I have updated the Fabric JS from version 1.6.0 to 4.6.0 and the image showing bigger and cutout the image. This is my code :

var CANVAS_HEIGHT =  $('#designing_main_image_container').height();
var CANVAS_WIDTH = CANVAS_HEIGHT;
var canvas_front_view = new fabric.Canvas('front_view');
canvas_front_view.setHeight(CANVAS_HEIGHT);
canvas_front_view.setWidth(CANVAS_WIDTH);

Same code with my previous fabric js version it was showing the perfect size image but after in version 4.6.0 it is not showing properly.

Few screenshoot to show you the issue :

Before, with FabricJS 1.6.0:

Now, with FabricJS 4.6.0: