fabricMOdule.js

            // Reset Zoom
            self.resetZoom = function() {
                var objects = canvas.getObjects();
                for (var i in objects) {
                    var scaleX = objects[i].scaleX;
                    var scaleY = objects[i].scaleY;
                    var left = objects[i].left;
                    var top = objects[i].top;

                    var tempScaleX = scaleX * (1 / canvasScale);
                    var tempScaleY = scaleY * (1 / canvasScale);
                    var tempLeft = left * (1 / canvasScale);
                    var tempTop = top * (1 / canvasScale);

                    objects[i].scaleX = tempScaleX;
                    objects[i].scaleY = tempScaleY;
                    objects[i].left = tempLeft;
                    objects[i].top = tempTop;

                    objects[i].setCoords();
                }

                var width = canvas.getWidth();
                var height = canvas.getHeight();

                var tempWidth = width * (1 / canvasScale);
                var tempHeight = height * (1 / canvasScale);

                canvas.setWidth(tempWidth);
                canvas.setHeight(tempHeight);

                canvas.renderAll();

                canvasScale = 1;
            };

            // Zoom In
            self.zoomIn = function() {
                // TODO limit the max canvas zoom in

                canvasScale = canvasScale * SCALE_FACTOR;

                var objects = canvas.getObjects();
                for (var i in objects) {
                    var scaleX = objects[i].scaleX;
                    var scaleY = objects[i].scaleY;
                    var left = objects[i].left;
                    var top = objects[i].top;

                    var tempScaleX = scaleX * SCALE_FACTOR;
                    var tempScaleY = scaleY * SCALE_FACTOR;
                    var tempLeft = left * SCALE_FACTOR;
                    var tempTop = top * SCALE_FACTOR;

                    objects[i].scaleX = tempScaleX;
                    objects[i].scaleY = tempScaleY;
                    objects[i].left = tempLeft;
                    objects[i].top = tempTop;

                    objects[i].setCoords();
                }

                var width = canvas.getWidth();
                var height = canvas.getHeight();

                var tempWidth = width * SCALE_FACTOR;
                var tempHeight = height * SCALE_FACTOR;

                canvas.setWidth(tempWidth);
                canvas.setHeight(tempHeight);

                canvas.renderAll();
            };

            // Zoom Out
            self.zoomOut = function() {
                // TODO limit max cavas zoom out

                canvasScale = canvasScale / SCALE_FACTOR;

                var objects = canvas.getObjects();
                for (var i in objects) {
                    var scaleX = objects[i].scaleX;
                    var scaleY = objects[i].scaleY;
                    var left = objects[i].left;
                    var top = objects[i].top;

                    var tempScaleX = scaleX * (1 / SCALE_FACTOR);
                    var tempScaleY = scaleY * (1 / SCALE_FACTOR);
                    var tempLeft = left * (1 / SCALE_FACTOR);
                    var tempTop = top * (1 / SCALE_FACTOR);

                    objects[i].scaleX = tempScaleX;
                    objects[i].scaleY = tempScaleY;
                    objects[i].left = tempLeft;
                    objects[i].top = tempTop;

                    objects[i].setCoords();
                }

                var width = canvas.getWidth();
                var height = canvas.getHeight();

                var tempWidth = width * (1 / SCALE_FACTOR);
                var tempHeight = height * (1 / SCALE_FACTOR);

                canvas.setWidth(tempWidth);
                canvas.setHeight(tempHeight);

                canvas.renderAll();
            };