HPGL 详细格式(PLT文件格式)

Using HPGL as a drawing interchange media

(Don't!Unfortunately many DOS/Windows insist on doing so)

Written by Paul Bourke
September 1992

This document isalso available in Russian , thanks to Sergey Paramonov.
(You will need the Russian font set!)

 

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Introduction

HPGL is the HPgraphics language designed for specifying 2D graphical information for the HPrange of plotters. It was not intended as an interchange format but somesoftware suppliers use it as such. At least it is efficient and easy to writeand read. This short note describes those aspects of the format which may beused to describe geometry. The language itself has a large number ofinstructions, most of the ones not touched on here relate directly to plotterdevices, for a full description of the language the HPGL description is normallyprovided with an HPGL compatable plotter.

Basics

HPGL commandsare basically two uppercase character instructions followed by any arguments,and finally ending in the separator character which is a semicolon by default.The arguments are normally separated by commas. String arguments are normallyterminated by carriage return.

In what follows,all the standard HPGL commands are listed, those which are likely to be usefulfor data interchange will be discussed at the end of this document. Optionalarguments for any command are shown in brackets.

Commands

    Instruction               Arguments

AA  Arc Absolute              x,y,angle(,tolerance)

AF  Advance page

AH  Advance page

AP  Automatic Pen Operations   n

AR  Arc Relative               x,y,angle(,tolerance)

AS  Acceleration Select       acceleration(,pennumber)

BF  Buffer Plot

BL  Buffer label               string

CA  Select Alternative Charset set

CC  Character chord angle      angle

CI  Circle                    radius(,tolerance)

CM  Character Selection Mode  switchmode(,fallbackmode)

CP  Character Plot            spaces,lines

CS  Select Standard Charset    set

CT  Chord Tolerance            n

CV  Curved line generator     n(,inputdelay)

CD  Digitize Clear

DF   Default

DI  Absolute Direction        run,rise

DL  Define Download character charnumber(,pencontrol),x,y(...)

DP  Digitze Point

DR  Relative Direction        run.rise

DS  Designate Charset         slot,set

DT  Define Label Terminator    terminator

EA  Edge Rectangle Absolute    x,y

EP  Edge Polygon           

ER  Edge Rectangle Relative    x,y

ES  Extra Space               spaces(,lines)

EW  Edge Wedge                radius,startangle,sweepangle(,tolerance)

FP  Fill Polygon            

FS  Force Select              force(.pennumber)

FT  Fill Type                 type(,spacing(,angle))

GC  Group Count               countnumber

GM  Graphics Memory           (polygonbuff)(,downloadbuff)(,replotbuff)(,vectorbuff)

GP   Group Pen                 (groupnumber(,pennumber(,numberofpens,(length))))

IM  Input Mask                emaskvalue(,smaskvalue(,pmaskvalue))

IN  Initialize

IP  Input p1 and p2           x,y(,x,y)

IV  Invoke Character Slot     slot,(left)

IW  Input Window               x,y,x,y

KY  Define Key                key(,function)

LB  Label                      string

LO  Label Origin              positionnumber

LT  Line Type                 patternnumber(,patternlength)

NR  Not Ready

PA  Plot Absolute             x,y(,...)

PB  Print Buffered Label

PD  Pen Down                  x,y(,...)

PG  Page Feed                  n

PM  Polygon Mode               n

PR  Plot Relative             x,y(,...)

PT  Pen Thickness              thickness

PU  Pen Up                    x,y(,...)

RA  Fill Rectangle Absolute    x,y

RO  Rotate Coordinate System   n

RP  Replot                     n

RR  Fill Rectangle Relative    x,y

SA  Select Alternative Charset     

SC  Scale                      x,y,x,y(,type(,left,bottom))

SG  Select Pen Group          groupnumber

SI  Absolute Character Size   width,height

SL  Character Slant           tantheta

SM  Symbol Mode               character

SP  Select Pen                 pennumber

SR  Relative Character Size   width,height

SS  Select Standard Charset

TL  Tick Length                tp(,tn)

UC  User Defined Character    (pencontrol,)x,y

UF  User Defined Fill         gap1(,gap2,...gap20)

VS  Velocity Select            speed(,pennumber)

WD  Write to Display           string

WG  Fill Wedge                radius,startangle,sweepangle(,tolerance)

XT  X Tick

YT  Y Tick

Output Instructions

The followinginstructions don't have any arguments but rather generate output from theplotting device. They are of no use for interchanging geometric data andtherefore the form of the output is not discussed. See an HPGL reference book.

OA  Output Actual Position

OC  Output Position

OD  Output Digitised Point

OE  Output Error

OF  Output Factors

OG  Output Group Count

OH  Output HardClip Limits

OI  Output Identification

OK  Output Key

OL  Output Label Length

OO  Output Options

OP  Output p1 and p2

OS  Output Status

OT  Output Carousel Type

OW  Output Window

Escape sequnces

The followingescape sequences are generally only applicable when connected through a serialinterface to a physical plotter, they have nothing to do with data interchangeand so their arguments will not be listed nor will the form of the output mostof them create .

esc@ Set Plotter Configuration

escA Output Identification

escB Output Buffer Space

escE Output Extended error

escH Set Handshake Mode 1

escI Set Handshake Mode 2

escJ Abort Device Control

escK Abort Graphics

escL Output Buffer Size When Empty

escM Set Output Mode

escN Set Extended Output and Handshake Mode

escO Output Extended Status

escP Set Handshake Mode

escQ Set Monitor Mode

escR Reset

escS Output Configurable Memory

escT Allocate Configurable Memory

escU End Flush Mode

escY Plotter On

esc( Plotter On

escZ Plotter Off

esc) Plotter Off

Useful Commands with examples

Since plottersare very basic line drawing hardware devices it is not surprising that the mostcommonly used commands are those that draw lines from one point to another.

This operationis controlled by 4 commands,
PA - plot absolute
PR - plot relative
PU - pen up
PD - pen down

 

Pen up and downdictate when a line is actually being created, the plot commands do themovement between points.

For example todraw a line from (1,0) to (2,0) might be specified as follows

 

PU;PA1,0;PD;Pr1,0;PU;

 

There are twobasic attributes that can be assigned to a line, as expected they are actuallyapplied to the pens of the plotting device. They are:

SP - pen number
PT - pen thickness

 

The pen numbernormally acts as an indexed colour system, most commonly there are only 8 pens(colour) available.

The othergeometry that can be specified is
AR - arc relative
CI - circle
EA - edge rectangle absolute
ER - edge rectangle relative
EP - edge polygon
EW - edge wedge
LB - label

 

There are alarge number of settings for controlling text, these and further details of theabove instructions will be left to the reader to experiment with or read in thefull HPGL manuals.