Set object drag limit in Fabric.js

Question

i am new in fabric js want to set the drag limit

i have also try with https://github.com/kangax/fabric.js/wiki/Working-with-events

not able to get the solution.

please check the attached image, object can move anyware but it should be display in red area only.i want this. help me...thanks in advance !!

Answer 1

While Orangepill's answer is correct, it produces a "stuttering" when your object hits the object bounds. If you have a rectangular bounding box (and not a complex bounding object) an alternative is to allow the object to be dragged along the bounds and "slide" along the bounding box. You do this by capping the coordinates values and letting the other dimension move as usual. An example snippet would look like so:

var canvas = new fabric.Canvas("bounded");

var boundingBox = new fabric.Rect({
  fill: "none",
  width: 600,
  height: 400,
  hasBorders: false,
  hasControls: false,
  lockMovementX: true,
  lockMovementY: true,
  evented: false,
  stroke: "red"
});

var movingBox = new fabric.Rect({
  width: 100,
  height: 100,
  hasBorders: false,
  hasControls: false
});

canvas.on("object:moving", function() {
  var top = movingBox.top;
  var bottom = top + movingBox.height;
  var left = movingBox.left;
  var right = left + movingBox.width;

  var topBound = boundingBox.top;
  var bottomBound = topBound + boundingBox.height;
  var leftBound = boundingBox.left;
  var rightBound = leftBound + boundingBox.width;

  // capping logic here
  movingBox.setLeft(Math.min(Math.max(left, leftBound), rightBound - movingBox.width));
  movingBox.setTop(Math.min(Math.max(top, topBound), bottomBound - movingBox.height));
});

canvas.add(boundingBox);
canvas.add(movingBox);

See this example in JSFiddle here