setPixelRatio(pixelRatio, triggerCallback) {
        this.pixelRatio = parseFloat(Math.max(pixelRatio, 1)) || 1;
        this.renderer.setPixelRatio(pixelRatio);
        // apply new pixel ratio to all our elements but don't trigger onAfterResize callback
        this.resize(triggerCallback);
    }
Set the pixel ratio property and update everything by calling the resize() method
*