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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
<?php             function set_4pixel($r, $g, $b, $x, $y)     {     global $sx, $sy, $pixels;
    $ofs = 3 * ($sx * $y + $x);     $pixels[$ofs] = chr($r);     $pixels[$ofs + 1] = chr($g);     $pixels[$ofs + 2] = chr($b);     $pixels[$ofs + 3] = chr($r);     $pixels[$ofs + 4] = chr($g);     $pixels[$ofs + 5] = chr($b);     $ofs += 3 * $sx;     $pixels[$ofs] = chr($r);     $pixels[$ofs + 1] = chr($g);     $pixels[$ofs + 2] = chr($b);     $pixels[$ofs + 3] = chr($r);     $pixels[$ofs + 4] = chr($g);     $pixels[$ofs + 5] = chr($b);     }     //生成数字图象的函数         function draw2digits($x, $y, $number)     {     draw_digit($x, $y, (int) ($number / 10));     draw_digit($x + 11, $y, $number % 10);     }              function draw_digit($x, $y, $digit)     {     global $sx, $sy, $pixels, $digits, $lines;                  $digit = $digits[$digit];     $m = 8;     for ($b = 1, $i = 0; $i < 7; $i++, $b *= 2) {         if (($b & $digit) == $b) {         $j = $i * 4;         $x0 = $lines[$j] * $m + $x;         $y0 = $lines[$j + 1] * $m + $y;         $x1 = $lines[$j + 2] * $m + $x;         $y1 = $lines[$j + 3] * $m + $y;         if ($x0 == $x1) {             $ofs = 3 * ($sx * $y0 + $x0);             for ($h = $y0; $h <= $y1; $h++, $ofs += 3 * $sx) {             $pixels[$ofs] = chr(0);             $pixels[$ofs + 1] = chr(0);             $pixels[$ofs + 2] = chr(0);             }         } else {             $ofs = 3 * ($sx * $y0 + $x0);             for ($w = $x0; $w <= $x1; $w++) {             $pixels[$ofs++] = chr(0);             $pixels[$ofs++] = chr(0);             $pixels[$ofs++] = chr(0);             }         }         }     }     }              //将文字加入到图象中      function add_chunk($type)     {     global $result, $data, $chunk, $crc_table;
    // chunk :为层     // length: 4 字节: 用来计算 chunk      // chunk type: 4 字节     // chunk data: length bytes     // CRC: 4 字节:  循环冗余码校验              // copy data and create CRC checksum     $len = strlen($data);     $chunk = pack("c*", ($len >> 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 << 24;     $c = $z;     for ($n = 4; $n < strlen($chunk); $n++) {         $c8 = ($c >> 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 < $sy; $h++) {     for ($w = 0; $w < $sx; $w++) {         $r = 100 / $sx * $w + 155;         $g = 100 / $sy * $h + 155;         $b = 255 - (100 / ($sx + $sy) * ($w + $h));         $pixels .= chr($r);         $pixels .= chr($g);         $pixels .= chr($b);     }     }              $date = getdate();     $s = $date["seconds"];     $m = $date["minutes"];     $h = $date["hours"];     $digits = array(95, 5, 118, 117, 45, 121, 123, 69, 127, 125);     $lines = array(1, 1, 1, 2, 0, 1, 0, 2, 1, 0, 1, 1, 0, 0, 0, 1, 0, 2, 1, 2, 0, 1, 1, 1, 0, 0, 1, 0);              draw2digits(4, 2, $h);     draw2digits(30, 2, $m);     draw2digits(56, 2, $s);     set_4pixel(0, 0, 0, 26, 7);     set_4pixel(0, 0, 0, 26, 13);     set_4pixel(0, 0, 0, 52, 7);     set_4pixel(0, 0, 0, 52, 13);
    // 创建循环冗余码校验表     $z = -306674912;  // = 0xedb88320     for ($n = 0; $n < 256; $n++) {         $c = $n;         for ($k = 0; $k < 8; $k++) {             $c2 = ($c >> 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     //   height:             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 < $sy; $h++) {     $data .= chr(0);     for ($w = 0; $w < $sx * 3; $w++) {         $data .= $pixels[$i2++];     }     }
    // calculate a Adler32 checksum with the bytes data[start..len-1]     $s1 = 1;     $s2 = 0;     for ($n = $start; $n < strlen($data); $n++) {     $s1 = ($s1 + ord($data[$n])) % 65521;     $s2 = ($s2 + $s1) % 65521;     }     $adler = ($s2 << 16) | $s1;
    $data .= chr(($adler >> 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:
<html>     <head>     <title>test</title>     <meta http-equiv="Content-Type" content="text/html">     </head>     <body>     <img src="Timeimg.php">  //以图象连接方式调用PHP文件 </body> </html>