From f6e7fbefce2703a0891b35fff34dc152abc3f283 Mon Sep 17 00:00:00 2001
From: Stephan Witt <switt@lyx.org>
Date: Thu, 24 Feb 2011 21:38:12 +0000
Subject: [PATCH] #6920 paint single characters only when Qt4.7 or better,
 otherwise automatic kerning breaks cursor positioning

git-svn-id: svn://svn.lyx.org/lyx/lyx-devel/trunk@37781 a592a061-630c-0410-9148-cb99ea01b6c8
---
 po/it.po                             |  1 +
 src/LyXRC.cpp                        | 21 +++++++++++++++++++++
 src/LyXRC.h                          |  3 +++
 src/frontends/qt4/GuiApplication.cpp |  7 +++++++
 src/rowpainter.cpp                   |  4 ++--
 5 files changed, 34 insertions(+), 2 deletions(-)

diff --git a/po/it.po b/po/it.po
index e8544df4ca..1ff97695e9 100644
--- a/po/it.po
+++ b/po/it.po
@@ -24750,6 +24750,7 @@ msgstr "Utente sconosciuto"
 #~ msgid "&Previous"
 #~ msgstr "&Precedente"
 
+
 #~ msgid "Ch. "
 #~ msgstr "Cap. "
 
diff --git a/src/LyXRC.cpp b/src/LyXRC.cpp
index 185067100a..d7e2a786ed 100644
--- a/src/LyXRC.cpp
+++ b/src/LyXRC.cpp
@@ -99,6 +99,7 @@ LexerKeyword lyxrcTags[] = {
 	{ "\\example_path", LyXRC::RC_EXAMPLEPATH },
 	{ "\\export_overwrite", LyXRC::RC_EXPORT_OVERWRITE },
 	{ "\\font_encoding", LyXRC::RC_FONT_ENCODING },
+	{ "\\force_paint_single_char", LyXRC::RC_FORCE_PAINT_SINGLE_CHAR },
 	{ "\\format", LyXRC::RC_FILEFORMAT },
 	{ "\\forward_search_dvi", LyXRC::RC_FORWARD_SEARCH_DVI },
 	{ "\\forward_search_pdf", LyXRC::RC_FORWARD_SEARCH_PDF },
@@ -422,6 +423,9 @@ LyXRC::ReturnValues LyXRC::read(Lexer & lexrc, bool check_format)
 	if (!lexrc.isOK())
 		return ReadError;
 
+	// default for current rowpainter capabilities
+	force_paint_single_char = true;
+
 	// format prior to 2.0 and introduction of format tag
 	unsigned int format = 0;
 
@@ -523,6 +527,10 @@ LyXRC::ReturnValues LyXRC::read(Lexer & lexrc, bool check_format)
 			lexrc >> fontenc;
 			break;
 
+		case RC_FORCE_PAINT_SINGLE_CHAR:
+			lexrc >> force_paint_single_char;
+			break;
+				
 		case RC_PRINTER:
 			lexrc >> printer;
 			break;
@@ -2180,6 +2188,14 @@ void LyXRC::write(ostream & os, bool ignore_system_lyxrc, string const & name) c
 		if (tag != RC_LAST)
 			break;
 
+	case RC_FORCE_PAINT_SINGLE_CHAR:
+		if (ignore_system_lyxrc ||
+		    force_paint_single_char != system_lyxrc.force_paint_single_char) {
+			os << "\\force_paint_single_char \"" << force_paint_single_char << "\"\n";
+		}
+		if (tag != RC_LAST)
+			break;
+
 		os << "\n#\n"
 		   << "# FILE SECTION ######################################\n"
 		   << "#\n\n";
@@ -2880,6 +2896,7 @@ void actOnUpdatedPrefs(LyXRC const & lyxrc_orig, LyXRC const & lyxrc_new)
 	case LyXRC::RC_ESC_CHARS:
 	case LyXRC::RC_EXAMPLEPATH:
 	case LyXRC::RC_FONT_ENCODING:
+	case LyXRC::RC_FORCE_PAINT_SINGLE_CHAR:
 	case LyXRC::RC_FILEFORMAT:
 	case LyXRC::RC_GROUP_LAYOUTS:
 	case LyXRC::RC_HUNSPELLDIR_PATH:
@@ -3122,6 +3139,10 @@ string const LyXRC::getDescription(LyXRCTags tag)
 		str = _("The font encoding used for the LaTeX2e fontenc package. T1 is highly recommended for non-English languages.");
 		break;
 
+	case RC_FORCE_PAINT_SINGLE_CHAR:
+		str = _("Disable any kerning and ligatures for text drawing on screen.");
+		break;
+
 	case RC_FILEFORMAT:
 		break;
 
diff --git a/src/LyXRC.h b/src/LyXRC.h
index d94b861cb3..cd2041abd2 100644
--- a/src/LyXRC.h
+++ b/src/LyXRC.h
@@ -79,6 +79,7 @@ public:
 		RC_EXAMPLEPATH,
 		RC_EXPORT_OVERWRITE,
 		RC_FONT_ENCODING,
+		RC_FORCE_PAINT_SINGLE_CHAR,
 		RC_FILEFORMAT,
 		RC_FORWARD_SEARCH_DVI,
 		RC_FORWARD_SEARCH_PDF,
@@ -527,6 +528,8 @@ public:
 	};
 	///
 	ScrollWheelZoom scroll_wheel_zoom;
+	///
+	bool force_paint_single_char;
 };
 
 
diff --git a/src/frontends/qt4/GuiApplication.cpp b/src/frontends/qt4/GuiApplication.cpp
index f2ba321c3d..34c44e2c5e 100644
--- a/src/frontends/qt4/GuiApplication.cpp
+++ b/src/frontends/qt4/GuiApplication.cpp
@@ -1838,6 +1838,13 @@ void GuiApplication::createView(QString const & geometry_arg, bool autoShow,
 	if (d->global_menubar_)
 		d->global_menubar_->releaseKeyboard();
 
+#if QT_VERSION < 0x040700
+	// the option to disable kerning in rowpainter
+	// is needed only with Qt4.7.0 or better
+	lyxrc.force_paint_single_char = false;
+	system_lyxrc.force_paint_single_char = false;
+#endif
+
 	// create new view
 	int id = view_id;
 	while (d->views_.find(id) != d->views_.end())
diff --git a/src/rowpainter.cpp b/src/rowpainter.cpp
index 12fb486a05..7625909e50 100644
--- a/src/rowpainter.cpp
+++ b/src/rowpainter.cpp
@@ -267,9 +267,9 @@ void RowPainter::paintChars(pos_type & vpos, FontInfo const & font,
 		// Maybe a more general fix would be draw character by character
 		// for some predefined fonts on some platform. In arabic and
 		// Hebrew we already do paint this way.
-		if (prev_char == 'f')
+		if (prev_char == 'f' || lyxrc.force_paint_single_char)
 			break;
-		
+
 		pos = bidi_.vis2log(vpos);
 		if (pos < font_span.first || pos > font_span.last)
 			break;