u8glib display library question: inverted text

Hi,

how can I show inverted text using u8glib library on monochrome oleds? by inverted I mean there is a dark box background surrounding the text. the text is light colored.

I'm using an oled display on a project to show values from sensors on screen. For certain sensor values that are above a threshold i would like to show them with dark background on light text.

this was pretty easy to do using setTextColor in adafruit library however that library seems to take up so much space on memory.