%D \module
%D   [       file=m-gnuplot,
%D        version=2020.02.10,
%D          title=\CONTEXT\ Extra Modules,
%D       subtitle=Gnuplot,
%D         author=Hans Hagen,
%D           date=\currentdate,
%D      copyright={PRAGMA ADE \& \CONTEXT\ Development Team}]
%C
%C This module is part of the \CONTEXT\ macro||package and is
%C therefore copyrighted by \PRAGMA. See mreadme.pdf for
%C details.

%D This is a variant on the \GNUPLOT\ terminal code. At some point (when there is a
%D reason) I will make a proper environment that can be used for embedded code. We
%D actually could do with a simpler context interface but then i need to be able to
%D compile the thing. I have no time to look into fonts or Mojca's \MKII\ context
%D terminal code either.

\permanent\protected\def\includegnuplotsvgfile[#1]%
  {\hbox\bgroup
     \ctxlua{metapost.startsvghashing()}%
     \includesvgfile[#1]%
     \ctxlua{metapost.stopsvghashing()}%
   \egroup}

\startluacode

local modificationtime = lfs.modification
local longtostring     = string.longtostring
local formatters       = string.formatters
local expandfilename   = dir.expandname
local isfile           = lfs.isfile

local runner = sandbox.registerrunner {
    name     = "gnuplot to svg",
    program  = "gnuplot",
    template = longtostring [[
        -e "set output '%newname%'; set terminal svg"
        "%oldname%"
    ]],
    checkers = {
        oldname = "readable",
        newname = "writable",
    },
}

figures.programs.gnuplot = {
    runner = runner,
}

local function remap(specification)
    local oldname = specification.fullname
    if oldname then
        local newname = file.replacesuffix(oldname,"svg")
        local oldtime = modificationtime(oldname) or 0
        local newtime = modificationtime(newname) or 0
        if newtime == 0 or oldtime > newtime then
            runner {
                newname = expandfilename(newname),
                oldname = expandfilename(oldname),
            }
        end
        if isfile(newname) then
            local only = file.nameonly(newname)
            local name = formatters["svg-%s-inclusion"](only)
            local code = formatters["\\includegnuplotsvgfile[%s]\\resetbuffer[%s]"](newname,name)
            buffers.assign(name,code)
            specification.format   = "buffer"
            specification.fullname = name
        end
    end
    return specification
end

figures.remappers.gp = { svg = remap }

\stopluacode

\continueifinputfile{m-gnuplot.mkxl}

\startluacode
io.savedata("m-gnuplot-demo-1.gp", [[
set format xy "$%g$"

set title  'This is a plot of $y=\\sin(x)$'
set xlabel 'This is the $x$ axis'
set ylabel 'This is the $y$ axis'

plot [0:6.28] [0:1] sin(4*x)
]])
\stopluacode

% from the demo site

\startluacode
io.savedata("m-gnuplot-demo-2.gp", [[
set view 42, 33, 1, 1
set samples 201, 201
set isosamples 201, 201
set hidden3d back offset 1 trianglepattern 3 undefined 1 altdiagonal bentover
set style data lines
set xyplane relative 0
set title "Modified Bessel functions of the second kind"
set trange [ * : * ] noreverse nowriteback
set urange [ * : * ] noreverse nowriteback
set vrange [ * : * ] noreverse nowriteback
set xlabel "x"
set xrange [ -5.00000 : 5.00000 ] noreverse nowriteback
set x2range [ * : * ] noreverse writeback
set ylabel "iy"
set yrange [ -5.00000 : 5.00000 ] noreverse nowriteback
set y2range [ * : * ] noreverse writeback
set zrange [ -10.0000 : 5.00000 ] noreverse writeback
set cbrange [ * : * ] noreverse writeback
set rrange [ * : * ] noreverse writeback
set colorbox vertical origin screen 0.9, 0.2 size screen 0.05, 0.6 front  noinvert bdefault
unset colorbox
VERSION = "gnuplot version 6.0.3"
NO_ANIMATION = 1
save_encoding = "utf8"
splot real(BesselK(0, x+y*I)) with lines lw .2

]])
\stopluacode

% from the demo site

\startluacode
io.savedata("m-gnuplot-demo-3.gp", [[
set border 4095 front lt black linewidth 1.000 dashtype solid
set style fill  transparent solid 0.50 border
unset key
set view 60, 60, 1.1, 0.6
set samples 40, 40
set isosamples 40, 40
set style data lines
set xyplane relative 0
set xtics border in scale 1,0.5 mirror norotate  offset character 0, -0.5, 0 autojustify
set xtics  norangelimit 2
set ytics border in scale 1,0.5 mirror norotate  offset character 0, -0.5, 0 autojustify
set ytics  norangelimit 2
set ztics  norangelimit 5
set title "set pm3d clip (Gnuplot 6)"
set xrange [ -1.00000 : 5.00000 ] noreverse
set yrange [ -3.00000 : 3.00000 ] noreverse
set zrange [ -10.0000 : 10.0000 ] noreverse
set bmargin  6
set pm3d depthorder
set pm3d interpolate 1,1 flush begin noftriangles border linewidth 0.100 dashtype solid corners2color mean
set pm3d lighting primary 0.5 specular 0.2 spec2 0
unset colorbox
f(x,y) = x**2 + y**2 * (1 - x)**3
NO_ANIMATION = 1
## Last plot was a multiplot
# saved multiplot
set multiplot layout 1,2 title "Gnuplot 6 pm3d default is smooth clipping against zrange"
set title "set pm3d clip4in (old default)"
set pm3d clip4in
splot f(x,y) with pm3d fc "cyan"
set title "set pm3d clip (Gnuplot 6)"
set pm3d clip
replot
unset multiplot
]])
\stopluacode

% from the demo site

\startluacode
io.savedata("m-gnuplot-demo-4.gp", [[
set dummy u, v
set key bmargin center horizontal Right noreverse enhanced autotitle nobox
set parametric
set view 50, 30, 1, 1
set isosamples 50, 20
set hidden3d back offset 1 trianglepattern 3 undefined 1 altdiagonal bentover
set style data lines
set xyplane relative 0
set title "Interlocking Tori"
set urange [ -3.14159 : 3.14159 ] noreverse
set vrange [ -3.14159 : 3.14159 ] noreverse
NO_ANIMATION = 1
splot cos(u)+.5*cos(u)*cos(v),sin(u)+.5*sin(u)*cos(v),.5*sin(v) with lines,       1+cos(u)+.5*cos(u)*cos(v),.5*sin(v),sin(u)+.5*sin(u)*cos(v) with lines
]])
\stopluacode

\starttext

%     \dorecurse {4} {
    \dorecurse {1} {
        \startTEXpage[offset=1ts]
          % \externalfigure[m-gnuplot-demo-#1.gp][conversion=svg,width=4cm,frame=on]
          % \vskip1ex
            \externalfigure[m-gnuplot-demo-#1.gp][conversion=svg,width=8cm,frame=on]
        \stopTEXpage
    }

\stoptext