'this file contains plot functions

function plot(a(),ax,ay,px,py,sx,sy)
 'find the array dimensions if omitted
 'by incrementing pointers until an error occurs
 if ax=0 then
   do
     ax=ax+1
     on error skip
     dummy=a(ax,1)
   loop while MM.ERRNO=0
   ax=ax-1
 end if
 if ay=0 then
   do
     ay=ay+1
     on error skip
     dummy=a(1,ay)
   loop while MM.ERRNO=0
   ay=ay-1
 end if

 'if no plot coordinates are provided assume full screen
 if px=0 and sx=0 then sx=MM.HRES
 if py=0 and sy=0 then sy=MM.VRES

 'print ax,ay,px,py,sx,sy

 'plot outline
 box px,py,sx,sy
 
 'slice array in separate arrays, assume minimal X Y
 local float a1(ay),a2(ay)
 math slice a(),1,,a1()
 math slice a(),2,,a2()
 'if ax=3 then
 '  local float a3(ay)
 '  math slice a(),3,,a3()
 'end if
 'if ax=4 then
 '  local float a4(ay)
 '  math slice a(),4,,a4()
 'end if

 'find extremes in input data
 local float max1,max2,min1,min2,gainx,gainy,offsetx,offsety,i
 max1=math(max a1()):min1=math(min a1())
 max2=math(max a2()):min2=math(min a2())
 gainx=(sx-1)/(max1-min1)
 offsetx=int(px-gainx*min1)
 gainy=(sy-1)/(min2-max2)
 offsety=int(py-gainy*max2)
 'print max1,min1,max2,min2,gainx,offsetx,gainy,offsety

 'plot zero axis
 line offsetx,py,offsetx,py+sy,,rgb(grey)
 line px,offsety,px+sx,offsety,,rgb(grey)

 'calculate ticks, multiply and divide until value between 1-10
 local float range,tickrange,tickval,tick,k
 range=(max1-min1)/1e12
 do:range=range*10:loop until range>4
 tickrange=int(sx*int(range)/range)
 tickval=(max1-min1)/range  
 tick=tickrange/int(range)
 for k=1 to int(range)
   'line px+k*tick,offsety-(sy/50),px+k*tick,offsety+(sy/50),,rgb(grey)
   'text px+k*tick,offsety+(sy/50),str$(tickval*k),"CTD",,,rgb(grey)
   line px+k*tick,py,px+k*tick,py+(sy/50),,rgb(grey)
   line px+k*tick,py+sy,px+k*tick,py+sy-(sy/50),,rgb(grey)
   if (k mod 2)=0 then
     tickval=(k/range)*(max1-min1)
     text px+k*tick,py+(sy/50),str$(tickval,1,-1),"CTD",7,,rgb(blue)
   end if
 next k

 range=(max2-min2)/1e12
 do:range=range*10:loop until range>4
 tickrange=int(sy*int(range)/range)
 tick=tickrange/int(range)
 for k=1 to int(range)
   line px,py+k*tick,px+(sx/50),py+k*tick,,rgb(grey)
   line px+sx,py+k*tick,px+sx-(sx/50),py+k*tick,,rgb(grey)
   if (k mod 2)=0 then
     tickval=max2-(k/range)*(max2-min2)
     text px+(sx/50),py+k*tick,str$(tickval,1,-1),"LM",7,,rgb(blue)
   endif
 next k

 'scale a() to plot window
 math scale a1(),gainx,a1()
 math scale a2(),gainy,a2()
 math add a1(),offsetx,a1()
 math add a2(),offsety,a2()

 'plot the actual graph
 for i=1 to ay-1
   line a1(i),a2(i),a1(i+1),a2(i+1),,rgb(yellow)
 next i
 plot=1  
end function

'test program for development of a generic plot routine

option base 1
dim integer i,x=2,y=200
dim float sinewave(x,y)

#include "plot"


for i=1 to y
 sinewave(1,i)=(i-1)/10
 sinewave(2,i)=sin((i-1)/10)
next i

'result=plot(sinewave(),,,100,100,400,300)
result=plot(sinewave())

'save image "sineplot"

do:loop until inkey$<>""

end

run "testplot.bas"
[7] #include "plot"
Error : Invalid character: #