textSize property
Returns the size of the text as laid out.
This can differ from size if the text overflowed or if the constraints provided by the parent RenderObject forced the layout to be bigger than necessary for the given text.
This returns the TextPainter.size of the underlying TextPainter.
Valid only after layout.
Implementation
Size get textSize {
assert(!debugNeedsLayout);
return _textPainter.size;
}