不用GD库生成当前时间的PNG格式图象的程序_php基础

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

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");

    //        压缩方法/标志代码：1 字节（$78 = 方法 8，32k 窗口）
    //        附加标志/检查位：   1 字节（ $01: FCHECK = 1, FDICT = 0, FLEVEL = 0)
    //        压缩数据块：        n 字节
    //            一个块 (RFC-1951):
    //               位 0: BFINAL: 1 为最后一个块
    //                位 1 和 2：BTYPE：0 表示不压缩
    //                接下来 2 个字节：LEN（LSB 在前）
    //                接下来 2 个字节：LEN 的补码
    / /                LEN 字节未压缩数据
    //        检查值：  4 个字节（未压缩数据的 Adler-32 校验和）
    //
    $len = ($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     $data .= chr(0);
    for ($w = 0; $w         $data .= $pixels[$i2 ];
    }
    }


    // 使用字节数据计算 Adler32 校验和 data[start..len-1]
    $s1 = 1;
    $s2 = 0;     for ($n = $start; $n     $s1 = ($s1 ord($data[$n])) % 65521;
    $s2 = ($s2 $s1) % 65521;
    }
    $adler = ($s2
    $data .= chr(($adler >> 24) & 255);
    $data .= chr(($adler >> 16) & 255);
    $data .= chr(($adler >> 8) & 255);
    $data .= chr($adler & 255);     add_chunk("IDAT");

    // IEND：标记 PNG 文件的结尾
    $data = "";
    add_chunk("IEND");

    // 列印表格

    echo($result);
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//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：

    ;

    测试标题>
   

   

    ;
      // 以视图连接方式调用PHP文件