MOBILE-3750 a11y: Listen resize events on scrolls

package-lock.json

@@ -4224,6 +4224,12 @@
       "integrity": "sha512-1HcDas8SEj4z1Wc696tH56G8OlRaH/sqZOynNNB+HF0WOeXPaxTtbYzJY2oEfiUxjSKjhCKr+MvR7dCHcEelug==",
       "dev": true
     },
+    "@types/resize-observer-browser": {
+      "version": "0.1.5",
+      "resolved": "https://registry.npmjs.org/@types/resize-observer-browser/-/resize-observer-browser-0.1.5.tgz",
+      "integrity": "sha512-8k/67Z95Goa6Lznuykxkfhq9YU3l1Qe6LNZmwde1u7802a3x8v44oq0j91DICclxatTr0rNnhXx7+VTIetSrSQ==",
+      "dev": true
+    },
     "@types/source-list-map": {
       "version": "0.1.2",
       "resolved": "https://registry.npmjs.org/@types/source-list-map/-/source-list-map-0.1.2.tgz",

package.json

@@ -140,6 +140,7 @@
     "@ionic/v4-migration-tslint": "^1.7.1",
     "@types/faker": "^5.1.3",
     "@types/node": "^12.12.64",
+    "@types/resize-observer-browser": "^0.1.5",
     "@types/webpack-env": "^1.16.0",
     "@typescript-eslint/eslint-plugin": "^4.22.0",
     "@typescript-eslint/parser": "^4.22.0",

src/addons/block/recentlyaccessedcourses/components/recentlyaccessedcourses/addon-block-recentlyaccessedcourses.html

@@ -29,9 +29,11 @@
         class="core-horizontal-scroll"
         (scroll)="scrollControls.updateScrollPosition()"
     >
+        <div (onResize)="scrollControls.updateScrollPosition()" class="flex-row">
             <ng-container *ngFor="let course of courses">
                 <core-courses-course-progress [course]="course" class="core-recentlyaccessedcourses"
                     [showDownload]="downloadCourseEnabled && downloadEnabled"></core-courses-course-progress>
             </ng-container>
         </div>
+    </div>
 </core-loading>

src/addons/block/recentlyaccesseditems/components/recentlyaccesseditems/addon-block-recentlyaccesseditems.html

@@ -12,6 +12,7 @@
         class="core-horizontal-scroll"
         (scroll)="scrollControls.updateScrollPosition()"
     >
+        <div *ngIf="items" (onResize)="scrollControls.updateScrollPosition()" class="flex-row">
             <div *ngFor="let item of items">
                 <ion-card>
                     <ion-item class="core-course-module-handler item-media ion-text-wrap" detail="false" (click)="action($event, item)"
@@ -33,6 +34,7 @@
                 </ion-card>
             </div>
         </div>
+    </div>
 
     <core-empty-box *ngIf="items.length <= 0" image="assets/img/icons/activities.svg" inline="true"
         [message]="'addon.block_recentlyaccesseditems.noitems' | translate"></core-empty-box>

src/addons/block/recentlyaccesseditems/components/recentlyaccesseditems/recentlyaccesseditems.scss

@@ -1,7 +1,7 @@
 @import "~theme/globals";
 
 :host {
-    .core-horizontal-scroll > div {
+    .core-horizontal-scroll > div > div {
         @include horizontal_scroll_item(80%, 250px, 300px);
     }
 

src/addons/block/starredcourses/components/starredcourses/addon-block-starredcourses.html

@@ -30,9 +30,11 @@
         class="core-horizontal-scroll"
         (scroll)="scrollControls.updateScrollPosition()"
     >
+        <div (onResize)="scrollControls.updateScrollPosition()" class="flex-row">
             <ng-container *ngFor="let course of courses">
                 <core-courses-course-progress [course]="course" class="core-block_starredcourses"
                     [showDownload]="downloadCourseEnabled && downloadEnabled"></core-courses-course-progress>
             </ng-container>
         </div>
+    </div>
 </core-loading>

src/core/directives/directives.module.ts

@@ -25,6 +25,7 @@ import { CoreLongPressDirective } from './long-press';
 import { CoreSupressEventsDirective } from './supress-events';
 import { CoreUserLinkDirective } from './user-link';
 import { CoreAriaButtonClickDirective } from './aria-button';
+import { CoreOnResizeDirective } from './on-resize';
 
 @NgModule({
     declarations: [
@@ -39,6 +40,7 @@ import { CoreAriaButtonClickDirective } from './aria-button';
         CoreSupressEventsDirective,
         CoreUserLinkDirective,
         CoreAriaButtonClickDirective,
+        CoreOnResizeDirective,
     ],
     exports: [
         CoreAutoFocusDirective,
@@ -52,6 +54,7 @@ import { CoreAriaButtonClickDirective } from './aria-button';
         CoreSupressEventsDirective,
         CoreUserLinkDirective,
         CoreAriaButtonClickDirective,
+        CoreOnResizeDirective,
     ],
 })
 export class CoreDirectivesModule {}

src/core/directives/on-resize.ts

@@ -0,0 +1,99 @@
+// (C) Copyright 2015 Moodle Pty Ltd.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+import { Directive, ElementRef, OnInit, Output, EventEmitter, OnDestroy } from '@angular/core';
+import { CoreUtils } from '@services/utils/utils';
+
+/**
+ * Directive to listen for element resize events.
+ */
+@Directive({
+    selector: '[onResize]',
+})
+export class CoreOnResizeDirective implements OnInit, OnDestroy {
+
+    @Output() onResize = new EventEmitter();
+
+    private element: HTMLElement;
+    private resizeObserver?: ResizeObserver;
+    private mutationObserver?: MutationObserver;
+
+    constructor(element: ElementRef) {
+        this.element = element.nativeElement;
+    }
+
+    /**
+     * @inheritdoc
+     */
+    ngOnInit(): void {
+        'ResizeObserver' in window
+            ? this.watchResize()
+            : this.watchMutations();
+    }
+
+    /**
+     * @inheritdoc
+     */
+    ngOnDestroy(): void {
+        this.resizeObserver?.disconnect();
+        this.mutationObserver?.disconnect();
+    }
+
+    /**
+     * Watch resize events.
+     */
+    private watchResize(): void {
+        this.resizeObserver = new ResizeObserver(() => this.onResize.emit());
+
+        this.resizeObserver.observe(this.element);
+    }
+
+    /**
+     * Watch mutation events to detect resizing.
+     */
+    private watchMutations(): void {
+        let size = this.getElementSize();
+        const onMutation = () => {
+            const newSize = this.getElementSize();
+
+            if (newSize.width !== size.width || newSize.height !== size.height) {
+                size = newSize;
+
+                this.onResize.emit();
+            }
+        };
+
+        // Debounce 20ms to let mutations resolve before checking the new size.
+        this.mutationObserver = new MutationObserver(CoreUtils.debounce(onMutation, 20));
+
+        this.mutationObserver.observe(this.element, {
+            subtree: true,
+            childList: true,
+            characterData: true,
+        });
+    }
+
+    /**
+     * Get element size.
+     *
+     * @returns Element size.
+     */
+    private getElementSize(): { width: number; height: number } {
+        return {
+            width: this.element.clientWidth,
+            height: this.element.clientHeight,
+        };
+    }
+
+}

tsconfig.app.json

@@ -8,6 +8,7 @@
       "cordova",
       "dom-mediacapture-record",
       "node",
+      "resize-observer-browser",
       "webpack-env"
     ],
     "paths": {

tsconfig.json

@@ -27,6 +27,7 @@
         "faker",
         "jest",
         "node",
+        "resize-observer-browser",
         "webpack-env"
     ],
     "paths": {

tsconfig.test.json

@@ -12,7 +12,8 @@
       "dom-mediacapture-record",
       "faker",
       "jest",
-      "node"
+      "node",
+      "resize-observer-browser"
     ],
     "paths": {
       "@addons/*": ["addons/*"],