=begin Chess - Visualization of attacked squares. ver. 1.0 (in progress) This app shows which squares are attacked by the pieces on the chessboard. The following symbols are used to refer to chess pieces on the chessboard: K - king, Q - queen, R - rook, B - bishop, N - kNight. You can change the location of the pieces on the chessboard by making changes to the aPieces[] array below. You can even put different chess pieces on the same square (for fun) and see how it looks. For example, if you place a queen and a knight in the same square, you will get a terrible monster, beating more than half squares on the chessboard: ['Qd4', 'Nd4'] =end # If you have a narrow screen (for example on a smartphone) or you use a large system font and the image of chess board is distorted, set the variable below to true. narrow_screen = false # or true # Don't place more than 4 pieces in one group because only the first 4 of them will be shown. # If the option 'narrow_screen' is selected, the maximum allowed pieces are 3. aPieces = [ ['Kd6', 'Re2', 'Ng5'], ['Qd4'], ['Bc6', 'Nf5'] ] RestrictLine = "---------------------------------------" RestrictLine2 = "-------------------------------" StartPosition = "Start chess position" AttackedSquares = "Displaying pieces (uppercase) and squares attacked by them (downcase):" a1=['8','7','6','5','4','3','2','1'] a2=['a','b','c','d','e','f','g','h'] ap=['R','N','B','Q','K','B','N','R'] pos1 = {} # hash for start position pos2 = {} # hash for attacked squares # -------------------------------- createStartPos = lambda do h1='1'; h2='2'; h8='8'; h7='7' i = 0; w = 'w'; b = 'b' ap.each do | fig | sq=a2[i]+h1; pos1[sq]= w + fig sq=a2[i]+h2; pos1[sq]= w + 'p' sq=a2[i]+h8; pos1[sq]= b + fig sq=a2[i]+h7; pos1[sq]= b + 'p' i += 1 end end print_pos = lambda do | pos, viz=true | if narrow_screen puts " " + RestrictLine2 else puts " " + RestrictLine end a1.each do |n| if narrow_screen print "#{n}" demarcatLine = " |" else print "#{n} " demarcatLine = " |" end a2.each do |m| c = m + n; s = "| " s="| " if narrow_screen if pos.key?(c) pc = pos[c] case pc.length when 1 b=" "; b=" " if narrow_screen pc = " " + pc + b when 2 pc=" "+pc pc+=" " unless narrow_screen when 3 pc=" "+pc unless narrow_screen end s = "|#{pc}" end # if pos.key?(c) print s if pos.key?(c) && pos[c][/[KQRBN]/] && viz if narrow_screen demarcatLine += "===" else demarcatLine += "====" end else if narrow_screen demarcatLine += "---" else demarcatLine += "----" end end demarcatLine += ':' if m!='h' end # a2.each do |m| print "|\n" puts demarcatLine+"|\n" if n!='1' end # a1.each do |n| if narrow_screen puts " " + RestrictLine2 else puts " " + RestrictLine end if narrow_screen print " " a2.each { |m| print " #{m} " } else print " " a2.each { |m| print " #{m} " } end end pos_modif = lambda do | fig, v, h | # fig - 1 of [K Q R B N or 'p'] # v - vertical 1 of [a b c ... h] # h = horizontal 1 of [1 2 3 ... 8] # Regexp 'f_p' contains uppercase and downcase letters of 'fig'. For example: (/[Qq]/) f_pat = '['+fig+fig.swapcase+']' f_p = Regexp.new(f_pat) sq = v + h if pos2.key?(sq) pos2[sq]+=fig if !pos2[sq][f_p] else pos2[sq] = fig end end horizon = lambda do | fig, h | a2.each do | c | pos_modif.call fig, c, h end end vertic = lambda do | fig, v | a1.each do | n | pos_modif.call fig, v, n end end diagon_SW = lambda do | fig, h, v | # SW - South-West direction i=a2.index(v); j=a1.index(h) while i>=0 && j>=0 # numb 1 pos_modif.call fig, a2[i], a1[j] i -= 1; j -= 1; end end diagon_NW = lambda do | fig, h, v | # NW - Noth-West direction i=a2.index(v); j=a1.index(h) while i>=0 && j<=7 # numb 2 pos_modif.call fig, a2[i], a1[j] i -= 1; j += 1; end end diagon_NE = lambda do | fig, h, v | # NE - Noth-East direction i=a2.index(v); j=a1.index(h) while i<=7 && j<=7 # numb 3 pos_modif.call fig, a2[i], a1[j] i += 1; j += 1; end end diagon_SE = lambda do | fig, h, v | # SE - South-East direction i=a2.index(v); j=a1.index(h) while i<=7 && j>=0 # numb 4 pos_modif.call fig, a2[i], a1[j] i += 1; j -= 1; end end setAttackedSq = lambda do | f_sq | fig=f_sq[0] # 1 of [K Q R B N or 'p'] sq=f_sq[1,2] # a square on the ch-board f = sq[0] # file 1 of [a b c ... h] r = sq[1] # rank 1 of [1 2 3 ... 8] # set the piece 'fig' in the 'fr' square pos_modif.call fig, f, r case fig when 'K' a1.reverse! jf = a2.index(f); jr = a1.index(r) # round in a clockwise direction: # 1) North if jr+1 <= 7 f1 = a2[jf]; r1 = a1[jr+1] pos_modif.call('k', f1, r1) end # 2) North-East if jf+1<=7 && jr+1<=7 f1 = a2[jf+1]; r1 = a1[jr+1] pos_modif.call('k', f1, r1) end # 3) East if jf+1<=7 f1 = a2[jf+1]; r1 = a1[jr] pos_modif.call('k', f1, r1) end # 4) South-East if jf+1<=7 && jr-1>=0 f1 = a2[jf+1]; r1 = a1[jr-1] pos_modif.call('k', f1, r1) end # 5) South if jr-1>=0 f1 = a2[jf]; r1 = a1[jr-1] pos_modif.call('k', f1, r1) end # 6) South-West if jf-1>=0 && jr-1>=0 f1 = a2[jf-1]; r1 = a1[jr-1] pos_modif.call('k', f1, r1) end # 7) West if jf-1>=0 f1 = a2[jf-1]; r1 = a1[jr] pos_modif.call('k', f1, r1) end # 8) North-West if jf-1>=0 && jr+1<=7 f1 = a2[jf-1]; r1 = a1[jr+1] pos_modif.call('k', f1, r1) end a1.reverse! when 'Q' horizon.call 'q', r vertic.call 'q', f diagon_SW.call 'q', r, f diagon_NW.call 'q', r, f diagon_NE.call 'q', r, f diagon_SE.call 'q', r, f when 'R' horizon.call 'r', r vertic.call 'r', f when 'B' diagon_SW.call 'b', r, f diagon_NW.call 'b', r, f diagon_NE.call 'b', r, f diagon_SE.call 'b', r, f when 'N' a1.reverse! jf = a2.index(f); jr = a1.index(r) # round in a clockwise direction: # 1) North-North-East if jf+1<=7 && jr+2<=7 f1 = a2[jf+1]; r1= a1[jr+2] pos_modif.call('n', f1, r1) end # 2) North-East-East if jf+2<=7 && jr+1<=7 f1 = a2[jf+2]; r1 = a1[jr+1] pos_modif.call('n', f1, r1) end # 3) South-East-East if jf+2<=7 && jr-1>=0 f1 = a2[jf+2]; r1 = a1[jr-1] pos_modif.call('n', f1, r1) end # 4) South-South-East if jf+1<=7 && jr-2>=0 f1 = a2[jf+1]; r1=a1[jr-2] pos_modif.call('n', f1, r1) end # 5) South-South-West if jf-1>=0 && jr-2>=0 f1 = a2[jf-1]; r1=a1[jr-2] pos_modif.call('n', f1, r1) end # 6) South-West-West if jf-2>=0 && jr-1>=0 f1 = a2[jf-2]; r1=a1[jr-1] pos_modif.call('n', f1, r1) end # 7) North-West-West if jf-2>=0 && jr+1<=7 f1 = a2[jf-2]; r1=a1[jr+1] pos_modif.call('n', f1, r1) end # 8) North-North-West if jf-1>=0 && jr+2<=7 f1 = a2[jf-1]; r1=a1[jr+2] pos_modif.call('n', f1, r1) end a1.reverse! else # case of pawn end # case fig end # ------------------------------ if narrow_screen max = 3 bl = " " else max = 4 bl = " " end puts bl + StartPosition; puts createStartPos.call print_pos.call pos1, false puts "\n\n\n" puts AttackedSquares aPieces.each do | sarr | k = 1 sarr.each do | f_sq | if k <= max setAttackedSq.call f_sq k += 1 end end puts "\n #{sarr}"; puts print_pos.call pos2 puts pos2.clear end