From: Jean-Marc Lasgouttes <lasgouttes@lyx.org>
Date: Wed, 2 Jan 2019 17:36:02 +0000 (+0100)
Subject: Remove premature (and bad) optimization
X-Git-Tag: 2.3.3~68
X-Git-Url: https://git.lyx.org/gitweb/?a=commitdiff_plain;h=1e2b503ac934e06cdd253b1d3d80c5ae7122c35b;p=features.git

Remove premature (and bad) optimization

When blinking the caret, it looks like a cool idea to only update the
small rectangle containing the caret. Actually it is an awful idea, since
the paint event will paint some rows, and these rows will not be
properly painted outside of the small rectangle. Unfortunately, the
painter will skip those "painted" rows on next paint events.

This leads to painting errors that depend on the ordering of "real"
and "caret" paint events. This is the reason why they only appeared
with split screens.

Quote of the day: ``The real problem is that programmers have spent far
too much time worrying about efficiency in the wrong places and at the
wrong times; premature optimization is the root of all evil (or at
least most of it) in programming.''
-- Donald Knuth, The Art of Computer Programming.

Fixes bug #11354.

(cherry picked from commit fba9f5b9e884f0a988bd77992772eb4986eecdec)
---

diff --git a/src/frontends/qt4/GuiWorkArea.cpp b/src/frontends/qt4/GuiWorkArea.cpp
index 18c25caac5..fee3c331a1 100644
--- a/src/frontends/qt4/GuiWorkArea.cpp
+++ b/src/frontends/qt4/GuiWorkArea.cpp
@@ -636,7 +636,7 @@ void GuiWorkArea::Private::showCaret()
 		return;
 
 	updateCaretGeometry();
-	p->viewport()->update(caret_->rect());
+	p->viewport()->update();
 }
 
 
@@ -647,7 +647,7 @@ void GuiWorkArea::Private::hideCaret()
 
 	caret_visible_ = false;
 	//if (!qApp->focusWidget())
-		p->viewport()->update(caret_->rect());
+		p->viewport()->update();
 }
 
 
diff --git a/status.23x b/status.23x
index e2f47e31b2..1ee2757d13 100644
--- a/status.23x
+++ b/status.23x
@@ -110,6 +110,8 @@ What's new
 
 - Completion popup context menu now properly responds to Esc key.
 
+- Fix document updating issues with split view (bug 11354).
+
 
 * INTERNALS