58 lines
2.0 KiB
PHP
58 lines
2.0 KiB
PHP
<?php
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// Martin Hozik
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// 24.5.2008
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// doublethink.cleverweb.cz
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session_start();
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// inicializace
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require __DIR__ . '/imagelightnessat.func.php';
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require __DIR__ . '/linear_perspective.class.php';
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$perspective = new linear_perspective();
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// konfigurace rozměrů a pozic
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$matrix_dim = ['x' => 80, 'y' => 30];
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$captcha_dim = ['x' => 300, 'y' => 90];
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$distance = ['x' => 1, 'y' => 1, 'z' => 1];
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$metric = ['x' => 10, 'y' => 20, 'z' => 5];
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$offset = ['x' => 0, 'y' => -60];
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// matrice
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$matrix = imagecreatetruecolor($matrix_dim['x'], $matrix_dim['y']);
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$black = imagecolorexact($matrix, 0, 0, 0);
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$white = imagecolorexact($matrix, 255, 255, 255);
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imagefill($matrix, 0, 0, $white);
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// font calibri neni kvůli licenčním podmínkám připojen, použijte jakýkoliv svůj
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imagefttext($matrix, 20, 0, 2, 25, $black, __DIR__ . '/3DCaptcha.ttf', $_SESSION['captcha']);
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// výpočet bodů ve 3d
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$point = [];
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for ($x = 0; $x < $matrix_dim['x']; ++$x) {
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for ($y = 0; $y < $matrix_dim['y']; ++$y) {
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$lightness = imagelightnessat($matrix, $x, $y);
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$point[$x][$y] = $perspective->get_projection(['x' => $x * $metric['x'] + $distance['x'], 'y' => $lightness * $metric['y'] + $distance['y'], 'z' => ($matrix_dim['y'] - $y) * $metric['z'] + $distance['z']]);
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}
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}
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imagedestroy($matrix);
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// obrázek captcha
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$captcha = imagecreatetruecolor($captcha_dim['x'], $captcha_dim['y']);
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// antialiasing čar - pro menší zátěž lze vypnout
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//imageantialias($captcha, true);
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$black = imagecolorexact($captcha, 255, 0, 0);
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$white = imagecolorexact($captcha, 255, 255, 255);
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imagefill($captcha, 0, 0, $white);
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// vykreslení vrstevnic
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for ($x = 1; $x < $matrix_dim['x']; ++$x) {
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for ($y = 1; $y < $matrix_dim['y']; ++$y) {
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imageline($captcha, -$point[$x - 1][$y - 1]['x'] + $offset['x'], -$point[$x - 1][$y - 1]['y'] + $offset['y'], -$point[$x][$y]['x'] + $offset['x'], -$point[$x][$y]['y'] + $offset['y'], $black);
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}
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}
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// výstup
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header('Content-type: image/png');
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imagepng($captcha);
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