2 Copyright (C) 2011-2013 Paul Davis
3 Author: Carl Hetherington <cth@carlh.net>
5 This program is free software; you can redistribute it and/or modify
6 it under the terms of the GNU General Public License as published by
7 the Free Software Foundation; either version 2 of the License, or
8 (at your option) any later version.
10 This program is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 GNU General Public License for more details.
15 You should have received a copy of the GNU General Public License
16 along with this program; if not, write to the Free Software
17 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
20 #include "canvas/poly_line.h"
22 using namespace ArdourCanvas;
24 PolyLine::PolyLine (Group* parent)
32 PolyLine::render (Rect const & area, Cairo::RefPtr<Cairo::Context> context) const
35 setup_outline_context (context);
36 render_path (area, context);
42 PolyLine::covers (Duple const & point) const
44 Duple p = canvas_to_item (point);
46 const Points::size_type npoints = _points.size();
55 /* repeat for each line segment */
57 for (i = 1, j = 0; i < npoints; ++i, ++j) {
59 /* compute area of triangle computed by the two line points and the one
60 we are being asked about. If zero (within a given tolerance), the
61 points are co-linear and the argument is on the line.
64 double area = fabs (_points[j].x * (_points[j].y - p.y)) +
65 (_points[i].x * (p.y - _points[j].y)) +
66 (p.x * (_points[j].y - _points[i].y));