80-Bus News


March–April 1983 · Volume 2 · Issue 2

Page 29 of 55
Graphpac Command ManualPage 1


The documentation for Graphpac is in two parts.

The Command Manual.

This gives the general description of the commands and features provided by all current versions of Graphpac.

The System Manual.

This gives specific details for implementing Graphpac on your computer and a summary of relevant commands.

Copyright and right to make backup copies

On receipt of this computer program and associated documentation, you are granted a non-exclusive license to execute the enclosed software and to make backup copies of the computer program for single user use only. Mbaslink and Graphpac are subject to copyright and all rights are reserved.


No representations or warranties with respect to the contents hereof are made and any implied warranties of merchantability or fitness for any particular purpose are specifically disclaimed.


1Manual Description And Copyright Notice
2Introduction To Graphpac
2Graphpac Commands
4Pen Commands
5Line Drawing Commands
7Cap Command
8Screen Management Commands
9Bar Graph Commands
10Disk Handling Commands
10Graphic Option Commands

Graphpac Command Manual(c) 1983 Gemini Microcomputers Ltd.
Graphpac Command ManualPage 2

Graphpac Command Manual


Graphpac allows the user to SET, RESET, INVERT or TEST any pixel on the screen. Routines are also supplied to draw lines using rectangular (based on X,Y values) or polar co-ordinates (described by an angle and distance). This manual gives a general description of Graphpac features and commands in a similar format and notation to Microsoft Mbasic documentation. An entry is given for each command showing the syntax used.

Plotting on the screen.

The resolution of the graphics is determined by the hardware used and can range from 96 pixels across the screen by 46 pixels down, to 512 X 256 or more.

Graphpac commands control an invisible graphics cursor, the position of this cursor is described by X,Y co-ordinates. Values supplied to Graphpac are treated as signed 16-bit values between −32768 and +32767. A screen X coordinate value of +32767 is the maximum distance to the right of the screen that the graphics cursor may be placed. Negative values are to the left of the screen, −32768 being the maximum. It is not necessary to use the INT function before passing a value to Graphpac.

Note that if Graphpac is used with Microsoft Mbasic or BASIC-80, numbers between +32768 and +65535 will be accepted. Graphpac will interpret these values and all values in between as negative numbers between −32768 and −1.

As a general rule numbers greater then 32767 should not be passed to Graphpac.

Graphpac Commands

Not all the commands described in this document will be available in the software supplied. Some would be unsuitable or impractical on your particular hardware, in other cases they may just be unnecessary. The documentation specific to your hardware (Graphpac System Manual) will inform you which commands are available.

Graphpac commands are stored in memory usually as normal ASCII characters and not as one byte tokens which represent normal BASIC reserved words.

The PLOT DRAW and DRAWTO commands may have more than one set of values passed at a time by separating each set with a semi colon.

i.e.    10 DRAWTO 0,0 ; 20,0 ; 20,20 ; 0,20

PSET (pixel set)

Graphpac format:



To SET a pixel.


X and Y are graphic co-ordinates. If a pixel is already bright there will be no change.

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