Rosetta Code task: Archimedean spiral

[David Drake]

I adapted the code below from the IS-BASIC example for the task Archimedean spiral (found here: rosettacode.org/wiki/Archimedean_spiral).

Requirements: The Archimedean spiral is a spiral named after the Greek mathematician Archimedes.  Draw an Archimedean spiral.



'The Archimedean spiral is a spiral named after the Greek mathematician Archimedes.
'Draw an Archimedean spiral.

nomainwin
WindowWidth=800
WindowHeight=600
UpperLeftX=1
UpperLeftY=1

open "Spiral" for graphics_nf_nsb as #1
#1 "trapclose [q];down;fill black;flush;color green;size 3;"

pi=acs(-1)
xcenter=DisplayWidth/4
ycenter=DisplayHeight/3
a=15:b=15

for c=0 TO 6.5*pi step 0.01
   r=a+b*c
   #1 "set ";xcenter+r*cos(c);" ";ycenter+r*sin(c)
next c
wait

[q] close #1:end


I look forward to hearing your thoughts.

[tsh73]

There is a way to get graphicbox/graphic window center
insert code here
#1 "home;posxy xcenter ycenter"
'The Archimedean spiral is a spiral named after the Greek mathematician Archimedes.
'Draw an Archimedean spiral.

nomainwin
WindowWidth=800
WindowHeight=600
UpperLeftX=1
UpperLeftY=1

open "Spiral" for graphics_nf_nsb as #1
#1 "trapclose [q];down;fill black;flush;color green;size 3;home;posxy xcenter ycenter"

pi=acs(-1)
a=15:b=15

for c=0 TO 6*pi step 0.01
   r=a+b*c
   #1 "set ";xcenter+r*cos(c);" ";ycenter+r*sin(c)
next c
wait

[q] close #1:end



[David Drake]

Nice tip. I have trouble remembering that I can do that.