This routine determines what to do if the mouse position
reaches a boundary.
state should be either
MOUSE_WRAP, MOUSE_NOWRAP, or a bitwise or of MOUSE_WRAPX,
MOUSE_WRAPY, MOUSE_WRAPZ, MOUSE_WRAPRX, MOUSE_WRAPRY, or
MOUSE_WRAPRZ. These define if all or the respective coordinates wrap or are clipped at the ends.
This variable has been overloaded for the case of
multi-dimensional mice that support rotations and can be
used to select the coordinate system used to return the
current position of the mouse.
If the above value of state is also ored with
MOUSE_ROT_RX_RY_RZ, rotational information will be returned
as the angular position as expressed by the total angle wound
around the X, Y, and Z axes. This is the simplest coordinate
system to use, but its also the least useful, since angular
rotations about perpendicular axes dont commute. There are
situations where this system might be useful, for controlling
truly independent quantities, such as color, with each axis
being used to dial a level of red, green, or blue, but
for modeling the actual orientation of a physical object,
its utterly hopeless.
If state is instead ored with
MOUSE_ROT_INFINITESIMAL, the angular positions returned are expressed as differences
from the previously reported position. If the differences
are sufficiently small, the angular displacements will
commute with each other and can be used to track the motion
of a physical object.
Other coordinate systems, such as yaw, pitch, and roll,
could be defined, but havent been done due to lack of
time. If you feel you need this feature, send mail
to Eric Sharkey <email@example.com>
and he just might consider coding it up.
MOUSE_WRAP and MOUSE_ROT_COORDS can be used to mask out the
bits used for wrap and coordinate states, respectively.
This manual page was edited by Michael Weller <firstname.lastname@example.org>. The
exact source of the referenced function as well as of the original documentation is
It is very likely that both are at least to some extent are due to
Harm Hanemaayer <H.Hanemaayer@inter.nl.net>.
Occasionally this might be wrong. I hereby
asked to be excused by the original author and will happily accept any additions or corrections
to this first version of the svgalib manual.