FORTRAN SCREEN PLOTTING SUBROUTINES

****NOTE FOR MACS:  I have not been able to get these to work with F90
on the Macs, evidentally because I cannot correctly link with the LeoLib 
C routines, which were compiled with the gcc compiler.  EZXPLOT will work
with F77 on the Macs using the free f77 compiler.  In this case, the 
routines are in /home/shearer/PROG/PLOT/X and documentation is in
ezxplot.man.  You also will need to enter "setenv OPENWINHOME /usr/X11R6"
which you may want to put into your .cshrc file.
************

The notes that follow apply to the Suns.

It is often convenient to plot results directly to the screen.  This is 
particularly true for designing interactive programs in which the user can 
digitize coordinates on the screen using the mouse.  Unfortunately, there 
is no simple, well-documented language like Postscript for screen plotting. 
Most UNIX workstations support the X windows environment, but the manuals 
for plotting within X windows are not very user friendly.

About 10 years ago, Guy Masters and I recognized the need for a library 
of subroutines that would enable us to plot in Fortran without having to 
deal with all of the X windows stuff.  We hired Paul Parker (yes, Bob Parker's 
son, then in high school) to write some routines to handle the X windows 
interface.  The result is the LeoLib package that can be found on the Fishnet 
at ~shearer/PLOT/X/PAUL/.  These routines are written in C but their object 
file can be linked to Fortran programs.  Using the LeoLib routines, I have
written a set of Fortran subroutines called EZXPLOT that are very similar 
to the PSPLOT routines for generating Postscript files.  Documentation for 
EZXPLOT may be found at  ~shearer/PLOT/X/ezxplot.doc.

To use these subroutines, link your program with: 
             ~shearer/PLOT/X/ezxplotlib_f90.a    (ezxplotlib.a for F77)
             ~shearer/PLOT/X/PAUL/LeoLib.0.9b/leolib.a   (both F77 and F90)

and with  -L$$OPENWINHOME/lib -lX11    (links to the Sun OpenWindows library)


Here is an example Makefile for the program testezxplot.f90


OBJS4 = /net/rock/shearer/PLOT/X/ezxplotlib_f90.a \
         /net/rock/shearer/PLOT/X/PAUL/LeoLib.0.9b/leolib.a 

testezxplot: Makefile testezxplot.f90 $(OBJS4)
	f90  testezxplot.f90 $(OBJS4) -L$$OPENWINHOME/lib -lX11 -o testezxplot


Here is the program itself, which demonstrates many of the EZXPLOT features:


program testezxplot
   implicit none
   integer :: i, isymb, ibut
   real :: x, y
   character (len=80) :: xlabel

   call EZXINIT(700, 500)
   call EZXLOADFONT(i, '9x15')
   call EZXWIND(100., 600., 100., 400., 0., 10., 0., 10.)
   call EZXAXES(1.0, 2.0, 5, 'i3', 1.0, 5.0, 5, 'i3')
   xlabel = 'X-axis label'
   call EZXLAX(xlabel, 30, 'Y-axis label', 35)

   do i=1, 9
      call EZXANG(float(i)*10.)
      x=float(i)
      y=5.
      call EZXMOVE(x, y)
      isymb=min(i, 6)
      call EZXCOL(i)
      call EZXSYMB(isymb, 5)
      call EZXLORG(i)
      call EZXLAB('text')
      call EZXCIR(x, y+2., (i+10)*2, i, 1)
      call EZXCIR(x, y-2. ,20, i, 0)
      call EZXCOL(1)
   enddo

   call EZXMESS('Hit mouse key to digitize')
   call EZXDIG(x, y, ibut)
   print *,'x, y, ibut = ', x, y, ibut

   call EZXQUIT

end program testezxplot



When using both PSPLOT and EZXPLOT, please remember the following differences:

(1)  Absolute position coordinates (e.g., the first four arguments of EZXWIND 
     and PSWIND) are in integer pixels for EZXPLOT, but are in real inches 
     for PSPLOT. 

(2)  EZXDUMP is a simple bitmap dump of the screen.  Thus, it does not have 
     the resolution of Postscript files with direct move and draw commands.

(3)  Large time series are drawn fastest using the EZXPOLY command rather than
     a series of EZXDRAW commands.  There is no PSPLOT equivalent.

(4)  Points can be digitized using the EZXDIG command.  There is no PSPLOT 
     equivalent.

(5)  There is no way to perform general fill operations within EZXPLOT.

(6)  It's EZXNUM and PSNUMB (extra B).  Don't ask me why.


ASSIGNMENT SCREEN1

Use the EZXPLOT routines to write a program to do the following:

(1) Draw a large box on the screen

(2) Digitize a series of points from the user.  If the point is
outside the box, terminate the program.  If the point is inside
the box, then perform the following depending upon which mouse
button is pushed:
  (a) Mouse button 1:  Move (without drawing) to the point
  (b) Mouse button 2:  Draw a line to the current point
  (c) Mouse button 3:  Input from the keyboard some text and plot this 
                       at the current point.
  (d) Mouse button 4 (button 1 with shift key):  Change color to red.
  (e) Mouse button 5 (button 2 with shift key):  Change color to blue.
  (f) Mouse button 6 (button 3 with shift key):  Change color to black.