JSFiddle - React, Tailwind, and code Playground

by endeepak

HTML

<script src="https://cdnjs.cloudflare.com/ajax/libs/underscore.js/1.8.3/underscore.js"></script>
<canvas id="c" width="450" height="400"></canvas>

CSS

#c {
  outline: 1px solid #ccc
}

JavaScript

var canvas = new fabric.Canvas('c');

var Container = function(canvas, objects) {
  var self = this;
  self.padding = 0;
  self.objects = objects || [];
  self.boundary = new fabric.Rect({
    left: 50 - self.padding,
    top: 50 - self.padding,
    strokeDashArray: [1, 1],
    stroke: 'black',
    strokeWidth: 1,
    fill: 'rgba(0,0,0,0)',
    lockRotation: true,
    hasRotatingPoint: false
  });

  self.add = function(object) {
    self.objects.push(object);
    canvas.add(object);
    drawBoundary();
  }

  self.remove = function(object) {
    self.objects = _.without(self.objects, object);
    canvas.remove(object);
    drawBoundary();
  }

  self._allObjects = function() {
    return _.union([self.boundary], self.objects)
  }

  self.contains = function(object) {
    return _.contains(self.objects, object)
  }

  var drawBoundary = function() {
    var left = _.min(_.map(self._allObjects(), function(object) {
      return object.getLeft();
    }));
    var top = _.min(_.map(self._allObjects(), function(object) {
      return object.getTop();
    }));
    var right = _.max(_.map(self._allObjects(), function(object) {
      return object.getLeft() + object.getWidth();
    }));
    var bottom = _.max(_.map(self._allObjects(), function(object) {
      return object.getTop() + object.getHeight();
    }));
    var width = right - left + self.padding;
    var height = bottom - top + self.padding;
    self.previousBoundaryPosition = {
      left: left,
      top: top
    };
    self.boundary.set({
      left: left,
      top: top,
      width: width - 1,
      height: height - 1,
      scaleX: 1,
      scaleY: 1
    });
    self.boundary.setCoords();
  }

  self.render = function() {
    canvas.add(self.boundary);
    self.objects.forEach(function(object) {
      canvas.add(object);
    });
    drawBoundary();
    canvas.renderAll();

    // ensure bondary is updated when objects are modified
    canvas.on('object:modified', function(e) {
      if...