Show a custom menu when right-clicking empty rack & patchbay areas

Closes #231

resources/ui/carla_host.ui

@@ -67,6 +67,9 @@
         </item>
         <item>
          <widget class="RackListWidget" name="listWidget">
+          <property name="contextMenuPolicy">
+           <enum>Qt::CustomContextMenu</enum>
+          </property>
           <property name="verticalScrollBarPolicy">
            <enum>Qt::ScrollBarAlwaysOff</enum>
           </property>

source/carla_host.py

@@ -390,6 +390,8 @@ class HostWindow(QMainWindow):
         self.ui.b_disk_remove.clicked.connect(self.slot_diskFolderRemove)
         self.ui.fileTreeView.doubleClicked.connect(self.slot_fileTreeDoubleClicked)
 
+        self.ui.listWidget.customContextMenuRequested.connect(self.showPluginActionsMenu)
+
         self.ui.graphicsView.horizontalScrollBar().valueChanged.connect(self.slot_horizontalScrollBarChanged)
         self.ui.graphicsView.verticalScrollBar().valueChanged.connect(self.slot_verticalScrollBarChanged)
 
@@ -740,6 +742,58 @@ class HostWindow(QMainWindow):
 
         return (btype, ptype, filename, label, uniqueId, extraPtr)
 
+    @pyqtSlot()
+    def showPluginActionsMenu(self):
+        menu = QMenu(self)
+
+        if config_UseQt5:
+            menu.addSection("Plugins")
+        else:
+            # fake section
+            act  = menu.addAction("  Plugins")
+            font = act.font()
+            font.setBold(True)
+            act.setFont(font)
+            act.setEnabled(False)
+            menu.addSeparator()
+
+        menu.addAction(self.ui.act_plugin_add)
+        menu.addAction(self.ui.act_plugin_remove_all)
+
+        if config_UseQt5:
+            menu.addSection("All plugins (macros)")
+        else:
+            # fake space
+            act  = menu.addAction(" ")
+            font = act.font()
+            font.setBold(True)
+            font.setPointSize(font.pointSize()/2)
+            act.setEnabled(False)
+
+            # fake section
+            act  = menu.addAction("  All plugins (macros)")
+            font = act.font()
+            font.setBold(True)
+            act.setFont(font)
+            act.setEnabled(False)
+            menu.addSeparator()
+
+        menu.addAction(self.ui.act_plugins_enable)
+        menu.addAction(self.ui.act_plugins_disable)
+        menu.addSeparator()
+        menu.addAction(self.ui.act_plugins_volume100)
+        menu.addAction(self.ui.act_plugins_mute)
+        menu.addSeparator()
+        menu.addAction(self.ui.act_plugins_wet100)
+        menu.addAction(self.ui.act_plugins_bypass)
+        menu.addSeparator()
+        menu.addAction(self.ui.act_plugins_center)
+        menu.addSeparator()
+        menu.addAction(self.ui.act_plugins_compact)
+        menu.addAction(self.ui.act_plugins_expand)
+
+        menu.exec_(QCursor.pos())
+
     @pyqtSlot()
     def slot_pluginAdd(self):
         data = self.showAddPluginDialog()
@@ -1959,6 +2013,9 @@ def canvasCallback(action, value1, value2, valueStr):
         if pwidget is not None:
             pwidget.showCustomUI()
 
+    elif action == patchcanvas.ACTION_BG_RIGHT_CLICK:
+        gCarla.gui.showPluginActionsMenu()
+
 # ------------------------------------------------------------------------------------------------------------
 # Engine callback
 

source/patchcanvas.py

@@ -76,6 +76,7 @@ ACTION_PLUGIN_RENAME    = 10 # plugin_id, N, N
 ACTION_PLUGIN_REPLACE   = 11 # plugin_id, N, N
 ACTION_PLUGIN_REMOVE    = 12 # plugin_id, N, N
 ACTION_PLUGIN_SHOW_UI   = 13 # plugin_id, N, N
+ACTION_BG_RIGHT_CLICK   = 14 # N, N, N
 
 # Icon
 ICON_APPLICATION = 0
@@ -1360,8 +1361,12 @@ class PatchScene(QGraphicsScene):
 
         QGraphicsScene.wheelEvent(self, event)
 
-    #def contextMenuEvent(self, event):
-        #print("context menu event")
+    def contextMenuEvent(self, event):
+        if len(self.selectedItems()) == 0:
+            event.accept()
+            canvas.callback(ACTION_BG_RIGHT_CLICK, 0, 0, "")
+        else:
+            QGraphicsScene.contextMenuEvent(self, event)
 
 # ------------------------------------------------------------------------------
 # canvasfadeanimation.cpp