ui: Change screen scaling on Linux (issue #518, #523)

* Set environment variables QT_AUTO_SCREEN_SCALE_FACTOR and QT_SCALE_FACTOR on Linux on app start
* Added ScreenAutoScaling and ScreenScaleFactor to ApplicationSettings with dropdown boxes in the preferences
  only visible on Linux
* Removed QtFontPicker and QtTextEncodingPicker
* Moved logging into preferences category "output"

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src/lib_gui/platform_includes/includesLinux.h

@@ -11,8 +11,35 @@
 #include "utility/ResourcePaths.h"
 #include "utility/UserPaths.h"
 
+#include "settings/ApplicationSettings.h"
+
 void setupPlatform(int argc, char *argv[])
 {
+	std::string home = std::getenv("HOME");
+	UserPaths::setUserDataPath(FilePath(home + "/.config/sourcetrail/"));
+
+	// Set QT screen scaling factor
+	ApplicationSettings appSettings;
+	appSettings.load(UserPaths::getAppSettingsPath());
+
+	qputenv("QT_AUTO_SCREEN_SCALE_FACTOR_SOURCETRAIL", qgetenv("QT_AUTO_SCREEN_SCALE_FACTOR"));
+	qputenv("QT_SCALE_FACTOR_SOURCETRAIL", qgetenv("QT_SCALE_FACTOR"));
+
+	int autoScaling = appSettings.getScreenAutoScaling();
+	if (autoScaling != -1)
+	{
+		QByteArray bytes;
+		bytes.setNum(autoScaling);
+		qputenv("QT_AUTO_SCREEN_SCALE_FACTOR", bytes);
+	}
+
+	float scaleFactor = appSettings.getScreenScaleFactor();
+	if (scaleFactor > 0.0)
+	{
+		QByteArray bytes;
+		bytes.setNum(scaleFactor);
+		qputenv("QT_SCALE_FACTOR", bytes);
+	}
 }
 
 void setupApp(int argc, char *argv[])
@@ -26,8 +53,6 @@ void setupApp(int argc, char *argv[])
 	QDir coatiDir((userdir + "/.config/coati").c_str());
 	userdir.append("/.config/sourcetrail/");
 
-	UserPaths::setUserDataPath(FilePath(userdir));
-
 	QString userDataPath(userdir.c_str());
 	QDir dataDir(userdir.c_str());
 	if (!dataDir.exists())

src/lib_gui/platform_includes/includesMac.h

@@ -12,10 +12,11 @@
 #include "utility/ResourcePaths.h"
 #include "utility/UserPaths.h"
 
-bool appIsMacBundle = false;
 
 void setupPlatform(int argc, char *argv[])
 {
+	UserPaths::setUserDataPath(FilePath("./user/"));
+
 	// ----------------------------------------------------------------------------
 	// This makes relative paths work in C++ in Xcode by changing directory to the Resources folder inside the .app bundle
 	// source: http://stackoverflow.com/questions/516200/relative-paths-not-working-in-xcode-c
@@ -81,19 +82,12 @@ void setupPlatform(int argc, char *argv[])
 
 	// ----------------------------------------------------------------------------
 	UserPaths::setUserDataPath(FilePath(dataPath.toStdString() + "/"));
-
-	appIsMacBundle = true;
 }
 
 void setupApp(int argc, char *argv[])
 {
 	FilePath path(QDir::currentPath().toStdString());
 	AppPath::setAppPath(path.getAbsolute().str() + "/");
-
-	if (!appIsMacBundle)
-	{
-		UserPaths::setUserDataPath(FilePath("./user/"));
-	}
 }
 
 #endif // INCLUDES_MAC_H