/* - * 说明：生成随机码，并用图形方式显示随机码。
- */
$ViewRandomCode = mt_rand(1000,10000); session_start(); - $_SESSION['checksum'] = $ViewRandomCode;
function set_4pixel($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 = 55; - $sy = 21;
- $pixels = rand(100,99990)%2?”qwer”:”";
// 填充 - for ($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);
- }
- }
$checknum = isset($ViewRandomCode)?$ViewRandomCode:1234; - $h = (int)($checknum/100);
- $m = (int)($checknum%100);
- $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);
// set_4pixel(0, 0, 0, 26, 7); - // set_4pixel(0, 0, 0, 26, 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) & 0×7fffffff;
- 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*”, 0×78, 0×01,
- 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); - ?>
|
