RenderPositionedBox to be the size of the screen, with
constraints of

Center widget (as described by the

RenderPadding, further inserts these constraints to ensure
there is room for the padding, and thus the

RenderConstrainedBox
has a loose constraint of

TextButton’s definition,
sets a minimum width of 88 pixels on its contents and a
specific height of 36.0. (This is the

The inner-most RenderPositionedBox loosens the constraints again,
this time to center the text within the button. The
RenderParagraph picks its size based on its contents.
If you now follow the sizes back up the chain,
you’ll see how the text’s size is what influences the
width of all the boxes that form the button, as they all take their
child’s dimensions to size themselves.