Add ability to reset the settings

This may be a bit crude and it doesn't actually FULLY reset the settings
(as for example the column widths will still be maintained), but it's a
good start, I think.

Fixes #552

Signed-off-by: Dirk Hohndel <dirk@hohndel.org>

qt-ui/preferences.cpp

@@ -350,6 +350,30 @@ void PreferencesDialog::on_chooseFile_clicked()
 		ui.defaultfilename->setText(choosenFileName);
 }
 
+void PreferencesDialog::on_resetSettings_clicked()
+{
+	QSettings s;
+
+	QMessageBox response(this);
+	response.setStandardButtons(QMessageBox::Ok | QMessageBox::Cancel);
+	response.setDefaultButton(QMessageBox::Cancel);
+	response.setWindowTitle(tr("Warning"));
+	response.setText(tr("If you click OK, all settings of Subsurface are reset to their default values. This will be applied immediately."));
+	response.setWindowModality(Qt::WindowModal);
+
+	int result = response.exec();
+	if (result == QMessageBox::Ok) {
+		prefs = default_prefs;
+		setUiFromPrefs();
+		QStringList keys = s.allKeys();
+		Q_FOREACH (QString key, keys) {
+			s.remove(key);
+		}
+		syncSettings();
+		close();
+	}
+}
+
 void PreferencesDialog::emitSettingsChanged()
 {
 	emit settingsChanged();

qt-ui/preferences.h

@@ -21,6 +21,7 @@ public
 slots:
 	void buttonClicked(QAbstractButton *button);
 	void on_chooseFile_clicked();
+	void on_resetSettings_clicked();
 	void syncSettings();
 	void loadSettings();
 	void restorePrefs();

qt-ui/preferences.ui

@@ -278,8 +278,7 @@
              </widget>
             </item>
             <item>
-             <widget class="QLineEdit" name="default_uid">
+             <widget class="QLineEdit" name="default_uid"/>
-             </widget>
             </item>
             <item>
              <widget class="QCheckBox" name="save_uid_local">
@@ -291,6 +290,22 @@
            </layout>
           </widget>
          </item>
+         <item>
+          <widget class="QGroupBox" name="groupBox_9">
+           <property name="title">
+            <string>Clear all settings</string>
+           </property>
+           <layout class="QVBoxLayout" name="verticalLayout_7b">
+            <item>
+             <widget class="QPushButton" name="resetSettings">
+              <property name="text">
+               <string>Reset all settings to their default value</string>
+              </property>
+             </widget>
+            </item>
+           </layout>
+          </widget>
+         </item>
          <item>
           <spacer name="verticalSpacer_2">
            <property name="orientation">
@@ -1086,12 +1101,12 @@
   </connection>
  </connections>
  <buttongroups>
-  <buttongroup name="buttonGroup_5"/>
-  <buttongroup name="buttonGroup_6"/>
-  <buttongroup name="buttonGroup"/>
   <buttongroup name="verticalSpeed"/>
   <buttongroup name="buttonGroup_2"/>
   <buttongroup name="buttonGroup_3"/>
+  <buttongroup name="buttonGroup"/>
   <buttongroup name="buttonGroup_4"/>
+  <buttongroup name="buttonGroup_5"/>
+  <buttongroup name="buttonGroup_6"/>
  </buttongroups>
 </ui>