## Copyright (C) 2009 Soren Hauberg
##
## This program is free software; you can redistribute it and/or modify it
## under the terms of the GNU General Public License as published by
## the Free Software Foundation; either version 3 of the License, or (at
## your option) any later version.
##
## This program is distributed in the hope that it will be useful, but
## WITHOUT ANY WARRANTY; without even the implied warranty of
## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
## General Public License for more details.
##
## You should have received a copy of the GNU General Public License
## along with this program; see the file COPYING.  If not, see
## <http://www.gnu.org/licenses/>.

## -*- texinfo -*-
## @deftypefn{Function File} print_tikz ()
## @deftypefnx{Function File} print_tikz (@var{fig})
## @deftypefnx{Function File} print_tikz (@var{fig}, @var{filename})
## @deftypefnx{Function File} address@hidden =} print_tikz (@dots{})
## @end deftypefn

function retval = print_tikz (fig = gcf (), filename = [])
  ## Make sure we got a figure
  type = get (fig, "type");
  if (!strcmp (type, "figure"))
    error ("print_tikz: first argument must be a valid figure handle");
  endif
  figure (fig); # XXX: can we avoid this?
    
  ## Paper information
  paperunits = get (fig, "paperunits");
  papersize = get (fig, "papersize");
  paperposition = get (fig, "paperposition");
  paperorientation = get (fig, "paperorientation");
  paper = struct ("units", paperunits, "size", papersize, "position", paperposition,
                  "orientation", paperorientation);
  
  ## Compute transformation between units
  if (strcmpi (paperunits, "inches"))
    paper.in2cm = 2.54;
  else
    paper.in2cm = 1;
  endif
  xl = xlim ();
  yl = ylim ();
  paper.ax = paper.in2cm * paperposition (3) / (xl (2) - xl (1));
  paper.ay = paper.in2cm * paperposition (4) / (yl (2) - yl (1));
  paper.bx = paper.in2cm * paperposition (1);
  paper.by = paper.in2cm * paperposition (2);

  ## Write header
  children = get (fig, "children");
  text = "\
\\documentclass{minimal}\n\
\\usepackage{tikz}\n\
\\usepackage{lscape}\n\
\n\
\\begin{document}\n\
\n";
  if (strcmp (paperorientation, "landscape"))
    text = strcat (text, "\\begin{lscape}\n");
  endif
  text = strcat (text, "\\begin{tikzpicture}[scale=2]\n");

  ## Traverse children
  for i = 1:length (children)
    kid = children (i);
    t = print_kid (kid, paper);
    text = strcat (text, t);
  endfor
  
  ## Write footer
  text = strcat (text, "\\end{tikzpicture}\n");
  if (strcmp (paperorientation, "landscape"))
    text = strcat (text, "\\end{lscape}\n");
  endif
  text = strcat (text, "\\end{document}\n");

  ## Return output or write it to a file
  if (nargout > 0)
    retval = text;
  elseif (ischar (filename))
    fid = fopen (filename, "w");
    if (fid < 0)
      error ("print_tikz: couldn't open '%s' for writing", filename);
    endif
    fputs (fid, text);
    fclose (fid);
  elseif (isnumeric (filename))
    fputs (filename, text); ## Treat 'filename' as a file ID
  else
    disp (text);
  endif
endfunction

function retval = print_kid (kid, paper)
  persistent num_call = 0;
  num_call ++;
  
  retval = "";
  
  visible = get (kid, "visible");
  if (!strcmp (visible, "off"))
    type = get (kid, "type");
    switch (type)
      case "line"
        retval = draw_line (kid, num_call, paper);
      case "axes"
        retval = draw_axes (kid, paper);
      otherwise
        printf ("Skipping type = %s\n", type);
    endswitch
  endif # if visible
  
  children = get (kid, "children");
  for i = 1:length (children)
    kid = children (i);
    t = print_kid (kid, paper);
    retval = strcat (retval, t);
  endfor
endfunction

function retval = linestyle_to_tikz (linestyle)
  switch (linestyle)
    case "-"
      retval = "";
    case "--"
      retval = "dashed";
    case ":"
      retval = "dotted";
    case "none"
      retval = "none";
    otherwise
      warning ("print_tikz: unsupported linestyle '%s'", linestyle);
      retval = "";
  endswitch
endfunction

function retval = draw_line (kid, num_call, paper)
  ## Get data
  xdata = paper.ax * get (kid, "xdata") + paper.bx;
  ydata = paper.ay * get (kid, "ydata") + paper.by;
  color = get (kid, "color");
  linestyle = get (kid, "linestyle");
  marker = get (kid, "marker");
  markeredgecolor = get (kid, "markeredgecolor");
  markerfacecolor = get (kid, "markerfacecolor");
  markersize = 0.005 * get (kid, "markersize") * paper.in2cm;
      
  ## Setup line style
  deflinecolor = sprintf ("\\definecolor{linecolor%d}{rgb}{%f, %f, %f}\n", num_call,
                          color (1), color (2), color (3));
  deflinestyle = linestyle_to_tikz (linestyle);

  ## The actual line drawing command
  if (!strcmp (deflinestyle, "none"))
    intro = sprintf ("\\draw [color=linecolor%d, %s]\n", num_call, deflinestyle);
    val = strcat (sprintf ("(%f, %f) -- ", [xdata(1:end-1).', ydata(1:end-1).'].'),
                  sprintf ("(%f, %f)", xdata (end), ydata (end)));
    outro = ";\n";
    line = strcat (deflinecolor, intro, val, outro);
  else
    line = "";
  endif
      
  ## Define marker colors
  edge_name = sprintf ("markeredgecolor%d", num_call);
  [markeredgecolor, edge_name] = get_marker_color (markeredgecolor, edge_name, color);
      
  face_name = sprintf ("markerfacecolor%d", num_call);
  [markerfacecolor, face_name] = get_marker_color (markerfacecolor, face_name, color);
      
  ## The actual marker drawing command
  markers = "";
  if (!isempty (markeredgecolor) || !isempty (markerfacecolor))
    markers = strcat (markeredgecolor, markerfacecolor);

    if (isempty (markeredgecolor))
      intro = sprintf ('\\draw [fill=%s] ', face_name);
    elseif (isempty (markerfacecolor))
      intro = sprintf ('\\draw [thick,draw=%s] ', edge_name);
    else
      intro = sprintf ('\\draw [thick,draw=%s,fill=%s] ', edge_name, face_name);
    endif

    switch (marker)
      case "o"
        cmd = @(x, y) sprintf ('%s (%f, %f) circle (%f); \n', intro, x, y, markersize);
      case "."
        cmd = @(x, y) sprintf ('%s (%f, %f) circle (%f); \n', intro, x, y, 0.1*markersize);
      case "+"
        delta = markersize;
        cmd = @(x, y) sprintf ('%s (%f, %f) -- (%f, %f);\n%s (%f, %f) -- (%f, %f);\n',
                               intro, x-delta, y, x+delta, y,
                               intro, x, y-delta, x, y+delta);
      case "x"
        delta = markersize;
        cmd = @(x, y) sprintf ('%s (%f, %f) -- (%f, %f);\n%s (%f, %f) -- (%f, %f);\n',
                               intro, x-delta, y+delta, x+delta, y-delta,
                               intro, x+delta, y+delta, x-delta, y-delta);
      case "*"
        cmd = @(x, y) sprintf ('%s (%f, %f) node {*}; \n', intro, x, y);
      case "p"
        cmd = @(x, y) print_pentagram (x, y, intro, markersize);
      case "s"
        cmd = @(x, y) print_square (x, y, intro, markersize);
      case "d"
        cmd = @(x, y) print_diamond (x, y, intro, markersize);
      case "none"
        cmd = [];
      otherwise
        cmd = [];
        warning ("print_tikz: no support for marker '%s'", marker);
    endswitch
        
    if (!isempty (cmd))
      for k = 1:length (xdata)
        val = cmd (xdata (k), ydata (k));
        markers = strcat (markers, val);
      endfor
    else
      markers = "";
    endif
  endif
      
  retval = strcat (line, markers);
endfunction

function retval = draw_axes (kid, paper)
  xlim = paper.ax * get (kid, "xlim") + paper.bx;
  ylim = paper.ay * get (kid, "ylim") + paper.by;
  xtick = paper.ax * get (kid, "xtick") + paper.bx;
  ytick = paper.ay * get (kid, "ytick") + paper.by;
  xticklabel = get (kid, "xticklabel");
  yticklabel = get (kid, "yticklabel");
      
  ## Draw axes
  fmt = "\\draw [thick] (%f, %f) -- (%f, %f) -- (%f, %f) -- (%f, %f) -- (%f, %f);\n";
  ax = sprintf (fmt, xlim (1), ylim (1), xlim (1), ylim (2), xlim (2), ylim (2),
                xlim (2), ylim (1), xlim (1), ylim (1));
  ## Draw tics
  ticsize = 0.1; # XXX: compute this from data
  xt = yt = "";
  for k = 1:length (xtick)
    xt1 = sprintf ("\\draw [thick] (%f, %f) -- (%f, %f) ", xtick (k), ylim (1),
                   xtick (k), ylim (1) - ticsize);
    xt2 = sprintf ("node [anchor=north] {%s};\n", xticklabel {k});
    xt = strcat (xt, xt1, xt2);
  endfor

  for k = 1:length (ytick)
    yt1 = sprintf ("\\draw [thick] (%f, %f) -- (%f, %f) ", xlim (1), ytick (k),
                   xlim (1) - ticsize, ytick (k));
    yt2 = sprintf ("node [anchor=east] {%s};\n", yticklabel {k});
    yt = strcat (yt, yt1, yt2);
  endfor
      
  retval = strcat (ax, xt, yt);
endfunction

function [define, name] = get_marker_color (markercolor, name, color)
  if (strcmp (markercolor, "auto"))
    markercolor = color;
  endif
      
  if (strcmp (markercolor, "none"))
    define = "";
    name = "";
  else
    define = sprintf ("\\definecolor{%s}{rgb}{%f, %f, %f}\n", name, markercolor);
  endif
endfunction

function retval = print_pentagram (x, y, intro, markersize)
  ## XXX: This approach is just waaay to hacky
  t = linspace (0, 2*pi, 6);
  innerscale = 0.3 * markersize;
  outerscale = innerscale;
  x_nodes (1:2:12) = outerscale * sin (t) + x;
  x_nodes (2:2:12) = innerscale * sin (t+0.5) + x;
  y_nodes (1:2:12) = outerscale * cos (t) + y;
  y_nodes (2:2:12) = innerscale * cos (t+0.5) + y;
  star = sprintf ('(%f, %f) -- ', [x_nodes(1:end-1).', y_nodes(1:end-1).'].');
  star = strcat (star, sprintf ('(%f, %f)', x_nodes (end), y_nodes (end)));
  retval = strcat (intro, star, ";\n");
endfunction

function retval = print_square (x, y, intro, markersize)
  delta = markersize;
  square = print_closed_polygon ([x-delta, x-delta, x+delta, x+delta],
                                 [y-delta, y+delta, y+delta, y-delta]);
  retval = strcat (intro, square, ";\n");
endfunction

function retval = print_diamond (x, y, intro, markersize)
  delta = markersize;
  diamond = print_closed_polygon ([x-delta, x, x+delta, x],
                                  [y, y+delta, y, y-delta]);
  retval = strcat (intro, diamond, ";\n");
endfunction

function retval = print_closed_polygon (x, y)
  polygon = sprintf ('(%f, %f) -- ', [x.', y.'].');
  closed = sprintf ('(%f, %f)', x (1), y (1));
  retval = strcat (polygon, closed, ";\n");
endfunction

%!demo
%! figure ("paperunits", "centimeters", "papersize", [6, 4], "paperposition", [1, 0.5, 5, 3]);
%! x = linspace (0, 5, 15);
%! t = linspace (0, 2*pi, 25);
%! plot (x, sqrt (x), "p", "linestyle", "none", "markerfacecolor", [0.1, 0.9, 0.1]);
%! hold on
%! plot (x, sin (x), "b-o", "markeredgecolor", [0.1, 0.9, 0.1], 
%!       "markerfacecolor", [0.4, 0.4, 0.4]);
%! plot (x, cos (x), "r:x");
%! plot (x, sqrt (1 + cos (x)), "--s", "color", [0.9, 0.1, 0.9],
%!       "markersize", 10, "markerfacecolor", [0.1, 0.9, 0.9]);
%! plot (cos (t), sin (t), "d");
%! plot (5*rand (1, 1000), 2*rand (1, 1000)-2, 'k.');
%! plot (x, (x-3).^2, '*')
%! hold off
%! set (gca, "ytick", [0, 1.5]);
%! set (gca, "yticklabel", {"cheese", "$\\cos (\\omega) \\neq \\mathrm{cheese}$"});
%! #axis off
%! print_tikz (:, "mytest.tex");