finger-pointer.js

class FingerPointer {
    constructor(event) {
        this.pointerId   = event.pointerId;
        this.pointerType = event.pointerType;
        
        this.epsilonX = event.width;
        this.epsilonY = event.height;

        this.initial = {
            x: event.offsetX,
            y: event.offsetY,
            t: Date.now()
        };
        this.latest = {
            x: event.offsetX,
            y: event.offsetY,
            t: Date.now()
        };
        
        this.deltaT = 0;
        this.deltaX = 0;
        this.deltaY = 0;
        this.deltaXY = 0;
        this.directionX = '';
        this.directionY = '';
        
        if (event.buttons == undefined) {
            this.leftButtonDown = false;
            this.wheelButtonDown = false;
            this.rightButtonDown = false;
        }
        else {
            this.leftButtonDown  =
                (event.buttons & 0b0001) ? true : false;
            this.rightButtonDown =
                (event.buttons & 0b0010) ? true : false;
            this.wheelButtonDown =
                (event.buttons & 0b0100) ? true : false;
        }

        this.ctrlKey  = !!event.ctrlKey;
        this.altKey   = !!event.altKey;
        this.shiftKey = !!event.shiftKey;
    }
}