php如何生成带logo的二维码_php二维码库叠加图片定位与透明度调整技巧

include 'phpqrcode/qrlib.php';
<p>$qr_data = '<a href="https://www.php.cn/link/b05edd78c294dcf6d960190bf5bde635">https://www.php.cn/link/b05edd78c294dcf6d960190bf5bde635</a>';
$filename = 'qrcode.png';
$size = 10; // 容错级别 L,M,Q,H，H 最高
QRcode::png($qr_data, $filename, 'H', $size, 2);

function addLogoToQR($qrfile, $logo, $output, $pct = 0.2, $transparency = 80) {
    $qr = imagecreatefrompng($qrfile);
    $logo_ext = strtolower(pathinfo($logo, PATHINFO_EXTENSION));
<pre class="brush:php;toolbar:false;"><pre class="brush:php;toolbar:false;">if ($logo_ext == 'png') {
    $logo_img = imagecreatefrompng($logo);
} elseif ($logo_ext == 'jpeg' || $logo_ext == 'jpg') {
    $logo_img = imagecreatefromjpeg($logo);
} else {
    return false;
}

$qr_size = imagesx($qr);
$logo_size = imagesx($logo_img);
$new_logo_size = (int)($qr_size * $pct);

// 创建临时画布存放缩放后的 logo
$tmp_logo = imagecreatetruecolor($new_logo_size, $new_logo_size);

// 处理透明背景
imagealphablending($tmp_logo, false);
imagesavealpha($tmp_logo, true);
$transparent = imagecolorallocatealpha($tmp_logo, 255, 255, 255, 127);
imagefilledrectangle($tmp_logo, 0, 0, $new_logo_size, $new_logo_size, $transparent);

// 缩放 logo
imagecopyresampled($tmp_logo, $logo_img, 0, 0, 0, 0, $new_logo_size, $new_logo_size, $logo_size, $logo_size);

// 计算居中位置
$pos_x = ($qr_size - $new_logo_size) / 2;
$pos_y = ($qr_size - $new_logo_size) / 2;

// 叠加 logo，设置透明度
imagecopymerge($qr, $tmp_logo, $pos_x, $pos_y, 0, 0, $new_logo_size, $new_logo_size, $transparency);

// 输出图像
imagepng($qr, $output);

imagedestroy($qr);
imagedestroy($logo_img);
imagedestroy($tmp_logo);

addLogoToQR('qrcode.png', 'logo.png', 'qrcode_with_logo.png', 0.25, 70);