小程序二维码功能

apps/mini-user/src/lib/redeem-qr.ts

@@ -0,0 +1,42 @@
+import './text-encoding-polyfill';
+import QRCode from 'qrcode';
+
+const QR_SIZE = 240;
+const QR_OPTIONS = {
+  width: QR_SIZE * 2,
+  margin: 0,
+  color: { dark: '#1f1a17', light: '#ffffff' },
+} as const;
+
+/** 在 2d Canvas 上绘制二维码（小程序 / H5 通用） */
+export function drawRedeemQrOnCanvas(
+  ctx: CanvasRenderingContext2D,
+  token: string,
+  sizePx = QR_SIZE,
+) {
+  const qr = QRCode.create(token, { errorCorrectionLevel: 'M' });
+  const count = qr.modules.size;
+  const cell = sizePx / count;
+
+  ctx.fillStyle = '#ffffff';
+  ctx.fillRect(0, 0, sizePx, sizePx);
+  ctx.fillStyle = '#1f1a17';
+  for (let row = 0; row < count; row++) {
+    for (let col = 0; col < count; col++) {
+      if (qr.modules.get(row, col)) {
+        ctx.fillRect(col * cell, row * cell, cell, cell);
+      }
+    }
+  }
+}
+
+/** H5：Data URL；失败时回退到与 h5-user 相同的外部 QR 服务 */
+export async function buildRedeemQrDataUrl(token: string): Promise<string> {
+  try {
+    return await QRCode.toDataURL(token, QR_OPTIONS);
+  } catch {
+    return `https://api.qrserver.com/v1/create-qr-code/?size=${QR_SIZE * 2}x${QR_SIZE * 2}&data=${encodeURIComponent(token)}`;
+  }
+}
+
+export const REDEEM_QR_DISPLAY_SIZE = QR_SIZE;

apps/mini-user/src/lib/text-encoding-polyfill.ts

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+/** 微信小程序基础库未内置 TextEncoder，qrcode 库依赖它编码 payload */
+function installTextEncodingPolyfill() {
+  const root = (typeof globalThis !== 'undefined'
+    ? globalThis
+    : typeof global !== 'undefined'
+      ? global
+      : typeof wx !== 'undefined'
+        ? wx
+        : {}) as typeof globalThis & { TextEncoder?: typeof TextEncoder };
+
+  if (typeof root.TextEncoder !== 'undefined') return;
+
+  class MiniTextEncoder implements TextEncoder {
+    readonly encoding = 'utf-8';
+
+    encode(input?: string): Uint8Array {
+      const str = input ?? '';
+      const bytes: number[] = [];
+      for (let i = 0; i < str.length; i++) {
+        let code = str.charCodeAt(i);
+        if (code < 0x80) {
+          bytes.push(code);
+        } else if (code < 0x800) {
+          bytes.push(0xc0 | (code >> 6), 0x80 | (code & 0x3f));
+        } else if (code >= 0xd800 && code <= 0xdbff && i + 1 < str.length) {
+          const next = str.charCodeAt(i + 1);
+          if (next >= 0xdc00 && next <= 0xdfff) {
+            i += 1;
+            code = 0x10000 + ((code - 0xd800) << 10) + (next - 0xdc00);
+            bytes.push(
+              0xf0 | (code >> 18),
+              0x80 | ((code >> 12) & 0x3f),
+              0x80 | ((code >> 6) & 0x3f),
+              0x80 | (code & 0x3f),
+            );
+          } else {
+            bytes.push(0xe0 | (code >> 12), 0x80 | ((code >> 6) & 0x3f), 0x80 | (code & 0x3f));
+          }
+        } else {
+          bytes.push(0xe0 | (code >> 12), 0x80 | ((code >> 6) & 0x3f), 0x80 | (code & 0x3f));
+        }
+      }
+      return new Uint8Array(bytes);
+    }
+  }
+
+  root.TextEncoder = MiniTextEncoder as unknown as typeof TextEncoder;
+}
+
+installTextEncodingPolyfill();
+
+export {};