# HG changeset patch
# User Markus Mützel <markus.muetzel@gmx.de>
# Date 1637849126 -3600
# Node ID 512f3d68bb49e7f9aebd96dc444667fd123107a0
# Parent  157180e55070ca42a48eafae4c6ad83abaf1d088
print: Use clearer error message on invalid input (bug #61557).

* scripts/plot/util/private/__print_parse_opts__.m: Use clearer error message
on invalid input.
* scripts/plot/util/print.m: Add BIST.

diff -r 157180e55070 -r 512f3d68bb49 scripts/plot/util/print.m
--- a/scripts/plot/util/print.m	Thu Nov 25 15:03:10 2021 +0100
+++ b/scripts/plot/util/print.m	Thu Nov 25 15:05:26 2021 +0100
@@ -808,6 +808,18 @@
 
 endfunction
 
+%!error <a graphics handle>
+%! hf = figure ("visible", "off");
+%! unwind_protect
+%!   x = 0:0.1:1;
+%!   y1 = x;
+%!   y2 = 2*x;
+%!   ax = plotyy (x, y1, x, y2);
+%!   saveas (ax, [tempname(), ".png"]);
+%! unwind_protect_cleanup
+%!   close (hf);
+%! end_unwind_protect
+
 function cmd = epstool (opts, filein, fileout)
   ## As epstool does not work with pipes, a subshell is used to
   ## permit piping.  Since this solution does not work with the DOS
diff -r 157180e55070 -r 512f3d68bb49 scripts/plot/util/private/__print_parse_opts__.m
--- a/scripts/plot/util/private/__print_parse_opts__.m	Thu Nov 25 15:03:10 2021 +0100
+++ b/scripts/plot/util/private/__print_parse_opts__.m	Thu Nov 25 15:05:26 2021 +0100
@@ -89,6 +89,9 @@
   endif
 
   for i = 1:numel (varargin)
+    if (! ischar (varargin{i}) && ! iscellstr (varargin{i}))
+      error ("print: input arguments must be a graphics handle or strings.");
+    endif
     arg = strtrim (varargin{i});
     if (ischar (arg))
       if (isempty (arg))