Screen And World Coordinates - Sanyo MBC-550 Series User Manual

Screen and World Coordinates
Sanyo Basic graphics are created with two types of
coordinate systems. One is the physical coordinate
system which corresponds on a 1 to 1 basis to the 640 x
200 dots on the screen. The other is the logical coor­
dinate system devised for Sanyo Sanyo Basic which can
be as large as 32768 x 32768. The physical coordinate
system is called the screen coordinate system whereas
the abstract coordinate system is called the world
coordinate system.
Most of the Sanyo Basic graphic instructions are issued
for the abstract world coordinate system. Which portion
of the huge coordinate system should be displayed where
on the screen (screen coordinate system) must be speci­
fied. This enables free programming on the abstract
coordinate system using a required number of dots which
are independent from the limited number of dots on the
real screen, and the graphics created are displayed in
the appropriate size and in the desirable position on
the screen. You may create graphics without worrying
about work space. If you write graphics with coordi­
nates of less than 640 x 200 you may write directly to
screen. With coordinates larger than 640 x 200, the
WINDOW and VIEW instructions are needed to be able to
see the finished graphic on the screen.
3-104