How to keep scaling always at 1 on FabricJS [Edited] - fabricjs

Question

I need in my application made in fabricJS, that when I modify an object with the scaling handlers, the scaling stays in 1, and that the size of the object takes the value of the height multiplied by scaleX. I can apply the same for the width. But I can not apply this in the images. How can I fix this?
I leave an example fiddle for a square, and an image, so that you can see the result.
The result in the image is similar to a crop, and I can not avoid this, because apparently, when I modify the container of the image, the _element property that also contains scaleX and scaleY does not change, so the image is not resized inside the container.
Here is jsFiddle.
var canvas = new fabric.Canvas('canvas');
var rect1 = new fabric.Rect({
width: 100,
height: 100,
left: 200,
top: 200,
angle: 0,
fill: 'rgba(0,0,255,1)',
originX: 'center',
originY: 'center'
});
canvas.add(rect1);
fabric.Image.fromURL('http://fabricjs.com/assets/pug_small.jpg', function(myImg) {
//i create an extra var for to change some image properties
var img1 = myImg.set({
left: 0,
top: 0,
width: 150,
height: 150
});
canvas.add(img1);
});
canvas.on('mouse:up', function(e) {
/*if(e.target != null){
//alert(e.target.width*e.target.scaleX);
}*/
//console.log(e.target);
canvas.getActiveObjects().forEach(function(obj) {
//if(obj.get('type')!='image'){
obj.set('width', obj.width * obj.scaleX, obj);
obj.set('height', obj.height * obj.scaleY, obj);
//if(obj.get('type')!='image'){
obj.scaleX = 1;
obj.scaleY = 1;
//}else{
// obj.scaleX = 1;
// obj.scaleY = 1;
// obj._element.scaleX = 1;
// obj._element.scaleY = 1;
// console.log("Width Contenedor Imagen: "+obj.width+" Width Imagen: "+obj._element.width);
// console.log("Scale Contenedor Imagen: "+obj.scaleX+" Scale Imagen: "+obj._element.scaleX);
//}
obj.setCoords();
//}
});
});
EDIT: New Discovery
Speaking of text, rect, images and polylines, it seems that I am modifying an external container, because the inner content remains intact. How can I modify the size of that let's say, inner container?