Drawing in freehand mode

We showed you how to draw features back in Chapter 5, Adding Controls in the Drawing features across multiple vector layers recipe. OpenLayers also offers a freehand mechanism to draw features on vector layers using the ol.interaction.Draw class. Freehand mode can be defined as sketching something over the map without the defined accuracy and direction that you get when drawing a geometry type without freehand mode.

Having the flexibility to draw with more freedom can be useful in many application requirements. For example, it may be less arduous to create a path along a road with the continuous drawing flow of freehand, rather than having to click to add a point each time on the road as you go. With freehand mode, points are automatically added for you as you move the mouse in the direction that you want to draw in.

OpenLayers supports the freehand drawing of either polygons or lines. In this recipe, we're going to explore drawing polygons in freehand mode. After...