13
0
livetrax/libs/canvas/poly_line.cc
Paul Davis 590882f3c8 change Canvas heirarchy and constructors
Items no longer need a parent group (they require a Canvas pointer instead), so all constructors have been rationalized
and have two variants, one with a parent and one with a canvas.

All Items now inherit from Fill and Outline, to banish diagonal inheritance and virtual base classes and all that.

There were zero changes to the Ardour GUI arising from these changes.
2014-06-12 14:53:44 -04:00

106 lines
2.3 KiB
C++

/*
Copyright (C) 2011-2013 Paul Davis
Author: Carl Hetherington <cth@carlh.net>
This program 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 2 of the License, or
(at your option) any later version.
This program 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.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <algorithm>
#include "canvas/poly_line.h"
#include "canvas/canvas.h"
#include "canvas/utils.h"
using namespace ArdourCanvas;
PolyLine::PolyLine (Canvas* c)
: PolyItem (c)
, _threshold (1.0)
{
}
PolyLine::PolyLine (Group* g)
: PolyItem (g)
, _threshold (1.0)
{
}
void
PolyLine::render (Rect const & area, Cairo::RefPtr<Cairo::Context> context) const
{
if (_outline) {
setup_outline_context (context);
render_path (area, context);
context->stroke ();
}
}
bool
PolyLine::covers (Duple const & point) const
{
Duple p = window_to_item (point);
const Points::size_type npoints = _points.size();
if (npoints < 2) {
return false;
}
Points::size_type i;
Points::size_type j;
/* repeat for each line segment */
const Rect visible (window_to_item (_canvas->visible_area()));
for (i = 1, j = 0; i < npoints; ++i, ++j) {
Duple at;
double t;
Duple a (_points[j]);
Duple b (_points[i]);
/*
Clamp the line endpoints to the visible area of the canvas. If we do
not do this, we may have a line segment extending to COORD_MAX and our
math goes wrong.
*/
a.x = std::min (a.x, visible.x1);
a.y = std::min (a.y, visible.y1);
b.x = std::min (b.x, visible.x1);
b.y = std::min (b.y, visible.y1);
double d = distance_to_segment_squared (p, a, b, t, at);
if (t < 0.0 || t > 1.0) {
continue;
}
if (d < _threshold + _outline_width) {
return true;
}
}
return false;
}
void
PolyLine::set_covers_threshold (double t)
{
_threshold = t;
}