Paul Davis
a1f69ee63b
Cairo uses 0 degrees to mean "east", so the "top" or "north" of a circle is actually -90 degrees
174 lines
3.4 KiB
C++
174 lines
3.4 KiB
C++
/*
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* Copyright (C) 2013-2015 Paul Davis <paul@linuxaudiosystems.com>
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* Copyright (C) 2015-2017 Robin Gareus <robin@gareus.org>
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*
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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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*
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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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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*/
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#include <cmath>
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#include <algorithm>
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#include <cairomm/context.h>
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#include "pbd/compose.h"
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#include "canvas/circle.h"
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#include "canvas/types.h"
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#include "canvas/debug.h"
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#include "canvas/canvas.h"
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using namespace std;
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using namespace ArdourCanvas;
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Arc::Arc (Canvas* c)
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: Item (c)
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, _radius (0.0)
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, _arc_degrees (0.0)
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, _start_degrees (0.0)
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{
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}
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Arc::Arc (Item* parent)
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: Item (parent)
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, _radius (0.0)
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, _arc_degrees (0.0)
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, _start_degrees (0.0)
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{
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}
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void
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Arc::compute_bounding_box () const
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{
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Rect bbox;
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/* this could be smaller in the case of small _arc values
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but I can't be bothered to optimize it.
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*/
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bbox.x0 = _center.x - _radius;
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bbox.y0 = _center.y - _radius;
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bbox.x1 = _center.x + _radius;
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bbox.y1 = _center.y + _radius;
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bbox = bbox.expand (0.5 + (_outline_width / 2));
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_bounding_box = bbox;
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set_bbox_clean ();
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}
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void
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Arc::render (Rect const & area, Cairo::RefPtr<Cairo::Context> context) const
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{
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if (_radius <= 0.0 || (!fill() && !outline())) {
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return;
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}
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Duple c = item_to_window (Duple (_center.x, _center.y));
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if (_arc_degrees != _start_degrees) {
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context->arc (c.x, c.y, _radius, _start_degrees * (M_PI/180.0), _arc_degrees * (M_PI/180.0));
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if (fill()) {
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setup_fill_context (context);
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if (outline()) {
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context->fill_preserve ();
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} else {
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context->fill ();
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}
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}
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if (outline()) {
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setup_outline_context (context);
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context->stroke ();
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}
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}
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render_children (area, context);
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}
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void
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Arc::set_center (Duple const & c)
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{
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begin_change ();
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_center = c;
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set_bbox_dirty ();
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end_change ();
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}
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void
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Arc::set_radius (Coord r)
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{
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begin_change ();
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_radius = r;
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set_bbox_dirty ();
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end_change ();
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}
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void
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Arc::set_arc (double deg)
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{
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begin_change ();
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_arc_degrees = deg;
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set_bbox_dirty ();
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end_change ();
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}
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void
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Arc::set_start (double deg)
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{
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begin_change ();
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_start_degrees = deg;
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set_bbox_dirty ();
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end_change ();
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}
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bool
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Arc::covers (Duple const & point) const
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{
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Duple p = window_to_item (point);
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double angle_degs = atan (p.y/p.x) * 2.0 * M_PI;
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double radius = sqrt (p.x * p.x + p.y * p.y);
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return (angle_degs >= _start_degrees) &&
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(angle_degs <= (_start_degrees + _arc_degrees)) &&
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(radius < _radius);
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}
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void
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Arc::_size_allocate (Rect const & r)
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{
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Item::_size_allocate (r);
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/* This is an arc - some section of a circle, so any difference between
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* height and width cannot change what is drawn. Pick width arbitrarily
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* as the "key" dimension
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*/
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_radius = min (r.width(),r.height()) / 2.0;
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_center = Duple ((r.width()/2.), (r.height() /2.));
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set_bbox_dirty ();
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}
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