option nolet
print "-----------------------------------------------------------------------"
print " user-pixel coord.:part4 save output of a program (*.bmp)  version 1.0 "
print " peter.vlasschaert@gmail.com,19/02/2019                                "
print "-----------------------------------------------------------------------"
print
!************************
! to find aspect ratio =>
!************************
ask pixels z1,z2
asp = z1/z2
!*************************************************
! default output : window (activ),only:save, *.bmp
!*************************************************
! filename : graphuserpixelpart4finalsub.tru 
!*******************************************
! online : help
! info : https://www.truebasic.com/node/1025
!*******************************************
! select : user or pixels  ? 'select case'
!*******************************************
input prompt "number : user = 1 , pixel = 2 => ":q
xmin = -7
xmax = 7
ymin = -7
ymax = 7
Lx = xmax-xmin
Ly = ymax-ymin 
select case q
case 1
!*******************************************
! user coordinates =>
!*******************************************
     set window xmin,xmax,ymin,ymax
print
print " set window xmin,xmax,ymin,ymax "
print
print " asp ( = aspectratio): ";asp
case else
!*******************************************
! pixel coordinates =>
!*******************************************
x_pix = z1
y_pix = z2
end select
!*********************************************
! from : part 1 (choose 'origin of zero ')
!*********************************************
! two ways : 1e) left bottom  (Mathematics   )
!            2e) left top     (book :John.A  )
!*********************************************
print
if q <> 1 then
input prompt "number : origin  lbottom = 1 ,ltop = 2 => ":qq
select case qq
case 1
   print
   print " origin :leftbottom "   
   set window 0,x_pix-1,0,y_pix -1
print " set window 0,x_pix-1,0,y_pix -1 "
print
print " asp ( = aspectratio): ";asp
print
case else
   print
   print " origin :lefttop    "  
   set window 0,x_pix-1,y_pix -1,0
print " set window 0,x_pix-1,y_pix -1,0 "
print
print " asp ( = aspectratio): ";asp
print
end select
end if
print
print "--------------------------"
print " draw a function =>       "
print "--------------------------"
print
print "--------------------------------------------"
print " How to save pixel window  => funcpict4.bmp "
print "--------------------------------------------"
print
!********************************************************************
! draw F(x) => circle (parametric plot),cos(x)
!********************************************************************
print " x = rr*cos(theta);y = rr*sin(theta), 'red '| cos(x) 'green' "
!********************************************************************
! < user coordinates > ' only graphics '  ( only when q = 1)
!********************************************************************
!*************************************
! parametric plot of circle "red"
!*************************************
set color "red"
rr  = 1           ! radius circle
val = 0.01        ! step value
!*************************************
! need have same axis for both x and y
!*************************************
for theta = 0 to 6.28 step val
!*******************************
! parametric equation of circle
!*******************************
     x = rr*cos(theta)
     y = rr*sin(theta)
 plot points :x,y*asp
next theta
!******************************
! F(x) => example : cos(x)
!******************************
set color "green"
for  x = xmin to xmax step val
     y = cos(x) 
     plot x,y*asp
next x
!******************************
! draw x-axis and y-axis
!******************************
set color "blue"
call draw_xas_user(xmin,xmax)
call draw_yas_user(ymin,ymax)
!***********************************
! box :  xl < x < xr , yb < y < yt *
!***********************************
! corrected with asp 'see above
box keep 0-rr,0+rr,(0-rr)*asp,(0+rr)*asp in kep1$
!*************************************************
! draw box " circle + some parts of the function "
!*************************************************
cor = 0.5 ! corrected position txt
!*************************************************
! math : first quadrant (x>0,y>0), also here.
!*************************************************
BOX SHOW kep1$ at 1,1 ! Draw at new position circle
set color "black"
PLOT TEXT, at 1+cor,1-cor : "new circle"
!********************************************************************
! < user coordinates > ' end user coordinates '
!********************************************************************

!********************************************************************
! How to save canvas as a picture. (funcpict.bmp)
!********************************************************************
if q = 1 then
   call save_userfullwin(xmin,xmax,ymin,ymax,keep$)
else 
     if qq = 1 then 

        call save_pixfullwin_math(x_pix,y_pix,keep$) 
        print
        print " no graphics "

     else

        call save_pixfullwin_JA(x_pix,y_pix,keep$)
        print
        print " no graphics "

     end if
end if
!------------------------------------------------------------------------,
!  Create a filename. Don't need an extention; the SUB will put ".bmp"
!------------------------------------------------------------------------,
ff$="C:\download\funcpict4.bmp" ! make sure this is a valid path...
CALL Write_Image("MS BMP", keep$, ff$) ! or you can use this 
print
end

sub save_pixfullwin_math(z11,z22,kep$)
! <help> 
! z11 : number of pixels x-direction , start :0 to z11-1,integer >0
! z22 : number of pixels y-direction , start :0 to z22-1,integer >0
! picture hold string : kep$
!************************************************
box keep 0, z11-1, 0, z22-1 in kep$ ! kep$ memory
end sub

sub save_pixfullwin_JA(z11,z22,kep$)
! <help> 
! z11 : number of pixels x-direction , start :0 to z11-1,integer >0
! z22 : number of pixels y-direction , start :0 to z22-1,integer >0
! picture hold string : kep$
!************************************************
box keep 0, z11-1, z22-1, 0 in kep$ ! kep$ memory
end sub


sub save_userfullwin(x_min,x_max,y_min,y_max,kep$)
! <help>
! x-direction : x_min < =  x < = x_max , float
! y-direction : y_min < =  x < = x_max , float
! picture hold string : kep$
!***************************************************
box keep x_min, x_max, y_min, y_max in kep$ ! kep$ memory
end sub


sub draw_xas_user(x_min,x_max)
! <help>
! x-direction : x_min < =  x < = x_max , float
! picture hold string : kep$
!***************************************************
pxa = 0
pxb = x_min
pxc = 0
pxd = x_max
plot lines : pxa,pxb ;pxc,pxd
end sub

sub draw_yas_user(y_min,y_max)
! <help>
! y-direction : y_min < =  x < = x_max , float
! picture hold string : kep$
!***************************************************
pxaa = y_min
pxbb = 0
pxcc = y_max
pxdd = 0
plot lines : pxaa,pxbb ;pxcc,pxdd
end sub