ARC_R

Syntax ARC_R [#ch][,x1,y1] TO x2,y2,angle *[[;xi,yi] TO xj,yj,anglej]*
Location QL ROM

This command draws an arc relative to the current graphic cursor. This means that rather than the co-ordinates (x,y) being relative to the graphic origin, they are relative to the current graphic cursor. Arcs are however still affected by the current SCALE.

Each set of co-ordinates used in the ARC_R command moves the graphic cursor, which means for example that (x1,y1) is relative to the graphic cursor when ARC_R is first called, whereas (x2,y2) is relative to (x1,y1).

Example 1

A short program to draw several equi-distant arcs using ARC_R:

100 WINDOW 448,200,32,16:SCALE 100,0,0
110 PAPER 0:INK 4:CLS
120 ARC 20,20 TO 90,20,PI/4
130 FOR i=1 TO 4
140   ARC_R 0,10 TO -70,0,-PI/4
150   ARC_R 0,10 TO 70,0,PI/4
160 END FOR i

Example 2

The same routine, but altered to use ARC:

100 WINDOW 448,200,32,16:SCALE 100,0,0
110 PAPER 0:INK 4:CLS
120 ARC 20,20 TO 90,20,PI/4
130 FOR i=30 TO 100 STEP 10
140   ARC 20,i TO 90,i,PI/4
150 END FOR i

CROSS-REFERENCE

The graphic cursor is moved with commands such as POINT, ARC, CIRCLE and LINE.

Please also see ARC.