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| 1 | +#! /usr/bin/env python |
| 2 | + |
| 3 | +from Tkinter import * |
| 4 | +from Canvas import Oval, Group, CanvasText |
| 5 | + |
| 6 | + |
| 7 | +# Fix a bug in Canvas.Group as distributed in Python 1.4. The |
| 8 | +# distributed bind() method is broken. This is what should be used: |
| 9 | + |
| 10 | +class Group(Group): |
| 11 | + def bind(self, sequence=None, command=None): |
| 12 | + return self.canvas.tag_bind(self.id, sequence, command) |
| 13 | + |
| 14 | +class Object: |
| 15 | + |
| 16 | + """Base class for composite graphical objects. |
| 17 | +
|
| 18 | + Objects belong to a canvas, and can be moved around on the canvas. |
| 19 | + They also belong to at most one ``pile'' of objects, and can be |
| 20 | + transferred between piles (or removed from their pile). |
| 21 | +
|
| 22 | + Objects have a canonical ``x, y'' position which is moved when the |
| 23 | + object is moved. Where the object is relative to this position |
| 24 | + depends on the object; for simple objects, it may be their center. |
| 25 | +
|
| 26 | + Objects have mouse sensitivity. They can be clicked, dragged and |
| 27 | + double-clicked. The behavior may actually determined by the pile |
| 28 | + they are in. |
| 29 | +
|
| 30 | + All instance attributes are public since the derived class may |
| 31 | + need them. |
| 32 | +
|
| 33 | + """ |
| 34 | + |
| 35 | + def __init__(self, canvas, x=0, y=0, fill='red', text='object'): |
| 36 | + self.canvas = canvas |
| 37 | + self.x = x |
| 38 | + self.y = y |
| 39 | + self.pile = None |
| 40 | + self.group = Group(self.canvas) |
| 41 | + self.createitems(fill, text) |
| 42 | + |
| 43 | + def __str__(self): |
| 44 | + return str(self.group) |
| 45 | + |
| 46 | + def createitems(self, fill, text): |
| 47 | + self.__oval = Oval(self.canvas, |
| 48 | + self.x-20, self.y-10, self.x+20, self.y+10, |
| 49 | + fill=fill, width=3) |
| 50 | + self.group.addtag_withtag(self.__oval) |
| 51 | + self.__text = CanvasText(self.canvas, |
| 52 | + self.x, self.y, text=text) |
| 53 | + self.group.addtag_withtag(self.__text) |
| 54 | + |
| 55 | + def moveby(self, dx, dy): |
| 56 | + if dx == dy == 0: |
| 57 | + return |
| 58 | + self.group.move(dx, dy) |
| 59 | + self.x = self.x + dx |
| 60 | + self.y = self.y + dy |
| 61 | + |
| 62 | + def moveto(self, x, y): |
| 63 | + self.moveby(x - self.x, y - self.y) |
| 64 | + |
| 65 | + def transfer(self, pile): |
| 66 | + if self.pile: |
| 67 | + self.pile.delete(self) |
| 68 | + self.pile = None |
| 69 | + self.pile = pile |
| 70 | + if self.pile: |
| 71 | + self.pile.add(self) |
| 72 | + |
| 73 | + def tkraise(self): |
| 74 | + self.group.tkraise() |
| 75 | + |
| 76 | + |
| 77 | +class Bottom(Object): |
| 78 | + |
| 79 | + """An object to serve as the bottom of a pile.""" |
| 80 | + |
| 81 | + def createitems(self, *args): |
| 82 | + self.__oval = Oval(self.canvas, |
| 83 | + self.x-20, self.y-10, self.x+20, self.y+10, |
| 84 | + fill='gray', outline='') |
| 85 | + self.group.addtag_withtag(self.__oval) |
| 86 | + |
| 87 | + |
| 88 | +class Pile: |
| 89 | + |
| 90 | + """A group of graphical objects.""" |
| 91 | + |
| 92 | + def __init__(self, canvas, x, y, tag=None): |
| 93 | + self.canvas = canvas |
| 94 | + self.x = x |
| 95 | + self.y = y |
| 96 | + self.objects = [] |
| 97 | + self.bottom = Bottom(self.canvas, self.x, self.y) |
| 98 | + self.group = Group(self.canvas, tag=tag) |
| 99 | + self.group.addtag_withtag(self.bottom.group) |
| 100 | + self.bindhandlers() |
| 101 | + |
| 102 | + def bindhandlers(self): |
| 103 | + self.group.bind('<1>', self.clickhandler) |
| 104 | + self.group.bind('<Double-1>', self.doubleclickhandler) |
| 105 | + |
| 106 | + def add(self, object): |
| 107 | + self.objects.append(object) |
| 108 | + self.group.addtag_withtag(object.group) |
| 109 | + self.position(object) |
| 110 | + |
| 111 | + def delete(self, object): |
| 112 | + object.group.dtag(self.group) |
| 113 | + self.objects.remove(object) |
| 114 | + |
| 115 | + def position(self, object): |
| 116 | + object.tkraise() |
| 117 | + i = self.objects.index(object) |
| 118 | + object.moveto(self.x + i*4, self.y + i*8) |
| 119 | + |
| 120 | + def clickhandler(self, event): |
| 121 | + pass |
| 122 | + |
| 123 | + def doubleclickhandler(self, event): |
| 124 | + pass |
| 125 | + |
| 126 | + |
| 127 | +class MovingPile(Pile): |
| 128 | + |
| 129 | + def bindhandlers(self): |
| 130 | + Pile.bindhandlers(self) |
| 131 | + self.group.bind('<B1-Motion>', self.motionhandler) |
| 132 | + self.group.bind('<ButtonRelease-1>', self.releasehandler) |
| 133 | + |
| 134 | + movethis = None |
| 135 | + |
| 136 | + def clickhandler(self, event): |
| 137 | + tags = self.canvas.gettags('current') |
| 138 | + for i in range(len(self.objects)): |
| 139 | + o = self.objects[i] |
| 140 | + if o.group.tag in tags: |
| 141 | + break |
| 142 | + else: |
| 143 | + self.movethis = None |
| 144 | + return |
| 145 | + self.movethis = self.objects[i:] |
| 146 | + for o in self.movethis: |
| 147 | + o.tkraise() |
| 148 | + self.lastx = event.x |
| 149 | + self.lasty = event.y |
| 150 | + |
| 151 | + doubleclickhandler = clickhandler |
| 152 | + |
| 153 | + def motionhandler(self, event): |
| 154 | + if not self.movethis: |
| 155 | + return |
| 156 | + dx = event.x - self.lastx |
| 157 | + dy = event.y - self.lasty |
| 158 | + self.lastx = event.x |
| 159 | + self.lasty = event.y |
| 160 | + for o in self.movethis: |
| 161 | + o.moveby(dx, dy) |
| 162 | + |
| 163 | + def releasehandler(self, event): |
| 164 | + objects = self.movethis |
| 165 | + if not objects: |
| 166 | + return |
| 167 | + self.movethis = None |
| 168 | + self.finishmove(objects) |
| 169 | + |
| 170 | + def finishmove(self, objects): |
| 171 | + for o in objects: |
| 172 | + self.position(o) |
| 173 | + |
| 174 | + |
| 175 | +class Pile1(MovingPile): |
| 176 | + |
| 177 | + x = 50 |
| 178 | + y = 50 |
| 179 | + tag = 'p1' |
| 180 | + |
| 181 | + def __init__(self, demo): |
| 182 | + self.demo = demo |
| 183 | + MovingPile.__init__(self, self.demo.canvas, self.x, self.y, self.tag) |
| 184 | + |
| 185 | + def doubleclickhandler(self, event): |
| 186 | + try: |
| 187 | + o = self.objects[-1] |
| 188 | + except IndexError: |
| 189 | + return |
| 190 | + o.transfer(self.other()) |
| 191 | + MovingPile.doubleclickhandler(self, event) |
| 192 | + |
| 193 | + def other(self): |
| 194 | + return self.demo.p2 |
| 195 | + |
| 196 | + def finishmove(self, objects): |
| 197 | + o = objects[0] |
| 198 | + p = self.other() |
| 199 | + x, y = o.x, o.y |
| 200 | + if (x-p.x)**2 + (y-p.y)**2 < (x-self.x)**2 + (y-self.y)**2: |
| 201 | + for o in objects: |
| 202 | + o.transfer(p) |
| 203 | + else: |
| 204 | + MovingPile.finishmove(self, objects) |
| 205 | + |
| 206 | +class Pile2(Pile1): |
| 207 | + |
| 208 | + x = 150 |
| 209 | + y = 50 |
| 210 | + tag = 'p2' |
| 211 | + |
| 212 | + def other(self): |
| 213 | + return self.demo.p1 |
| 214 | + |
| 215 | + |
| 216 | +class Demo: |
| 217 | + |
| 218 | + def __init__(self, master): |
| 219 | + self.master = master |
| 220 | + self.canvas = Canvas(master, |
| 221 | + width=200, height=200, |
| 222 | + background='yellow', |
| 223 | + relief=SUNKEN, borderwidth=2) |
| 224 | + self.canvas.pack(expand=1, fill=BOTH) |
| 225 | + self.p1 = Pile1(self) |
| 226 | + self.p2 = Pile2(self) |
| 227 | + o1 = Object(self.canvas, fill='red', text='o1') |
| 228 | + o2 = Object(self.canvas, fill='green', text='o2') |
| 229 | + o3 = Object(self.canvas, fill='light blue', text='o3') |
| 230 | + o1.transfer(self.p1) |
| 231 | + o2.transfer(self.p1) |
| 232 | + o3.transfer(self.p2) |
| 233 | + |
| 234 | + |
| 235 | +# Main function, run when invoked as a stand-alone Python program. |
| 236 | + |
| 237 | +def main(): |
| 238 | + root = Tk() |
| 239 | + demo = Demo(root) |
| 240 | + root.protocol('WM_DELETE_WINDOW', root.quit) |
| 241 | + root.mainloop() |
| 242 | + |
| 243 | +if __name__ == '__main__': |
| 244 | + main() |
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