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livetrax/libs/canvas/arc.cc

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/*
Copyright (C) 2013 Paul Davis
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 <cmath>
#include <algorithm>
#include <cairomm/context.h>
#include "pbd/compose.h"
#include "canvas/circle.h"
#include "canvas/types.h"
#include "canvas/debug.h"
#include "canvas/utils.h"
#include "canvas/canvas.h"
using namespace std;
using namespace ArdourCanvas;
Arc::Arc (Group* parent)
: Item (parent)
, Outline (parent)
, Fill (parent)
, _radius (0.0)
, _arc_degrees (0.0)
, _start_degrees (0.0)
{
}
void
Arc::compute_bounding_box () const
{
Rect bbox;
/* this could be smaller in the case of small _arc values
but I can't be bothered to optimize it.
*/
bbox.x0 = _center.x - _radius;
bbox.y0 = _center.y - _radius;
bbox.x1 = _center.x + _radius;
bbox.y1 = _center.y + _radius;
bbox = bbox.expand (0.5 + (_outline_width / 2));
_bounding_box = bbox;
_bounding_box_dirty = false;
}
void
Arc::render (Rect const & /*area*/, Cairo::RefPtr<Cairo::Context> context) const
{
if (_radius <= 0.0 || _arc_degrees <= 0.0) {
return;
}
Duple c = item_to_window (Duple (_center.x, _center.y));
context->arc (c.x, c.y, _radius, _start_degrees * (M_PI/180.0), _arc_degrees * (M_PI/180.0));
setup_fill_context (context);
context->fill_preserve ();
setup_outline_context (context);
context->stroke ();
}
void
Arc::set_center (Duple const & c)
{
begin_change ();
_center = c;
_bounding_box_dirty = true;
end_change ();
}
void
Arc::set_radius (Coord r)
{
begin_change ();
_radius = r;
_bounding_box_dirty = true;
end_change ();
}
void
Arc::set_arc (double deg)
{
begin_change ();
_arc_degrees = deg;
_bounding_box_dirty = true;
end_change ();
}
void
Arc::set_start (double deg)
{
begin_change ();
_start_degrees = deg;
_bounding_box_dirty = true;
end_change ();
}
bool
Arc::covers (Duple const & point) const
{
Duple p = window_to_item (point);
double angle_degs = atan (p.y/p.x) * 2.0 * M_PI;
double radius = sqrt (p.x * p.x + p.y * p.y);
return (angle_degs >= _start_degrees) &&
(angle_degs <= (_start_degrees + _arc_degrees)) &&
(radius < _radius);
}