[LyX/master] Attempt to reflect tabular width in workarea

[Juergen Spitzmueller]

commit e5c79a43ee78192f45a9ab34873f8bb426b5f37e
Author: Juergen Spitzmueller <sp...@lyx.org>
Date:   Mon Jul 2 17:05:46 2018 +0200

    Attempt to reflect tabular width in workarea
    
    This is not perfect, since variable width columns will break at a certain
    treshold, but it is better than what we have now (no tabular width
    indication at all)
---
 src/insets/InsetTabular.cpp |   45 +++++++++++++++++++++++++++++++++++++++++-
 src/insets/InsetTabular.h   |    2 +-
 2 files changed, 44 insertions(+), 3 deletions(-)

diff --git a/src/insets/InsetTabular.cpp b/src/insets/InsetTabular.cpp
index a25f4d6..7cb486f 100644
--- a/src/insets/InsetTabular.cpp
+++ b/src/insets/InsetTabular.cpp
@@ -1029,15 +1029,54 @@ int Tabular::cellHeight(idx_type cell) const
 }
 
 
-bool Tabular::updateColumnWidths()
+bool Tabular::updateColumnWidths(MetricsInfo & mi)
 {
        vector<int> max_dwidth(ncols(), 0);
+       // collect max. fixed width of column
+       map<col_type, int> max_pwidth;
+       // collect max. variable width of column
+       map<col_type, int> max_width;
+       
        for(col_type c = 0; c < ncols(); ++c)
                for(row_type r = 0; r < nrows(); ++r) {
                        idx_type const i = cellIndex(r, c);
                        if (getAlignment(i) == LYX_ALIGN_DECIMAL)
                                max_dwidth[c] = max(max_dwidth[c], 
cell_info[r][c].decimal_width);
+                       if (!getPWidth(i).zero())
+                               max_pwidth[c] = max(max_pwidth[c], 
cell_info[r][c].width);
+                       else
+                               max_width[c] = max(max_width[c], 
cell_info[r][c].width);
+               }
+
+       // If we have a fixed tabular width, we take this into account
+       int restwidth = -1;
+       if (!tabular_width.zero()) {
+               restwidth = mi.base.inPixels(tabular_width);
+               // Substract the fixed widths from the table width
+               for (auto const w : max_pwidth)
+                       restwidth -= w.second;
+       }
+
+       // If we have a fixed width, distribute the available table width
+       // (minus the fixed widths) to the variable-width columns
+       int vcolwidth = -1;
+       int restcols = ncols() - max_pwidth.size();
+       if (restwidth > 0)
+               vcolwidth = restwidth / restcols;
+
+       // Now consider that some variable width columns exceed the vcolwidth
+       if (vcolwidth > 0) {
+               bool changed = false;
+               for (auto const w : max_width) {
+                       if (w.second > vcolwidth) {
+                               --restcols;
+                               restwidth -= w.second;
+                               changed = true;
+                       }
                }
+               if (changed && restwidth > 0)
+                       vcolwidth = restwidth / restcols;
+       }
 
        bool update = false;
        // for each col get max of single col cells
@@ -1050,6 +1089,8 @@ bool Tabular::updateColumnWidths()
                                        && cell_info[r][c].decimal_width != 0)
                                        new_width = max(new_width, 
cellInfo(i).width
                                                + max_dwidth[c] - 
cellInfo(i).decimal_width);
+                               else if (getPWidth(i).zero() && vcolwidth > 0)
+                                       new_width = max(vcolwidth, 
max(new_width, cellInfo(i).width));
                                else
                                        new_width = max(new_width, 
cellInfo(i).width);
                        }
@@ -4006,7 +4047,7 @@ void InsetTabular::metrics(MetricsInfo & mi, Dimension & 
dim) const
                tabular.setRowDescent(r, maxdes + ADD_TO_HEIGHT + bottom_space);
        }
 
-       tabular.updateColumnWidths();
+       tabular.updateColumnWidths(mi);
        dim.asc = tabular.rowAscent(0) - tabular.offsetVAlignment();
        dim.des = tabular.height() - dim.asc;
        dim.wid = tabular.width() + 2 * ADD_TO_TABULAR_WIDTH;
diff --git a/src/insets/InsetTabular.h b/src/insets/InsetTabular.h
index b915181..87114ec 100644
--- a/src/insets/InsetTabular.h
+++ b/src/insets/InsetTabular.h
@@ -807,7 +807,7 @@ public:
        ///
        bool setFixedWidth(row_type r, col_type c);
        /// return true of update is needed
-       bool updateColumnWidths();
+       bool updateColumnWidths(MetricsInfo & mi);
        ///
        idx_type columnSpan(idx_type cell) const;
        ///