addressed issue #173

    - pep8 clean up.
    - added more doc strings.
    - updated docs.

Author: jchanvfx

NodeGraphQt/base/graph.py

@@ -502,7 +502,7 @@ def close(self):
 
     def viewer(self):
         """
-        Returns the view interface used by the node graph.
+        Returns the internal view interface used by the node graph.
 
         Warnings:
             Methods in the ``NodeViewer`` are used internally
@@ -572,8 +572,17 @@ def set_grid_mode(self, mode=VIEWER_GRID_LINES):
         """
         Set node graph grid mode.
 
+        Note:
+            By default grid mode is set to "VIEWER_GRID_LINES".
+
+            Node graph background types:
+
+            * :attr:`NodeGraphQt.constants.VIEWER_GRID_NONE`
+            * :attr:`NodeGraphQt.constants.VIEWER_GRID_DOTS`
+            * :attr:`NodeGraphQt.constants.VIEWER_GRID_LINES`
+
         Args:
-            mode: VIEWER_GRID_LINES/VIEWER_GRID_DOTS/VIEWER_GRID_NONE.
+            mode (int): background styles.
         """
         self.scene().grid_mode = mode
         self._viewer.force_update()
@@ -734,8 +743,11 @@ def set_pipe_style(self, style=PIPE_LAYOUT_CURVED):
         """
         Set node graph pipes to be drawn as straight, curved or angled.
 
+        .. image:: _images/pipe_layout_types.gif
+            :width: 80%
+
         Note:
-            By default all pipes are set curved.
+            By default pipe layout is set to "PIPE_LAYOUT_CURVED".
 
             Pipe Layout Styles:
 
@@ -1239,6 +1251,7 @@ def _deserialize(self, data, relative_pos=False, pos=None, set_parent=True):
         Args:
             data (dict): node data.
             relative_pos (bool): position node relative to the cursor.
+            pos (tuple or list): custom x, y position.
             set_parent (bool): set node parent to current node space.
 
         Returns:
@@ -1280,7 +1293,10 @@ def _deserialize(self, data, relative_pos=False, pos=None, set_parent=True):
                     self.add_node(node, n_data.get('pos'), unique_name=set_parent)
 
                 if n_data.get('dynamic_port', None):
-                    node.set_ports({'input_ports': n_data['input_ports'], 'output_ports': n_data['output_ports']})
+                    node.set_ports({
+                        'input_ports': n_data['input_ports'],
+                        'output_ports': n_data['output_ports']
+                    })
 
         # build the connections.
         for connection in data.get('connections', []):

NodeGraphQt/base/port.py

@@ -145,6 +145,9 @@ def connect_to(self, port=None):
         if not port:
             return
 
+        if self in port.connected_ports():
+            return
+
         graph = self.node().graph
         viewer = graph.viewer()
 

NodeGraphQt/constants.py

@@ -88,8 +88,11 @@
 
 # === NODE VIEWER ===
 
+#: Style to render the node graph background with nothing.
 VIEWER_GRID_NONE = 0
+#: Style to render the node graph background with dots.
 VIEWER_GRID_DOTS = 1
+#: Style to render the node graph background with grid lines.
 VIEWER_GRID_LINES = 2
 
 VIEWER_BG_COLOR = (35, 35, 35)

NodeGraphQt/widgets/node_publish_widget.py

@@ -1,6 +1,7 @@
+import os
+
 from .properties import PropFileSavePath
 from .. import QtWidgets
-import os
 
 
 class _element_widget(QtWidgets.QWidget):

NodeGraphQt/widgets/viewer.py

@@ -23,7 +23,7 @@ class NodeViewer(QtWidgets.QGraphicsView):
     """
     The widget interface used for displaying the scene and nodes.
 
-    functions in this class are called by the
+    functions in this class should mainly be called by the
     class:`NodeGraphQt.NodeGraph` class.
     """
 
@@ -665,6 +665,13 @@ def apply_live_connection(self, event):
             self.end_live_connection()
             return
 
+        # end connection if starting port is already connected.
+        if self._start_port.multi_connection and \
+                self._start_port in end_port.connected_ports:
+            self._detached_port = None
+            self.end_live_connection()
+            return
+
         # register as disconnected if not acyclic.
         if self.acyclic and not self.acyclic_check(self._start_port, end_port):
             if self._detached_port:
@@ -814,6 +821,16 @@ def message_dialog(text, title='Node Graph'):
         BaseDialog.message_dialog(text, title)
 
     def load_dialog(self, current_dir=None, ext=None):
+        """
+        Prompt node viewer file load dialog widget.
+
+        Args:
+            current_dir (str): directory path starting point. (optional)
+            ext (str): custom file extension filter type. (optional)
+
+        Returns:
+            str: selected file path.
+        """
         ext = '*{} '.format(ext) if ext else ''
         ext_filter = ';;'.join([
             'Node Graph ({}*json)'.format(ext), 'All Files (*)'
@@ -824,6 +841,16 @@ def load_dialog(self, current_dir=None, ext=None):
         return file
 
     def save_dialog(self, current_dir=None, ext=None):
+        """
+        Prompt node viewer file save dialog widget.
+
+        Args:
+            current_dir (str): directory path starting point. (optional)
+            ext (str): custom file extension filter type. (optional)
+
+        Returns:
+            str: selected file path.
+        """
         ext_label = '*{} '.format(ext) if ext else ''
         ext_type = '.{}'.format(ext) if ext else '.json'
         ext_map = {'Node Graph ({}*json)'.format(ext_label): ext_type,
@@ -924,6 +951,14 @@ def remove_node(node):
             node.delete()
 
     def move_nodes(self, nodes, pos=None, offset=None):
+        """
+        Globally move specified nodes.
+
+        Args:
+            nodes (list[AbstractNodeItem]): node items.
+            pos (tuple or list): custom x, y position.
+            offset (tuple or list): x, y position offset.
+        """
         group = self.scene().createItemGroup(nodes)
         group_rect = group.boundingRect()
         if pos:

README.md

@@ -40,6 +40,10 @@ applications that supports PySide2.
 #### Vertical Layout
 <img src="/docs/_images/vertical_layout.png" width="600" title="Vertical Layout">
 
+#### Pipe Layout
+
+<img src="/docs/_images/pipe_layout_types.gif" width="600" title="Vertical Layout">
+
 #### Example
 
 ```python

docs/_images/menu_hotkeys.png

@@ -162,7 +162,7 @@
 #  author, documentclass [howto, manual, or own class]).
 latex_documents = [
     (master_doc, 'NodeGraphQT.tex', 'NodeGraphQt Documentation',
-     'Johnny Chan', 'manual'),
+     author, 'manual'),
 ]