I copied a layer from another image file , and created a empty canvas to hold the image copied.

But when I create the new canvas , the default size was as same as the original canvas , where I copied this layer.

How can I resize the canvas size to exactly the size of the image I copied ?
As you can see , it's already under selection , maybe there's some way out from here.

Or if anyone knows how to set the canvas size from layer , when you create the empty cavnas , it's a neat solution as well.