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## Copyright (C) 2005-2013 John W. Eaton
##
## This file is part of Octave.
##
## Octave 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.
##
## Octave 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 Octave; see the file COPYING. If not, see
## <http://www.gnu.org/licenses/>.
## -*- texinfo -*-
## @deftypefn {Function File} {} newplot ()
## @deftypefnx {Function File} {} newplot (@var{hfig})
## @deftypefnx {Function File} {} newplot (@var{hax})
## @deftypefnx {Function File} {@var{hax} =} newplot (@dots{})
## Prepare graphics engine to produce a new plot.
##
## This function is called at the beginning of all high-level plotting
## functions. It is not normally required in user programs. @code{newplot}
## queries the @qcode{"NextPlot"} field of the current figure and axis to
## determine what to do.
##
## @multitable @columnfractions .25 .75
## @headitem Figure NextPlot @tab Action
## @item @qcode{"new"} @tab Create a new figure and make it the current figure.
##
## @item @qcode{"add"} (default) @tab Add new graphic objects to the current figure.
##
## @item @qcode{"replacechildren"} @tab Delete child objects whose HandleVisibility is
## set to @qcode{"on"}. Set NextPlot property to @qcode{"add"}. This
## typically clears a figure, but leaves in place hidden objects such as
## menubars. This is equivalent to @code{clf}.
##
## @item @qcode{"replace"} @tab Delete all child objects of the figure and
## reset all figure properties to their defaults. However, the following
## four properties are not reset: Position, Units, PaperPosition, PaperUnits.
## This is equivalent to @code{clf reset}.
## @end multitable
##
## @multitable @columnfractions .25 .75
## @headitem Axis NextPlot @tab Action
## @item @qcode{"add"} @tab Add new graphic objects to the current axes. This is
## equivalent to @code{hold on}.
##
## @item @qcode{"replacechildren"} @tab Delete child objects whose HandleVisibility is
## set to @qcode{"on"}, but leave axis properties unmodified. This typically
## clears a plot, but preserves special settings such as log scaling for
## axes. This is equivalent to @code{cla}.
##
## @item @qcode{"replace"} (default) @tab Delete all child objects of the
## axis and reset all axis properties to their defaults. However, the
## following properties are not reset: Position, Units. This is equivalent
## to @code{cla reset}.
## @end multitable
##
## If the optional input @var{hfig} or @var{hax} is given then prepare the
## specified figure or axes rather than the current figure and axes.
##
## The optional return value @var{hax} is a graphics handle to the created
## axes object (not figure).
##
## @strong{Caution:} Calling @code{newplot} may change the current figure and
## current axis.
## @end deftypefn
## FIXME: The Matlab function takes an optional list of file handles, hsave,
## which are not deleted when the figure and axes are prepared.
## I'm sure there is a good reason for that, but coding such
## compatibility is really tricky and doesn't serve much purpose since
## newplot is nearly exclusively used by Octave's internal plotting
## functions. In Octave's case the argument is almost always null,
## or occasionally the axis handle to plot into.
function hax = newplot (hsave = [])
if (nargin > 1)
print_usage ();
endif
cf = [];
ca = [];
if (! isempty (hsave))
## Find the first valid axes
ca = ancestor (hsave, "axes", "toplevel");
if (iscell (ca))
ca = [ca{:}];
endif
ca = ca(find (ca, 1));
hsave(hsave == ca) = [];
## Next, find the figure associated with any axis found
if (! isempty (ca))
cf = ancestor (ca, "figure", "toplevel");
else
cf = ancestor (hsave, "figure", "toplevel");
if (iscell (cf))
cf = [cf{:}];
endif
cf = cf(find (cf, 1));
endif
endif
if (isempty (cf))
## get current figure, or create a new one if necessary
cf = gcf ();
else
## switch to figure provided without causing other updates
set (0, "currentfigure", cf);
endif
fnp = get (cf, "nextplot");
switch (fnp)
case "add"
## Default case. Doesn't require action.
case "new"
## Ordinarily, create a new figure to hold plot.
## But, if user has requested preparing a specific axis, then
## use the existing figure to hold the requested axis.
if (isempty (ca))
cf = figure ();
endif
case "replacechildren"
kids = get (cf, "children");
if (! isempty (ca))
kids(kids == ca) = [];
endif
delete (kids);
case "replace"
kids = allchild (cf);
if (! isempty (ca))
kids(kids == ca) = [];
endif
delete (kids);
reset (cf);
endswitch
set (cf, "nextplot", "add"); # Matlab compatibility
if (isempty (ca))
ca = gca ();
deleteall = true;
else
set (cf, "currentaxes", ca);
deleteall = false;
endif
## FIXME: Is this necessary anymore?
## It seems like a kluge that belongs somewhere else.
if (strcmp (get (ca, "__hold_all__"), "off"))
__next_line_color__ (true);
__next_line_style__ (true);
else
__next_line_color__ (false);
__next_line_style__ (false);
endif
anp = get (ca, "nextplot");
switch (anp)
case "add"
## Default case. Doesn't require action.
case "replacechildren"
if (! deleteall && ca != hsave)
## preserve hsave and its parents, uncles, ...
kids = allchild (ca);
hkid = hsave;
while (! any (hkid == kids))
hkid = get (hkid, "parent");
endwhile
kids(kids == hkid) = [];
delete (kids);
else
delete (get (ca, "children"));
endif
case "replace"
if (! deleteall && ca != hsave)
## preserve hsave and its parents, uncles, ...
kids = allchild (ca);
hkid = hsave;
while (! any (hkid == kids))
hkid = get (hkid, "parent");
endwhile
kids(kids == hkid) = [];
delete (kids);
else
__go_axes_init__ (ca, "replace");
__request_drawnow__ ();
endif
## FIXME: The code above should perform the following:
###########################
## delete (allchild (ca));
## reset (ca);
###########################
## Actually, __go_axes_init__ does both less and more.
## It doesn't really remove all children since it re-instantiates
## xlabel, ylabel, zlabel, and title text objects.
## Also it preserves font properties like fontsize.
## For the time being, in order to have axis labels and title work,
## the above code is is required.
endswitch
if (nargout > 0)
hax = ca;
endif
endfunction
%!test
%! hf = figure ("visible", "off");
%! unwind_protect
%! p = plot ([0, 1]);
%! hax = newplot ();
%! assert (hax, gca);
%! assert (isempty (get (gca, "children")));
%! unwind_protect_cleanup
%! close (hf);
%! end_unwind_protect
%!test
%! hf = figure ("visible", "off");
%! unwind_protect
%! hax = axes ();
%! hold on;
%! hg1 = hggroup ();
%! hg2 = hggroup ("parent", hg1);
%! li0 = line (1:10, 1:10);
%! li1 = line (1:10, -1:-1:-10, "parent", hg1);
%! li2 = line (1:10, sin (1:10), "parent", hg2);
%! hold off;
%! newplot (hg2);
%! assert (ishandle (li0), false);
%! assert (get (hax, "children"), hg1);
%!
%! ## kids are preserved for hggroups
%! kids = get (hg1, "children");
%! newplot (hg1);
%! assert (get (hg1, "children"), kids);
%!
%! ## preserve objects
%! newplot (li1);
%! assert (ishandle (li1));
%!
%! ## kids are deleted for axes
%! newplot (hax);
%! assert (isempty (get (hax, "children")));
%! unwind_protect_cleanup
%! close (hf);
%! end_unwind_protect
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