option nolet
! =>  black default color
print "----------------------------------------------------------"
print " How to make picture from the canvas (*.BMP),version 1.0  "
print " peter.vlasschaert@gmail.com,09/02/2019       'user'      "
print "----------------------------------------------------------"
! =>  user coordinates
! =>  filename :canvaswriteimageusercoordversion1final.tru
print
! ------------- SET UP SCREEN--------------------------------------------,
xmin = -10
xmax = 10
ymin = -10
ymax = 10
set window xmin,xmax, ymin, ymax ! coordinates given for the 'main window'
! -------------- create something to keep in a boxkeep ------------------,
set color "green"
print "-------------------------------------------"
print " dimension of the canvas(user coordinates) "
print "-------------------------------------------"
print "xmin,xmax = "; xmin,xmax
print "ymin,ymax = "; ymin,ymax
print
print "------------------------------"
print " cursor values of the canvas  "
print "------------------------------"
ask max cursor h,w
!********************************************************
! may be depend on the resolution of the screen (monitor)
!********************************************************
print " height (cursor max) = ";h," width (cursor max) = ";w
set cursor 30,50
set color "black"
print "plot :( x ,ymax*sin(x) )"
set color "blue"
! horizontal line (axes)
plot lines : xmin,0;xmax,0
! vertical line (axes)
plot lines : 0,ymin;0,ymax
! plot function
set color "red" 
for x= xmin to xmax step 0.001
 plot points: x,ymax*sin(x)
next x

box keep xmin, xmax, ymin, ymax in keep$ ! area for the picture (*.bmp)
!------------------------------------------------------------------------,
!  Create a filename. Don't need an extention; the SUB will put ".bmp"
!------------------------------------------------------------------------,
 ff$="C:\download\testzzz.bmp" ! make sure this is a valid path...
 CALL Write_Image("MS BMP", keep$, ff$) ! or you can use this 
get key k
END