feat: 英语描红 字母选择修改

miniprogram/englishPages/letterTracing/letterTracing.ts

@@ -91,8 +91,6 @@ type PageData = CanvasDataState & {
     tripleGroups: { label: string; letters: string[] }[];
     selectedTripleGroupIdx: number;
     letterGrid: string[];
-    letterGridExpanded: boolean;
-    letterGridPreview: string[];
     modeOptions: ReadonlyArray<{ id: string; label: string; desc: string }>;
 };
 
@@ -122,8 +120,6 @@ createPage(
             tripleGroups: TRIPLE_GROUPS,
             selectedTripleGroupIdx: 0,
             letterGrid: LETTERS_PAIRS,
-            letterGridExpanded: false,
-            letterGridPreview: LETTERS_PAIRS.slice(0, 6),
             modeOptions: [...MODES],
         } as unknown as PageData,
 
@@ -242,13 +238,6 @@ createPage(
             }
         },
 
-        /** 展开/收起字母网格 */
-        toggleLetterGrid() {
-            this.setData({
-                letterGridExpanded: !this.data.letterGridExpanded,
-            });
-        },
-
         /** 用户在字母网格中选择了一个字母（item 为 "Aa" 格式，取首字母作为 selectedLetter） */
         onSelectLetter(e: WechatMiniprogram.TouchEvent) {
             const raw = e.currentTarget.dataset.letter as string;