Just be sure we are speaking about the same thing: For example, there is a button with a label and you change the label’s text. In this case
- some pixels remain the same
- some pixel changes: button color-> text color, or vice versa
And your goal is to refresh the pixels which are in the 2) category, right?
If so it’s not possible by default in LittelvGL. You can keep the current display image in RAM, compare the image to flush with that and send only the required pixels. However, it will be slower IMO because you continuously need to set “window address” therefore you can’t use DMA.