
+ m_colWidths.assign(ncols, -1);
+
+ // n is the index of the item in left-to-right top-to-bottom order
+ size_t n = 0;
+ for ( wxSizerItemList::iterator i = m_children.begin();
+ i != m_children.end();
+ ++i, ++n )
+ {
+ wxSizerItem * const item = *i;
+ if ( item->IsShown() )
+ {
+ // NOTE: Not doing the calculation here, this is just
+ // for finding max values.
+ const wxSize sz(item->GetMinSizeWithBorder());
+
+ const int row = n / ncols;
+ const int col = n % ncols;
+
+ if ( sz.y > m_rowHeights[row] )
+ m_rowHeights[row] = sz.y;
+ if ( sz.x > m_colWidths[col] )
+ m_colWidths[col] = sz.x;
+ }
+ }
+
+ AdjustForFlexDirection();
+
+ m_calculatedMinSize = wxSize(SumArraySizes(m_colWidths, m_hgap),
+ SumArraySizes(m_rowHeights, m_vgap));
+}
+