viewer: store and restore the scroll position through navigation

GitHub: closes #58

2 files changed, 33 insertions, 2 deletions

diff --git a/viewer/src/@types/scrollposition.d.ts b/viewer/src/@types/scrollposition.d.ts
new file mode 100644
index 0000000..d4fad52
--- /dev/null
+++ b/viewer/src/@types/scrollposition.d.ts
@@ -0,0 +1,20 @@
+/* ldgallery - A static generator which turns a collection of tagged
+--             pictures into a searchable web gallery.
+--
+-- Copyright (C) 2019-2020  Guillaume FOUET
+--
+-- This program is free software: you can redistribute it and/or modify
+-- it under the terms of the GNU Affero General Public License as
+-- published by the Free Software Foundation, either version 3 of the
+-- License, or (at your option) any later version.
+--
+-- This program is distributed in the hope that it will be useful,
+-- but WITHOUT ANY WARRANTY; without even the implied warranty of
+-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+-- GNU Affero General Public License for more details.
+--
+-- You should have received a copy of the GNU Affero General Public License
+-- along with this program.  If not, see <https://www.gnu.org/licenses/>.
+*/
+
+type ScrollPosition = { [index: string]: number }
\ No newline at end of file
diff --git a/viewer/src/views/MainLayout.vue b/viewer/src/views/MainLayout.vue
index 31b0440..12388a9 100644
--- a/viewer/src/views/MainLayout.vue
+++ b/viewer/src/views/MainLayout.vue
@@ -21,7 +21,7 @@
   <div :class="{'fullscreen': $uiStore.fullscreen, 'fullwidth': $uiStore.fullWidth}">
     <panel-top v-if="!isLoading" class="layout layout-top" />
     <panel-left v-if="!isLoading" class="layout layout-left" />
-    <router-view v-if="!isLoading" class="layout layout-content scrollbar" />
+    <router-view v-if="!isLoading" ref="content" class="layout layout-content scrollbar" />
     <b-loading :active="isLoading" is-full-page />
     <ld-key-press :keycode="27" @action="$uiStore.fullscreen=false" />
 
@@ -32,20 +32,31 @@
 </template>
 
 <script lang="ts">
-import { Component, Vue } from "vue-property-decorator";
+import { Component, Vue, Ref, Watch } from "vue-property-decorator";
 import PanelLeft from "./PanelLeft.vue";
 import PanelTop from "./PanelTop.vue";
+import { Route } from "vue-router";
 
 @Component({
   components: { PanelLeft, PanelTop },
 })
 export default class MainLayout extends Vue {
+  @Ref() readonly content!: Vue;
+
   isLoading: boolean = true;
+  scrollPositions: ScrollPosition = {};
 
   mounted() {
     this.fetchGalleryItems();
   }
 
+  @Watch("$route")
+  routeChanged(newRoute: Route, oldRoute: Route) {
+    const el = this.content.$el;
+    this.scrollPositions[oldRoute.path] = el.scrollTop;
+    this.$nextTick(() => (el.scrollTop = this.scrollPositions[newRoute.path]));
+  }
+
   fetchGalleryItems() {
     this.isLoading = true;
     this.$galleryStore