added tag v1_9_0_4

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/tags/v1_9_0_4@18845 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 271 insertions, 0 deletions

diff --git a/trunk/ext/tk/sample/demos-en/knightstour.rb b/trunk/ext/tk/sample/demos-en/knightstour.rb
new file mode 100644
index 0000000000..618fce5f02
--- /dev/null
+++ b/trunk/ext/tk/sample/demos-en/knightstour.rb
@@ -0,0 +1,271 @@
+# Based on the widget demo of Tcl/Tk8.5.2
+# The following is the original copyright text.
+#----------------------------------------------------------------------------
+# Copyright (C) 2008 Pat Thoyts <patthoyts@users.sourceforge.net>
+#
+#	Calculate a Knight's tour of a chessboard.
+#
+#	This uses Warnsdorff's rule to calculate the next square each
+#	time. This specifies that the next square should be the one that
+#	has the least number of available moves.
+#
+#	Using this rule it is possible to get to a position where
+#	there are no squares available to move into. In this implementation
+#	this occurs when the starting square is d6.
+#
+#	To solve this fault an enhancement to the rule is that if we
+#	have a choice of squares with an equal score, we should choose
+#	the one nearest the edge of the board.
+#
+#	If the call to the Edgemost function is commented out you can see
+#	this occur.
+#
+#	You can drag the knight to a specific square to start if you wish.
+#	If you let it repeat then it will choose random start positions
+#	for each new tour.
+#----------------------------------------------------------------------------
+require 'tk'
+
+class Knights_Tour
+  # Return a list of accessible squares from a given square
+  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
+
+  # Return the number of available moves for this square
+  def check_square(square)
+    valid_moves(square).find_all{|pos| ! @visited.include?(pos)}.length
+  end
+
+  # Select the next square to move to. Returns -1 if there are no available
+  # squares remaining that we can move to.
+  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
+
+  # Select the square nearest the edge of the board
+  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
+
+  # Display a square number as a standard chess square notation.
+  def _N(square)
+    '%c%d' % [(97 + square % 8), (square.div(8) + 1)]
+  end
+
+  # Perform a Knight's move and schedule the next move.
+  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
+
+  # Begin a new tour of the board given a random start position
+  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
+
+  def _stop
+    Tk.after_cancel(@after_id) rescue nil
+  end
+
+  def _exit
+    _stop
+    $knightstour.destroy
+  end
+
+  def set_delay(new)
+    @delay.numeric = new.to_i
+  end
+
+  def drag_start(w, x, y)
+    w.dtag('selected')
+    w.addtag('selected', :withtag, 'current')
+    @dragging = [x, y]
+  end
+
+  def drag_motion(w, x, y)
+    return unless @dragging
+    w.move('selected', x - @dragging[0], y - @dragging[1])
+    @dragging = [x, y]
+  end
+
+  def drag_end(w, x, y)
+    square = w.find_closest(x, y, 0, 65)
+    w.coords('selected', w.coords(square)[0..1])
+    w.dtag('selected')
+    @dragging = nil
+  end
+
+  def make_SeeDismiss
+    ## See Code / Dismiss
+    frame = Ttk::Frame.new($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
+
+  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
+
+  def initialize(parent = nil)
+    create_gui(parent)
+  end
+end
+
+Tk.root.withdraw unless $RubyTk_WidgetDemo
+Thread.new{Tk.mainloop} if __FILE__ == $0
+Knights_Tour.new