Add example of math node with a basic evaluation system.

Author: Leandro Inocencio

example_math_nodes.py

@@ -0,0 +1,248 @@
+#!/usr/bin/python
+# -*- coding: utf-8 -*-
+import os
+import inspect
+from functools import partial
+
+from NodeGraphQt import (NodeGraph,
+                         BaseNode,
+                         setup_context_menu)
+from NodeGraphQt import QtWidgets, QtCore, PropertiesBinWidget, NodeTreeWidget
+
+
+def update_streams(node):
+    """
+    Update all nodes joined by pipes
+    """
+    nodes = []
+    trash = []
+
+    for port, nodeList in node.connected_output_nodes().items():
+        nodes.extend(nodeList)
+
+    while nodes:
+        node = nodes.pop()
+        if node not in trash:
+            trash.append(node)
+
+        for port, nodeList in node.connected_output_nodes().items():
+            nodes.extend(nodeList)
+
+        if not nodes:
+            try:
+                node.run()
+            except Exception as error:
+                print("Error Update Streams: %s" % str(error))
+
+
+class DataInputNode(BaseNode):
+    """
+    Input node data.
+    """
+
+    __identifier__ = 'com.chantasticvfx'
+    NODE_NAME = 'Input Numbers'
+
+    def __init__(self):
+        super(DataInputNode, self).__init__()
+        self.output = self.add_output('out')
+        self.add_text_input('out', 'Data Input', text='4', tab='widgets')
+
+    def run(self):
+        return
+
+
+def add(a, b):
+    return a + b
+
+
+def sub(a, b):
+    return a - b
+
+
+def mul(a, b):
+    return a * b
+
+
+def div(a, b):
+    return a / b
+
+
+# create a dict with all function
+funcs = {'add': add, 'sub': sub, 'mul': mul, 'div': div}
+
+
+class MathFunctionsNode(BaseNode):
+    """
+    Math functions node.
+
+    """
+
+    # set a unique node identifier.
+    __identifier__ = 'com.chantasticvfx'
+
+    # set the initial default node name.
+    NODE_NAME = 'Functions node'
+
+    def __init__(self):
+        super(MathFunctionsNode, self).__init__()
+        self.set_color(25, 58, 51)
+        self.add_combo_menu('functions', 'Functions',
+                            items=funcs.keys(), tab='widgets')
+        # switch math function type
+        self.view.widgets['functions'].value_changed.connect(self.addFunction)
+        self.set_property('functions', 'add')
+        self.view.widgets['functions'].value_changed.connect(
+            partial(update_streams, self))
+        self.output = self.add_output('output')
+        self.create_property(self.output.name(), None)
+
+    def addFunction(self, prop, func):
+        """
+        Create inputs based on math functions arguments.
+        """
+        self.func = funcs[func]   # add, sub, mul, div
+
+        dataFunc = inspect.getargspec(self.func)
+
+        for arg in dataFunc.args:
+            if not self.has_property(arg):
+                self.add_input(arg)
+                self.create_property(arg, None)
+
+    def run(self):
+        """
+        Evaluate all entries, pass them as arguments of the
+        chosen mathematical function.
+        """
+        for to_port in self.input_ports():
+            from_ports = to_port.connected_ports()
+            if not from_ports:
+                raise Exception('Port %s not connected!' % to_port.name())
+
+            for from_port in from_ports:
+                from_port.node().run()
+                data = from_port.node().get_property(from_port.name())
+                self.set_property(to_port.name(), int(data))
+
+        try:
+            # Execute math function with arguments.
+            output = self.func(*[self.get_property(prop)
+                                 for prop in self.properties()['inputs']])
+            self.set_property('output', output)
+        except KeyError as error:
+            print("An input is missing! %s" % str(error))
+        except TypeError as error:
+            print("Error evaluating function: %s" % str(error))
+
+    def on_input_connected(self, to_port, from_port):
+        """Override node callback method."""
+        self.set_property(to_port.name(), from_port.node().run())
+        update_streams(self)
+
+    def on_input_disconnected(self, to_port, from_port):
+        """Override node callback method."""
+        self.set_property('output', None)
+        update_streams(self)
+
+
+class DataViewerNode(BaseNode):
+    __identifier__ = 'com.chantasticvfx'
+    NODE_NAME = 'Result View'
+
+    def __init__(self):
+        super(DataViewerNode, self).__init__()
+        self.input = self.add_input('in data')
+        self.add_text_input('data', 'Data Viewer', tab='widgets')
+
+    def run(self):
+        """Evaluate input to show it."""
+        for source in self.input.connected_ports():
+            from_node = source.node()
+            try:
+                from_node.run()
+            except Exception as error:
+                print("%s no inputs connected: %s" % (from_node.name(), str(error)))
+                self.set_property('data', None)
+                return
+            value = from_node.get_property(source.name())
+            self.set_property('data', str(value))
+
+    def on_input_connected(self, to_port, from_port):
+        """Override node callback method"""
+        self.run()
+
+    def on_input_disconnected(self, to_port, from_port):
+        """Override node callback method"""
+        self.set_property('data', None)
+
+
+if __name__ == '__main__':
+    app = QtWidgets.QApplication([])
+
+    # create node graph.
+    graph = NodeGraph()
+
+    # set up default menu and commands.
+    setup_context_menu(graph)
+
+    # widget used for the node graph.
+    graph_widget = graph.widget
+    graph_widget.resize(1100, 800)
+    graph_widget.show()
+
+    # show the properties bin when a node is "double clicked" in the graph.
+    properties_bin = PropertiesBinWidget(node_graph=graph)
+    properties_bin.setWindowFlags(QtCore.Qt.Tool)
+
+    def show_prop_bin(node):
+        if not properties_bin.isVisible():
+            properties_bin.show()
+    graph.node_double_clicked.connect(show_prop_bin)
+
+    # show the nodes list when a node is "double clicked" in the graph.
+    node_tree = NodeTreeWidget(node_graph=graph)
+
+    def show_nodes_list(node):
+        if not node_tree.isVisible():
+            node_tree.update()
+            node_tree.show()
+    graph.node_double_clicked.connect(show_nodes_list)
+
+    # registered nodes.
+    reg_nodes = [DataInputNode, DataViewerNode, MathFunctionsNode]
+
+    for n in reg_nodes:
+        graph.register_node(n)
+
+    my_node = graph.create_node('com.chantasticvfx.MathFunctionsNode',
+                                name='Math Functions A',
+                                color='#0a1e20',
+                                text_color='#feab20',
+                                pos=[-250, 70])
+
+    my_node = graph.create_node('com.chantasticvfx.MathFunctionsNode',
+                                name='Math Functions B',
+                                color='#0a1e20',
+                                text_color='#feab20',
+                                pos=[-250, -70])
+
+    my_node = graph.create_node('com.chantasticvfx.MathFunctionsNode',
+                                name='Math Functions C',
+                                color='#0a1e20',
+                                text_color='#feab20',
+                                pos=[0, 0])
+
+    inputANode = graph.create_node('com.chantasticvfx.DataInputNode',
+                                   name='Input A',
+                                   pos=[-500, -50])
+
+    inputBNode = graph.create_node('com.chantasticvfx.DataInputNode',
+                                   name='Input B',
+                                   pos=[-500, 50])
+
+    outputNode = graph.create_node('com.chantasticvfx.DataViewerNode',
+                                   name='Output',
+                                   pos=[250, 0])
+
+    app.exec_()