In OpenLayers, when you are giving a style to layer, say a WFS layer, we can give stroke width, like this:

var layerWFS = new ol.layer.Vector({
    source: sourceWFS,
    title: 'plot_layer',
    name: 'plot_layer',
    style: new ol.style.Style({
        stroke: new ol.style.Stroke({
            color: 'rgba(255, 0, 255, 1)',
            width: 1
        })
    })
});

Here width is 1 , I would like to know in which dimension that we are giving the stroke width, whether:

1. millimeter (mm) 1 means 1mm
2. centimeter (cm) 1 means 1cm