You have to manually draw a black box in that area. Or print out " " to cover the space.
When I ported the Adafruit GFX library to work on chipKIT products
, I added some features:
1) Current cursor position, so you can save a local variable for the X,Y of text you want to update. Then you have temx and tempy for current cursor position, allowing you to go to the other place, update text, then setcursor back to where it currently is.
2) Actually implemented their "background color" so that when I print text somewhere, it blanks out the background of the character.
3) Text inversion, so that it's easy to invert letters for maximum highlighting and easiest implementation.
... so you can review the changes I made to the GFX.cpp for these simple updates.
Also, the chipKIT uc32
is SO FAST that a fill screen is almost a blink! So you can just buy one of these instead and the Adafruit GFX library
I linked to is TURN KEY.