[LyX/master] Some tweaks to selection painting

[Jean-Marc Lasgouttes]

commit 695b0cc33b04fa10c8134738e4726de5336267f4
Author: Jean-Marc Lasgouttes <lasgout...@lyx.org>
Date:   Wed Oct 26 14:23:59 2016 +0200

    Some tweaks to selection painting
    
    1/ simplify logic that triggers margin selection painting
    
    2/ fix logic for end of paragraph markers. They are now selected when
       there is an end row margin selection.
    
    3/ avoid rounding problems due to int/double conversions.
---
 src/RowPainter.cpp |   20 ++++++++++++++------
 1 files changed, 14 insertions(+), 6 deletions(-)

diff --git a/src/RowPainter.cpp b/src/RowPainter.cpp
index da0e4f3..7f8456f 100644
--- a/src/RowPainter.cpp
+++ b/src/RowPainter.cpp
@@ -614,21 +614,29 @@ void RowPainter::paintSelection() const
        bool const rtl = text_.isRTL(par_);
 
        // draw the margins
-       if ((row_.begin_margin_sel && !rtl) || (row_.end_margin_sel && rtl))
+       if (rtl ? row_.end_margin_sel : row_.begin_margin_sel)
                pi_.pain.fillRectangle(int(xo_), y1, row_.left_margin, y2 - y1,
                                       Color_selection);
+
        // go through row and draw from RTL boundary to RTL boundary
        double x = xo_ + row_.left_margin;
        for (auto const & e : row_) {
+               // These are the same tests as in paintStringAndSel, except
+               // that all_sel has an additional clause that triggers for end
+               // of paragraph markers. The clause was not used in
+               // paintStringAndSel to avoid changing the drawing color.
                // at least part of text selected?
-               bool const some_sel = (e.endpos >= row_.sel_beg && e.pos <= 
row_.sel_end)
+               bool const some_sel = (e.endpos >= row_.sel_beg && e.pos < 
row_.sel_end)
                        || pi_.selected;
                // all the text selected?
-               bool const all_sel = (e.pos >= row_.sel_beg && e.endpos <= 
row_.sel_end)
-                       || pi_.selected;
+               bool const all_sel = (e.pos >= row_.sel_beg && e.endpos < 
row_.sel_end)
+                   || (e.isVirtual() && e.pos == row_.endpos() && 
row_.end_margin_sel)
+                   || pi_.selected;
 
                if (all_sel) {
-                       pi_.pain.fillRectangle(int(x), y1, int(e.full_width()), 
y2 - y1,
+                       // the 3rd argument is written like that to avoid 
rounding issues
+                       pi_.pain.fillRectangle(int(x), y1,
+                                              int(x + e.full_width()) - 
int(x), y2 - y1,
                                               Color_selection);
                } else if (some_sel) {
                        pos_type const from = min(max(row_.sel_beg, e.pos), 
e.endpos);
@@ -643,7 +651,7 @@ void RowPainter::paintSelection() const
                x += e.full_width();
        }
 
-       if ((row_.begin_margin_sel && rtl) || (row_.end_margin_sel && !rtl))
+       if (rtl ? row_.begin_margin_sel : row_.end_margin_sel)
                pi_.pain.fillRectangle(x, y1, int(xo_) + text_metrics_.width() 
- x, y2 - y1,
                                       Color_selection);