272 lines
8.7 KiB
Ruby
272 lines
8.7 KiB
Ruby
# Based on the widget demo of Tcl/Tk8.5.2
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# The following is the original copyright text.
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#----------------------------------------------------------------------------
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# Copyright (C) 2008 Pat Thoyts <patthoyts@users.sourceforge.net>
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#
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# Calculate a Knight's tour of a chessboard.
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#
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# This uses Warnsdorff's rule to calculate the next square each
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# time. This specifies that the next square should be the one that
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# has the least number of available moves.
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#
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# Using this rule it is possible to get to a position where
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# there are no squares available to move into. In this implementation
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# this occurs when the starting square is d6.
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#
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# To solve this fault an enhancement to the rule is that if we
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# have a choice of squares with an equal score, we should choose
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# the one nearest the edge of the board.
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#
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# If the call to the Edgemost function is commented out you can see
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# this occur.
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#
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# You can drag the knight to a specific square to start if you wish.
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# If you let it repeat then it will choose random start positions
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# for each new tour.
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#----------------------------------------------------------------------------
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require 'tk'
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class Knights_Tour
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# Return a list of accessible squares from a given square
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def valid_moves(square)
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moves = []
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[
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[-1,-2], [-2,-1], [-2,1], [-1,2], [1,2], [2,1], [2,-1], [1,-2]
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].each{|col_delta, row_delta|
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col = (square % 8) + col_delta
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row = (square.div(8)) + row_delta
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moves << (row * 8 + col) if row > -1 && row < 8 && col > -1 && col < 8
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}
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moves
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end
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# Return the number of available moves for this square
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def check_square(square)
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valid_moves(square).find_all{|pos| ! @visited.include?(pos)}.length
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end
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# Select the next square to move to. Returns -1 if there are no available
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# squares remaining that we can move to.
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def next_square(square)
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minimum = 9
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nxt = -1
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valid_moves(square).each{|pos|
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unless @visited.include?(pos)
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cnt = check_square(pos)
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if cnt < minimum
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minimum = cnt
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nxt = pos
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elsif cnt == minimum
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nxt = edgemost(nxt, pos)
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end
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end
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}
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nxt
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end
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# Select the square nearest the edge of the board
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def edgemost(nxt, pos)
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col_A = 3 - ((3.5 - nxt % 8).abs.to_i)
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col_B = 3 - ((3.5 - pos % 8).abs.to_i)
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row_A = 3 - ((3.5 - nxt.div(8)).abs.to_i)
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row_B = 3 - ((3.5 - pos.div(8)).abs.to_i)
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(col_A * row_A < col_B * row_B)? nxt : pos
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end
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# Display a square number as a standard chess square notation.
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def _N(square)
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'%c%d' % [(97 + square % 8), (square.div(8) + 1)]
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end
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# Perform a Knight's move and schedule the next move.
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def move_piece(last, square)
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@log.insert(:end, "#{@visited.length}. #{_N last} -> #{_N square}\n", '')
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@log.see(:end)
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@board.itemconfigure(1+last, :state=>:normal, :outline=>'black')
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@board.itemconfigure(1+square, :state=>:normal, :outline=>'red')
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@knight.coords(@board.coords(1+square)[0..1])
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@visited << square
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if (nxt = next_square(square)) != -1
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@after_id = Tk.after(@delay.numeric){move_piece(square, nxt) rescue nil}
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else
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@start_btn.state :normal
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if @visited.length == 64
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if @initial == square
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@log.insert :end, 'Closed tour!'
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else
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@log.insert :end, "Success\n", {}
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Tk.after(@delay.numeric * 2){tour(rand(64))} if @continuous.bool
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end
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else
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@log.insert :end, "FAILED!\n", {}
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end
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end
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end
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# Begin a new tour of the board given a random start position
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def tour(square = nil)
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@visited.clear
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@log.clear
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@start_btn.state :disabled
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1.upto(64){|n|
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@board.itemconfigure(n, :state=>:disabled, :outline=>'black')
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}
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unless square
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square = @board.find_closest(*(@knight.coords << 0 << 65))[0].to_i - 1
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end
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@initial = square
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Tk.after_idle{ move_piece(@initial, @initial) rescue nil }
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end
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def _stop
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Tk.after_cancel(@after_id) rescue nil
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end
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def _exit
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_stop
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$knightstour.destroy
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end
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def set_delay(new)
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@delay.numeric = new.to_i
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end
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def drag_start(w, x, y)
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w.dtag('selected')
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w.addtag('selected', :withtag, 'current')
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@dragging = [x, y]
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end
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def drag_motion(w, x, y)
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return unless @dragging
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w.move('selected', x - @dragging[0], y - @dragging[1])
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@dragging = [x, y]
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end
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def drag_end(w, x, y)
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square = w.find_closest(x, y, 0, 65)
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w.coords('selected', w.coords(square)[0..1])
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w.dtag('selected')
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@dragging = nil
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end
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def make_SeeDismiss
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## See Code / Dismiss
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frame = Ttk::Frame.new($knightstour)
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sep = Ttk::Separator.new(frame)
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Tk.grid(sep, :columnspan=>4, :row=>0, :sticky=>'ew', :pady=>2)
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TkGrid('x',
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Ttk::Button.new(frame, :text=>'See Code',
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:image=>$image['view'], :compound=>:left,
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:command=>proc{showCode 'knightstour'}),
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Ttk::Button.new(frame, :text=>'Dismiss',
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:image=>$image['delete'], :compound=>:left,
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:command=>proc{
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$knightstour.destroy
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$knightstour = nil
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}),
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:padx=>4, :pady=>4)
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frame.grid_columnconfigure(0, :weight=>1)
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frame
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end
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def create_gui(parent = nil)
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$knightstour.destroy rescue nil
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$knightstour = Tk::Toplevel.new(parent, :title=>"Knight's tour")
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$knightstour.withdraw
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base_f = Ttk::Frame.new($knightstour)
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@board = Tk::Canvas.new(base_f, :width=>240, :height=>240)
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@log = Tk::Text.new(base_f, :width=>12, :height=>1,
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:font=>'Arial 8', :background=>'white')
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scr = @log.yscrollbar(Ttk::Scrollbar.new(base_f))
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@visited = []
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@delay = TkVariable.new(600)
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@continuous = TkVariable.new(false)
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tool_f = Ttk::Frame.new($knightstour)
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label = Ttk::Label.new(tool_f, :text=>'Speed')
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scale = Ttk::Scale.new(tool_f, :from=>8, :to=>2000, :variable=>@delay,
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:command=>proc{|n| set_delay(n)})
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check = Ttk::Checkbutton.new(tool_f, :text=>'Repeat',
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:variable=>@continuous)
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@start_btn = Ttk::Button.new(tool_f, :text=>'Start',
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:command=>proc{tour()})
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@exit_btn = Ttk::Button.new(tool_f, :text=>'Exit',
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:command=>proc{_exit()})
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7.downto(0){|row|
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0.upto(7){|col|
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if ((col & 1) ^ (row & 1)).zero?
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fill = 'bisque'
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dfill = 'bisque3'
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else
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fill = 'tan3'
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dfill = 'tan4'
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end
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coords = [col * 30 + 4, row * 30 + 4, col * 30 + 30, row * 30 + 30]
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@board.create(TkcRectangle, coords,
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:fill=>fill, :disabledfill=>dfill,
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:width=>2, :state=>:disabled)
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}
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}
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@knight_font = TkFont.new(:size=>-24)
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@knight = TkcText.new(@board, 0, 0, :font=>@knight_font,
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:text=>Tk::UTF8_String.new('\u265e'),
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:anchor=>'nw', # :tags=>'knight',
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:fill=>'black', :activefill=>'#600000')
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@knight.coords(@board.coords(rand(64)+1)[0..1])
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@knight.bind('ButtonPress-1', '%W %x %y'){|w,x,y| drag_start(w,x,y)}
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@knight.bind('Motion', '%W %x %y'){|w,x,y| drag_motion(w,x,y)}
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@knight.bind('ButtonRelease-1', '%W %x %y'){|w,x,y| drag_end(w,x,y)}
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Tk.grid(@board, @log, scr, :sticky=>'news')
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base_f.grid_rowconfigure(0, :weight=>1)
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base_f.grid_columnconfigure(0, :weight=>1)
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Tk.grid(base_f, '-', '-', '-', '-', '-', :sticky=>'news')
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widgets = [label, scale, check, @start_btn]
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sg = nil
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unless $RubyTk_WidgetDemo
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widgets << @exit_btn
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if Tk.windowingsystem != 'aqua'
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#widgets.unshift(Ttk::SizeGrip.new(tool_f))
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Ttk::SizeGrip.new(tool_f).pack(:side=>:right, :anchor=>'se')
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end
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end
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Tk.pack(widgets, :side=>:right)
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if Tk.windowingsystem == 'aqua'
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TkPack.configure(widgets, :padx=>[4, 4], :pady=>[12, 12])
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TkPack.configure(widgets[0], :padx=>[4, 24])
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TkPack.configure(widgets[-1], :padx=>[16, 4])
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end
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Tk.grid(tool_f, '-', '-', '-', '-', '-', :sticky=>'ew')
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if $RubyTk_WidgetDemo
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Tk.grid(make_SeeDismiss(), '-', '-', '-', '-', '-', :sticky=>'ew')
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end
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$knightstour.grid_rowconfigure(0, :weight=>1)
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$knightstour.grid_columnconfigure(0, :weight=>1)
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$knightstour.bind('Control-F2'){TkConsole.show}
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$knightstour.bind('Return'){@start_btn.invoke}
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$knightstour.bind('Escape'){@exit_btn.invoke}
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$knightstour.bind('Destroy'){ _stop }
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$knightstour.protocol('WM_DELETE_WINDOW'){ _exit }
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$knightstour.deiconify
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$knightstour.tkwait_destroy
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end
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def initialize(parent = nil)
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create_gui(parent)
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end
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end
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Tk.root.withdraw unless $RubyTk_WidgetDemo
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Thread.new{Tk.mainloop} if __FILE__ == $0
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Knights_Tour.new
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