Description
    Everything in this module is exported by default. This module is not
    intended to be used directly, but is required by each module in the
    CAD::Drawing tree.

AUTHOR
      Eric L. Wilhelm
      ewilhelm at sbcglobal dot net
      http://pages.sbcglobal.net/mycroft

COPYRIGHT
    This module is copyright (C) 2003 by Eric L. Wilhelm and A. Zahner Co.

LICENSE
    This module is distributed under the same terms as Perl. See the Perl
    source package for details.

    You may use this software under one of the following licenses:

      (1) GNU General Public License
        (found at http://www.gnu.org/copyleft/gpl.html)
      (2) Artistic License
        (found at http://www.perl.com/pub/language/misc/Artistic.html)

NO WARRANTY
    This software is distributed with ABSOLUTELY NO WARRANTY. The author and
    his employer will in no way be held liable for any loss or damages
    resulting from its use.

Modifications
    The source code of this module is made freely available and
    distributable under the GPL or Artistic License. Modifications to and
    use of this software must adhere to one of these licenses. Changes to
    the code should be noted as such and this notification (as well as the
    above copyright information) must remain intact on all copies of the
    code.

    Additionally, while the author is actively developing this code,
    notification of any intended changes or extensions would be most helpful
    in avoiding repeated work for all parties involved. Please contact the
    author with any such development plans.

Changes
      0.60 First public release
      0.61 Minor improvements

Useful Functions
    These were functions that didn't seem appropriate as object-oriented but
    were needed in multiple places. They are exported by default (as is
    nearly everything in this package.

  check_select

    Provides a uniform interface to selection processing.

    NOTE: this is not an object method and is exported by default!

    Direct calling should be for internal use only, but you may have been
    sent to this documentation by one of the modules which uses this
    function to process %option arguments.

    %opts hash may contain (alias)

      Inclusive lists:
      "select layers"      (sl)
      "select colors"      (sc)
      "select types"       (st)
      "select linetypes"   (slt)

      Exclusive lists:
      "not layers"         (nl)
      "not colors"         (nc)
      "not types"          (nt)
      "not linetypes"      (nlt)

    The values must be list references.

    The space-separated terms in the keys above may now be underscore ("_")
    separated as well (this saves having to double-quote the item when using
    it as a hash key in the %options argument.)

    If an option is omitted, all of that category are selected.

      ($s, $n) = check_select(\%selection_options);

    $s will be a hash reference to inclusive items $n will be a hash
    reference to excluded items

    Keys in the returned hash references are according to the above-listed
    alias conventions ($s->{l} contains a set of true values for selected
    layers (where the layer name is a string acting as the hash key.))

    Note that the \%selection_options hash reference is a required argument
    (at this level.) Any functions which make it optional must declare a
    hash before passing to this.

  checkarcangs

    Performs in-place modification of arc angles in \@angs.

    NOTE: this is not an object method and is exported by default!

    Internal use only.

      checkarcangs(\@angs);

  color_translate

    Translates a list of colors into numbers. Numbers will be passed through
    (as will unrecognized names!)

      @colors = color_translate(@colors);

Various definitions
  @aci2hex

    256 value array which contains #RRGGBB photo-style hex codes for each
    aci color

  @aci2rgb

    Generated from @aci2hex for use in postscript and other items. The idea
    here is that it is a fairly small set of values and may as well have
    been generated and placed in this file, rather than constantly
    loading-down the tight loop of saving values to postscript.

  regen_aci2rgb

    Fairly self-explanatory. Saved here only so I don't lose it.

