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