When working with canvas in JavaScript, the usual approach is:
var canvas = document.getElementById('tutorial');
var ctx = canvas.getContext('2d');
However, when it comes to Angular2, I am unable to access the HTMLCanvasElement object using the "canvas" variable. Instead, only the HTMLElement is obtained in Angular2. How can I effectively utilize canvas in Angular2? Additionally, how can third-party JavaScript libraries be incorporated into Angular2 using TypeScript?
To achieve this task, utilize the @ViewChild method.
In your component class, implement the following steps:
import { Component, ViewChild, ElementRef, AfterViewInit } from '@angular/core';
@Component({
name: 'my-component',
// ensure variable name matches myCanvas
template: `<canvas #myCanvas></canvas>`
})
export class myComponent implements AfterViewInit {
@ViewChild('myCanvas')
canvas: ElementRef<HTMLCanvasElement>;
context: CanvasRenderingContext2D;
ngAfterViewInit(): void {
this.context = this.canvas.nativeElement.getContext('2d');
}
}
Avoid relying on document as much as possible to prevent future complications. Using @ViewChild is advantageous over direct DOM manipulation in Angular because it allows for targeted modifications without needing to search the DOM each time.
Refer to this demo for a comprehensive example.
Update
For Angular 8, adjust the ViewChild usage as follows:
@ViewChild('myCanvas', {static: false}) myCanvas: ElementRef;
Visit How should I use the new static option for @ViewChild in Angular 8? for further details.
In my experience with Angular 13, I found this method to be effective.
@ViewChild('myCanvas')
private myCanvas: ElementRef = {} as ElementRef;
Even though I attempted the solution provided by realappie, I continued to encounter errors.
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