"""Rect Tracker class for Python Tkinter Canvas"""
def groups(glist, numPerGroup=2):
result = []
i = 0
cur = []
for item in glist:
if not i < numPerGroup:
result.append(cur)
cur = []
i = 0
cur.append(item)
i += 1
if cur:
result.append(cur)
return result
def average(points):
aver = [0,0]
for point in points:
aver[0] += point[0]
aver[1] += point[1]
return aver[0]/len(points), aver[1]/len(points)
class RectTracker:
def __init__(self, canvas):
self.canvas = canvas
self.item = None
def draw(self, start, end, **opts):
"""Draw the rectangle"""
return self.canvas.create_rectangle(*(list(start)+list(end)), **opts)
def autodraw(self, **opts):
"""Setup automatic drawing; supports command option"""
self.start = None
self.canvas.bind("<Button-1>", self.__update, '+')
self.canvas.bind("<B1-Motion>", self.__update, '+')
self.canvas.bind("<ButtonRelease-1>", self.__stop, '+')
self._command = opts.pop('command', lambda *args: None)
self.rectopts = opts
def __update(self, event):
if not self.start:
self.start = [event.x, event.y]
return
if self.item is not None:
self.canvas.delete(self.item)
self.item = self.draw(self.start, (event.x, event.y), **self.rectopts)
self._command(self.start, (event.x, event.y))
def __stop(self, event):
self.start = None
self.canvas.delete(self.item)
self.item = None
def hit_test(self, start, end, tags=None, ignoretags=None, ignore=[]):
"""
Check to see if there are items between the start and end
"""
ignore = set(ignore)
ignore.update([self.item])
# first filter all of the items in the canvas
if isinstance(tags, str):
tags = [tags]
if tags:
tocheck = []
for tag in tags:
tocheck.extend(self.canvas.find_withtag(tag))
else:
tocheck = self.canvas.find_all()
tocheck = [x for x in tocheck if x != self.item]
if ignoretags:
if not hasattr(ignoretags, '__iter__'):
ignoretags = [ignoretags]
tocheck = [x for x in tocheck if x not in self.canvas.find_withtag(it) for it in ignoretags]
self.items = tocheck
# then figure out the box
xlow = min(start[0], end[0])
xhigh = max(start[0], end[0])
ylow = min(start[1], end[1])
yhigh = max(start[1], end[1])
items = []
for item in tocheck:
if item not in ignore:
x, y = average(groups(self.canvas.coords(item)))
if (xlow < x < xhigh) and (ylow < y < yhigh):
items.append(item)
return items
def main():
from random import shuffle
canv = Canvas(width=500, height=500)
canv.create_rectangle(50, 50, 250, 150, fill='red')
canv.pack(fill=BOTH, expand=YES)
rect = RectTracker(canv)
# draw some base rectangles
rect.draw([50,50], [250, 150], fill='red', tags=('red', 'box'))
rect.draw([300,300], [400, 450], fill='green', tags=('gre', 'box'))
# just for fun
x, y = None, None
def cool_design(event):
global x, y
kill_xy()
dashes = [3, 2]
x = canv.create_line(event.x, 0, event.x, 1000, dash=dashes, tags='no')
y = canv.create_line(0, event.y, 1000, event.y, dash=dashes, tags='no')
def kill_xy(event=None):
canv.delete('no')
canv.bind('<Motion>', cool_design, '+')
# command
def onDrag(start, end):
global x,y
items = rect.hit_test(start, end)
for x in rect.items:
if x not in items:
canv.itemconfig(x, fill='grey')
else:
canv.itemconfig(x, fill='blue')
rect.autodraw(fill="", width=2, command=onDrag)
mainloop()
if __name__ == '__main__':
try:
from tkinter import *
except ImportError:
from Tkinter import *
main()
