clearClip is almost 4 more times expensive then setClip

You are wrong

- name of town can be longer than width of filed - I have to calculate length of string, shorten it or simple clip

- drawing hours/minutes/seconds/ am/pm - overleaped others regions

- bottom icon without clip overlaps progress and upper icons

- all numbers overleaps progresses

....

try to draw this pictures without clips

I need a lot of data not only time and steps so have to use each pixels

You are wrong

- name of town can be longer than width of filed - I have to calculate length of string, shorten it or simple clip

- drawing hours/minutes/seconds/ am/pm - overleaped others regions

- bottom icon without clip overlaps progress and upper icons

- all numbers overleaps progresses

....

try to draw this pictures without clips

I need a lot of data not only time and steps so have to use each pixels

Looks to me you have big bugs in onUpdate and you set clips to hide them.  In onUpdate, you ALWAYS want to update the entire screen.

Looks to me you have a bug with displaying hours and whatever the "16" is The fact you also lost seconds means you're not doing that properly in onUpdate, where you don't even have to set a clip region.

no, I need clip in onUpdate:

with clip

without

You can do this with only one clip region (for seconds in onPartialUpdate())  I do it all the time! Figure out how many characters will fit, limit the length of a sting and just display that many.