!This file is part of VEL_demo, copyright David Keyes, 2007. 
    !
    !This source file 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 code 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.
    !
    !For terms of the GNU General Public license see <http://www.gnu.org/licenses/>.

GLOBAL DRAWING MODULE dim_aline(
VECTOR p1 > "start pos";
VECTOR p2 > "end pos";
FLOAT offset:=10.0 > "offset";
INT arr_slash:=1 > "0=slash, 1=arrow";
VAR FLOAT d_inch;
VAR FLOAT ang);

FLOAT  pos, t_off, t_sizeA, t_sizeB, t_width, slash_len, dim_ext, dim_off; 
VECTOR rot_ang; 
INT scale, pen_col, i; 

BEGINMODULE

  part(#2,dim_vars(scale, pen_col, t_off, t_sizeA, t_sizeB, t_width, slash_len, dim_ext, dim_off));
  set(PEN=pen_col);
  part(#3, negpos(offset, i));

  lin_free(#12,p1, p2:BLANK=1);
  lin_offs(#13,#12, offset);
  lin_offs(#14,#12, dim_off * i:BLANK=1);
  lin_offs(#15,#13, dim_ext * i:BLANK=1);
  lin_free(#16,startp(#14), startp(#15));
  lin_free(#17,endp(#14), endp(#15));
  rot_ang:=vec(p2.x - p1.x, p2.y - p1.y);
  ang:=angle(rot_ang.x, rot_ang.y);
  csys_1p(#18,"a", startp(#13), 0.0, 0.0, ang:BLANK=1);
  csys_1p(#19,"b", endp(#13), 0.0, 0.0, ang - 180:BLANK=1);

  IF arr_slash = 0 THEN 
    part(#20,slash(slash_len),#18);
    part(#21,slash(slash_len),#19);
  ELSE 
    part(#22,arrow(slash_len*0.5),#18);
    part(#23,arrow(slash_len*0.5),#19);
  ENDIF;

  part(#25, get_len2D(p1, p2, d_inch));


ENDMODULE