%%%---------------------------------------------------------------------- %%% File : png.erl %%% Author : %%% Author : %%% Purpose : Creating PNG from erlang list %%% Created : 2 Sep 2002 by %%%---------------------------------------------------------------------- -module(png). -author('Jozsef.Berces@ecz.ericsson.se'). %%-compile(export_all). %%-export([Function/Arity, ...]). -export([make_crc_table/0, bw/3]). %-export([stuff0/2]). %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% -define(CRCTAB,[0, 1996959894, 3993919788, 2567524794, 124634137, 1886057615, 3915621685, 2657392035, 249268274, 2044508324, 3772115230, 2547177864, 162941995, 2125561021, 3887607047, 2428444049, 498536548, 1789927666, 4089016648, 2227061214, 450548861, 1843258603, 4107580753, 2211677639, 325883990, 1684777152, 4251122042, 2321926636, 335633487, 1661365465, 4195302755, 2366115317, 997073096, 1281953886, 3579855332, 2724688242, 1006888145, 1258607687, 3524101629, 2768942443, 901097722, 1119000684, 3686517206, 2898065728, 853044451, 1172266101, 3705015759, 2882616665, 651767980, 1373503546, 3369554304, 3218104598, 565507253, 1454621731, 3485111705, 3099436303, 671266974, 1594198024, 3322730930, 2970347812, 795835527, 1483230225, 3244367275, 3060149565, 1994146192, 31158534, 2563907772, 4023717930, 1907459465, 112637215, 2680153253, 3904427059, 2013776290, 251722036, 2517215374, 3775830040, 2137656763, 141376813, 2439277719, 3865271297, 1802195444, 476864866, 2238001368, 4066508878, 1812370925, 453092731, 2181625025, 4111451223, 1706088902, 314042704, 2344532202, 4240017532, 1658658271, 366619977, 2362670323, 4224994405, 1303535960, 984961486, 2747007092, 3569037538, 1256170817, 1037604311, 2765210733, 3554079995, 1131014506, 879679996, 2909243462, 3663771856, 1141124467, 855842277, 2852801631, 3708648649, 1342533948, 654459306, 3188396048, 3373015174, 1466479909, 544179635, 3110523913, 3462522015, 1591671054, 702138776, 2966460450, 3352799412, 1504918807, 783551873, 3082640443, 3233442989, 3988292384, 2596254646, 62317068, 1957810842, 3939845945, 2647816111, 81470997, 1943803523, 3814918930, 2489596804, 225274430, 2053790376, 3826175755, 2466906013, 167816743, 2097651377, 4027552580, 2265490386, 503444072, 1762050814, 4150417245, 2154129355, 426522225, 1852507879, 4275313526, 2312317920, 282753626, 1742555852, 4189708143, 2394877945, 397917763, 1622183637, 3604390888, 2714866558, 953729732, 1340076626, 3518719985, 2797360999, 1068828381, 1219638859, 3624741850, 2936675148, 906185462, 1090812512, 3747672003, 2825379669, 829329135, 1181335161, 3412177804, 3160834842, 628085408, 1382605366, 3423369109, 3138078467, 570562233, 1426400815, 3317316542, 2998733608, 733239954, 1555261956, 3268935591, 3050360625, 752459403, 1541320221, 2607071920, 3965973030, 1969922972, 40735498, 2617837225, 3943577151, 1913087877, 83908371, 2512341634, 3803740692, 2075208622, 213261112, 2463272603, 3855990285, 2094854071, 198958881, 2262029012, 4057260610, 1759359992, 534414190, 2176718541, 4139329115, 1873836001, 414664567, 2282248934, 4279200368, 1711684554, 285281116, 2405801727, 4167216745, 1634467795, 376229701, 2685067896, 3608007406, 1308918612, 956543938, 2808555105, 3495958263, 1231636301, 1047427035, 2932959818, 3654703836, 1088359270, 936918000, 2847714899, 3736837829, 1202900863, 817233897, 3183342108, 3401237130, 1404277552, 615818150, 3134207493, 3453421203, 1423857449, 601450431, 3009837614, 3294710456, 1567103746, 711928724, 3020668471, 3272380065, 1510334235, 755167117]). %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% make_crc_table() -> make_crc_table_n(). make_crc_table_n() -> make_crc_table_n(0). make_crc_table_n(N) when N < 256 -> [make_crc_table_k(N)] ++ make_crc_table_n(N + 1); make_crc_table_n(_) -> []. make_crc_table_k(X) -> make_crc_table_k(X, 0). make_crc_table_k(X, K) when K < 8 -> Comp= X band 1, case Comp of 1 -> make_crc_table_k(16#edb88320 bxor (X bsr 1), K + 1); _ -> make_crc_table_k(X bsr 1, K + 1) end; make_crc_table_k(X, _) -> X. %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% update_crc(CRC, [H | T], CRCTAB) -> NCRC= lists:nth(((CRC bxor H) band 16#ff) + 1, CRCTAB) bxor (CRC bsr 8), update_crc(NCRC, T, CRCTAB); update_crc(CRC, _, _) -> CRC. crc(List) -> %CRCTAB= make_crc_table(), update_crc(16#ffffffff, List, ?CRCTAB) bxor 16#ffffffff. %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% % Creates a chunk based on the chunk type and chunk data % Type= string() % Data= list() chunk(Type, Data) -> Len= length(Data), L1= Len band 255, L2= (Len bsr 8) band 255, L3= (Len bsr 16) band 255, L4= (Len bsr 24) band 255, CRC= crc(Type ++ Data), C1= CRC band 255, C2= (CRC bsr 8) band 255, C3= (CRC bsr 16) band 255, C4= (CRC bsr 24) band 255, [L4, L3, L2, L1 | Type ++ Data ++ [C4, C3, C2, C1]]. sig() -> [137, 80, 78, 71, 13, 10, 26, 10]. % IHDR % Width, Height, Bit depth, Color type ihdr(W, H, BD, CT) -> W1= W band 255, W2= (W bsr 8) band 255, W3= (W bsr 16) band 255, W4= (W bsr 24) band 255, H1= H band 255, H2= (H bsr 8) band 255, H3= (H bsr 16) band 255, H4= (H bsr 24) band 255, FM= 0, % Filter method IM= 0, % Interlace method chunk("IHDR", [W4, W3, W2, W1, H4, H3, H2, H1, BD band 255, CT band 255, 0, FM, IM]). % IDAT % Width, Height, Bit depth, Pixel list idat(W, H, 1, PL) -> SL= scanlines_1(W, H, PL), DL= deflate00(SL), ZL= zlib(DL, SL), chunk("IDAT", ZL); idat(_, _, _, _) -> {error, "Bit depth not supported"}. % Width, Height, Byte list idatBWbytes(W, H, BL) -> BW= W div 8, SL= stuff0(BW, BL), DL= deflate00(SL), ZL= zlib(DL, SL), chunk("IDAT", ZL). % IEND % iend() -> chunk("IEND", []). % Stuff 0 after each Nth element stuff0(N, []) -> []; stuff0(N, List) when N >= 1 -> {H, T}= apautil:splitat(N, List), [0 | H] ++ stuff0(N, T). % B&W scan lines scanlines_1(_, 0, _) -> []; scanlines_1(W, H, PL) -> {ThisLine, Rest}= apautil:splitat(W, PL), [0 | apautil:bits2bytesMSB(ThisLine)] ++ scanlines_1(W, H - 1, Rest). % zlib zlib(D, DO) -> [16#78, 16#da | D] ++ adler(DO). % deflate BTYPE=00 deflate00(D) -> Len= length(D), L1= Len band 255, L2= (Len bsr 8) band 255, NL1= L1 bxor 16#ff, NL2= L2 bxor 16#ff, [16#01, L1, L2, NL1, NL2 | D]. % Adler-32 algorithm adler(D) -> {S1, S2}= adler(D, 1, 0), [(S2 bsr 8) band 255, S2 band 255, (S1 bsr 8) band 255, S1 band 255]. adler([H | T], S1, S2) -> NS1= (S1 + H) rem 65521, NS2= (S2 + NS1) rem 65521, adler(T, NS1, NS2); adler(_, S1, S2) -> {S1, S2}. %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% % black-and-white picture: bw(W, H, Data) when W * H == length(Data) -> if (length(Data) div 8) < (32 * 1024) -> sig() ++ ihdr(W, H, 1, 0) ++ idat(W, H, 1, Data) ++ iend(); true -> {error, "Data is bigger than 32K"} end; bw(W, H, Data) when W * H div 8 == length(Data), W rem 8 == 0 -> if length(Data) < (32 * 1024) -> sig() ++ ihdr(W, H, 1, 0) ++ idatBWbytes(W, H, Data) ++ iend(); true -> {error, "Data is bigger than 32K"} end; bw(_, _, _) -> {error, "Data size mismatch"}.