CaptchaBundle/Generator/CaptchaGenerator.php

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PHP
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2011-08-25 23:10:24 +02:00
<?php
namespace Gregwar\CaptchaBundle\Generator;
/**
* Generates a CAPTCHA image
*/
class CaptchaGenerator {
public $value;
public function __construct($value)
{
$this->value = $value;
}
public function getCode()
{
return 'data:image/jpeg;base64,'.base64_encode($this->generate());
}
public function generate()
{
$i = imagecreatetruecolor(120,40);
$col = imagecolorallocate($i, mt_rand(0,110), mt_rand(0,110), mt_rand(0,110));
imagefill($i, 0, 0, 0xFFFFFF);
// Draw random lines
for ($t=0; $t<10; $t++) {
$tcol = imagecolorallocate($i, 100+mt_rand(0,150), 100+mt_rand(0,150), 100+mt_rand(0,150));
$Xa = mt_rand(0, 120);
$Ya = mt_rand(0, 40);
$Xb = mt_rand(0, 120);
$Yb = mt_rand(0, 40);
imageline($i, $Xa, $Ya, $Xb, $Yb, $tcol);
}
// Write CAPTCHA text
imagettftext($i, 28, 0, 5, 32, $col, dirname(__FILE__).'/Font/captcha.ttf', $this->value);
// Distort the image
$X = mt_rand(0, 120);
$Y = mt_rand(0, 40);
$Phase=mt_rand(0,10);
$Scale = 1.3 + mt_rand(0,10000)/30000;
$Amp=1+mt_rand(0,1000)/1000;
$out = imagecreatetruecolor(120,40);
for ($x=0; $x<120; $x++)
for ($y=0; $y<40; $y++) {
$Vx=$x-$X;
$Vy=$y-$Y;
$Vn=sqrt($Vx*$Vx+$Vy*$Vy);
if ($Vn!=0) {
$Vn2=$Vn+4*sin($Vn/8);
$nX=$X+($Vx*$Vn2/$Vn);
$nY=$Y+($Vy*$Vn2/$Vn);
} else {
$nX=$X;
$nY=$Y;
}
$nY = $nY+$Scale*sin($Phase + $nX*0.2);
$p = $this->bilinearInterpolate($nX-floor($nX), $nY-floor($nY),
$this->getCol($i,floor($nX),floor($nY)),
$this->getCol($i,ceil($nX),floor($nY)),
$this->getCol($i,floor($nX),ceil($nY)),
$this->getCol($i,ceil($nX),ceil($nY)));
if ($p==0) {
$p=0xFFFFFF;
}
imagesetpixel($out, $x, $y, $p);
}
// Renders it
ob_start();
imagejpeg($out, null, 15);
return ob_get_clean();
}
function getCol($image, $x, $y)
{
$L = imagesx($image);
$H = imagesy($image);
if ($x<0 || $x>=$L || $y<0 || $y>=$H)
return 0xFFFFFF;
else return imagecolorat($image, $x, $y);
}
function getRGB($col) {
return array(
(int)($col >> 16) & 0xff,
(int)($col >> 8) & 0xff,
(int)($col) & 0xff,
);
}
function bilinearInterpolate($x, $y, $nw, $ne, $sw, $se)
{
list($r0, $g0, $b0) = $this->getRGB($nw);
list($r1, $g1, $b1) = $this->getRGB($ne);
list($r2, $g2, $b2) = $this->getRGB($sw);
list($r3, $g3, $b3) = $this->getRGB($se);
$cx = 1.0 - $x;
$cy = 1.0 - $y;
$m0 = $cx * $r0 + $x * $r1;
$m1 = $cx * $r2 + $x * $r3;
$r = (int)($cy * $m0 + $y * $m1);
$m0 = $cx * $g0 + $x * $g1;
$m1 = $cx * $g2 + $x * $g3;
$g = (int)($cy * $m0 + $y * $m1);
$m0 = $cx * $b0 + $x * $b1;
$m1 = $cx * $b2 + $x * $b3;
$b = (int)($cy * $m0 + $y * $m1);
return ($r << 16) | ($g << 8) | $b;
}
}