ports can now only have one connection at a time to them

Author: Bryan

node_editor/gui/connection.py

@@ -22,7 +22,8 @@ def __init__(self, parent):
     def delete(self):
         for port in (self._start_port, self._end_port):
             if port:
-                port.remove_connection(self)
+                # port.remove_connection(self)
+                port.connection = None
             port = None
 
         self.scene().removeItem(self)
@@ -38,12 +39,12 @@ def end_port(self):
     @start_port.setter
     def start_port(self, port):
         self._start_port = port
-        self._start_port.add_connection(self)
+        self._start_port.connection = self
 
     @end_port.setter
     def end_port(self, port):
         self._end_port = port
-        self._end_port.add_connection(self)
+        self._end_port.connection = self
 
     def nodes(self):
         return (self._start_port().node(), self._end_port().node())
@@ -54,7 +55,7 @@ def update_start_and_end_pos(self):
         Get the start and end ports and use them to set the start and end positions.
         """
 
-        if not self.start_port.is_output():
+        if self.start_port and not self.start_port.is_output():
             print("flipping connection")
             temp = self.end_port
             self._end_port = self.start_port

node_editor/gui/node.py

@@ -158,9 +158,12 @@ def build(self):
 
     def select_connections(self, value):
         for port in self._ports:
-            for connection in port.connections():
-                connection._do_highlight = value
-                connection.update_path()
+            if port.connection:
+                port.connection._do_highlight = value
+                port.connection.update_path()
+            # for connection in port.connections():
+            #     connection._do_highlight = value
+            #     connection.update_path()
 
     def contextMenuEvent(self, event):
         menu = QtWidgets.QMenu(self)
@@ -196,8 +199,8 @@ def delete(self):
         to_delete = []
 
         for port in self._ports:
-            for connection in port.connections():
-                to_delete.append(connection)
+            if port.connection:
+                to_delete.append(port.connection)
 
         for connection in to_delete:
             connection.delete()

node_editor/gui/node_editor.py

@@ -9,6 +9,7 @@ class NodeEditor(QtCore.QObject):
     def __init__(self, parent):
         super(NodeEditor, self).__init__(parent)
         self.connection = None
+        self.port = None
         self.scene = None
         self._last_selected = None
 
@@ -37,16 +38,19 @@ def eventFilter(self, watched, event):
                 if isinstance(item, Port):
                     self.connection = Connection(None)
                     self.scene.addItem(self.connection)
-                    self.connection.start_port = item
+                    # self.connection.start_port = item
+                    self.port = item
                     self.connection.start_pos = item.scenePos()
                     self.connection.end_pos = event.scenePos()
                     self.connection.update_path()
                     return True
 
                 elif isinstance(item, Connection):
                     self.connection = Connection(None)
+                    self.connection.start_pos = item.start_pos
                     self.scene.addItem(self.connection)
-                    self.connection.start_port = item.start_port
+                    # self.connection.start_port = item.start_port
+                    self.port = item.start_port
                     self.connection.end_pos = event.scenePos()
                     self.connection.update_start_and_end_pos()  # to fix the offset
                     return True
@@ -94,28 +98,35 @@ def eventFilter(self, watched, event):
         elif event.type() == QtCore.QEvent.GraphicsSceneMouseRelease:
             if self.connection and event.button() == QtCore.Qt.LeftButton:
                 item = self.item_at(event.scenePos())
+
+                # connecting a port
                 if isinstance(item, Port):
-                    start_port = self.connection.start_port
-                    end_port = item
+                    if self.port.can_connect_to(item):
+                        print("Making connection")
 
-                    if (
-                        start_port.node() != end_port.node()
-                        and start_port.is_output() != end_port.is_output()
-                        and not start_port.is_connected(end_port)
-                    ):
-                        self.connection.end_port = end_port
+                        # delete existing connection on the new port
+                        if item.connection:
+                            item.connection.delete()
 
-                        self.connection.update_start_and_end_pos()
-                        self.connection = None
+                        # delete existing connection to the original port
+                        self.port.clear_connection()
+                        item.clear_connection()
+
+                        self.connection.start_port = self.port
 
-                        # # Flip them aroud if wired the wrong way
-                        # if not self.connection.start_port.is_output():
-                        #     self.connection.flip_connections()
+                        self.connection.end_port = item
 
-                        return True
+                        self.connection.update_start_and_end_pos()
+                        self.connection = None
+                    else:
+                        print("Deleting connection")
+                        self.connection.delete()
+                        self.connection = None
 
-                self.connection.delete()
+                if self.connection:
+                    self.connection.delete()
                 self.connection = None
+                self.port = None
                 return True
 
         return super(NodeEditor, self).eventFilter(watched, event)

node_editor/gui/port.py

@@ -20,24 +20,24 @@ def __init__(self, parent, scene):
 
         self.port_text_height = self.font_metrics.height()
 
-        self.is_output_ = False
+        self._is_output = False
         self._name = None
         self.margin = 2
 
         self.m_node = None
-        self.m_connections = []
+        self.connection = None
 
         self.text_path = QtGui.QPainterPath()
 
     def set_is_output(self, is_output):
-        self.is_output_ = is_output
+        self._is_output = is_output
 
     def set_name(self, name):
         self._name = name
         nice_name = self._name.replace("_", " ").title()
         self.port_text_width = self.font_metrics.width(nice_name)
 
-        if self.is_output_:
+        if self._is_output:
             x = -self.radius_ - self.margin - self.port_text_width
             y = self.port_text_height / 4
 
@@ -62,7 +62,7 @@ def name(self):
         return self._name
 
     def is_output(self):
-        return self.is_output_
+        return self._is_output
 
     def node(self):
         return self.m_node
@@ -76,27 +76,30 @@ def paint(self, painter, option=None, widget=None):
         painter.setBrush(QtCore.Qt.white)
         painter.drawPath(self.text_path)
 
-    def add_connection(self, connection):
-        self.m_connections.append(connection)
+    def clear_connection(self):
+        if self.connection:
+            self.connection.delete()
 
-    def remove_connection(self, connection):
-        try:
-            self.m_connections.remove(connection)
-        except:
-            pass
+    def can_connect_to(self, port):
+        print(port.node(), self.node())
+        if not port:
+            return False
+        if port.node() == self.node():
+            return False
 
-    def connections(self):
-        return self.m_connections
+        if self._is_output == port._is_output:
+            return False
 
-    def is_connected(self, other):
-        for connection in self.m_connections:
-            if connection.start_port == other or connection.end_port == other:
-                return True
+        return True
+
+    def is_connected(self):
+        if self.connection:
+            return True
         return False
 
     def itemChange(self, change, value):
         if change == QtWidgets.QGraphicsItem.ItemScenePositionHasChanged:
-            for connection in self.m_connections:
-                connection.update_start_and_end_pos()
+            if self.connection:
+                self.connection.update_start_and_end_pos()
 
         return value