fix map scale

miniprogram/pages/main/journal-map/index.ts

@@ -57,6 +57,37 @@ Page({
 	async onLoad() {
 		await this.loadJournals();
 	},
+	/** 计算合适的缩放级别以显示所有标记点 */
+	calculateScale(journals: JournalMarker[]): number {
+		if (journals.length === 0) return 13;
+		if (journals.length === 1) return 15;
+
+		// 计算经纬度的范围
+		const lats = journals.map(j => j.lat);
+		const lngs = journals.map(j => j.lng);
+		const minLat = Math.min(...lats);
+		const maxLat = Math.max(...lats);
+		const minLng = Math.min(...lngs);
+		const maxLng = Math.max(...lngs);
+
+		// 计算跨度
+		const latSpan = maxLat - minLat;
+		const lngSpan = maxLng - minLng;
+		const maxSpan = Math.max(latSpan, lngSpan);
+
+		// 根据跨度映射到缩放级别（scale 范围 3-20）
+		if (maxSpan > 10) return 5;
+		if (maxSpan > 5) return 7;
+		if (maxSpan > 2) return 9;
+		if (maxSpan > 1) return 10;
+		if (maxSpan > .5) return 11;
+		if (maxSpan > .2) return 12;
+		if (maxSpan > .1) return 13;
+		if (maxSpan > .05) return 14;
+		if (maxSpan > .02) return 15;
+		if (maxSpan > .01) return 16;
+		return 17;
+	},
 	/** 加载所有记录 */
 	async loadJournals() {
 		this.setData({ isLoading: true });
@@ -131,6 +162,8 @@ Page({
 			// 计算中心点（所有标记的平均位置）
 			const centerLat = journals.reduce((sum, j) => sum + j.lat, 0) / journals.length;
 			const centerLng = journals.reduce((sum, j) => sum + j.lng, 0) / journals.length;
+			// 计算合适的缩放级别
+			const scale = this.calculateScale(journals) - 2;
 
 			this.setData({
 				journals,
@@ -138,6 +171,7 @@ Page({
 				customCalloutMarkerIds,
 				centerLat,
 				centerLng,
+				scale,
 				isLoading: false
 			});
 		} catch (err: any) {