The graphical needs to be repainted. The graphical->request_compute graphical->compute
mechanism is used by graphical
objects that need complex computations to determine their area and
appearance from some internal state.
For example, a menu is determined by its member menu_items and
several flags manipulating its visual appearance. It would be a waste to
recompute the entire layout of the menu on each change of its state as
there will often be multiple changes before it actually needs to be
repainted on the screen. A menu will therefore just issue
graphical->request_compute
on itself if recomputation is needed. PCE graphics kernel will cause a
message graphical->compute
to be send to the graphical just before the graphical->_redraw_area.
The definition of this method at the level of class graphical
just assigns graphical<-request_compute
to @nil.
- See also
- - device
-recompute
- graphical-request_compute
