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6473cc7cb4
Default implementation for Item still uses bounding box, but specializations for Arc (Circle), Polygon, Line and PolyLine have been added
73 lines
1.8 KiB
C++
73 lines
1.8 KiB
C++
/*
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Copyright (C) 2011-2013 Paul Davis
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Author: Carl Hetherington <cth@carlh.net>
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This program is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program; if not, write to the Free Software
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Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#include "canvas/poly_line.h"
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using namespace ArdourCanvas;
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PolyLine::PolyLine (Group* parent)
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: Item (parent)
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, PolyItem (parent)
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{
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}
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void
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PolyLine::render (Rect const & area, Cairo::RefPtr<Cairo::Context> context) const
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{
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if (_outline) {
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setup_outline_context (context);
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render_path (area, context);
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context->stroke ();
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}
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}
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bool
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PolyLine::covers (Duple const & point) const
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{
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Duple p = canvas_to_item (point);
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const Points::size_type npoints = _points.size();
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if (npoints < 2) {
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return false;
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}
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Points::size_type i;
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Points::size_type j;
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/* repeat for each line segment */
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for (i = 1, j = 0; i < npoints; ++i, ++j) {
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/* compute area of triangle computed by the two line points and the one
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we are being asked about. If zero (within a given tolerance), the
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points are co-linear and the argument is on the line.
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*/
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double area = fabs (_points[j].x * (_points[j].y - p.y)) +
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(_points[i].x * (p.y - _points[j].y)) +
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(p.x * (_points[j].y - _points[i].y));
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if (area < 0.001) {
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return true;
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}
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}
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return false;
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}
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