Prepare for mutlicolumn lines

The \multicolumn command allows to set vertical lines for individual rows.
These are not yet displayed, but if they are supported one day, the code in
a27ff13663 needs to be adjusted. This change hints at the adjustment.

diff --git a/src/mathed/InsetMathGrid.cpp b/src/mathed/InsetMathGrid.cpp
index 4e9de1de1034f8d01524220e2624da7b03de737d..3d60683a9bf2bce26042d99cf6d271928822d109 100644 (file)
--- a/src/mathed/InsetMathGrid.cpp
+++ b/src/mathed/InsetMathGrid.cpp
@@ -636,10 +636,13 @@ void InsetMathGrid::drawWithMargin(PainterInfo & pi, int x, int y,
                                                - i * vlinesep()
                                                - vlinesep()/2 - colsep()/2;
                                        int top_offset;
-                                       if (r > 0)
+                                       // prevRowHasLine needs to be changed if multicolumn lines are supported
+                                       bool const prevRowHasLine(r > 0);
+                                       if (prevRowHasLine)
+                                               // start from offset of previous row to create a continous line
                                                top_offset = rowinfo_[r - 1].offset_ + rowinfo_[r - 1].descent_;
                                        else
-                                               top_offset = rowinfo_[0].offset_- rowinfo_[0].ascent_;
+                                               top_offset = rowinfo_[r].offset_- rowinfo_[r].ascent_;
                                        pi.pain.line(xx, y + top_offset,
                                                xx, y + rowinfo_[r].offset_ + rowinfo_[r].descent_,
                                                Color_foreground);