More reliable way to detect connections, crossed by mouse, with less overhead

Search for line widgets, crossing the line between last two
move event points, to avoid miss.
Check widget type instead of search connection list on each sneeze.

src/patchcanvas.py

@@ -1205,12 +1205,11 @@ class PatchScene(QGraphicsScene):
             return event.accept()
 
         if self.m_mouse2_down:
-            item = self.itemAt(event.scenePos())
-            if item:
-                for connection in canvas.connection_list:
-                    if (connection.widget == item):
-                        canvas.callback(ACTION_PORTS_DISCONNECT, connection.connection_id, 0, "")
-                        break
+            trail = QPolygonF([event.scenePos(), event.lastScenePos(), event.scenePos()])
+            items = self.items(trail)
+            for item in items:
+                if item and item.type() in [CanvasLineType, CanvasBezierLineType]:
+                    item.delete()
 
         QGraphicsScene.mouseMoveEvent(self, event)
 
@@ -1351,6 +1350,12 @@ class CanvasLine(QGraphicsLineItem):
         self.m_lineSelected = yesno
         self.updateLineGradient()
 
+    def delete(self):
+        for connection in canvas.connection_list:
+            if (connection.port_out_id == self.item1.getPortId() and connection.port_in_id == self.item2.getPortId()):
+                canvas.callback(ACTION_PORTS_DISCONNECT, connection.connection_id, 0, "")
+                break
+
     def hoverEnterEvent(self, event):
         self.m_mouse_over = True
         self.setLineSelected(True)
@@ -1361,10 +1366,7 @@ class CanvasLine(QGraphicsLineItem):
 
     def mousePressEvent(self, event):
         if event.button() == Qt.MidButton:
-            for connection in canvas.connection_list:
-                if (connection.port_out_id == self.item1.getPortId() and connection.port_in_id == self.item2.getPortId()):
-                    canvas.callback(ACTION_PORTS_DISCONNECT, connection.connection_id, 0, "")
-                    break
+            self.delete()
 
     def updateLinePos(self):
         if self.item1.getPortMode() == PORT_MODE_OUTPUT:
@@ -1470,6 +1472,12 @@ class CanvasBezierLine(QGraphicsPathItem):
         self.m_lineSelected = yesno
         self.updateLineGradient()
 
+    def delete(self):
+        for connection in canvas.connection_list:
+            if (connection.port_out_id == self.item1.getPortId() and connection.port_in_id == self.item2.getPortId()):
+                canvas.callback(ACTION_PORTS_DISCONNECT, connection.connection_id, 0, "")
+                break
+
     def hoverEnterEvent(self, event):
         self.m_mouse_over = True
         self.setLineSelected(True)
@@ -1480,10 +1488,7 @@ class CanvasBezierLine(QGraphicsPathItem):
 
     def mousePressEvent(self, event):
         if event.button() == Qt.MidButton:
-            for connection in canvas.connection_list:
-                if (connection.port_out_id == self.item1.getPortId() and connection.port_in_id == self.item2.getPortId()):
-                    canvas.callback(ACTION_PORTS_DISCONNECT, connection.connection_id, 0, "")
-                    break
+            self.delete()
 
     def updateLinePos(self):
         if self.item1.getPortMode() == PORT_MODE_OUTPUT: