These printer files are utility subroutines for special printing functions in
ZBasic-PC/386.

LASERPRT is a library of subroutines supporting different features of laser
printers including font downloading and selection, forms control and graphic
printing routines including printing a portion of a graphics screen as well
as a simple vector drawing command.

Most of these routines are self-explanatory and are self-documented by their
label and variable names. Many require input passed into them for proper
function. For example the "Download Font" routine obviously needs you to
supply a fontname (in Fontname$) and a font number to which it is to be
assigned (in FontNumber).

There are 3 classes of routines.

The first has to do with font downloading ... which should be done at the
beginning of the program.

Section 2 controls general printer settings such as margins, page orientation,
line spacing, number of copies and similar operations.

Section 3 has routines to simplify graphic operations. It is interesting to
note that the printer only can draw "boxes", which can be used to draw
vertical or horizontal lines of specified width. To draw an angular line
(most often referred to as a "vector") requires considerable coding, as
illustrated in the "Draw Angle" routine {which must have passed into it
X1,Y1 and X2,Y2 coordinates}.

More complex images are best handled by bit image printing. For those
experienced in bit image handling on dot matrix printers there are some
twists introduced in laser printing. The bit images are horizontal rather
than vertical and there is no automatic updating of print head / cursor.
Before each stream of bits is sent the cursor positions ###must### be
updated. Bit image printing is illustrated in the "Print Graphics Area"
routine which can be used to print any rectangular graphics area.