# -*- coding: utf-8 -*-
"""The Tk graphical representation of an edge in the graph, i.e. an
arrow connecting nodes.
The information is stored in the graph object as attributes of the
edge so that the graphical representation can be restored as needed.
"""
import logging
import math
import seamm
from tkinter import font
import tkinter as tk
import weakref
logger = logging.getLogger(__name__)
[docs]
class TkEdge(seamm.Edge):
str_to_object = weakref.WeakValueDictionary()
def __init__(
self,
graph,
node1,
node2,
edge_type="execution",
edge_subtype="next",
canvas=None,
anchor1="s",
anchor2="n",
coords=None,
**kwargs
):
"""Initialize the edge, ensuring that it is
in the graph.
Keyword arguments:
"""
self._data = []
logger.debug("Creating TkEdge {}".format(self))
logger.debug("\tnode1 = {}".format(node1))
logger.debug("\tnode2 = {}".format(node2))
# Initialize the parent class
super().__init__(graph, node1, node2, edge_type, edge_subtype, **kwargs)
self._data["canvas"] = canvas
self.anchor1 = anchor1
self.anchor2 = anchor2
if coords is None:
x0, y0 = self.node1.anchor_point(self.anchor1)
x1, y1 = self.node2.anchor_point(self.anchor2)
self.coords = [x0, y0, x1, y1]
else:
self.coords = coords
# Remember the object so can get from tags on the canvas
TkEdge.str_to_object[str(id(self))] = self
# Arrange that the graphics are deleted when we are
self._finalizer = weakref.finalize(self, self.canvas.delete, self.tag())
self._finalizer.atexit = False
def __eq__(self, other):
"""Return a boolean if this object is equal to another"""
return super().__eq__(other)
@property
def canvas(self):
return self._data["canvas"]
@property
def anchor1(self):
return self._data["anchor1"]
@anchor1.setter
def anchor1(self, value):
self._data["anchor1"] = value
@property
def anchor2(self):
return self._data["anchor2"]
@anchor2.setter
def anchor2(self, value):
self._data["anchor2"] = value
@property
def coords(self):
return self._data["coords"]
@coords.setter
def coords(self, value):
self._data["coords"] = value
@property
def has_label(self):
return "label_id" in self._data
@property
def label_id(self):
return self._data["label_id"]
@property
def label_bg_id(self):
return self._data["label_bg_id"]
[docs]
def tag(self):
"""Return a string tag for self"""
return "edge=" + str(id(self))
[docs]
def draw(self):
"""Draw the arrow for this edge"""
self.move()
[docs]
def move(self):
"""Redraw the arrow when the nodes have moved"""
x0, y0 = self.node1.anchor_point(self.anchor1)
x1, y1 = self.node2.anchor_point(self.anchor2)
self.coords[0] = x0
self.coords[1] = y0
self.coords[-2] = x1
self.coords[-1] = y1
# the arrow
self.canvas.delete(self.tag() + "&& type=arrow")
arrow_id = self.canvas.create_line(
self.coords, arrow=tk.LAST, tags=[self.tag(), "type=arrow"]
)
self._data["arrow_id"] = arrow_id
# and the label
if self.edge_subtype != "next":
self.canvas.delete(self.tag() + "&& type=label")
text = self.canvas.create_text(
self.label_position(x0, y0, x1, y1),
text=self.edge_subtype,
font=font.Font(family="Helvetica", size=8),
tags=[self.tag(), "type=label"],
)
self._data["label_id"] = text
self.canvas.delete(self.tag() + "&& type=label_bg")
bg = self.canvas.create_rectangle(
self.canvas.bbox(text),
outline="white",
fill="white",
tags=[self.tag(), "type=label_bg"],
)
self._data["label_bg_id"] = bg
self.canvas.tag_lower(bg, text)
[docs]
def label_position(self, x0, y0, x1, y1, offset=15):
"""Work out the position for the label on an edge"""
dx = x1 - x0
dy = y1 - y0
length = math.sqrt(dx * dx + dy * dy)
if length < 2 * offset:
offset = int(length / 2)
xy = [
x0 if dx == 0.0 else x0 + dx / length * offset,
y0 if dy == 0.0 else y0 + dy / length * offset,
]
return xy
[docs]
def undraw(self):
"""Remove any graphics"""
self.canvas.delete(self.tag())
if "arrow_id" in self._data:
del self._data["arrow_id"]
if "label_id" in self._data:
del self._data["label_id"]
if "label_bg_id" in self._data:
del self._data["label_bg_id"]
