bangle js1 draw speed flicker

Bangle 1 and Bangle 2 use very different technologies for the screen. I cant remember the exact hardware terminology but I am sure others can explain it. In short Bangle 1 does flicker and Bangle 2 hardly ever. To reduce flicker on Bangle 1 only redraw the part of the screen that you need to. So if you had a clock that showed 3 square boxes with the digts for hour, minutes and seconds; then only update each when previousValue !== currentValue.