Logo Arts

To New
  # set default screen, pen and turtle values
  ResetAll SetScreenSize [400 400] HideTurtle
  SetSC Black SetPC Green SetPS 1 PenUp
End

to init
Make "Title [Chebyshev's Linkage]
Make "FixedP [0 -115]
Make "CrankP [115 -115]
Make "A 140 Make "B 140
Make "Points [ ]
Repeat 80 [Make "Points LPut [0 0] :Points]
end

to title
SetPC White SetPW 3 Repeat 80 [
Dot Item RepCount :Points]
SetPos [-190 178] SetH 0 Label :Title
end

to distancebetween :pos1 :pos2
  # return distance between two points
Make "Hor (First :Pos1) - (First :Pos2)
Make "Ver (Last :Pos1) - (Last :Pos2)
Output SqRt ( (Power :Hor 2) + (Power :Ver 2) )
end

to marks1
SetPC [64 64 64] SetPW 1
SetPos :FixedP Arc 140 350 57 PenDown Forward 200 Back 200
SetPos :CrankP Circle 60 PenUp
SetPC [0 0 200] SetPW 21 Dot :FixedP Dot :CrankP
end

to marks3
SetPC [64 64 64] SetPW 7
Dot :FixedP
Dot :PC Dot :PP Dot Last :Points
end

to drawcrank
SetH Towards MousePos Forward 60
SetPC Red SetPW 3 Circle 11 Back 60 PenDown
SetPC [0 160 0] SetPW 11 Forward 60 Make "PC Pos
SetPC [64 64 64] SetPW 7 Dot :CrankP
end

to cheb
Make "Dist DistanceBetween Pos :FixedP
Make "aa ((Power :Dist 2)+(Power :A 2)-(Power :B 2))/(2*:Dist)
SetH Towards :FixedP
Right ArcCosine :aa/:A
SetPC Green SetPW 11 Forward 2*:A PenUp
Make "Points ButFirst LPut Pos :Points
Back :A Make "PP Pos
SetPC [0 160 0] PenDown SetPos :FixedP PenUp
end

to go
New Animation Init
Forever [
If 95>DistanceBetween MousePos :CrankP [
Title Marks1 DrawCrank
Cheb
Marks3
Refresh Wash] ]
end