57 lines
1.5 KiB
Markdown
57 lines
1.5 KiB
Markdown
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Here is some example code for implementing a CAPTCHA, using the gd extension to create a server-rendered, randomized image.
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```php
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<?php
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// Start the session to store the CAPTCHA answer
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session_start();
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// Define the image dimensions
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$width = 200;
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$height = 60;
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// Create the image resource
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$image = imagecreatetruecolor($width, $height);
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// Define colors
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$bg_color = imagecolorallocate($image, 255, 255, 255); // White background
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$text_color = imagecolorallocate($image, 0, 0, 0); // Black text
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$noise_color = imagecolorallocate($image, 100, 100, 100); // Gray for noise
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// Fill the background
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imagefill($image, 0, 0, $bg_color);
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// Generate a random math equation (e.g., 3 + 5)
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$num1 = rand(1, 9);
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$num2 = rand(1, 9);
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$operator = rand(0, 1) ? '+' : '-'; // Randomly choose addition or subtraction
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$equation = "$num1 $operator $num2 = ?";
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$answer = $operator == '+' ? ($num1 + $num2) : ($num1 - $num2);
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// Store the answer in the session
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$_SESSION['captcha'] = $answer;
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// Add noise to the image (random dots)
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for ($i = 0; $i < 1000; $i++) {
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imagesetpixel($image, rand(0, $width), rand(0, $height), $noise_color);
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}
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// Set the path to the ZXX font
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$font = __DIR__ . '/fonts/ZXX-Regular.ttf'; // Path to the ZXX font file
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// Add the math equation using ZXX font
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$font_size = 30;
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$x = 20;
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$y = 40;
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imagettftext($image, $font_size, rand(-10, 10), $x, $y, $text_color, $font, $equation);
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// Output the image as PNG
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header('Content-Type: image/png');
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imagepng($image);
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// Free the image resource
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imagedestroy($image);
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?>
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```
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https://github.com/kawaiidesune/zxx
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