Add branded QR renderer with centered app logo overlay.

High error correction qrencode plus GD logo plate for 2FA and short-link QR PNGs.

Co-authored-by: Cursor <cursoragent@cursor.com>

src/QrBrandedRenderer.php

@@ -0,0 +1,120 @@
+<?php
+declare(strict_types=1);
+
+/** Branded QR PNG: high error correction + centered app logo with white border. */
+final class QrBrandedRenderer {
+    private const LOGO_FRACTION = 0.22;
+    private const BORDER_FRACTION = 0.045;
+
+    private function __construct() {
+    }
+
+    public static function renderPng(string $text, int $size = 256): ?string {
+        $text = trim($text);
+        if ($text === '') {
+            return null;
+        }
+        $raw = self::rawQrPng($text, $size);
+        if ($raw === null) {
+            return null;
+        }
+        $branded = self::overlayLogo($raw);
+        return $branded ?? $raw;
+    }
+
+    public static function dataUri(string $text, int $size = 256): ?string {
+        $png = self::renderPng($text, $size);
+        if ($png === null) {
+            return null;
+        }
+        return 'data:image/png;base64,' . base64_encode($png);
+    }
+
+    /** @return list<string> */
+    private static function logoCandidates(): array {
+        return [
+            __DIR__ . '/../public/assets/ac_qr_logo.png',
+            __DIR__ . '/../assets/ac_qr_logo.png',
+        ];
+    }
+
+    private static function logoPath(): ?string {
+        foreach (self::logoCandidates() as $path) {
+            if (is_readable($path)) {
+                return $path;
+            }
+        }
+        return null;
+    }
+
+    private static function rawQrPng(string $text, int $size): ?string {
+        $qrencode = trim((string) shell_exec('command -v qrencode 2>/dev/null') ?? '');
+        if ($qrencode === '') {
+            return null;
+        }
+        $size = max(128, min(512, $size));
+        $moduleSize = max(3, (int) round($size / 33));
+        $cmd = sprintf(
+            '%s -l H -t PNG -s %d -m 2 -o - %s 2>/dev/null',
+            escapeshellcmd($qrencode),
+            $moduleSize,
+            escapeshellarg($text)
+        );
+        $out = shell_exec($cmd);
+        if (!is_string($out) || strlen($out) < 8) {
+            return null;
+        }
+        return $out;
+    }
+
+    private static function overlayLogo(string $pngBytes): ?string {
+        if (!extension_loaded('gd')) {
+            return null;
+        }
+        $logoPath = self::logoPath();
+        if ($logoPath === null) {
+            return null;
+        }
+        $qr = @imagecreatefromstring($pngBytes);
+        if ($qr === false) {
+            return null;
+        }
+        $logo = @imagecreatefrompng($logoPath);
+        if ($logo === false) {
+            imagedestroy($qr);
+            return null;
+        }
+        $qrW = imagesx($qr);
+        $qrH = imagesy($qr);
+        if ($qrW < 32 || $qrH < 32) {
+            imagedestroy($qr);
+            imagedestroy($logo);
+            return null;
+        }
+
+        $logoBox = (int) round(min($qrW, $qrH) * self::LOGO_FRACTION);
+        $border = max(2, (int) round(min($qrW, $qrH) * self::BORDER_FRACTION));
+        $plate = $logoBox + 2 * $border;
+        $plateX = (int) floor(($qrW - $plate) / 2);
+        $plateY = (int) floor(($qrH - $plate) / 2);
+
+        $white = imagecolorallocate($qr, 255, 255, 255);
+        imagefilledrectangle($qr, $plateX, $plateY, $plateX + $plate - 1, $plateY + $plate - 1, $white);
+
+        $srcW = imagesx($logo);
+        $srcH = imagesy($logo);
+        $dstX = $plateX + $border;
+        $dstY = $plateY + $border;
+        imagecopyresampled($qr, $logo, $dstX, $dstY, 0, 0, $logoBox, $logoBox, $srcW, $srcH);
+
+        ob_start();
+        imagepng($qr);
+        $out = ob_get_clean();
+        imagedestroy($qr);
+        imagedestroy($logo);
+        if (!is_string($out) || strlen($out) < 8) {
+            return null;
+        }
+        return $out;
+    }
+}

src/bootstrap.php

@@ -76,6 +76,7 @@ require_once __DIR__ . '/WireGuardTrafficStats.php';
 require_once __DIR__ . '/RsshSessionProvisioner.php';
 require_once __DIR__ . '/RsshBastionProvisioner.php';
 require_once __DIR__ . '/AuthTwoFactorPage.php';
+require_once __DIR__ . '/QrBrandedRenderer.php';
 require_once __DIR__ . '/AnalyticsHead.php';
 
 function cfg(string $key, $default = null) {