From a700d657b3b06541b10ddae8cc5847bd46d06aae Mon Sep 17 00:00:00 2001
From: Jean-Marc Lasgouttes <lasgouttes@lyx.org>
Date: Tue, 25 Oct 2016 09:28:14 +0200
Subject: [PATCH] Reimplement RowPainter::paintSelection() using row elements

The code is much simpler now and can be actually understood.

As a byproduct, fix bug #10424.
---
 src/RowPainter.cpp | 114 ++++++++++++---------------------------------
 1 file changed, 31 insertions(+), 83 deletions(-)

diff --git a/src/RowPainter.cpp b/src/RowPainter.cpp
index 0bbcb5723d..0d92136bd2 100644
--- a/src/RowPainter.cpp
+++ b/src/RowPainter.cpp
@@ -608,96 +608,44 @@ void RowPainter::paintSelection() const
 {
 	if (!row_.selection())
 		return;
-	Cursor const & curs = pi_.base.bv->cursor();
-	DocIterator beg = curs.selectionBegin();
-	beg.pit() = row_.pit();
-	beg.pos() = row_.sel_beg;
-
-	DocIterator end = curs.selectionEnd();
-	end.pit() = row_.pit();
-	end.pos() = row_.sel_end;
-
-	bool const begin_boundary = beg.pos() >= row_.endpos();
-	bool const end_boundary = row_.sel_end == row_.endpos();
-
-	DocIterator cur = beg;
-	cur.boundary(begin_boundary);
-	int x1 = text_metrics_.cursorX(beg.top(), begin_boundary);
-	int x2 = text_metrics_.cursorX(end.top(), end_boundary);
+
 	int const y1 = yo_ - row_.ascent();
 	int const y2 = y1 + row_.height();
-
-	int const rm = text_.isMainText() ? pi_.base.bv->rightMargin() : 0;
-	int const lm = text_.isMainText() ? pi_.base.bv->leftMargin() : 0;
+	bool const rtl = text_.isRTL(par_);
 
 	// draw the margins
-	if (row_.begin_margin_sel) {
-		if (text_.isRTL(beg.paragraph())) {
-			pi_.pain.fillRectangle(int(xo_ + x1), y1,
-				text_metrics_.width() - rm - x1, y2 - y1, Color_selection);
-		} else {
-			pi_.pain.fillRectangle(int(xo_ + lm), y1, x1 - lm, y2 - y1,
-				Color_selection);
-		}
-	}
-
-	if (row_.end_margin_sel) {
-		if (text_.isRTL(beg.paragraph())) {
-			pi_.pain.fillRectangle(int(xo_ + lm), y1, x2 - lm, y2 - y1,
-				Color_selection);
-		} else {
-			pi_.pain.fillRectangle(int(xo_ + x2), y1, text_metrics_.width() - rm - x2,
-				y2 - y1, Color_selection);
-		}
-	}
-
-	// if we are on a boundary from the beginning, it's probably
-	// a RTL boundary and we jump to the other side directly as this
-	// segement is 0-size and confuses the logic below
-	if (cur.boundary())
-		cur.boundary(false);
+	if ((row_.begin_margin_sel && !rtl) || (row_.end_margin_sel && rtl))
+		pi_.pain.fillRectangle(int(xo_), y1, row_.left_margin, y2 - y1,
+		                       Color_selection);
+	if ((row_.begin_margin_sel && rtl) || (row_.end_margin_sel && !rtl))
+		pi_.pain.fillRectangle(int(xo_ + row_.width()), y1,
+		                       text_metrics_.width() - row_.width(), y2 - y1,
+		                       Color_selection);
 
 	// go through row and draw from RTL boundary to RTL boundary
-	while (cur < end) {
-		bool draw_now = false;
-
-		// simplified cursorForward code below which does not
-		// descend into insets and which does not go into the
-		// next line. Compare the logic with the original cursorForward
-
-		// if left of boundary -> just jump to right side, but
-		// for RTL boundaries don't, because: abc|DDEEFFghi -> abcDDEEF|Fghi
-		if (cur.boundary()) {
-			cur.boundary(false);
-		}	else if (text_metrics_.isRTLBoundary(cur.pit(), cur.pos() + 1)) {
-			// in front of RTL boundary -> Stay on this side of the boundary
-			// because:  ab|cDDEEFFghi -> abc|DDEEFFghi
-			++cur.pos();
-			cur.boundary(true);
-			draw_now = true;
-		} else {
-			// move right
-			++cur.pos();
-
-			// line end?
-			if (cur.pos() == row_.endpos())
-				cur.boundary(true);
-		}
-
-		if (x1 == -1) {
-			// the previous segment was just drawn, now the next starts
-			x1 = text_metrics_.cursorX(cur.top(), cur.boundary());
-		}
-
-		if (!(cur < end) || draw_now) {
-			x2 = text_metrics_.cursorX(cur.top(), cur.boundary());
-			pi_.pain.fillRectangle(int(xo_ + min(x1, x2)), y1, abs(x2 - x1),
-				y2 - y1, Color_selection);
-
-			// reset x1, so it is set again next round (which will be on the
-			// right side of a boundary or at the selection end)
-			x1 = -1;
+	int x = xo_ + row_.left_margin;
+	for (auto const & e : row_) {
+		// at least part of text selected?
+		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;
+
+		if (all_sel) {
+			pi_.pain.fillRectangle(x, y1, e.full_width(), y2 - y1,
+			                       Color_selection);
+		} else if (some_sel) {
+			pos_type const from = min(max(row_.sel_beg, e.pos), e.endpos);
+			pos_type const to = max(min(row_.sel_end, e.endpos), e.pos);
+			int x1 = e.pos2x(from);
+			int x2 = e.pos2x(to);
+			if (x1 > x2)
+				swap(x1, x2);
+			pi_.pain.fillRectangle(x + x1, y1, x2 - x1, y2 - y1,
+			                       Color_selection);
 		}
+		x += e.full_width();
 	}
 }
 
-- 
2.39.2