php生成随机码的一段代码，生成随机码，并用图形方式显示随机码，有需要的朋友可以参考下。
<?php
/*
* 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);
?>
php写的一个验证码：实现上下左右随即浮动，字符+数字，随机干扰线等。
供初学者参考吧。
session_start();
$image = imagecreatetruecolor(58,22);
$color_Background = imagecolorallocate($image,255,255,255);
imagefill($image,0,0,$color_Background);
$key = array(
‘0′,’1′,’2′,’3′,’4′,’5′,’6′,’7′,’8′,’9′,
‘a’,'b’,'c’,'d’,'e’,'f’,'g’,'h’,'i’,'j’,'k’,'l’,'m’,'n’,'o’,'p’,'q’,'r’,’s’,'t’,'u’,'v’,'w’,'x’,'y’,'z’,
‘A’,'B’,'C’,'D’,'E’,'F’,'G’,'H’,'I’,'J’,'K’,'L’,'M’,'N’,'O’,'P’,'Q’,'R’,'S’,'T’,'U’,'V’,'W’,'X’,'Y’,'Z’);
$string = null;
$char_X = 6;
$char_Y = 0;
for($i=0;$i<4;$i++)
{
$char_Y = mt_rand(0,5);
$char = $key[mt_rand(0,61)];
$string .= $char;
$color_Char = imagecolorallocate($image,mt_rand(0,230),mt_rand(0,230),mt_rand(0,230));
imagechar($image,5,$char_X,$char_Y,$char,$color_Char);
$char_X = $char_X + mt_rand(8,15);
}
$line_X1 = 0;
$line_Y1 = 0;
$line_X2 = 0;
$line_Y2 = 0;
for($i=0;$i
{
$line_X1 = mt_rand(0,58);
$line_Y1 = mt_rand(0,22);
$line_X2 = mt_rand(0,58);
$line_Y2 = mt_rand(0,22);
$line_X1 = $line_X1;
$line_Y1 = $line_Y1;
$line_X2 = $line_X1 + mt_rand(1,8);
$line_Y2 = $line_Y1 + mt_rand(1,8);
$color_Line = imagecolorallocate($image,mt_rand(0,230),mt_rand(0,230),mt_rand(0,230));
imageline($image,$line_X1,$line_Y1,$line_X2,$line_Y2,$color_Line);
}
$_SESSION['seccode'] = $string;
@header(“Expires: -1″);
@header(“Cache-Control: no-store, private, post-check=0, pre-check=0, max-age=0″, FALSE);
@header(“Pragma: no-cache”);
header(‘Content-Type: image/jpeg’);
imagepng($image);
imagedestroy($image);
?>
UTF-8与GBK编码下PHP获取字符串长度的函数，完美的解决了PHP下获取UTF-8或者GBK字符集的字符串长度问题。
有需要的朋友，建议参考学习下。
<?php
/*
* 统计字符串长度
*@param $str 被统计字符串
*/
function sstrlen($str) {
global $charset;
$n = 0; $p = 0; $c = ”;
$len = strlen($str);
if($charset == ‘utf-8′) {
for($i = 0; $i < $len; $i++) {
$c = ord($str{$i});
if($c > 252) {
$p = 5;
} elseif($c > 248) {
$p = 4;
} elseif($c > 240) {
$p = 3;
} elseif($c > 224) {
$p = 2;
} elseif($c > 192) {
$p = 1;
} else {
$p = 0;
}
$i+=$p;$n++;
}
} else {
for($i = 0; $i < $len; $i++) {
$c = ord($str{$i});
if($c > 127) {
$p = 1;
} else {
$p = 0;
}
$i+=$p;$n++;
}
}
return $n;
}
?>