Remove support for pixmap cache

This code has issues and there is no evidence that it improves performance.

Remove LyXRC variable \use_pixmap_cache and update rc format to 29.

Now the global pixmap cache is only used by GuiCompleter. Therefore
there is no need to reset it when fonts change.

lib/RELEASE-NOTES

@@ -29,6 +29,9 @@
 * \use_qimage
   This is no longer necessary due to the rewrite of the painter.
 
+* \use_pixmap_cacheqimage
+  There is no evidence that this painting mode was useful anymore.
+
 * \date_insert_format
   The function date-insert has been removed and superseded by info-insert date.
   The latter does not need a pref value anymore.

lib/configure.py

@@ -1798,7 +1798,7 @@ if __name__ == '__main__':
     lyx_check_config = True
     lyx_kpsewhich = True
     outfile = 'lyxrc.defaults'
-    lyxrc_fileformat = 27
+    lyxrc_fileformat = 29
     rc_entries = ''
     lyx_keep_temps = False
     version_suffix = ''

lib/scripts/prefs2prefs_prefs.py

@@ -114,6 +114,9 @@
 # Incremented to format 28, by spitz
 #   Remove date_insert_format
 
+# Incremented to format 29, by lasgouttes
+#   Remove use_pixmap_cache
+
 # NOTE: The format should also be updated in LYXRC.cpp and
 # in configure.py.
 
@@ -413,6 +416,11 @@ def remove_date_insert_format(line):
 		return no_match
 	return (True, "")
 
+def remove_use_pixmap_cache(line):
+	if not line.lower().startswith("\\use_pixmap_cache "):
+		return no_match
+	return (True, "")
+
 # End conversions for LyX 2.3 to 2.4
 ####################################
 
@@ -455,5 +463,6 @@ conversions = [
 	[ 25, [remove_use_qimage]],
 	[ 26, [remove_font_encoding]],
 	[ 27, []],
-	[ 28, [remove_date_insert_format]]
+	[ 28, [remove_date_insert_format]],
+	[ 29, [remove_use_pixmap_cache]]
 ]

src/LyXRC.cpp

@@ -59,7 +59,7 @@ namespace {
 
 // The format should also be updated in configure.py, and conversion code
 // should be added to prefs2prefs_prefs.py.
-static unsigned int const LYXRC_FILEFORMAT = 28; // spitz: remove \\date_insert_format
+static unsigned int const LYXRC_FILEFORMAT = 29; // spitz: remove \\date_insert_format
 // when adding something to this array keep it sorted!
 LexerKeyword lyxrcTags[] = {
 	{ "\\accept_compound", LyXRC::RC_ACCEPT_COMPOUND },
@@ -193,7 +193,6 @@ LexerKeyword lyxrcTags[] = {
 	{ "\\use_converter_needauth_forbidden", LyXRC::RC_USE_CONVERTER_NEEDAUTH_FORBIDDEN },
 	{ "\\use_lastfilepos", LyXRC::RC_USELASTFILEPOS },
 	{ "\\use_native_filedialog", LyXRC::RC_USE_NATIVE_FILEDIALOG },
-	{ "\\use_pixmap_cache", LyXRC::RC_USE_PIXMAP_CACHE },
 	// compatibility with versions older than 1.4.0 only
 	{ "\\use_system_colors", LyXRC::RC_USE_SYSTEM_COLORS },
 	{ "\\use_system_theme_icons", LyXRC::RC_USE_SYSTEM_THEME_ICONS },
@@ -326,7 +325,6 @@ void LyXRC::setDefaults()
 	use_converter_needauth = true;
 	use_system_colors = false;
 	use_tooltip = true;
-	use_pixmap_cache = false;
 	converter_cache_maxage = 6 * 30 * 24 * 3600; // 6 months
 	user_name = to_utf8(support::user_name());
 	user_email = to_utf8(support::user_email());
@@ -877,9 +875,6 @@ LyXRC::ReturnValues LyXRC::read(Lexer & lexrc, bool check_format)
 		case RC_USE_TOOLTIP:
 			lexrc >> use_tooltip;
 			break;
-		case RC_USE_PIXMAP_CACHE:
-			lexrc >> use_pixmap_cache;
-			break;
 		case RC_SPELLCHECKER:
 			lexrc >> spellchecker;
 			break;
@@ -2414,16 +2409,6 @@ void LyXRC::write(ostream & os, bool ignore_system_lyxrc, string const & name) c
 		if (tag != RC_LAST)
 			break;
 		// fall through
-	case RC_USE_PIXMAP_CACHE:
-		if (ignore_system_lyxrc ||
-		    use_pixmap_cache != system_lyxrc.use_pixmap_cache) {
-			os << "\\use_pixmap_cache "
-			   << convert<string>(use_pixmap_cache)
-			   << '\n';
-		}
-		if (tag != RC_LAST)
-			break;
-		// fall through
 
 		os << "\n#\n"
 		   << "# LANGUAGE SUPPORT SECTION ##########################\n"
@@ -3005,7 +2990,6 @@ void actOnUpdatedPrefs(LyXRC const & lyxrc_orig, LyXRC const & lyxrc_new)
 	case LyXRC::RC_USE_NATIVE_FILEDIALOG:
 	case LyXRC::RC_USE_SYSTEM_COLORS:
 	case LyXRC::RC_USE_TOOLTIP:
-	case LyXRC::RC_USE_PIXMAP_CACHE:
 	case LyXRC::RC_USE_SYSTEM_THEME_ICONS:
 	case LyXRC::RC_VIEWDVI_PAPEROPTION:
 	case LyXRC::RC_SINGLE_CLOSE_TAB_BUTTON:
@@ -3419,10 +3403,6 @@ string const LyXRC::getDescription(LyXRCTags tag)
 		str = _("Enable the automatic appearance of tool tips in the work area.");
 		break;
 
-	case RC_USE_PIXMAP_CACHE:
-		str = _("Enable the pixmap cache that might improve performance on Mac and Windows.");
-		break;
-
 	case RC_VIEWDVI_PAPEROPTION:
 		_("Specify the paper command to DVI viewer (leave empty or use \"-paper\")");
 		break;

src/LyXRC.h

@@ -173,7 +173,6 @@ public:
 		RC_USE_NATIVE_FILEDIALOG,
 		RC_USE_SYSTEM_COLORS,
 		RC_USE_TOOLTIP,
-		RC_USE_PIXMAP_CACHE,
 		RC_USE_SYSTEM_THEME_ICONS,
 		RC_VIEWDVI_PAPEROPTION,
 		RC_VIEWER,
@@ -333,8 +332,6 @@ public:
 	bool use_system_colors;
 	/// use native file dialog or our own ?
 	bool use_native_filedialog;
-	/// Use pixmap cache?
-	bool use_pixmap_cache;
 	/// Spellchecker engine: aspell, hunspell, etc
 	std::string spellchecker;
 	/// Alternate language for spellchecker

src/frontends/qt4/GuiApplication.cpp

@@ -102,7 +102,6 @@
 #include <QMimeData>
 #include <QObject>
 #include <QPixmap>
-#include <QPixmapCache>
 #include <QRegExp>
 #include <QSessionManager>
 #include <QSettings>
@@ -1078,10 +1077,6 @@ GuiApplication::GuiApplication(int & argc, char ** argv)
 
 	guiApp = this;
 
-	// Set the cache to 5120 kilobytes which corresponds to screen size of
-	// 1280 by 1024 pixels with a color depth of 32 bits.
-	QPixmapCache::setCacheLimit(5120);
-
 	// Initialize RC Fonts
 	if (lyxrc.roman_font_name.empty())
 		lyxrc.roman_font_name = fromqstr(romanFontName());

src/frontends/qt4/GuiPainter.cpp

@@ -29,17 +29,8 @@
 
 #include <algorithm>
 
-#include <QPixmapCache>
 #include <QTextLayout>
 
-// Set USE_PIXMAP_CACHE to 1 for enabling the use of a Pixmap cache when
-// drawing text. This is especially useful for older PPC/Mac systems.
-#if defined(Q_WS_X11) || defined(QPA_XCB)
-#define USE_PIXMAP_CACHE 0
-#else
-#define USE_PIXMAP_CACHE 1
-#endif
-
 using namespace std;
 using namespace lyx::support;
 
@@ -49,8 +40,7 @@ namespace frontend {
 const int Painter::thin_line = 1;
 
 GuiPainter::GuiPainter(QPaintDevice * device, double pixel_ratio)
-	: QPainter(device), Painter(pixel_ratio),
-	  use_pixmap_cache_(lyxrc.use_pixmap_cache && USE_PIXMAP_CACHE)
+	: QPainter(device), Painter(pixel_ratio)
 {
 	// set cache correctly
 	current_color_ = pen().color();
@@ -93,33 +83,6 @@ void GuiPainter::setQPainterPen(QColor const & col,
 }
 
 
-QString GuiPainter::generateStringSignature(QString const & str,
-                                            FontInfo const & f,
-                                            double wordspacing)
-{
-	QString sig = str;
-	sig.append(QChar(static_cast<short>(f.family())));
-	sig.append(QChar(static_cast<short>(f.series())));
-	sig.append(QChar(static_cast<short>(f.realShape())));
-	sig.append(QChar(static_cast<short>(f.size())));
-	Color const & color = f.realColor();
-	sig.append(QChar(static_cast<short>(color.baseColor)));
-	sig.append(QChar(static_cast<short>(color.mergeColor)));
-	sig.append(QString::number(wordspacing));
-	if (!monochrome_min_.empty()) {
-		QColor const & min = monochrome_min_.top();
-		QColor const & max = monochrome_max_.top();
-		sig.append(QChar(static_cast<short>(min.red())));
-		sig.append(QChar(static_cast<short>(min.green())));
-		sig.append(QChar(static_cast<short>(min.blue())));
-		sig.append(QChar(static_cast<short>(max.red())));
-		sig.append(QChar(static_cast<short>(max.green())));
-		sig.append(QChar(static_cast<short>(max.blue())));
-	}
-	return sig;
-}
-
-
 QColor GuiPainter::computeColor(Color col)
 {
 	return filterColor(guiApp->colorCache().get(col));
@@ -396,7 +359,7 @@ void GuiPainter::text(int x, int y, docstring const & s,
 
 	int textwidth = 0;
 	if (tw == 0.0)
-		// Note that we have to take in account space stretching (word spacing)
+		// Take into account space stretching (word spacing)
 		textwidth = fm.width(s) +
 			static_cast<int>(fm.countExpanders(s) * wordspacing);
 	else
@@ -404,55 +367,6 @@ void GuiPainter::text(int x, int y, docstring const & s,
 
 	textDecoration(f, x, y, textwidth);
 
-	if (use_pixmap_cache_) {
-		QPixmap pm;
-		QString key = generateStringSignature(str, f, wordspacing);
-
-		// Warning: Left bearing is in general negative! Only the case
-		// where left bearing is negative is of interest WRT the
-		// pixmap width and the text x-position.
-		// Only the left bearing of the first character is important
-		// as we always write from left to right, even for
-		// right-to-left languages.
-		// FIXME: this is probably broken for RTL now that we draw full strings.
-		// Morover the first/last element is possibly not the right one since the glyph may have changed.
-		int const lb = min(fm.lbearing(s[0]), 0);
-		int const mA = fm.maxAscent();
-		if (QPixmapCache::find(key, pm)) {
-			// Draw the cached pixmap.
-			drawPixmap(x + lb, y - mA, pm);
-			return;
-		}
-
-		// Only the right bearing of the last character is
-		// important as we always write from left to right,
-		// even for right-to-left languages.
-		int const rb = fm.rbearing(s[s.size()-1]);
-		int const w = textwidth + rb - lb;
-		int const mD = fm.maxDescent();
-		int const h = mA + mD;
-		if (w > 0 && h > 0) {
-			pm = QPixmap(static_cast<int>(pixelRatio() * w),
-						 static_cast<int>(pixelRatio() * h));
-#if QT_VERSION >= 0x050000
-			pm.setDevicePixelRatio(pixelRatio());
-#endif
-			pm.fill(Qt::transparent);
-			GuiPainter p(&pm, pixelRatio());
-			p.do_drawText(-lb, mA, str, dir, f, ff);
-			QPixmapCache::insert(key, pm);
-			//LYXERR(Debug::PAINTING, "h=" << h << "  mA=" << mA << "  mD=" << mD
-			//	<< "  w=" << w << "  lb=" << lb << "  tw=" << textwidth
-			//	<< "  rb=" << rb);
-
-			// Draw the new cached pixmap.
-			drawPixmap(x + lb, y - mA, pm);
-			//rectangle(x-lb, y-mA, w, h, Color_green);
-		}
-		return;
-	}
-
-	// don't use the pixmap cache
 	setQPainterPen(computeColor(f.realColor()));
 	if (dir != Auto) {
 		shared_ptr<QTextLayout const> ptl =

src/frontends/qt4/GuiPainter.h

@@ -196,8 +196,6 @@ private:
 	Painter::line_style current_ls_;
 	int current_lw_;
 	///
-	bool const use_pixmap_cache_;
-	///
 	std::stack<QColor> monochrome_min_;
 	///
 	std::stack<QColor> monochrome_max_;
@@ -205,9 +203,6 @@ private:
 	QColor computeColor(Color col);
 	/// possibly apply monochrome mode
 	QColor filterColor(QColor const & col);
-	///
-	QString generateStringSignature(QString const & str, FontInfo const & f,
-	                                double wordspacing);
 };
 
 } // namespace frontend

src/frontends/qt4/GuiPrefs.cpp

@@ -61,7 +61,6 @@
 #include <QHeaderView>
 #include <QLineEdit>
 #include <QMessageBox>
-#include <QPixmapCache>
 #include <QPushButton>
 #include <QSpinBox>
 #include <QString>
@@ -995,8 +994,6 @@ PrefScreenFonts::PrefScreenFonts(GuiPreferences * form)
 		this, SIGNAL(changed()));
 	connect(screenHugerED, SIGNAL(textChanged(QString)),
 		this, SIGNAL(changed()));
-	connect(pixmapCacheCB, SIGNAL(toggled(bool)),
-		this, SIGNAL(changed()));
 
 	screenTinyED->setValidator(new QDoubleValidator(screenTinyED));
 	screenSmallestED->setValidator(new QDoubleValidator(screenSmallestED));
@@ -1033,17 +1030,12 @@ void PrefScreenFonts::applyRC(LyXRC & rc) const
 	rc.font_sizes[FONT_SIZE_LARGEST] = widgetToDoubleStr(screenLargestED);
 	rc.font_sizes[FONT_SIZE_HUGE] = widgetToDoubleStr(screenHugeED);
 	rc.font_sizes[FONT_SIZE_HUGER] = widgetToDoubleStr(screenHugerED);
-	rc.use_pixmap_cache = pixmapCacheCB->isChecked();
 
 	if (rc.font_sizes != oldrc.font_sizes
 		|| rc.roman_font_name != oldrc.roman_font_name
 		|| rc.sans_font_name != oldrc.sans_font_name
 		|| rc.typewriter_font_name != oldrc.typewriter_font_name
 		|| rc.defaultZoom != oldrc.defaultZoom) {
-		// The global QPixmapCache is used in GuiPainter to cache text
-		// painting so we must reset it in case any of the above
-		// parameter is changed.
-		QPixmapCache::clear();
 		guiApp->fontLoader().update();
 		form_->updateScreenFonts();
 	}
@@ -1065,12 +1057,6 @@ void PrefScreenFonts::updateRC(LyXRC const & rc)
 
 	screenZoomSB->setValue(rc.defaultZoom);
 	updateScreenFontSizes(rc);
-
-	pixmapCacheCB->setChecked(rc.use_pixmap_cache);
-#if defined(Q_WS_X11) || defined(QPA_XCB)
-	pixmapCacheCB->setEnabled(false);
-#endif
-
 }
 
 

src/frontends/qt4/GuiView.cpp

@@ -100,7 +100,6 @@
 #include <QMovie>
 #include <QPainter>
 #include <QPixmap>
-#include <QPixmapCache>
 #include <QPoint>
 #include <QPushButton>
 #include <QScrollBar>
@@ -4293,9 +4292,6 @@ void GuiView::dispatch(FuncRequest const & cmd, DispatchResult & dr)
 			dr.setMessage(bformat(_("Zoom level is now %1$d% (default value: %2$d%)"),
 					      lyxrc.currentZoom, lyxrc.defaultZoom));
 
-			// The global QPixmapCache is used in GuiPainter to cache text
-			// painting so we must reset it.
-			QPixmapCache::clear();
 			guiApp->fontLoader().update();
 			dr.screenUpdate(Update::Force | Update::FitCursor);
 			break;

src/frontends/qt4/ui/PrefScreenFontsUi.ui

@@ -407,16 +407,6 @@
      </property>
     </spacer>
    </item>
-   <item row="3" column="0">
-    <widget class="QCheckBox" name="pixmapCacheCB">
-     <property name="toolTip">
-      <string>Checking this improves performance, but might decrease the on-screen quality of fonts</string>
-     </property>
-     <property name="text">
-      <string>&amp;Use pixmap cache to speed up font rendering</string>
-     </property>
-    </widget>
-   </item>
    <item row="4" column="0">
     <spacer>
      <property name="orientation">