Fix output encoding information for non-TeX fonts XeTeX/LuaTeX on preview pane

Fixes: #8919

src/Buffer.cpp

@@ -1624,6 +1624,11 @@ void Buffer::writeLaTeXSource(otexstream & os,
 
 	OutputParams runparams = runparams_in;
 
+	// This is necessary for LuaTeX/XeTeX with tex fonts.
+	// See FIXME in BufferParams::encoding()
+	if (runparams.isFullUnicode())
+		runparams.encoding = encodings.fromLyXName("utf8-plain");
+
 	// If we are compiling a file standalone, even if this is the
 	// child of some other buffer, let's cut the link here, so the
 	// file is really independent and no concurring settings from

src/BufferParams.cpp

@@ -2989,7 +2989,8 @@ Encoding const & BufferParams::encoding() const
 	// FIXME: actually, we should check for the flavor
 	// or runparams.isFullyUnicode() here:
 	// This check will not work with XeTeX/LuaTeX and tex fonts.
-	// Thus we have to reset the encoding in Buffer::makeLaTeXFile.
+	// Thus we have to reset the encoding in Buffer::makeLaTeXFile
+	// (for export) and Buffer::writeLaTeXSource (for preview).
 	if (useNonTeXFonts)
 		return *(encodings.fromLyXName("utf8-plain"));
 	if (inputenc == "auto" || inputenc == "default")

status.21x

@@ -64,6 +64,9 @@ What's new
 
 - Fix name and hint of figure captions in documents using the class aastex.
 
+- Fix output encoding information for non-TeX fonts XeTeX/LuaTeX on preview
+  pane (bug 8919).
+
 
 
 * INTERNALS