Function font_tweak_ui 

pub fn font_tweak_ui(
    ui: &mut Ui,
    tweak: &mut FontTweak,
    axes: &[FontVariationAxis],
) -> Response

Show a UI for editing a FontTweak.

axes are the variation axes of the font this tweak applies to, as returned by epaint::text::FontData::variation_axes. When non-empty, the variation coordinates are shown as named sliders pre-populated with each axis’ valid range and default value, so the user doesn’t have to guess tags and numbers. Pass an empty slice if the axes are unknown (e.g. a static font) to fall back to free-form tag/value entry.

Widget for &mut FontTweak calls this with no axes.