Sinclair QL User Manual

•
40
- ---------'
(50,50)
A circle
Screen Output
•
•
If you add two more parameters:
e,g, CIRCLE 50,50,40,.5
You will get an ellipse, The keywords CIRCLE and ELLIPSE are interchangeable
An ellipse
The height of the ellipse is 40 as before but the horizontal 'radius' is now only 0.5 of
the height The number 0.5 is called the eccentricity, If the eccentricity is 1 you get a
circle
if it is less than 1 and greater than zero you get an ellipse, If you want to tilt an
ellipse you can change the fith parameter for example:
CIRCLE 50,50,40,.5,1
This will tilt the ellipse anti-clockwise by one radian, about 57 degrees, as shown in figure
Ellipse at angle one radian
A straight angle IS 180 degrees or PI radians, so you can make a pattern of ellipses
with the program:
100 FOR rot =0 TO 2*PI STEP PII6
110 CIRCLE 50,50,40,0.5, rot
120 END FOR rot
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Sinclair QL Specifications

General

Processor	Motorola 68008
Clock Speed	7.5 MHz
RAM	128 KB (expandable to 640 KB)
ROM	48 KB
Operating System	Sinclair QDOS
Release Year	1984
Storage	Microdrive tape loop
Graphics	256x256 pixels, 8 colors
Ports	RS-232, ROM cartridge
Sound	Beeper (internal speaker)