Visual display of files HPGL

Development Visual BASIC

This program makes it possible to visualize files CAD with format HPGL.

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Source file and éxécutable HPGL.zip (110 KB)
Executable version 0.0.2 (2.02 MB)

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The program

This program allows visulaiser files the format hpgl.

HPGL

HPGL, some times also called HP-GL, it is the first language used by the company HP for the control of these tracers. The name is an acronym of Hewlett-Packard Graphics Language. It became thereafter a standard for all the tracers.

This language is made of a series of two letters of code, followed by optional parameters. For example an arc can be drawn on a page by sending the following code:

AA100,100,50;

Who wants to say Arc in Absolut, and the parameters places the center of the arc at co-ordinates 100,100, with a degrées starting angle of 50 measured in the Trigo direction. A fourth optional parameter (not used here) specifies the error cordale anguliare used to trace the arc. The ray and starting points are given by the preceding point.

The origin of this code corresponds to a technology of the time based on tracers using of the feathers (Pen). The color and the thickness of the features traced were thus given by the feather used. With lorigine there is thus no instruction to specify this type of information. But thereafter the code it is enriched by instruction such as PW to specify the thickness of the feature for example. A traditional file HPGL starts favec some orders of initialization, Suivi of a long list of order gaphic. For example:

Example of file HPGL

Order	Explanations
IN;	Initialization, beginning of the layout
IP;	Fix the point of origin (Not starting), In this case they are 0,0
SC0,100,0,100;	The echlle page (SCale) from 0 defines to 100 in two directions X and Y
SP1;	Selection of feather 1 (PEN)
PD100,0,100,100,0,100,0,0;	Descent of the pen and displacement to the various positions (Here a rectangle around the page draws)
PU50,50;	Go up the pen and moves with co-ordinate 50,50
CI25;	draw a cerlce with a radius of 25
SS;	Select the standard bill of character
DT*, 1;	Fix the delimitor of chains of text at the asterisk and does not trace it (the 1, wants to say "true here")
PU20,80;	Move the pen without tracing with position 20,80
LBBonjour *;	Draw the text Hello

The frame of reference is based on the smallest unit which the tracer can support, and is often fixed at 0.025mm.(HP: we are here in American system with inches or more exactly of INCHs 1 Inch = 25.4 mm)
This language used to trace with a pen was also included in step badly of application of milling or more exactly of routing or gravage. Indeed this code makes it possible perfectly to control a cutter, with a high position of displacement and a low position of work. That indeed makes it possible to control a machine directly starting from a software of CAD.


In the code of present on this page a negligible part of standard HPGL is treated (primarily linear displacements). But it is also this type of code which one generally finds.

Documentation with format pdf on standard HPGL (In 
English). 
I do not know any more or I found this 
document.
Thus me do not please any not give the author or the owner of 
origin.

You can zoom on a part of the drawing or move it. while Double-clicking on the drawing the software will center the drawing automatically

Double.click: To center the drawing with the
screen.

The functions of posting allow you toomer and to move the drawing.

Function PEN UP On/Off makes it possible to also visualize
the trajectories associated with the instruction PU (PEN Up) with code
HPGL.

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Links

Fast documentation on standard HPGL (In English)