FabricJS double click on objects

Question

I am trying to perform a special action whenever the user double clicks any object located inside the canvas. I have read the docs and not found any mouse:dblclick-like event in the documentation. I tried doing something like:

fabric.util.addListener(fabric.document, 'dblclick', callback);

Which does trigger the dblclick event but does not give specific information about the actual object that is being clicked on the canvas.

Any ideas of the most FabricJS-y way of doing this?

Answer 1

Here is a quick and easy way to add a double click event handler to Fabric JS -

Include following code snippet to your html file. Just ensure this is loaded after the main fabric.js library

<script type="text/javascript">
        fabric = (function(f) { var nativeOn = f.on; var dblClickSubscribers = []; var nativeCanvas = f.Canvas;   f.Canvas = (function(domId, options) { var canvasDomElement = document.getElementById(domId); var c = new nativeCanvas(domId, options);   c.dblclick = function(handler) { dblClickSubscribers.push(handler) };   canvasDomElement.nextSibling.ondblclick = function(ev){ for(var i = 0; i < dblClickSubscribers.length; i++) { console.log(ev); dblClickSubscribers[i]({ e :ev }); } }; return c; });   return f; }(fabric)); 
</script>

Then add this code to listen a double click event:

canvas.dblclick(function(e) { 

}); 

To get information about the actual object that is being clicked on the canvas, use following method -

canvas.getActiveObject();

eg.

canvas.dblclick(function(e) { 
     activeObject = canvas.getActiveObject();
}); 

Answer 2

I'm using this workaround:

  var timer = 0;
  canvas.item(0).on('mouseup', function() {
    var d = new Date();
    timer = d.getTime();
  });
  canvas.item(0).on('mousedown', function() {
    var d = new Date();
    if ((d.getTime() - timer) < 300) {
      console.log('double click')
    }
  });

Answer 3

The Correct way to add custom events to Fabric.js

window.fabric.util.addListener(canvas.upperCanvasEl, 'dblclick', function (event, self) {
  yourFunction(event);
});

or use fabric.ext

Answer 4

The more elegant way is to override fabric.Canvas._initEventListeners to add the dblclick support

_initEventListeners: function() {
  var self = this;
  self.callSuper('_initEventListeners');

  addListener(self.upperCanvasEl, 'dblclick', self._onDoubleClick);
}

_onDoubleClick: function(e) {
  var self = this;

  var target = self.findTarget(e);
  self.fire('mouse:dblclick', {
    target: target,
    e: e
  });

  if (target && !self.isDrawingMode) {
    // To unify the behavior, the object's double click event does not fire on drawing mode.
    target.fire('object:dblclick', {
      e: e
    });
  }
}

I've also developed a library to implement more events missed in fabricjs : https://github.com/mazong1123/fabric.ext

Answer 5

This is similar to @LeoCreer's answer but actually gets access to the targeted object

fabric.util.addListener(canvas.upperCanvasEl, 'dblclick', function (e) {
  var target = canvas.findTarget(e);
});