Typical cases - Troubleshooting
This chapter provides practical instructions on how to deal with typical
cases, problems and solutions.
Thickness management
To manage line thickness (line weight or line width), use a combination of the directives GRA PWIDTH
and GRA MWIDTH (see also section 2.4).
To do this, proceed as follows:
-
Define a pen thickness table for GBPLO; i.e.: assign the desired
thickness to some or all of the pens (colours) with the directive GRA PWIDTH.
For example:
GRA PWIDTH 1 1 MM 2 1.5 MM 3 1.8 MM 4 0.5 MM
indicates that the entities with pen (colour) attribute 1 will be drawn
with a thickness of 1 millimetre, those with pen attribute two 1.5 millimeters,
etc. However, this also depends on the current thickness management mode,
which in this case must be 3.
-
Define the current thickness management mode with GRA MWIDTH.
This allows you not only to define the thickness in a preset unit such
as millimeters, centimeters and inches, but also to print in units of the
device (pixels, dots, etc.) and in the unit relative to the current scale
(the latter mode is, for example, very useful for managing thickness in
hybrid raster files, to improve smoothness at the joints between raster
lines and vector lines).
Merging or nesting drawings
You can "merge" drawings in output, i.e.: generate a single output file
containing two or more drawings or print two or more drawings on the same
sheet: whether they overlap or not.
To do this, you must use the -COM key in the run string; to this
key you must add an argument which is the pathname of a file which, in
turn, contains the GBPLO run strings relative to each of the drawings to
be merged.
This is the most practical and widely used method, since it allows you
to obtain drawing composite drawings even in output to file: in
contrast, all of the other methods allow you only to print two or more
files on the same sheet, suitably managing the output device (repositioning
the pen, moving the paper, etc.).
In contrast, with this method, once you have generated a "composite"
output file, you can print it with a single action, avoiding any problems
which may arise on the plotter or printer due to reuse of the same sheet,
pen repositioning and paper movement: in other words, this method, is "neater"
than the others.
Note:
-
In the run string file supplied with -COM as a parameter, you may specify
only those options "necessary to running" (see Instructions necessary to run GBPLO):
-F pathname_of_file
-S print_scale default is 1
-U unit_of_measure default is M: stored
-L layers_to_be_printed default is M: stored
-W window_to_be_printed
and two more options which allow you to position drawings on the sheet
-ALF?rotation_of_drawing_on_sheet default is 0
-DXY?origin_of_drawing_on_sheet default is 0
Any other options specified in the file are always ignored.
-
All options specified in the main run string (at -COM level) also apply
for all drawings specified in the run string
-
If you specify the same option with different parameters in the main run
string and in the -COM run string file, the latter applies.
-
The maximum length of each run string in the file is 1024 characters.
-
You need not specify a file name (-F) in the main run string: it would
be ignored anyway.
-
Framing (-FR, HP-GL and BGL formats) is always Off
-
The mode is always batch.
Example
An example of a run string file for merging 10 drawings on the same
sheet
-f \drawings\a001.d -dim A4R -alf
90 -s o
-f \drawings\a002.d -dim A4R -alf
90 -DXY 0 29.7 -s o
-f \drawings\a003.d -dim A4R -alf
90 -DXY 0 59.4 -s o
-f \drawings\a004.d -dim A4R -alf
90 -DXY 21 0 -s o
-f \drawings\a005.d -dim A4R -alf
90 -DXY 21 29.7 -s o
-f \drawings\a006.d -dim A4R -alf
90 -DXY 21 59.4 -s o
-f \drawings\a007.d -dim A4R -alf
90 -DXY 42 0 -s o
-f \drawings\a008.d -dim A4R -alf
90 -DXY 42 29.7 -s o
-f \drawings\a009.d -dim A4R -alf
90 -DXY 42 59.4 -s o
-f \drawings\a010.d -dim A4R -alf
90 -DXY 63 0 -s o
5.3.1 Alternative merging modes
With suitable device management
An alternative mode to that offered by -COM and which relies on the performance
of the output device involves a combination, depending on requirements,
of the following directives:
GRA RORIG to redefine position of drawing origin on sheet at start of
plotting: notice that the current position depends on the type of plotter;
PPE to redefine the position of the drawing origin on the sheet at the
end of plotting
AVA to manage paper feed at the end of the drawing.
With this mode, you use the same sheet more than once for different
drawings, positioning it accordingly.
Note: this mode is less "convenient" than that offered by -COM
and does not allow nesting in a file, but only printing on the actual device.
With GRA MERGE in HP-GL format
In HP-GL format only, you can create composite drawings using the GRA
MERGE directive, according to the steps described relative to the latter.
Additional considerations on PostScript format
General
Created by Adobe System, PostScript is an interpreted language for page
description used by the latest generation of laser printers, photocomposition
devices and other graphics devices; consider by many as an authentic programming
language, it has fast become a standard item on the market.
PostScript, like other programming languages, is able to interpret and
carry out commands which are particularly graphics oriented.
The PostScript command sequence must be sent to the interpreter in the
form of an ASCII file. This feature involves significant advantages, since
you can modify a PostScript file to suit your own requirements, using the
editor of the operating system used. Moreover, it is completely portable,
that is to say, you can transfer it from computer to computer without corrupting
it in any way. The disadvantage is that PostScript files are much larger
than the corresponding binary files.
An interesting feature of PostScript is the device-dependent
resolution (for laser printers, usually 300x300 DPI or even 600x600) which
allows you to use the features of the graphics device to best advantage.
The device-dependent resolution derives from vector management of the characters
and graphic entities.
A useful possibility is offered by specific programs on the market,
which allow you to obtain on-screen an image which exactly represents that
defined in a PostScript file, or rather display what would be obtained
if you printed the file on paper, using it according to specific requirements,
e.g.: insertion in documents.
The GBPLO PostScript driver
The PostScript driver created by CAD.LAB can manage only graphics data,
more specifically: segments, arcs and points, while all other entities
are represented using segments. The standard fonts offered by PostScript
are not managed and all texts are represented with the GBG DraftMaker internal
character fonts. As a result, only software fonts can be used (QTE 3 or
QTE 4).
Point entities can be represented in PostScript either in hardware
mode (as points) or in software mode (as markers, i.e.: small crosses,
small circles, etc.). In software mode, you can also modify the size of
the points.
For the specific directives and options of the PostScript format, refer
to sectionPostScript format.
Printing and serial port problems
You may, at times, be unable to print, although there are no apparent errors.
In such cases, go through the normal checks (printer On and ready to
print, paper and ink available), then try one of the following procedures.
-
Ensure that the printer is connected to the computer correctly and that
the name of the device defined with GRA ODVT corresponds to the device
(or port) to which the printer is connected.
-
Ensure that the printer-computer connecting cable satisfies requirements.
-
Ensure than the transmission protocol for the printer is defined correctly
in accordance with that defined by GRA ODVC, if the protocol is used.
Note: GRA ODVC is always On by default on the serial port (with
values: 9600, 0, 8, 1), and modifies the current configuration.
Finally, try switching Off automatic serial port configuration, by
entering the following directive:
GRA ODVC 0
or
GRA ODVC OFF.