static-photos-page/generate.php

<?php

const SIZE = 256;

$photos = [];

foreach (scandir('./images') as $inode) {
    echo "Scanning file: $inode\n";
    
    if ( ! preg_match('/\.(gif|jpe?g|png|webp)$/i', $inode)) {
        continue;
    }
    
    $file_name      = basename($inode);
    $image_path     = "./images/$file_name";
    $thumbnail_path = "./images/thumbnails/$file_name";
    
    if ( ! file_exists($thumbnail_path)) {
        $image_bytes = file_get_contents($image_path);
        
        if ( ! $image_bytes) {
            echo "Warning: couldn't get contents of file $file_name\n";
            continue;
        }
        
        $image = imagecreatefromstring($image_bytes);
        
        if ( ! $image) {
            echo "Warning: couldn't parse image $file_name\n";
            continue;
        }
        
        echo "Creating thumbnail: $thumbnail_path\n";
        
        $source_width  = imagesx($image);
        $source_height = imagesy($image);
        $dest_width = ($source_width / $source_height) * SIZE;
        
        $thumbnail = imagecreate($dest_width, SIZE);
        
        imagecopyresampled(
            $thumbnail,
            $image,
            0, 0,
            0,0,
            $dest_width, SIZE,
            $source_width, $source_height
        );
        
        imagejpeg($thumbnail, $thumbnail_path);
    }
    
    // could generate a "view photo on its own" kinda HTML page with a mid-size version of the photo
    
    // if file is "blah.jpg", look for "blah.jpg.txt" and use this as alt text
    $alt_text = file_get_contents("./images/$file_name.txt");
    
    if ( ! $alt_text) {
        echo "Warning: no alt text for file $file_name\n";
    }
    
    $photos[] = sprintf(
        '
            <div class="photo">
                <a href="%s">
                    <img src="%s" alt="%s">
                </a>
            </div>
        ',
        $image_path,
        $thumbnail_path,
        $alt_text ?: ''
    );
}

file_put_contents(
    'index.html',
    sprintf(
        file_get_contents('template.html'),
        implode('', $photos)
    )
);