110 lines
3.5 KiB
C++
110 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())*((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())*((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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//printf( "%.2f,%.2f\n", float_x, float_y );
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centre = Coord( (int)round(float_x), (int)round(float_y) );
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}
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Polygon::Polygon(int p_n_coords, const Coord *p_coords) : n_coords( p_n_coords ) {
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coords = new Coord[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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{
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coords = new Coord[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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if ( n_coords < p_polygon.n_coords ) {
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delete[] coords;
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coords = new Coord[p_polygon.n_coords];
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}
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n_coords = p_polygon.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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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 Coord &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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