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livetrax/libs/canvas/polygon.cc

152 lines
3.3 KiB
C++

/*
* Copyright (C) 2012 Carl Hetherington <carl@carlh.net>
* Copyright (C) 2013-2015 Paul Davis <paul@linuxaudiosystems.com>
*
* 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.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#include "canvas/polygon.h"
using namespace ArdourCanvas;
Polygon::Polygon (Canvas* c)
: PolyItem (c)
, multiple (0)
, constant (0)
, cached_size (0)
{
}
Polygon::Polygon (Item* parent)
: PolyItem (parent)
, multiple (0)
, constant (0)
, cached_size (0)
{
}
Polygon::~Polygon ()
{
delete [] multiple;
delete [] constant;
}
void
Polygon::render (Rect const & area, Cairo::RefPtr<Cairo::Context> context) const
{
Points::size_type npoints = _points.size();
if (npoints < 2) {
return;
}
if (_outline || _fill) {
const double pixel_adjust = (_outline_width == 1.0 ? 0.5 : 0.0);
for (Points::size_type i = 0; i < npoints; i++) {
Duple c = item_to_window (Duple (_points[i].x, _points[i].y));
if (i == 0) {
context->move_to (c.x + pixel_adjust, c.y + pixel_adjust);
} else {
context->line_to (c.x + pixel_adjust, c.y + pixel_adjust);
}
}
context->close_path ();
}
if (_outline) {
setup_outline_context (context);
if (_fill) {
context->stroke_preserve ();
} else {
context->stroke ();
}
}
if (_fill) {
setup_fill_context (context);
context->fill ();
}
}
void
Polygon::cache_shape_computation () const
{
Points::size_type npoints = _points.size();
if (npoints == 0) {
return;
}
Points::size_type i;
Points::size_type j = npoints -1;
if (cached_size < npoints) {
cached_size = npoints;
delete [] multiple;
multiple = new float[cached_size];
delete [] constant;
constant = new float[cached_size];
}
for (i = 0; i < npoints; i++) {
if (_points[j].y == _points[i].y) {
constant[i] = _points[i].x;
multiple[i] = 0;
} else {
constant[i] = _points[i].x-(_points[i].y*_points[j].x)/(_points[j].y-_points[i].y)+(_points[i].y*_points[i].x)/(_points[j].y-_points[i].y);
multiple[i] = (_points[j].x-_points[i].x)/(_points[j].y-_points[i].y);
}
j = i;
}
}
bool
Polygon::covers (Duple const & point) const
{
Duple p = window_to_item (point);
Points::size_type npoints = _points.size();
if (npoints == 0) {
return false;
}
Points::size_type i;
Points::size_type j = npoints -1;
bool oddNodes = false;
if (bbox_dirty()) {
(void) bounding_box ();
}
for (i = 0; i < npoints; i++) {
if (((_points[i].y < p.y && _points[j].y >= p.y) || (_points[j].y < p.y && _points[i].y >= p.y))) {
oddNodes ^= (p.y * multiple[i] + constant[i] < p.x);
}
j = i;
}
return oddNodes;
}
void
Polygon::compute_bounding_box () const
{
PolyItem::compute_bounding_box ();
cache_shape_computation ();
}