Class: Knights_Tour

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

Instance Method Summary collapse

• Display a square number as a standard chess square notation.

• Return the number of available moves for this square.

• Select the square nearest the edge of the board.

• constructor

A new instance of Knights_Tour.

• Perform a Knight’s move and schedule the next move.

• Select the next square to move to.

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

• Return a list of accessible squares from a given square.

Constructor Details

#initialize(parent = nil) ⇒ Knights_Tour

Returns a new instance of Knights_Tour.

 ``` 264 265 266``` ```# File 'sample/demos-en/knightstour.rb', line 264 def initialize(parent = nil) create_gui(parent) end```

Instance Method Details

#_exit ⇒ Object

 ``` 125 126 127 128``` ```# File 'sample/demos-en/knightstour.rb', line 125 def _exit _stop \$knightstour.destroy end```

#_N(square) ⇒ Object

Display a square number as a standard chess square notation.

 ``` 77 78 79``` ```# File 'sample/demos-en/knightstour.rb', line 77 def _N(square) '%c%d' % [(97 + square % 8), (square.div(8) + 1)] end```

#_stop ⇒ Object

 ``` 121 122 123``` ```# File 'sample/demos-en/knightstour.rb', line 121 def _stop Tk.after_cancel(@after_id) rescue nil end```

#check_square(square) ⇒ Object

Return the number of available moves for this square

 ``` 44 45 46``` ```# File 'sample/demos-en/knightstour.rb', line 44 def check_square(square) valid_moves(square).find_all{|pos| ! @visited.include?(pos)}.length end```

#create_gui(parent = nil) ⇒ Object

 ``` 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262``` ```# File 'sample/demos-en/knightstour.rb', line 173 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

 ``` 146 147 148 149 150 151``` ```# File 'sample/demos-en/knightstour.rb', line 146 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

 ``` 140 141 142 143 144``` ```# File 'sample/demos-en/knightstour.rb', line 140 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

 ``` 134 135 136 137 138``` ```# File 'sample/demos-en/knightstour.rb', line 134 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

 ``` 68 69 70 71 72 73 74``` ```# File 'sample/demos-en/knightstour.rb', line 68 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_SeeDismiss ⇒ Object

 ``` 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171``` ```# File 'sample/demos-en/knightstour.rb', line 153 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.

 ``` 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104``` ```# File 'sample/demos-en/knightstour.rb', line 82 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.

 ``` 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65``` ```# File 'sample/demos-en/knightstour.rb', line 50 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

 ``` 130 131 132``` ```# File 'sample/demos-en/knightstour.rb', line 130 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

 ``` 107 108 109 110 111 112 113 114 115 116 117 118 119``` ```# File 'sample/demos-en/knightstour.rb', line 107 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

 ``` 31 32 33 34 35 36 37 38 39 40 41``` ```# File 'sample/demos-en/knightstour.rb', line 31 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```