From: Scott Kostyshak <skostysh@lyx.org>
Date: Mon, 23 May 2016 00:39:46 +0000 (-0400)
Subject: Fix using system theme icons with Qt 5 (#10052)
X-Git-Tag: 2.2.0~5
X-Git-Url: https://git.lyx.org/gitweb/?a=commitdiff_plain;h=594748374bc0a92681cf18046e9b019591b20621;p=features.git

Fix using system theme icons with Qt 5 (#10052)

With Qt 5, our code did not correctly detect when icons were
available and thus tried to use nonexistent icons.

QIcon::hasThemeIcon(theme_icon) returns true when theme_icon is
empty. We now rely on the behavior that QIcon::isNull() returns true
if the icon is empty.

The same code is used with Qt 4 and Qt 5.
---

diff --git a/src/frontends/qt4/GuiApplication.cpp b/src/frontends/qt4/GuiApplication.cpp
index 6fb5499981..8b613794df 100644
--- a/src/frontends/qt4/GuiApplication.cpp
+++ b/src/frontends/qt4/GuiApplication.cpp
@@ -600,12 +600,16 @@ QIcon getIcon(FuncRequest const & f, bool unknown)
 {
 #if (QT_VERSION >= 0x040600)
 	if (lyxrc.use_system_theme_icons) {
+		// use the icons from system theme that are available
 		QString action = toqstr(lyxaction.getActionName(f.action()));
 		if (!f.argument().empty())
 			action += " " + toqstr(f.argument());
 		QString const theme_icon = themeIconName(action);
-		if (QIcon::hasThemeIcon(theme_icon))
-			return QIcon::fromTheme(theme_icon);
+		if (QIcon::hasThemeIcon(theme_icon)) {
+			QIcon const thmicn = QIcon::fromTheme(theme_icon);
+			if (!thmicn.isNull())
+				return thmicn;
+		}
 	}
 #endif