| #! /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 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() |