import { Cscreenshot } from 'nativescript-cscreenshot';
    import { ImageSource } from "tns-core-modules/image-source";

    // then in your take a screenshot method
    let screen = new Cscreenshot();

    // Using vanilla Nativescript
    let view = page.getViewById('main');

    // Using Angular Nativescript
    @ViewChild("main", { static: true }) main: ElementRef;
    let view = this.view.nativeElement;

    // Using Vue Nativescript
    let view = this.$refs.main.nativeView;

    screen.take(view, (image: ImageSource)=>{
        // Do whatever you want with the returned source image
    });