| Dizainoff |
20.11.2008 11:36 |
Вложений: 2
На мой взгляд, проверку на соответствие введенного кода с кодом отображенного на рисунке, необходимо производить на стороне сервера. Следовательно и сервер должен генерировать такое изображение.
Пример генерации изображения с защитным кодом с поддержкой ttf шрифта. [PHP - На скорую руку]
Код:
<?php
//session_start();
header ("Content-type: image/jpeg");
function captcha_generator_print_string(&$image, $width, $height, $font, $font_size, $text,$clr_start,$clr_end) {
$bbox = imagettfbbox($font_size, 0, $font, $text);
$textwidth = $bbox[2] - $bbox[0];
$captcha_len = strlen($text);
$spacing = ($width - $textwidth) / ($captcha_len);
$jittering_x = 0.3 * $font_size;
$jittering_y = 0.3 * $font_size;
$x = $spacing/2;
for($i=0;$i<$captcha_len;$i++){
$character = $text[$i];
$bbox = imagettfbbox($font_size, 0, realpath($font), $character);
$character_width = $bbox[2] - $bbox[0];
$character_height = $bbox[5] - $bbox[3];
$y = 0.5 * ($height - $character_height);
$pos_x = $x + mt_rand(-$jittering_x, $jittering_x);
$pos_y = $y + mt_rand(-$jittering_y, $jittering_y);
$r = mt_rand($clr_start,$clr_end);
$g = mt_rand($clr_start,$clr_end);
$b = mt_rand($clr_start,$clr_end);
$color = imagecolorallocate($image,$r,$g,$b);
imagettftext($image, $font_size, 0, $pos_x, $pos_y, $color, $font, $character);
$x += $character_width + $spacing;
}
}
$seccode_array = array("S","A","P","W","E","R","T","Y","U","I","O");
$seccode = "";
$s_count = 5;
$captcha_string = "";
$font_size = 30;
$character_spacing = 1.2;
$font = realpath("./fonts/frizzed.ttf");
$background_color = 0xFFFFFF;
$clr_rnd_start = 64;
$clr_rnd_end = 255;
$noise_quantity_k = 2.0;
$line_quantity_k = 2.0;
$sh_clr_start = 200;
$sh_clr_end = 200;
$s_clr_start = 0;
$s_clr_end = 128;
for($i=0;$i<$s_count;$i++){
$ind = mt_rand(0,count($seccode_array)-1);
$captcha_string .= $seccode_array[$ind];
}
//$_SESSION['captcha']['seccode'] = $captcha_string;
$captcha_len = strlen($captcha_string);
$width = $character_spacing * $font_size * $captcha_len+100;
$height = 2 * $font_size;
$image = imagecreatetruecolor($width, $height);
imagefilledrectangle($image, 0, 0, $width, $height, $background_color);
captcha_generator_print_string($image,$width, $height,$font,$font_size,$captcha_string,$sh_clr_start,$sh_clr_end);
captcha_generator_print_string($image,$width, $height,$font,$font_size,$captcha_string,$s_clr_start, $s_clr_end );
// Добавляем шум
$noise_colors = array();
for ($i = 0; $i < 20; $i++) {
$color_r = mt_rand($clr_rnd_start, $clr_rnd_end);
$color_g = mt_rand($clr_rnd_start, $clr_rnd_end);
$color_b = mt_rand($clr_rnd_start, $clr_rnd_end);
$noise_colors[] = imagecolorallocate($image, $color_r, $color_g, $color_b);
}
$noise_quantity = ($width * $height)/ $noise_quantity_k * 0.3;
for ($i = 0; $i < $noise_quantity; $i++ ) {
imagesetpixel($image, mt_rand(0, $width), mt_rand(0, $height), $noise_colors[array_rand($noise_colors)]);
}
$line_quantity = $width * $height/($line_quantity_k * 100) * 0.3;
for ($i = 0; $i < $line_quantity; $i++) {
imageline($image, mt_rand(0, $width), mt_rand(0, $height), mt_rand(0, $width), mt_rand(0, $height), $noise_colors[array_rand($noise_colors)]);
}
if($image){
imagepng($image);
}
?>
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