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