Add "pyplot" backend to hex_plotter

The "gnuplot" backend remains available, but "pyplot" is the new default.

The output from the two backends is tuned to look fairly similar.

There are options to pass a script filename and a picture filename, if
the script name is not passed a default one will be produced, as we want
to /always/ have a saved script, for reproducibility. If the figure name
is not passed there will be no saved picture, but just a GUI popup for
both backends (or something similar for peculiar cases).

The "gnuplot" backend aimsˆ† to support also a custom <terminal> such as
<qt>, <wxt>, <dumb> (especially useful on HPC servers), <png>, <svg>,…
which instead are necessary to allow correct I/O if figure_name is given.

†) Issue kookma/ogpf#41 needs to be solved...
   > for now I just redirect the fpm.toml pointer to a relevant "devel"
     branch on my personal fork ==> for now just changes the default
     terminal, so to allow proper testing here, but a new public API
     should be defined to allow the user choose.

—————————————————————————————————————————————————————————————————————————

Let me brag the <dumb> terminal "gnuplot" output :)

—————————————————————————————————————————————————————————————————————————

                 7 +-------------------------------------------+
                   |                                           |
                   |               F          F                |
                 6 |-+        F          F          F          |
                   |                                           |
                   |                                           |
                 5 |-+        F          F          F          |
                   |                                           |
                   |    F          F          F          F     |
                 4 |-+                                         |
              y    |                                           |
                   |    F          F          F          F     |
                   |                                           |
                 3 |-+        F          F          F          |
                   |                                           |
                   |                                           |
                 2 |-+        F          F          F          |
                   |               F          F                |
                   |     +      +     +     +     +      +     |
                 1 +-------------------------------------------+
                  -1     0      1     2     3     4      5     6
                                         x

—————————————————————————————————————————————————————————————————————————

.gitignore

@@ -1,4 +1,23 @@
+# Build files
 **/*.mod
+# FORD files
 doc/
+# RAW debugging
 fort.*
-**/*.gp
+# OGPF output script files
+**/*.gp
+# PyPlot allowed output files
+**/*.eps
+**/*.jpeg
+**/*.jpg
+**/*.pdf
+**/*.pgf
+**/*.png
+**/*.ps
+**/*.raw
+**/*.rgba
+**/*.svg
+**/*.svgz
+**/*.tif
+**/*.tiff
+**/*.py

fpm.toml

@@ -13,5 +13,7 @@ library = true
 [dependencies]
 assert.git  = "https://github.com/sourceryinstitute/assert.git"
 assert.tag  = "1.4.0"
-ogpf.git    = "https://github.com/kookma/ogpf.git"
-ogpf.branch = "master" 
+ogpf.git    = "https://github.com/bellomia/OGPF.git"
+ogpf.branch = "expose-term-options-to-user" 
+pyplot-fortran.git = "https://github.com/jacobwilliams/pyplot-fortran.git"
+pyplot-fortran.tag = "3.2.0"

src/hex_plotter.f90

@@ -1,6 +1,7 @@
 module hex_plotter
    !! Providing plotting facilities for hex tessellations
 
+   use pyplot_module
    use ogpf
    use hex_coordinates
    use hex_layout
@@ -16,18 +17,27 @@ module hex_plotter
 
 contains
 
-   subroutine hex_plot(layout,hexagons)
+   subroutine hex_plot(layout,hexagons,backend,figure_name,script_name,set_terminal)
       type(unit_cell),intent(in)       :: layout
       type(hex),intent(in)             :: hexagons(:)
+      character(*),intent(in),optional :: backend !! default: "pyplot" (or "gnuplot")
+      character(*),intent(in),optional :: figure_name
+      character(*),intent(in),optional :: script_name
+      character(*),intent(in),optional :: set_terminal !! relevant to gnuplot backend
+      character(8)                     :: engine
+      character(32)                    :: source_name
       integer                          :: M
-      type(gpf)                        :: plotter
+      type(pyplot)                     :: plt
+      type(gpf)                        :: gnu
       type(xy_tile),allocatable        :: corner(:)
       real(8),dimension(N)             :: xtmp,ytmp
       real(8),allocatable              :: x(:),y(:)
       integer                          :: i,j
+
       M = size(hexagons)
       allocate(x(N*M),y(N*M),corner(M))
       corner = hex2corner(layout,hexagons)
+
       do i = 1,M
          do j = 1,N
             xtmp(j) = corner(i)%vertex(j)%x
@@ -36,11 +46,79 @@ subroutine hex_plot(layout,hexagons)
          x((1+N*(i-1)):N*i) = xtmp
          y((1+N*(i-1)):N*i) = ytmp
       enddo
-      call plotter%xlabel('x')
-      call plotter%ylabel('y')
-      call plotter%filename("hex_temp_script.gp")
-      call plotter%plot(x,y,'with points pt 6 ps 1.2 lc rgb "#000000"')
+
+      if(present(backend))then
+         engine = trim(backend)
+      else
+         engine = "pyplot"
+      end if
+
+      select case(trim(engine))
+
+       case default
+         print*, "unknown backend: no plot generated"
+
+       case ("pyplot")
+
+         call plt%initialize(xlabel='x',ylabel='y',axis_equal=.true.)
+         call plt%add_plot(x,y,label='',linestyle='o',markersize=5)
+
+         if(present(script_name))then
+            source_name = script_name
+         else
+            source_name = "hex_plot.py"
+         endif
+
+         if(present(figure_name))then
+            call plt%savefig(trim(figure_name), pyfile=trim(source_name))
+            print*
+            print*, "> PyPlot figure saved to: "//trim(figure_name)
+            print*
+         else
+            print*
+            print*, "> PyPlot GUI popping up..."
+            print*
+            call plt%showfig(pyfile=trim(source_name))
+         endif
+
+       case ("gnuplot")
+
+         if(present(script_name))then
+            source_name = script_name
+         else
+            source_name = "hex_plot.gp"
+         endif
+
+         if(present(script_name))then
+            source_name = script_name
+         else
+            source_name = "hex_plot.gp"
+         endif
+
+         if(present(set_terminal))then
+            call gnu%options("set term "//set_terminal//";")
+         else
+            call gnu%options("set term qt;")
+         endif
+
+         if(present(figure_name))then
+            call gnu%options('set output "'//figure_name//'"')
+         endif
+
+         call gnu%options("set size ratio -1;")
+         call gnu%options("unset grid")
+         call gnu%xlabel('x')
+         call gnu%ylabel('y')
+         call gnu%filename(source_name)
+         print*
+         print*, "> Gnuplot GUI popping up..."
+         print*
+         call gnu%plot(x,y,'with points pt 6 ps 1.2 lc rgb "#000000"')
+
+      end select
+
       deallocate(x,y)
+
    end subroutine
 
 

test/unit.f90

@@ -121,6 +121,10 @@ program unit_test
 
    print*, ""
    print*, "Plotting neighborhood of hex a..."
-   call hex_plot(v,neighborhood)
+   call hex_plot(v,neighborhood,backend="pyplot",figure_name='pyflower.svg')
+   call hex_plot(v,neighborhood,backend="gnuplot",figure_name='gnuflower.svg')
+   call hex_plot(v,neighborhood,backend="gnuplot",set_terminal='dumb')
+   call hex_plot(v,neighborhood,backend="pyplot")
+   ! THIS HAS TO BE TESTED MUCH MORE CAREFULLY TO ASSURE GOOD COVERAGE
 
 end program unit_test