Number of move() steps before object removes itself, -1 (default)
is never; -2 means expire when off-playfield, -3 means expire when
off-view, -4 means suspend when off-view, -5 means suspend when
off-view and expire when off-playfield.
Actual scaled canvas size; that is, the size of the playfield view,
which may be smaller than the desired size of the game window
to accommodate for integer-sized scaled tiles.
Create timer; the timer may be one-shot (it runs only once, then
triggers the alarm and removes itself), or continuous (it continues
running and triggering the alarm)
Snap object to grid using the default gridsnap margin of
(xspeed*gamespeed-epsilon, yspeed*gamespeed-epsilon),
corresponding to the default is...Aligned margin.
Turn a (possibly) translucent or indexed image into a
display-compatible bitmask image using the given alpha threshold and
render-to-background colour, or to display-compatible translucent image.
Actual scaled canvas size; that is, the size of the playfield view,
which may be smaller than the desired size of the game window
to accommodate for integer-sized scaled tiles.