public override bool OnScale(ScaleGestureDetector detector) { float span = detector.CurrentSpan; float newFactor = _zoomAndPanView.ZoomFactor * span / _lastSpan; _lastSpan = span; _zoomAndPanView.ChangeZoom( zoomFactor: newFactor, zoomCenterX: detector.FocusX, zoomCenterY: detector.FocusY); _zoomAndPanView._didScrollOrZoomFromTouch = true; return(true); }