Determines the type of automatic sizing allowed.

The following names can be used to specify the automatic sizing behavior used to fit a shape’s text within the shape bounding box, for example:

from pptx.enum.text import MSO_AUTO_SIZE

shape.text_frame.auto_size = MSO_AUTO_SIZE.TEXT_TO_FIT_SHAPE

The word-wrap setting of the text frame interacts with the auto-size setting to determine the specific auto-sizing behavior.

Note that TextFrame.auto_size can also be set to None, which removes the auto size setting altogether. This causes the setting to be inherited, either from the layout placeholder, in the case of a placeholder shape, or from the theme.

No automatic sizing of the shape or text will be done. Text can freely extend beyond the horizontal and vertical edges of the shape bounding box.
The shape height and possibly width are adjusted to fit the text. Note this setting interacts with the TextFrame.word_wrap property setting. If word wrap is turned on, only the height of the shape will be adjusted; soft line breaks will be used to fit the text horizontally.
The font size is reduced as necessary to fit the text within the shape.
Return value only; indicates a combination of automatic sizing schemes are used.