不用GD库生成当前时间的PNG格式图象的程序

该程序是不用GD库可以生成当前时间的PNG格式图象，给人大开眼界，很有参考价值. teaman整理
   
  > 24) & 255,
   ($len >> 16) & 255,
   ($len >> 8) & 255,
   $len & 255);
   $chunk .= $type;
   $chunk .= $data;
   
   // calculate a CRC checksum with the bytes chunk[4..len-1]
   $z = 16777215;
   $z |= 255 > 8) & 0xffffff;
   $c = $crc_table[($c ^ ord($chunk][$n])) & 0xff] ^ $c8;
   }
   $crc = $c ^ $z;
   
   $chunk .= chr(($crc >> 24) & 255);
   $chunk .= chr(($crc >> 16) & 255);
   $chunk .= chr(($crc >> 8) & 255);
   $chunk .= chr($crc & 255);
   
   // 将结果加到$result中
   $result .= $chunk;
   }
   
   
   //主程序
   
   $sx = 80;
   $sy = 21;
   $pixels = "";
   
   // 填充
   for ($h = 0; $h > 1) & 0x7fffffff;
   if ($c & 1) $c = $z ^ ($c2); else $c = $c2;
   }
   $crc_table[$n] = $c;
   }
   
   // PNG file signature
   $result = pack("c*", 137,80,78,71,13,10,26,10);
   
   // IHDR chunk data:
   // width: 4 bytes
   //  // bit depth: 1 byte (8 bits per RGB value)
   // color type: 1 byte (2 = RGB)
   // compression method: 1 byte (0 = deflate/inflate)
   // filter method: 1 byte (0 = adaptive filtering)
   // interlace method: 1 byte (0 = no interlace)
   $data = pack("c*", ($sx >> 24) & 255,
   ($sx >> 16) & 255,
   ($sx >> 8) & 255,
   $sx & 255,
   ($sy >> 24) & 255,
   ($sy >> 16) & 255,
   ($sy >> 8) & 255,
   $sy & 255,
   8,
   2,
   0,
   0,
   0);
   add_chunk("IHDR");
   
   // 以下不敢乱翻译，请自行参考
   // scanline:
   // filter byte: 0 = none
   // RGB bytes for the line
   // the scanline is compressed with "zlib", method 8 (RFC-1950):
   // compression method/flags code: 1 byte ($78 = method 8, 32k window)
   // additional flags/check bits: 1 byte ($01: FCHECK = 1, FDICT = 0, FLEVEL = 0)
   // compressed data blocks: n bytes
   // one block (RFC-1951):
   // bit 0: BFINAL: 1 for the last block
   // bit 1 and 2: BTYPE: 0 for no compression
   // next 2 bytes: LEN (LSB first)
   // next 2 bytes: one's complement of LEN
   // LEN bytes uncompressed data
   // check value: 4 bytes (Adler-32 checksum of the uncompressed data)
   //
   $len = ($sx * 3 + 1) * $sy;
   $data = pack("c*", 0x78, 0x01,
   1,
   $len & 255,
   ($len >> 8) & 255,
   255 - ($len & 255),
   255 - (($len >> 8) & 255));
   $start = strlen($data);
   $i2 = 0;
   for ($h = 0; $h > 24) & 255);
   $data .= chr(($adler >> 16) & 255);
   $data .= chr(($adler >> 8) & 255);
   $data .= chr($adler & 255);
   add_chunk("IDAT");
   
   // IEND: marks the end of the PNG-file
   $data = "";
   add_chunk("IEND");
   
   // 列印图象
   
   echo($result);
  ?>
   
  //如何调用，其实很简单，将上面存为Timeimg.php
  //然后新建一个页面如下：
   
   
   
   test
   
   
   
    //以图象连接方式调用
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