Allows for negative x offsets in fonts
readAddrWindow is a private function to support pixel and block reads of the TFT screen. Tested on ILI9341.
Using D6 (MISO) for the DC line is not recommended as transaction support and TFT reads may cause it to become and input! However if a hardware setup has no other pins spare, then this is an option that can be tried.
Not yet fully tested but seems to work OK!