From e11c8ba81b3a803734727087c4e48213046a8448 Mon Sep 17 00:00:00 2001
From: Jean-Marc Lasgouttes <lasgouttes@lyx.org>
Date: Mon, 12 Feb 2018 11:12:50 +0100
Subject: [PATCH] Disable and hide the pixmap cache feature

---
 lib/RELEASE-NOTES                |  6 ++++++
 lib/doc/UserGuide.lyx            | 18 ------------------
 src/frontends/qt4/GuiPainter.cpp |  2 +-
 src/frontends/qt4/GuiPrefs.cpp   |  2 +-
 4 files changed, 8 insertions(+), 20 deletions(-)

diff --git a/lib/RELEASE-NOTES b/lib/RELEASE-NOTES
index dccd1f10ed..95485d6635 100644
--- a/lib/RELEASE-NOTES
+++ b/lib/RELEASE-NOTES
@@ -20,6 +20,10 @@
   See chapter 3.9.1.1 "Dashes and Line Breaks" of the User Guide and
   "Caveats when upgrading from earlier versions to 2.3.x" below.
 
+* The preference "Tools->Preferences->Look&Feel->Screen Fonts->Use
+  pixmap cache to speed up font rendering" is not available anymore.
+  It was of dubious value and led to rendering issues.
+
 * The following UI translations were dropped, because the lack of translation
   maintenance:  Russian, Danish, Greek, Serbian, Galician, Catalan, Romanian,
   Dutch.
@@ -87,6 +91,8 @@
 * \screen_zoom
   This is now independent of the value set via buffer-zoom[-in|-out].
 
+* \use_pixmap_cache
+  The value of this variable is now ignored.
 
 !!!The following new LyX functions have been introduced in 2.3:
 
diff --git a/lib/doc/UserGuide.lyx b/lib/doc/UserGuide.lyx
index 06cfd1f924..fb8cac9d10 100644
--- a/lib/doc/UserGuide.lyx
+++ b/lib/doc/UserGuide.lyx
@@ -46198,24 +46198,6 @@ reference "subsec:Document-Font"
 .
 \end_layout
 
-\begin_layout Standard
-With the option 
-\family sans
-Use pixmap cache to speed up font rendering
-\family default
- enabled, \SpecialChar LyX
- needs to redraw the screen less often.
- This results in better performance, especially on slow systems.
- On the other hand, the characters might look more fuzzy on screen.
- So whether you enable this or not depends on whether you prefer speed over
- aesthetics.
- Note that the Pixmap Cache is only available and useful under Mac
-\begin_inset space ~
-\end_inset
-
-OS and Windows.
-\end_layout
-
 \begin_layout Subsection
 Colors
 \begin_inset Index idx
diff --git a/src/frontends/qt4/GuiPainter.cpp b/src/frontends/qt4/GuiPainter.cpp
index a3cb089e78..e832f23e99 100644
--- a/src/frontends/qt4/GuiPainter.cpp
+++ b/src/frontends/qt4/GuiPainter.cpp
@@ -50,7 +50,7 @@ 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)
+	  use_pixmap_cache_(false)
 {
 	// new QPainter has default QPen:
 	current_color_ = guiApp->colorCache().get(Color_black);
diff --git a/src/frontends/qt4/GuiPrefs.cpp b/src/frontends/qt4/GuiPrefs.cpp
index 4681dd3219..dc04ec5c3d 100644
--- a/src/frontends/qt4/GuiPrefs.cpp
+++ b/src/frontends/qt4/GuiPrefs.cpp
@@ -1137,7 +1137,7 @@ void PrefScreenFonts::updateRC(LyXRC const & rc)
 #if defined(Q_WS_X11) || defined(QPA_XCB)
 	pixmapCacheCB->setEnabled(false);
 #endif
-
+	pixmapCacheCB->hide();
 }