lazarus/components/aggpas/src/agg_arrowhead.pas

//----------------------------------------------------------------------------
// Anti-Grain Geometry - Version 2.4 (Public License)
// Copyright (C) 2002-2005 Maxim Shemanarev (http://www.antigrain.com)
//
// Anti-Grain Geometry - Version 2.4 Release Milano 3 (AggPas 2.4 RM3)
// Pascal Port By: Milan Marusinec alias Milano
//                 milan@marusinec.sk
//                 http://www.aggpas.org
// Copyright (c) 2005-2006
//
// Permission to copy, use, modify, sell and distribute this software
// is granted provided this copyright notice appears in all copies.
// This software is provided "as is" without express or implied
// warranty, and with no claim as to its suitability for any purpose.
//
//----------------------------------------------------------------------------
// Contact: mcseem@antigrain.com
//          mcseemagg@yahoo.com
//          http://www.antigrain.com
//
//----------------------------------------------------------------------------
//
// Simple arrowhead/arrowtail generator 
//
// [Pascal Port History] -----------------------------------------------------
//
// 24.02.2006-Milano: Unit port establishment
//
{ agg_arrowhead.pas }
unit
 agg_arrowhead ;

INTERFACE

{$I agg_mode.inc }

uses
 agg_basics ,
 agg_vertex_source ;

{ TYPES DEFINITION }
type
 arrowhead = object(vertex_source )
   m_head_d1 ,
   m_head_d2 ,
   m_head_d3 ,
   m_head_d4 ,
   m_tail_d1 ,
   m_tail_d2 ,
   m_tail_d3 ,
   m_tail_d4 : double;

   m_head_flag ,
   m_tail_flag : boolean;

   m_coord : array[0..15 ] of double;
   m_cmd   : array[0..7 ] of unsigned;

   m_curr_id    ,
   m_curr_coord : unsigned;

   constructor Construct;

   procedure head_(d1 ,d2 ,d3 ,d4 : double );

   procedure head;
   procedure no_head;

   procedure tail_(d1 ,d2 ,d3 ,d4 : double );

   procedure tail;
   procedure no_tail;

   procedure rewind(path_id : unsigned ); virtual;
   function  vertex(x ,y : double_ptr ) : unsigned; virtual;

  end;

{ GLOBAL PROCEDURES }


IMPLEMENTATION
{ LOCAL VARIABLES & CONSTANTS }
{ UNIT IMPLEMENTATION }
{ CONSTRUCT }
constructor arrowhead.Construct;
begin
 m_head_d1:=1.0;
 m_head_d2:=1.0;
 m_head_d3:=1.0;
 m_head_d4:=0.0;
 m_tail_d1:=1.0;
 m_tail_d2:=1.0;
 m_tail_d3:=1.0;
 m_tail_d4:=0.0;

 m_head_flag:=false;
 m_tail_flag:=false;

 m_curr_id   :=0;
 m_curr_coord:=0;

end;

{ HEAD_ }
procedure arrowhead.head_;
begin
 m_head_d1:=d1;
 m_head_d2:=d2;
 m_head_d3:=d3;
 m_head_d4:=d4;

 m_head_flag:=true;

end;

{ HEAD }
procedure arrowhead.head;
begin
 m_head_flag:=true;

end;

{ NO_HEAD }
procedure arrowhead.no_head;
begin
 m_head_flag:=false;

end;

{ TAIL_ }
procedure arrowhead.tail_;
begin
 m_tail_d1:=d1;
 m_tail_d2:=d2;
 m_tail_d3:=d3;
 m_tail_d4:=d4;

 m_tail_flag:=true;

end;

{ TAIL }
procedure arrowhead.tail;
begin
 m_tail_flag:=true;

end;

{ NO_TAIL }
procedure arrowhead.no_tail;
begin
 m_tail_flag:=false;

end;

{ REWIND }
procedure arrowhead.rewind;
begin
 m_curr_id   :=path_id;
 m_curr_coord:=0;

 if path_id = 0 then
  begin
   if not m_tail_flag then
    begin
     m_cmd[0 ]:=path_cmd_stop;

     exit;

    end;

   m_coord[0  ]:=m_tail_d1;
   m_coord[1  ]:=0.0;
   m_coord[2  ]:=m_tail_d1 - m_tail_d4;
   m_coord[3  ]:=m_tail_d3;
   m_coord[4  ]:=-m_tail_d2 - m_tail_d4;
   m_coord[5  ]:=m_tail_d3;
   m_coord[6  ]:=-m_tail_d2;
   m_coord[7  ]:=0.0;
   m_coord[8  ]:=-m_tail_d2 - m_tail_d4;
   m_coord[9  ]:=-m_tail_d3;
   m_coord[10 ]:= m_tail_d1 - m_tail_d4;
   m_coord[11 ]:=-m_tail_d3;

   m_cmd[0 ]:=path_cmd_move_to;
   m_cmd[1 ]:=path_cmd_line_to;
   m_cmd[2 ]:=path_cmd_line_to;
   m_cmd[3 ]:=path_cmd_line_to;
   m_cmd[4 ]:=path_cmd_line_to;
   m_cmd[5 ]:=path_cmd_line_to;
   m_cmd[7 ]:=path_cmd_end_poly or path_flags_close or path_flags_ccw;
   m_cmd[6 ]:=path_cmd_stop;

   exit;

  end;

 if path_id = 1 then
  begin
   if not m_head_flag then
    begin
     m_cmd[0 ]:=path_cmd_stop;

     exit;

    end;

  m_coord[0 ]:=-m_head_d1;
  m_coord[1 ]:=0.0;
  m_coord[2 ]:=m_head_d2 + m_head_d4;
  m_coord[3 ]:=-m_head_d3;
  m_coord[4 ]:=m_head_d2;
  m_coord[5 ]:=0.0;
  m_coord[6 ]:=m_head_d2 + m_head_d4;
  m_coord[7 ]:=m_head_d3;

  m_cmd[0 ]:=path_cmd_move_to;
  m_cmd[1 ]:=path_cmd_line_to;
  m_cmd[2 ]:=path_cmd_line_to;
  m_cmd[3 ]:=path_cmd_line_to;
  m_cmd[4 ]:=path_cmd_end_poly or path_flags_close or path_flags_ccw;
  m_cmd[5 ]:=path_cmd_stop;

  exit;

 end;

end;

{ VERTEX }
function arrowhead.vertex;
var
 curr_idx : unsigned;

begin
 if m_curr_id < 2 then
  begin
   curr_idx:=m_curr_coord * 2;

   x^:=m_coord[curr_idx ];
   y^:=m_coord[curr_idx + 1 ];

   result:=m_cmd[m_curr_coord ];

   inc(m_curr_coord );

  end
 else
  result:=path_cmd_stop;

end;

END.