% AXES: Axis/grid-tick formatter, for the METAPLOT package.
% Copyright(C) 2004, Brooks Moses
%
% This work may be distributed and/or modified under the
% conditions of the LaTeX Project Public License, either
% version 1.3 of this license or (at your option) any
% later version.
% The latest version of the license is in
% http://www.latex-project.org/lppl.txt
% and version 1.3 or later is part of all distributions of
% LaTeX version 2003/06/01 or later.
%
% This work has the LPPL maintenance status "author-maintained".
%
% Version 0.9.
%
% The n < 1.0 release number indicates that this is a beta release;
% the author at present makes no assurances that the command syntax
% will remain unchanged between this and the final Version 1.0
% release.
%
% Bug reports, feature requests, and all other suggestions should
% be directed to Brooks Moses, bmoses@stanford.edu.
input format
% axes_tick(pair tickorigin,
% numeric ticklength,
% pair tickdir)
%
% Draws a grid tick, located on tickorigin, in the direction indicated by
% tickdir, with length ticklength.
def axes_tick(expr tickorigin, ticklength, tickdir) =
begingroup
interim linecap := butt;
save theaxistick; picture theaxistick; theaxistick := nullpicture;
addto theaxistick doublepath ((0,0)--(ticklength * unitvector(tickdir)));
theaxistick shifted tickorigin
endgroup
enddef;
% axes_ticklabeled(pair tickorigin,
% numeric ticklength,
% numeric tickspace,
% pair tickdir,
% picture ticklabel)
%
% Draws a grid tick, located on tickorigin, in the direction indicated by
% tickdir, with length ticklength. In addition, ticklabel is placed as
% a label such that its center is along the line of the tick, and the
% bounding box is a distance tickspace from the end of the tick.
def axes_ticklabeled(expr tickorigin, ticklength, tickspace, tickdir, ticklabel) =
begingroup
interim linecap := butt;
save tickunitvector; pair tickunitvector;
tickunitvector := unitvector(tickdir);
% We calculate an intersection point between the bbox of ticklabel
% and a ray extending from center(ticklabel) in the direction of
% tickdir (approximated by a line guaranteed to be long enough to
% exit the bbox), in the coordinates of ticklabel. Thus, shifting
% ticklabel by the negative of this amount will put this intersection
% point at (0,0).
save thelabelshift; pair thelabelshift;
thelabelshift =
(center(ticklabel) -- (center(ticklabel)
- tickunitvector * (xpart(urcorner ticklabel - llcorner ticklabel)
+ ypart(urcorner ticklabel - llcorner ticklabel))))
intersectionpoint (llcorner ticklabel -- lrcorner ticklabel
-- urcorner ticklabel -- ulcorner ticklabel -- cycle);
save thetick; picture thetick; thetick := nullpicture;
addto thetick doublepath ((0,0)--(ticklength * tickunitvector));
addto thetick also ticklabel
shifted ((ticklength + tickspace)*tickunitvector - thelabelshift);
thetick shifted tickorigin
endgroup
enddef;
% axes_ticknumbered(pair tickorigin,
% numeric ticklength,
% numeric tickspace,
% pair tickdir,
% numeric tickvalue)
% string ticklabelformat)
%
% Draws a grid tick with a formatted number (tickvalue) as the label,
% according to the format given in ticklabelformat, with the remainder
% of the syntax identical to axes_ticklabeled.
def axes_ticknumbered(expr tickorigin, ticklength, tickspace, tickdir,
tickvalue, ticklabelformat) =
axes_ticklabeled(tickorigin, ticklength, tickspace, tickdir,
format(ticklabelformat, tickvalue))
enddef;
% axes_tickrow(pair startpoint,
% pair endpoint,
% numeric ticklength,
% pair tickdir,
% numeric ntickspaces)
%
% Draws a row of ntickspaces+1 grid ticks (that is, ticks with ntickspaces
% spaces between them) from startpoint to endpoint, with parameters given
% by ticklength and tickdir.
def axes_tickrow(expr startpoint, endpoint,
ticklength, tickdir, ntickspaces) =
begingroup
save thetickrow; picture thetickrow; thetickrow := nullpicture;
save tickpoint; pair tickpoint;
for itick=0 upto ntickspaces:
tickpoint := (itick/ntickspaces) * (endpoint - startpoint) + startpoint;
addto thetickrow also
axes_tick(tickpoint, ticklength, tickdir);
endfor
thetickrow
endgroup
enddef;
% axes_tickrow_numbered(pair startpoint,
% pair endpoint,
% numeric ticklength,
% numeric tickspace,
% pair tickdir,
% numeric startvalue,
% numeric endvalue,
% numeric ntickspaces,
% string ticklabelformat)
%
% Draws a row of ntickspaces+1 labeled grid ticks (that is, ticks with
% ntickspaces spaces between them) from startpoint to endpoint, with
% parameters given by ticklength, tickspace, and tickdir. These ticks
% are labeled with numeric values that range from startvalue (at'
% startpoint) to endvalue (at endpoint), according to the format given
% in ticklabelformat.
def axes_tickrow_numbered(expr startpoint, endpoint,
ticklength, tickspace, tickdir,
startvalue, endvalue, ntickspaces,
ticklabelformat) =
begingroup
save thetickrow; picture thetickrow; thetickrow := nullpicture;
save tickpoint; pair tickpoint;
save tickvalue; numeric tickvalue;
for itick=0 upto ntickspaces:
tickpoint := (itick/ntickspaces) * (endpoint - startpoint) + startpoint;
tickvalue := (itick/ntickspaces) * (endvalue - startvalue) + startvalue;
addto thetickrow also
axes_ticknumbered(tickpoint, ticklength, tickspace, tickdir,
tickvalue, ticklabelformat);
endfor
thetickrow
endgroup
enddef;
% axes_tickscale(pair startpoint,
% pair endpoint,
% numeric ticklength,
% numeric tickspace,
% pair tickdir,
% numeric startvalue,
% numeric endvalue,
% numeric tickzero,
% numeric tickstep,
% string ticklabelformat)
%
% Draws a row of grid ticks from startpoint to endpoint, arranged
% such that their values increase in steps of size tickstep, and
% located so that the sequence of grid ticks, if continued to
% infinity, will include a tick with value tickzero. The ticks
% will be labeled according to format ticklabelformat, or if
% ticklabelformat is "", they will be unlabeled.
def axes_tickscale(expr startpoint, endpoint,
ticklength, tickspace, tickdir,
startvalue, endvalue, tickzero, tickstep,
ticklabelformat) =
begingroup
% tickepsilon is a small tolerance value to avoid roundoff errors.
save tickepsilon; numeric tickepsilon;
tickepsilon = 0.005 * min(1.0, abs(endvalue-startvalue)/tickstep);
save firstticknumber; numeric firstticknumber;
save lastticknumber; numeric lastticknumber;
firstticknumber = ceiling((min(startvalue,endvalue)-tickzero)/tickstep - tickepsilon);
lastticknumber = floor((max(startvalue,endvalue)-tickzero)/tickstep + tickepsilon);
save firsttickvalue; numeric firsttickvalue;
save lasttickvalue; numeric lasttickvalue;
firsttickvalue = firstticknumber * tickstep + tickzero;
lasttickvalue = lastticknumber * tickstep + tickzero;
if ticklabelformat="":
axes_tickrow(
((firsttickvalue-startvalue)/(endvalue-startvalue))[startpoint, endpoint],
((lasttickvalue-startvalue)/(endvalue-startvalue))[startpoint, endpoint],
ticklength, tickdir, lastticknumber - firstticknumber)
else:
axes_tickrow_numbered(
((firsttickvalue-startvalue)/(endvalue-startvalue))[startpoint, endpoint],
((lasttickvalue-startvalue)/(endvalue-startvalue))[startpoint, endpoint],
ticklength, tickspace, tickdir,
firsttickvalue, lasttickvalue, lastticknumber - firstticknumber,
ticklabelformat)
fi
endgroup
enddef;