It's normal for a graphic displays to require you blank areas of the screen you're going to re-draw. Your headers will be safe. Also, writing text will do both of setting pixels on and off so overwriting existing text will work properly as well.
It's normal for a graphic displays to require you blank areas of the screen you're going to re-draw. Your headers will be safe. Also, writing text will do both of setting pixels on and off so overwriting existing text will work properly as well.