openlayers3如何始终启用徒手绘制

Question

In OpenLayers3 v3.5, how do you always enable freehand draw? The default for enabling freehand draw is done through the freehandCondition property of ol.interaction.Draw , which is currently set to the shift key by default.

draw = new ol.interaction.Draw({
  source: drawLayer.getSource(),
  type: 'LineString',
  freehandCondition: ol.events.condition.shiftKeyOnly
});

But I dont want that. I dont want the shift key to be pressed to enable freehand. I want freehand to be enabled by click-and-drag without any key modifiers.

I've tried:

freehandCondition: ol.events.condition.always

freehandCondition: ol.events.condition.click

freehandCondition: ol.events.condition.noModifierKeys

But none of these work.

You may wonder that by doing this would pan the map, but I've already disabled panning by changing my default interactions so that dragPan: false

Answer 1

You missed in the documentation , the condition parameter for the ol.interaction.Draw . It conflicts with freehandCondition .

It should be like below (tested)

draw = new ol.interaction.Draw({
  source: drawLayer.getSource(),
  type: 'LineString',
   condition: ol.events.condition.singleClick,
   freehandCondition: ol.events.condition.noModifierKeys
});

Look at this Fiddle for a demo.

I may missed a better option. You may also need to try with other conditions if the behaviour is not exactly the expected one.