| #! /usr/bin/env python | |
| from Tkinter import * | |
| from Canvas import Oval, Group, CanvasText | |
| # Fix a bug in Canvas.Group as distributed in Python 1.4. The | |
| # distributed bind() method is broken. This is what should be used: | |
| class Group(Group): | |
| def bind(self, sequence=None, command=None): | |
| return self.canvas.tag_bind(self.id, sequence, command) | |
| class Object: | |
| """Base class for composite graphical objects. | |
| Objects belong to a canvas, and can be moved around on the canvas. | |
| They also belong to at most one ``pile'' of objects, and can be | |
| transferred between piles (or removed from their pile). | |
| Objects have a canonical ``x, y'' position which is moved when the | |
| object is moved. Where the object is relative to this position | |
| depends on the object; for simple objects, it may be their center. | |
| Objects have mouse sensitivity. They can be clicked, dragged and | |
| double-clicked. The behavior may actually be determined by the pile | |
| they are in. | |
| All instance attributes are public since the derived class may | |
| need them. | |
| """ | |
| def __init__(self, canvas, x=0, y=0, fill='red', text='object'): | |
| self.canvas = canvas | |
| self.x = x | |
| self.y = y | |
| self.pile = None | |
| self.group = Group(self.canvas) | |
| self.createitems(fill, text) | |
| def __str__(self): | |
| return str(self.group) | |
| def createitems(self, fill, text): | |
| self.__oval = Oval(self.canvas, | |
| self.x-20, self.y-10, self.x+20, self.y+10, | |
| fill=fill, width=3) | |
| self.group.addtag_withtag(self.__oval) | |
| self.__text = CanvasText(self.canvas, | |
| self.x, self.y, text=text) | |
| self.group.addtag_withtag(self.__text) | |
| def moveby(self, dx, dy): | |
| if dx == dy == 0: | |
| return | |
| self.group.move(dx, dy) | |
| self.x = self.x + dx | |
| self.y = self.y + dy | |
| def moveto(self, x, y): | |
| self.moveby(x - self.x, y - self.y) | |
| def transfer(self, pile): | |
| if self.pile: | |
| self.pile.delete(self) | |
| self.pile = None | |
| self.pile = pile | |
| if self.pile: | |
| self.pile.add(self) | |
| def tkraise(self): | |
| self.group.tkraise() | |
| class Bottom(Object): | |
| """An object to serve as the bottom of a pile.""" | |
| def createitems(self, *args): | |
| self.__oval = Oval(self.canvas, | |
| self.x-20, self.y-10, self.x+20, self.y+10, | |
| fill='gray', outline='') | |
| self.group.addtag_withtag(self.__oval) | |
| class Pile: | |
| """A group of graphical objects.""" | |
| def __init__(self, canvas, x, y, tag=None): | |
| self.canvas = canvas | |
| self.x = x | |
| self.y = y | |
| self.objects = [] | |
| self.bottom = Bottom(self.canvas, self.x, self.y) | |
| self.group = Group(self.canvas, tag=tag) | |
| self.group.addtag_withtag(self.bottom.group) | |
| self.bindhandlers() | |
| def bindhandlers(self): | |
| self.group.bind('<1>', self.clickhandler) | |
| self.group.bind('<Double-1>', self.doubleclickhandler) | |
| def add(self, object): | |
| self.objects.append(object) | |
| self.group.addtag_withtag(object.group) | |
| self.position(object) | |
| def delete(self, object): | |
| object.group.dtag(self.group) | |
| self.objects.remove(object) | |
| def position(self, object): | |
| object.tkraise() | |
| i = self.objects.index(object) | |
| object.moveto(self.x + i*4, self.y + i*8) | |
| def clickhandler(self, event): | |
| pass | |
| def doubleclickhandler(self, event): | |
| pass | |
| class MovingPile(Pile): | |
| def bindhandlers(self): | |
| Pile.bindhandlers(self) | |
| self.group.bind('<B1-Motion>', self.motionhandler) | |
| self.group.bind('<ButtonRelease-1>', self.releasehandler) | |
| movethis = None | |
| def clickhandler(self, event): | |
| tags = self.canvas.gettags('current') | |
| for i in range(len(self.objects)): | |
| o = self.objects[i] | |
| if o.group.tag in tags: | |
| break | |
| else: | |
| self.movethis = None | |
| return | |
| self.movethis = self.objects[i:] | |
| for o in self.movethis: | |
| o.tkraise() | |
| self.lastx = event.x | |
| self.lasty = event.y | |
| doubleclickhandler = clickhandler | |
| def motionhandler(self, event): | |
| if not self.movethis: | |
| return | |
| dx = event.x - self.lastx | |
| dy = event.y - self.lasty | |
| self.lastx = event.x | |
| self.lasty = event.y | |
| for o in self.movethis: | |
| o.moveby(dx, dy) | |
| def releasehandler(self, event): | |
| objects = self.movethis | |
| if not objects: | |
| return | |
| self.movethis = None | |
| self.finishmove(objects) | |
| def finishmove(self, objects): | |
| for o in objects: | |
| self.position(o) | |
| class Pile1(MovingPile): | |
| x = 50 | |
| y = 50 | |
| tag = 'p1' | |
| def __init__(self, demo): | |
| self.demo = demo | |
| MovingPile.__init__(self, self.demo.canvas, self.x, self.y, self.tag) | |
| def doubleclickhandler(self, event): | |
| try: | |
| o = self.objects[-1] | |
| except IndexError: | |
| return | |
| o.transfer(self.other()) | |
| MovingPile.doubleclickhandler(self, event) | |
| def other(self): | |
| return self.demo.p2 | |
| def finishmove(self, objects): | |
| o = objects[0] | |
| p = self.other() | |
| x, y = o.x, o.y | |
| if (x-p.x)**2 + (y-p.y)**2 < (x-self.x)**2 + (y-self.y)**2: | |
| for o in objects: | |
| o.transfer(p) | |
| else: | |
| MovingPile.finishmove(self, objects) | |
| class Pile2(Pile1): | |
| x = 150 | |
| y = 50 | |
| tag = 'p2' | |
| def other(self): | |
| return self.demo.p1 | |
| class Demo: | |
| def __init__(self, master): | |
| self.master = master | |
| self.canvas = Canvas(master, | |
| width=200, height=200, | |
| background='yellow', | |
| relief=SUNKEN, borderwidth=2) | |
| self.canvas.pack(expand=1, fill=BOTH) | |
| self.p1 = Pile1(self) | |
| self.p2 = Pile2(self) | |
| o1 = Object(self.canvas, fill='red', text='o1') | |
| o2 = Object(self.canvas, fill='green', text='o2') | |
| o3 = Object(self.canvas, fill='light blue', text='o3') | |
| o1.transfer(self.p1) | |
| o2.transfer(self.p1) | |
| o3.transfer(self.p2) | |
| # Main function, run when invoked as a stand-alone Python program. | |
| def main(): | |
| root = Tk() | |
| demo = Demo(root) | |
| root.protocol('WM_DELETE_WINDOW', root.quit) | |
| root.mainloop() | |
| if __name__ == '__main__': | |
| main() |