From 696ea82b21f5f0729e14bdefe90d8e18563ddf2e Mon Sep 17 00:00:00 2001
From: Enrico Forestieri <forenr@lyx.org>
Date: Tue, 25 Oct 2016 00:49:26 +0200
Subject: [PATCH] Factor out common code used to underline/strike out math

Also use the exact amount of vertical space TeX adds after a
math display (instead of 1ex) for vertically shifting the box.
We have to use \belowdisplayshortskip here, instead of
\belowdisplayskip, because the math formula is typeset by alone
in a box, and thus there is no following line.
---
 src/mathed/InsetMathHull.cpp | 67 +++++++++++++++++++-----------------
 1 file changed, 35 insertions(+), 32 deletions(-)

diff --git a/src/mathed/InsetMathHull.cpp b/src/mathed/InsetMathHull.cpp
index 345ee44af7..2bb8822acc 100644
--- a/src/mathed/InsetMathHull.cpp
+++ b/src/mathed/InsetMathHull.cpp
@@ -121,6 +121,37 @@ namespace {
 	}
 
 
+	// writes a preamble for underlined or struck out math display
+	void writeMathdisplayPreamble(WriteStream & os)
+	{
+		if (os.strikeoutMath()) {
+			if (os.ulemCmd() == WriteStream::UNDERLINE)
+				os << "\\raisebox{-\\belowdisplayshortskip}{"
+				      "\\lyxmathsout{\\parbox[b]{\\columnwidth}{";
+			else
+				os << "\\lyxmathsout{\\parbox{\\columnwidth}{";
+		} else if (os.ulemCmd() == WriteStream::UNDERLINE)
+			os << "\\raisebox{-\\belowdisplayshortskip}{"
+			      "\\parbox[b]{\\columnwidth}{";
+		else if (os.ulemCmd() == WriteStream::STRIKEOUT)
+			os << "\\parbox{\\columnwidth}{";
+	}
+
+
+	// writes a postamble for underlined or struck out math display
+	void writeMathdisplayPostamble(WriteStream & os)
+	{
+		if (os.strikeoutMath()) {
+			if (os.ulemCmd() == WriteStream::UNDERLINE)
+				os << "}";
+			os << "}}\\\\\n";
+		} else if (os.ulemCmd() == WriteStream::UNDERLINE)
+			os << "}}\\\\\n";
+		else if (os.ulemCmd() == WriteStream::STRIKEOUT)
+			os << "}\\\\\n";
+	}
+
+
 } // end anon namespace
 
 
@@ -1029,14 +1060,7 @@ void InsetMathHull::header_write(WriteStream & os) const
 		break;
 
 	case hullEquation:
-		if (os.strikeoutMath()) {
-			if (os.ulemCmd() == WriteStream::UNDERLINE)
-				os << "\\raisebox{1ex}{";
-			os << "\\lyxmathsout{\\parbox{\\columnwidth}{";
-		} else if (os.ulemCmd() == WriteStream::UNDERLINE)
-			os << "\\raisebox{-1ex}{\\parbox[b]{\\columnwidth}{";
-		else if (os.ulemCmd() == WriteStream::STRIKEOUT)
-			os << "\\parbox{\\columnwidth}{";
+		writeMathdisplayPreamble(os);
 		os << "\n";
 		os.startOuterRow();
 		if (n)
@@ -1050,14 +1074,7 @@ void InsetMathHull::header_write(WriteStream & os) const
 	case hullFlAlign:
 	case hullGather:
 	case hullMultline:
-		if (os.strikeoutMath()) {
-			if (os.ulemCmd() == WriteStream::UNDERLINE)
-				os << "\\raisebox{1ex}{";
-			os << "\\lyxmathsout{\\parbox{\\columnwidth}{";
-		} else if (os.ulemCmd() == WriteStream::UNDERLINE)
-			os << "\\raisebox{-1ex}{\\parbox[b]{\\columnwidth}{";
-		else if (os.ulemCmd() == WriteStream::STRIKEOUT)
-			os << "\\parbox{\\columnwidth}{";
+		writeMathdisplayPreamble(os);
 		os << "\n";
 		os.startOuterRow();
 		os << "\\begin{" << hullName(type_) << star(n) << "}\n";
@@ -1113,14 +1130,7 @@ void InsetMathHull::footer_write(WriteStream & os) const
 			os << "\\end{equation" << star(n) << "}\n";
 		else
 			os << "\\]\n";
-		if (os.strikeoutMath()) {
-			if (os.ulemCmd() == WriteStream::UNDERLINE)
-				os << "}";
-			os << "}}\\\\\n";
-		} else if (os.ulemCmd() == WriteStream::UNDERLINE)
-			os << "}}\\\\\n";
-		else if (os.ulemCmd() == WriteStream::STRIKEOUT)
-			os << "}\\\\\n";
+		writeMathdisplayPostamble(os);
 		break;
 
 	case hullEqnArray:
@@ -1131,14 +1141,7 @@ void InsetMathHull::footer_write(WriteStream & os) const
 		os << "\n";
 		os.startOuterRow();
 		os << "\\end{" << hullName(type_) << star(n) << "}\n";
-		if (os.strikeoutMath()) {
-			if (os.ulemCmd() == WriteStream::UNDERLINE)
-				os << "}";
-			os << "}}\\\\\n";
-		} else if (os.ulemCmd() == WriteStream::UNDERLINE)
-			os << "}}\\\\\n";
-		else if (os.ulemCmd() == WriteStream::STRIKEOUT)
-			os << "}\\\\\n";
+		writeMathdisplayPostamble(os);
 		break;
 
 	case hullAlignAt:
-- 
2.39.2