PNet/js/graphics/tragable.ts

export class Tragable {
    static getRootSVG(elem: SVGElement): SVGSVGElement {
        while (!(elem instanceof SVGSVGElement)) {
            if (!(elem instanceof SVGElement)) throw new Error("Not in an SVG");
            elem = elem.parentElement as any;
        }
        return elem;
    }

    #moveCB: (event: MouseEvent) => any = () => { };
    #clickCB: (event: MouseEvent) => any = () => { };
    initTrag(element: SVGElement) {
        let svg = Tragable.getRootSVG(element);
        let selected = false;
        element.addEventListener('mousedown', () => {
            selected = true;
        });
        svg.addEventListener('mousemove', event => {
            if (selected) this.#moveCB(event);
        });
        svg.addEventListener('mouseup', () => {
            selected = false;
        });
        svg.addEventListener('mouseleave', event => {
            selected = false;
        });
        element.addEventListener('click', event => {
            if (!selected) this.#clickCB(event);
        });
    }

    onMove(cb: (event: MouseEvent) => any) {
        this.#moveCB = cb;
    }
    onClick(cb: (event: MouseEvent) => any) {
        this.#clickCB = cb;
    }
}