From 6dfbab31245df074df4d1664321e2ff434f3ca6a Mon Sep 17 00:00:00 2001
From: Jean-Marc Lasgouttes <lasgouttes@lyx.org>
Date: Mon, 7 Nov 2016 10:14:39 +0100
Subject: [PATCH] Handle properly unicode paragraph/line break

They are shown on screen by arrow or pilcrow symbol and cause a line break.

They are still not handled in LaTeX output, though.
---
 src/Paragraph.cpp   |  5 +++++
 src/TextMetrics.cpp | 19 ++++++++++++++++++-
 2 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/src/Paragraph.cpp b/src/Paragraph.cpp
index 8afa475a74..05c10b5fa6 100644
--- a/src/Paragraph.cpp
+++ b/src/Paragraph.cpp
@@ -3147,6 +3147,11 @@ bool Paragraph::isHfill(pos_type pos) const
 
 bool Paragraph::isNewline(pos_type pos) const
 {
+	// U+2028 LINE SEPARATOR
+	// U+2029 PARAGRAPH SEPARATOR
+	char_type const c = d->text_[pos];
+	if (c == 0x2028 || c == 0x2029)
+		return true;
 	Inset const * inset = getInset(pos);
 	return inset && inset->lyxCode() == NEWLINE_CODE;
 }
diff --git a/src/TextMetrics.cpp b/src/TextMetrics.cpp
index 8f7ac821e8..17ee2e410a 100644
--- a/src/TextMetrics.cpp
+++ b/src/TextMetrics.cpp
@@ -864,7 +864,23 @@ bool TextMetrics::breakRow(Row & row, int const right_margin) const
 		} else if (c == '\t')
 			row.addSpace(i, theFontMetrics(*fi).width(from_ascii("    ")),
 				     *fi, par.lookupChange(i));
-		else {
+		else if (c == 0x2028 || c == 0x2029) {
+			/**
+			 * U+2028 LINE SEPARATOR
+			 * U+2029 PARAGRAPH SEPARATOR
+
+			 * These are special unicode characters that break
+			 * lines/pragraphs. Not handling them lead to trouble wrt
+			 * Qt QTextLayout formatting. We add a visible character
+			 * on screen so that the user can see that something is
+			 * happening.
+			*/
+			row.finalizeLast();
+			// ⤶ U+2936 ARROW POINTING DOWNWARDS THEN CURVING LEFTWARDS
+			// ¶ U+00B6 PILCROW SIGN
+			char_type const screen_char = (c == 0x2028) ? 0x2936 : 0x00B6;
+			row.add(i, screen_char, *fi, par.lookupChange(i));
+		} else {
 			// FIXME: please someone fix the Hebrew/Arabic parenthesis mess!
 			// see also Paragraph::getUChar.
 			if (fi->language()->lang() == "hebrew") {
@@ -925,6 +941,7 @@ bool TextMetrics::breakRow(Row & row, int const right_margin) const
 		BufferParams const & bparams
 			= text_->inset().buffer().params();
 		f.setLanguage(par.getParLanguage(bparams));
+		// ¶ U+00B6 PILCROW SIGN
 		row.addVirtual(end, docstring(1, char_type(0x00B6)), f, Change());
 	}
 
-- 
2.39.5