php不用GD庫生成當前時間的PNG格式圖象的程序

更新時間：2008年09月28日 14:40:24 作者：

該程序是不用GD庫可以生成當前時間的PNG格式圖象，給人大開眼界，很有參考價值. teaman整理

$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);

// 創(chuàng)建循環(huán)冗余碼校驗表
$z = -306674912; // = 0xedb88320
for ($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");

// 以下不敢亂翻譯，請自行參考
// 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");

// 列印圖象

echo($result);
?>

//如何調用，其實很簡單，將上面存為Timeimg.php
//然后新建一個頁面如下：

<html>
<head>
<title>test</title>
<meta http-equiv="Content-Type" content="text/html">
</head>
<body>
<img src="Timeimg.php"> //以圖象連接方式調用PHP文件
</body>
</html>

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