coupon/captcha.php

50 lines
1.5 KiB
PHP
Executable File
Raw Blame History

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<?php
session_start();
$width = 120;
$height = 42;
$fontSize = 20;
$image = imagecreatetruecolor($width, $height);
$bgColor = imagecolorallocate($image, 255, 255, 255);
imagefill($image, 0, 0, $bgColor);
// 干扰线
for ($i = 0; $i < 5; $i++) {
$lineColor = imagecolorallocatealpha($image, rand(100, 200), rand(100, 200), rand(100, 200), 50);
imageline($image, rand(0, $width), rand(0, $height), rand(0, $width), rand(0, $height), $lineColor);
}
// 干扰点
for ($i = 0; $i < 80; $i++) {
$pixelColor = imagecolorallocate($image, rand(150, 200), rand(150, 200), rand(150, 200));
imagesetpixel($image, rand(0, $width), rand(0, $height), $pixelColor);
}
$chars = 'ABCDEFGHJKLMNPQRSTUVWXYZ23456789';
$code = '';
for ($i = 0; $i < 4; $i++) {
$code .= $chars[rand(0, strlen($chars) - 1)];
}
$_SESSION['captcha'] = $code;
// 尝试使用TTF字体不存在则用内置字体
$fontFile = __DIR__ . '/assets/arial.ttf';
if (file_exists($fontFile)) {
for ($i = 0; $i < 4; $i++) {
$angle = rand(-15, 15);
$x = 8 + $i * 28;
$textColor = imagecolorallocate($image, rand(30, 100), rand(30, 100), rand(30, 100));
imagettftext($image, $fontSize, $angle, $x, 34, $textColor, $fontFile, $code[$i]);
}
} else {
$textColor = imagecolorallocate($image, 50, 50, 50);
imagestring($image, 5, 10, 12, $code, $textColor);
}
header('Content-Type: image/png');
header('Cache-Control: no-cache, no-store, must-revalidate');
imagepng($image);
imagedestroy($image);