captcha.class.php
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<?php
defined('IN_IA') or exit('Access Denied');
class Captcha {
public $maxAngle = 15;
public $maxOffset = 5;
public $phrase = '';
public function build($width, $height) {
$image = @imagecreatetruecolor($width, $height);
if(empty($image)) {
return error('1', 'Not supplied GD');
}
$bg = imagecolorallocate($image, $this->rand(200, 255), $this->rand(200, 255), $this->rand(200, 255));
imagefill($image, 0, 0, $bg);
$square = $width * $height * 3;
$effects = $this->rand($square/2000, $square/1000);
for ($e = 0; $e < $effects; $e++) {
$this->drawLine($image, $width, $height);
}
$this->phrase = $this->phrase();
$color = $this->writePhrase($image, $this->phrase, $this->font(), $width, $height);
$square = $width * $height;
$effects = $this->rand($square/3000, $square/2000);
if ($this->maxFrontLines !== 0) {
for ($e = 0; $e < $effects; $e++) {
$this->drawLine($image, $width, $height, $color);
}
}
$image = $this->distort($image, $width, $height, $bg);
$this->image = $image;
return $this;
}
public function output($quality = 90) {
header('content-type: image/png');
imagepng($this->image);
imagedestroy($this->image);
}
protected function phrase() {
return random(4, true);
}
protected function rand($min, $max) {
mt_srand((double) microtime() * 1000000);
return mt_rand($min, $max);
}
protected function drawLine($image, $width, $height, $tcol = null) {
if ($tcol === null) {
$tcol = imagecolorallocate($image, $this->rand(100, 255), $this->rand(100, 255), $this->rand(100, 255));
}
if ($this->rand(0, 1)) { $Xa = $this->rand(0, $width/2);
$Ya = $this->rand(0, $height);
$Xb = $this->rand($width/2, $width);
$Yb = $this->rand(0, $height);
} else { $Xa = $this->rand(0, $width);
$Ya = $this->rand(0, $height/2);
$Xb = $this->rand(0, $width);
$Yb = $this->rand($height/2, $height);
}
imagesetthickness($image, $this->rand(1, 3));
imageline($image, $Xa, $Ya, $Xb, $Yb, $tcol);
}
protected function writePhrase($image, $phrase, $font, $width, $height) {
$size = $width / strlen($phrase) - $this->rand(0, 3) - 1;
$box = imagettfbbox($size, 0, $font, $phrase);
$textWidth = $box[2] - $box[0];
$textHeight = $box[1] - $box[7];
$x = ($width - $textWidth) / 2;
$y = ($height - $textHeight) / 2 + $size;
$textColor = array($this->rand(0, 150), $this->rand(0, 150), $this->rand(0, 150));
$col = imagecolorallocate($image, $textColor[0], $textColor[1], $textColor[2]);
$length = strlen($phrase);
for ($i=0; $i<$length; $i++) {
$box = imagettfbbox($size, 0, $font, $phrase[$i]);
$w = $box[2] - $box[0];
$angle = $this->rand(-$this->maxAngle, $this->maxAngle);
$offset = $this->rand(-$this->maxOffset, $this->maxOffset);
imagettftext($image, $size, $angle, $x, $y + $offset, $col, $font, $phrase[$i]);
$x += $w;
}
return $col;
}
public function distort($image, $width, $height, $bg) {
$contents = imagecreatetruecolor($width, $height);
$X = $this->rand(0, $width);
$Y = $this->rand(0, $height);
$phase = $this->rand(0, 10);
$scale = 1.1 + $this->rand(0, 10000) / 30000;
for ($x = 0; $x < $width; $x++) {
for ($y = 0; $y < $height; $y++) {
$Vx = $x - $X;
$Vy = $y - $Y;
$Vn = sqrt($Vx * $Vx + $Vy * $Vy);
if ($Vn != 0) {
$Vn2 = $Vn + 4 * sin($Vn / 30);
$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->interpolate(
$nX - floor($nX),
$nY - floor($nY),
$this->getCol($image, floor($nX), floor($nY), $bg),
$this->getCol($image, ceil($nX), floor($nY), $bg),
$this->getCol($image, floor($nX), ceil($nY), $bg),
$this->getCol($image, ceil($nX), ceil($nY), $bg)
);
if ($p == 0) {
$p = $bg;
}
imagesetpixel($contents, $x, $y, $p);
}
}
return $contents;
}
protected function interpolate($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) | $b;
}
protected function getRGB($col) {
return array(
(int) ($col >> 16) & 0xff,
(int) ($col >> 8) & 0xff,
(int) ($col) & 0xff,
);
}
protected function getCol($image, $x, $y, $background) {
$L = imagesx($image);
$H = imagesy($image);
if ($x < 0 || $x >= $L || $y < 0 || $y >= $H) {
return $background;
}
return imagecolorat($image, $x, $y);
}
protected function font() {
return IA_ROOT . '/web/resource/fonts/captcha.ttf';
}
}
?>