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https://github.com/ZoneMinder/zoneminder.git
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60db1c2eaf
The class is not only used to represent coordinates but also lengths in XY. Vector2 is a more fitting/general name for this purpose.
111 lines
3.5 KiB
C++
111 lines
3.5 KiB
C++
//
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// ZoneMinder Polygon Class Implementation, $Date$, $Revision$
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// Copyright (C) 2001-2008 Philip Coombes
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//
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// This program is free software; you can redistribute it and/or
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// modify it under the terms of the GNU General Public License
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// as published by the Free Software Foundation; either version 2
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// of the License, or (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
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// along with this program; if not, write to the Free Software
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// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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//
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#include "zm_poly.h"
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#include <cmath>
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void Polygon::calcArea() {
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double float_area = 0.0L;
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for (int i = 0, j = n_coords - 1; i < n_coords; j = i++) {
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double trap_area = ((coords[i].X() - coords[j].X()) * ((coords[i].Y() + coords[j].Y()))) / 2.0L;
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float_area += trap_area;
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//printf( "%.2f (%.2f)\n", float_area, trap_area );
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}
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area = (int) round(fabs(float_area));
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}
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void Polygon::calcCentre() {
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if (!area && n_coords)
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calcArea();
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double float_x = 0.0L, float_y = 0.0L;
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for (int i = 0, j = n_coords - 1; i < n_coords; j = i++) {
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float_x += ((coords[i].Y() - coords[j].Y())
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* ((coords[i].X() * 2) + (coords[i].X() * coords[j].X()) + (coords[j].X() * 2)));
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float_y += ((coords[j].X() - coords[i].X())
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* ((coords[i].Y() * 2) + (coords[i].Y() * coords[j].Y()) + (coords[j].Y() * 2)));
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}
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float_x /= (6 * area);
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float_y /= (6 * area);
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centre = Vector2((int) round(float_x), (int) round(float_y));
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}
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Polygon::Polygon(int p_n_coords, const Vector2 *p_coords) : n_coords(p_n_coords) {
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coords = new Vector2[n_coords];
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int min_x = -1;
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int max_x = -1;
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int min_y = -1;
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int max_y = -1;
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for (int i = 0; i < n_coords; i++) {
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coords[i] = p_coords[i];
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if (min_x == -1 || coords[i].X() < min_x)
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min_x = coords[i].X();
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if (max_x == -1 || coords[i].X() > max_x)
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max_x = coords[i].X();
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if (min_y == -1 || coords[i].Y() < min_y)
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min_y = coords[i].Y();
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if (max_y == -1 || coords[i].Y() > max_y)
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max_y = coords[i].Y();
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}
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extent = Box(min_x, min_y, max_x, max_y);
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calcArea();
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calcCentre();
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}
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Polygon::Polygon(const Polygon &p_polygon) :
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n_coords(p_polygon.n_coords),
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extent(p_polygon.extent),
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area(p_polygon.area),
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centre(p_polygon.centre) {
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coords = new Vector2[n_coords];
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for (int i = 0; i < n_coords; i++) {
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coords[i] = p_polygon.coords[i];
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}
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}
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Polygon &Polygon::operator=(const Polygon &p_polygon) {
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n_coords = p_polygon.n_coords;
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Vector2 *new_coords = new Vector2[n_coords];
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for (int i = 0; i < n_coords; i++) {
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new_coords[i] = p_polygon.coords[i];
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}
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delete[] coords;
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coords = new_coords;
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extent = p_polygon.extent;
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area = p_polygon.area;
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centre = p_polygon.centre;
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return *this;
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}
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bool Polygon::isInside(const Vector2 &coord) const {
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bool inside = false;
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for ( int i = 0, j = n_coords-1; i < n_coords; j = i++ ) {
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if ( (((coords[i].Y() <= coord.Y()) && (coord.Y() < coords[j].Y()) )
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|| ((coords[j].Y() <= coord.Y()) && (coord.Y() < coords[i].Y())))
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&& (coord.X() < (coords[j].X() - coords[i].X()) * (coord.Y() - coords[i].Y()) / (coords[j].Y() - coords[i].Y()) + coords[i].X()))
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{
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inside = !inside;
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}
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}
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return inside;
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}
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