Class: Knights_Tour

Inherits:
Object show all
Defined in:
sample/demos-en/knightstour.rb,
sample/demos-jp/knightstour.rb

Instance Method Summary collapse

Constructor Details

#initialize(parent = nil) ⇒ Knights_Tour

Returns a new instance of Knights_Tour.


265
266
267
# File 'sample/demos-en/knightstour.rb', line 265

def initialize(parent = nil)
  create_gui(parent)
end

Instance Method Details

#_exitObject


126
127
128
129
# File 'sample/demos-en/knightstour.rb', line 126

def _exit
  _stop
  $knightstour.destroy
end

#_N(square) ⇒ Object

Display a square number as a standard chess square notation.


78
79
80
# File 'sample/demos-en/knightstour.rb', line 78

def _N(square)
  '%c%d' % [(97 + square % 8), (square.div(8) + 1)]
end

#_stopObject


122
123
124
# File 'sample/demos-en/knightstour.rb', line 122

def _stop
  Tk.after_cancel(@after_id) rescue nil
end

#check_square(square) ⇒ Object

Return the number of available moves for this square


45
46
47
# File 'sample/demos-en/knightstour.rb', line 45

def check_square(square)
  valid_moves(square).find_all{|pos| ! @visited.include?(pos)}.length
end

#create_gui(parent = nil) ⇒ Object


174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
# File 'sample/demos-en/knightstour.rb', line 174

def create_gui(parent = nil)
  $knightstour.destroy rescue nil
  $knightstour = Tk::Toplevel.new(parent, :title=>"Knight's tour")
  $knightstour.withdraw
  base_f = Ttk::Frame.new($knightstour)
  @board = Tk::Canvas.new(base_f, :width=>240, :height=>240)
  @log = Tk::Text.new(base_f, :width=>12, :height=>1,
                      :font=>'Arial 8', :background=>'white')
  scr = @log.yscrollbar(Ttk::Scrollbar.new(base_f))

  @visited = []
  @delay = TkVariable.new(600)
  @continuous = TkVariable.new(false)

  tool_f = Ttk::Frame.new($knightstour)
  label = Ttk::Label.new(tool_f, :text=>'Speed')
  scale = Ttk::Scale.new(tool_f, :from=>8, :to=>2000, :variable=>@delay,
                         :command=>proc{|n| set_delay(n)})
  check = Ttk::Checkbutton.new(tool_f, :text=>'Repeat',
                               :variable=>@continuous)
  @start_btn = Ttk::Button.new(tool_f, :text=>'Start',
                               :command=>proc{tour()})
  @exit_btn = Ttk::Button.new(tool_f, :text=>'Exit',
                              :command=>proc{_exit()})

  7.downto(0){|row|
    0.upto(7){|col|
      if ((col & 1) ^ (row & 1)).zero?
        fill  = 'bisque'
        dfill = 'bisque3'
      else
        fill  = 'tan3'
        dfill = 'tan4'
      end
      coords = [col * 30 + 4, row * 30 + 4, col * 30 + 30, row * 30 + 30]
      @board.create(TkcRectangle, coords,
                    :fill=>fill, :disabledfill=>dfill,
                    :width=>2, :state=>:disabled)
    }
  }

  @knight_font = TkFont.new(:size=>-24)
  @knight = TkcText.new(@board, 0, 0, :font=>@knight_font,
                        :text=>Tk::UTF8_String.new('\u265e'),
                        :anchor=>'nw', # :tags=>'knight',
                        :fill=>'black', :activefill=>'#600000')
  @knight.coords(@board.coords(rand(64)+1)[0..1])
  @knight.bind('ButtonPress-1', '%W %x %y'){|w,x,y| drag_start(w,x,y)}
  @knight.bind('Motion', '%W %x %y'){|w,x,y| drag_motion(w,x,y)}
  @knight.bind('ButtonRelease-1', '%W %x %y'){|w,x,y| drag_end(w,x,y)}

  Tk.grid(@board, @log, scr, :sticky=>'news')
  base_f.grid_rowconfigure(0, :weight=>1)
  base_f.grid_columnconfigure(0, :weight=>1)

  Tk.grid(base_f, '-', '-', '-', '-', '-', :sticky=>'news')
  widgets = [label, scale, check, @start_btn]
  sg = nil
  unless $RubyTk_WidgetDemo
    widgets << @exit_btn
    if Tk.windowingsystem != 'aqua'
      #widgets.unshift(Ttk::SizeGrip.new(tool_f))
      Ttk::SizeGrip.new(tool_f).pack(:side=>:right, :anchor=>'se')
    end
  end
  Tk.pack(widgets, :side=>:right)
  if Tk.windowingsystem == 'aqua'
    TkPack.configure(widgets, :padx=>[4, 4], :pady=>[12, 12])
    TkPack.configure(widgets[0], :padx=>[4, 24])
    TkPack.configure(widgets[-1], :padx=>[16, 4])
  end

  Tk.grid(tool_f, '-', '-', '-', '-', '-', :sticky=>'ew')

  if $RubyTk_WidgetDemo
    Tk.grid(make_SeeDismiss(), '-', '-', '-', '-', '-', :sticky=>'ew')
  end

  $knightstour.grid_rowconfigure(0, :weight=>1)
  $knightstour.grid_columnconfigure(0, :weight=>1)

  $knightstour.bind('Control-F2'){TkConsole.show}
  $knightstour.bind('Return'){@start_btn.invoke}
  $knightstour.bind('Escape'){@exit_btn.invoke}
  $knightstour.bind('Destroy'){ _stop }
  $knightstour.protocol('WM_DELETE_WINDOW'){ _exit }

  $knightstour.deiconify
  $knightstour.tkwait_destroy
end

#drag_end(w, x, y) ⇒ Object


147
148
149
150
151
152
# File 'sample/demos-en/knightstour.rb', line 147

def drag_end(w, x, y)
  square = w.find_closest(x, y, 0, 65)
  w.coords('selected', w.coords(square)[0..1])
  w.dtag('selected')
  @dragging = nil
end

#drag_motion(w, x, y) ⇒ Object


141
142
143
144
145
# File 'sample/demos-en/knightstour.rb', line 141

def drag_motion(w, x, y)
  return unless @dragging
  w.move('selected', x - @dragging[0], y - @dragging[1])
  @dragging = [x, y]
end

#drag_start(w, x, y) ⇒ Object


135
136
137
138
139
# File 'sample/demos-en/knightstour.rb', line 135

def drag_start(w, x, y)
  w.dtag('selected')
  w.addtag('selected', :withtag, 'current')
  @dragging = [x, y]
end

#edgemost(nxt, pos) ⇒ Object

Select the square nearest the edge of the board


69
70
71
72
73
74
75
# File 'sample/demos-en/knightstour.rb', line 69

def edgemost(nxt, pos)
  col_A = 3 - ((3.5 - nxt % 8).abs.to_i)
  col_B = 3 - ((3.5 - pos % 8).abs.to_i)
  row_A = 3 - ((3.5 - nxt.div(8)).abs.to_i)
  row_B = 3 - ((3.5 - pos.div(8)).abs.to_i)
  (col_A * row_A < col_B * row_B)? nxt : pos
end

#make_SeeDismissObject


154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
# File 'sample/demos-en/knightstour.rb', line 154

def make_SeeDismiss
  ## See Code / Dismiss
  frame = Ttk::Frame.new($knightstour)
  sep = Ttk::Separator.new(frame)
  Tk.grid(sep, :columnspan=>4, :row=>0, :sticky=>'ew', :pady=>2)
  TkGrid('x',
         Ttk::Button.new(frame, :text=>'See Code',
                         :image=>$image['view'], :compound=>:left,
                         :command=>proc{showCode 'knightstour'}),
         Ttk::Button.new(frame, :text=>'Dismiss',
                         :image=>$image['delete'], :compound=>:left,
                         :command=>proc{
                           $knightstour.destroy
                           $knightstour = nil
                         }),
         :padx=>4, :pady=>4)
  frame.grid_columnconfigure(0, :weight=>1)
  frame
end

#move_piece(last, square) ⇒ Object

Perform a Knight's move and schedule the next move.


83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
# File 'sample/demos-en/knightstour.rb', line 83

def move_piece(last, square)
  @log.insert(:end, "#{@visited.length}. #{_N last} -> #{_N square}\n", '')
  @log.see(:end)
  @board.itemconfigure(1+last, :state=>:normal, :outline=>'black')
  @board.itemconfigure(1+square, :state=>:normal, :outline=>'red')
  @knight.coords(@board.coords(1+square)[0..1])
  @visited << square
  if (nxt = next_square(square)) != -1
    @after_id = Tk.after(@delay.numeric){move_piece(square, nxt) rescue nil}
  else
    @start_btn.state :normal
    if @visited.length == 64
      if @initial == square
        @log.insert :end, 'Closed tour!'
      else
        @log.insert :end, "Success\n", {}
        Tk.after(@delay.numeric * 2){tour(rand(64))} if @continuous.bool
      end
    else
      @log.insert :end, "FAILED!\n", {}
    end
  end
end

#next_square(square) ⇒ Object

Select the next square to move to. Returns -1 if there are no available squares remaining that we can move to.


51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
# File 'sample/demos-en/knightstour.rb', line 51

def next_square(square)
  minimum = 9
  nxt = -1
  valid_moves(square).each{|pos|
    unless @visited.include?(pos)
      cnt = check_square(pos)
      if cnt < minimum
        minimum = cnt
        nxt = pos
      elsif cnt == minimum
        nxt = edgemost(nxt, pos)
      end
    end
  }
  nxt
end

#set_delay(new) ⇒ Object


131
132
133
# File 'sample/demos-en/knightstour.rb', line 131

def set_delay(new)
  @delay.numeric = new.to_i
end

#tour(square = nil) ⇒ Object

Begin a new tour of the board given a random start position


108
109
110
111
112
113
114
115
116
117
118
119
120
# File 'sample/demos-en/knightstour.rb', line 108

def tour(square = nil)
  @visited.clear
  @log.clear
  @start_btn.state :disabled
  1.upto(64){|n|
    @board.itemconfigure(n, :state=>:disabled, :outline=>'black')
  }
  unless square
    square = @board.find_closest(*(@knight.coords << 0 << 65))[0].to_i - 1
  end
  @initial = square
  Tk.after_idle{ move_piece(@initial, @initial) rescue nil }
end

#valid_moves(square) ⇒ Object

Return a list of accessible squares from a given square


32
33
34
35
36
37
38
39
40
41
42
# File 'sample/demos-en/knightstour.rb', line 32

def valid_moves(square)
  moves = []
  [
    [-1,-2], [-2,-1], [-2,1], [-1,2], [1,2], [2,1], [2,-1], [1,-2]
  ].each{|col_delta, row_delta|
    col = (square % 8) + col_delta
    row = (square.div(8)) + row_delta
    moves << (row * 8 + col) if row > -1 && row < 8 && col > -1 && col < 8
  }
  moves
end