feat: 分栏对照开发，字体缩放、定位调整

miniprogram/englishPages/letterTracing/letterTracing.ts

@@ -10,6 +10,7 @@ import {
     type LetterTracingMode,
 } from '../shared/generators/letter-tracing-generator';
 import { LETTERS_UPPER } from '../shared/data/alphabet';
+import { loadLetterFont } from '../shared/draw/drawTools';
 
 /** 各 worksheetId 对应的页面标题和描述 */
 const PAGE_META: Record<string, { title: string; desc: string }> = {
@@ -80,13 +81,34 @@ createPage(
             modeOptions: [...MODE_OPTIONS],
         } as unknown as PageData,
 
-        /** 页面加载：从路由参数获取 worksheetId 并应用 */
-        onLoad(options: { id?: string }) {
+        /** 页面加载：从路由参数获取 worksheetId、letter、case 并应用，同时预加载字体 */
+        onLoad(options: {
+            id?: string;
+            letter?: string;
+            case?: 'upper' | 'lower';
+        }) {
+            loadLetterFont().catch(() => {});
             const worksheetId =
                 options.id && PAGE_META[options.id]
                     ? options.id
                     : 'letter-tracing-single';
             this.applyWorksheet(worksheetId);
+
+            const updates: Partial<PageData> = {};
+            if (options.letter) {
+                const normalized = normalizeLetter(options.letter);
+                if (normalized) updates.selectedLetter = normalized;
+            }
+            if (options.case === 'lower') {
+                updates.letterCaseLower = true;
+            } else if (options.case === 'upper') {
+                updates.letterCaseLower = false;
+            }
+            if (Object.keys(updates).length > 0) {
+                this.setData(
+                    updates as Partial<PageData> & WechatMiniprogram.IAnyObject,
+                );
+            }
         },
 
         /** 用户点击模式选择器时切换 worksheet */
@@ -140,10 +162,11 @@ createPage(
             });
         },
 
-        /** 执行 Canvas 绘制：生成数据 → 调用 drawService 渲染 */
+        /** 执行 Canvas 绘制：等待字体就绪 → 生成数据 → 调用 drawService 渲染 */
         async drawCanvas() {
             if (!this.ctx || !this.drawService) return;
             try {
+                await loadLetterFont();
                 const config = this.buildRuntimeConfig();
                 const data = generateLetterTracing(config);
                 console.log('drawCanvas data', data);