#!/usr/bin/env python
"""
Node and Edge Artist Customisation
==================================

Node artists
------------

The shape, size, and colour of node representations can be controlled via the following parameters:

- :code:`node_shape` : node shape; one of 'so^>v<dph8'
- :code:`node_size` : node radius
- :code:`node_edge_width` : line width of node marker border
- :code:`node_color` : node face colour
- :code:`node_edge_color` : node edge colour
- :code:`node_alpha` : node transparency
- :code:`node_zorder` : node z-order; artists with higher z-order occlude artists with lower z-order

Edge artists
------------

The shape, size, and colour of edge representations can be controlled via the following parameters:

- :code:`edge_width` : edge width
- :code:`edge_color` : edge face colour
- :code:`edge_alpha` : edge transparency
- :code:`edge_zorder` : node zorder; artists with higher z-order occlude artists with lower z-order
- :code:`arrows` : boolean flag that turn the drawing of arrow heads on or off

All node and edge artist properties can be specified in three ways:
"""

################################################################################
# 1. Using a single scalar or string that will be applied to all artists.

import matplotlib.pyplot as plt
from netgraph import Graph

edges = [(0, 1), (1, 1)]
Graph(edges, node_color='red', node_size=4.)
plt.show()

################################################################################
# 2. Using a dictionary mapping individual nodes or individual edges to a property:

import numpy as np
import matplotlib.pyplot as plt
from netgraph import Graph

Graph([(0, 1), (1, 2), (2, 0)],
      edge_color={(0, 1) : 'g', (1, 2) : 'lightblue', (2, 0) : np.array([1, 0, 0])},
      node_size={0 : 20, 1 : 4.2, 2 : np.pi},
)
plt.show()

################################################################################
# 3. By directly manipulating the node and edge artists.
#
# Node and edge artists are derived from the :code:`matplotlib.patches.PathPatch` class,
# such that any of its methods can be used to modify node and edge artists properties.

import matplotlib.pyplot as plt; plt.ion()
from netgraph import Graph

fig, ax = plt.subplots()
g = Graph([(0, 1), (1, 2), (2, 0)], ax=ax)
plt.show()

# make some changes
g.node_artists[0].set_alpha(0.2)
g.edge_artists[(1, 2)].set_facecolor('red')

# force redraw to display changes
fig.canvas.draw()