OpenLayers 3 – Undoing Last Point When Drawing Linestring

openlayers

I would like to be able to draw a linestring and to be able to undo the last drawn point when the key ESC is pressed.

I used that code when I first wrote my application :

  // create the interaction
  draw_interaction = new ol.interaction.Draw({
    source: vector_layer.getSource(),
    type: /** @type {ol.geom.GeometryType} */ ($geom_type.val())
  });
    // add it to the map
  map.addInteraction(draw_interaction);

  // when a new feature has been drawn...
  draw_interaction.on('drawstart', function(evt) {
    var feature = evt.feature;
    var geom = feature.getGeometry();
    document.addEventListener('keyup', function() {
      if (event.keyCode === 27) {
        if (geom.getType() === "LineString") {
          var coords = geom.getCoordinates();
          var len = coords.length;
          console.log("undo");
          if (len > 1) {
           geom.setCoordinates(geom.getCoordinates().slice(0, len - 1));
          }
        }
      }
    });
  });

You can see a live version on codepen following that link:

http://codepen.io/anon/pen/waPXyG

My problem is when I upgraded from 3.5.0 to 3.6.0, the behaviour changed :

http://codepen.io/anon/pen/LVOrrq

As you can see on the live example, when undoing (pressing ESC) it seems to be working but when you want to add a new point to the linestring, the points I removed are back in place. Looks like a caching behaviour as been added to 3.6.0

I hope someone can help me, it's either a regression or a api modification that I did not notice in the change log.

Best Answer

Since OpenLayers 3.9.0, this is as simple as using the removeLastPoint method of the DrawInteraction. So you can do something like this:

document.addEventListener('keydown', function(e) {
    if (e.which == 27)
        draw_interaction.removeLastPoint()
});
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