The following screen recordings show before and after slowing an animation.

Show guidelines

This feature draws guidelines over your app that display render boxes, alignments,
paddings, scroll views, clippings and spacers.

This tool can be used for better understanding your layout. For instance,
by finding unwanted padding or understanding widget alignment.

You can also enable this in code:

Render boxes

Widgets that draw to the screen create a render box, the 
building blocks of Flutter layouts. They’re shown with a bright blue border:

Alignments

Alignments are shown with yellow arrows. These arrows show the vertical
and horizontal offsets of a widget relative to its parent.
For example, this button’s icon is shown as being centered by the four arrows:

Padding

Padding is shown with a semi-transparent blue background:

Scroll views