PHPGD库添加水印与图像处理教程

$src = 'photo.jpg';
$image = imagecreatefromjpeg($src);
header('Content-Type: image/jpeg');
imagejpeg($image);
imagedestroy($image);

$src = 'photo.jpg';
$image = imagecreatefromjpeg($src);
$color = imagecolorallocate($image, 255, 255, 255); // 白色
$font = 'arial.ttf'; // 字体文件路径
$text = '版权所有';
imagettftext($image, 20, 0, 20, 50, $color, $font, $text);
header('Content-Type: image/jpeg');
imagejpeg($image, null, 90); // 质量90%
imagedestroy($image);

$main = imagecreatefromjpeg('photo.jpg');
$logo = imagecreatefrompng('logo.png');
$logo_width = imagesx($logo);
$logo_height = imagesy($logo);
$dest_x = imagesx($main) - $logo_width - 10;
$dest_y = imagesy($main) - $logo_height - 10;
// 合并图像，透明度为50%
imagecopymerge($main, $logo, $dest_x, $dest_y, 0, 0, $logo_width, $logo_height, 50);
header('Content-Type: image/jpeg');
imagejpeg($main);
imagedestroy($main);
imagedestroy($logo);

function createThumbnail($src, $width = 200, $height = 200) {
    $original = imagecreatefromjpeg($src);
    $thumb = imagecreatetruecolor($width, $height);
    imagecopyresampled($thumb, $original, 0, 0, 0, 0, $width, $height, imagesx($original), imagesy($original));
    imagejpeg($thumb, 'thumb.jpg', 80);
    imagedestroy($original);
    imagedestroy($thumb);
}
createThumbnail('photo.jpg');