105 lines
2.3 KiB
C
105 lines
2.3 KiB
C
#include <stdio.h>
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#include <string.h>
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#include <math.h>
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#include "Polygon.h"
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/* considered to be protected */
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void Polygon_constructor (Polygon *this, const struct point *points, int npoints)
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{
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Figure_constructor ((Figure *) this);
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this->npoints = npoints;
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this->points = strdup (points, npoints * sizeof (struct point));
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}
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void Polygon_destructor (Polygon *this)
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{
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free (this->points);
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}
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void Polygon_copy (Polygon *dest, const Polygon *src)
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{
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dest->npoints = src->npoints;
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dest->points = strdup (src->points, src->npoints * sizeof (struct point));
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}
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/* private */
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static const char* __Polygon_type ()
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{
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return "Polygon";
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}
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static Polygon* __Polygon_clone (const Polygon *this)
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{
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Polygon *poly = malloc (sizeof (Polygon));
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memset (poly, 0, sizeof (
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Polygon_copy (poly, this);
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return poly;
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}
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static void __Polygon_destroy (Polygon *this)
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{
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Polygon_destructor (this);
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g_free (this);
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}
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static void __Polygon_draw (const Polygon *this)
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{
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int i = 0;
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for (i = 0; i < this->npoints; i++)
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{
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printf ("{%f;%f}, ", this->points[i].x, this->points[i].y);
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}
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printf ("{%f;%f}, ", this->points[0].x, this->points[0].y);
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}
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static double __Polygon_area (const Polygon *this)
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{
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double s = 0.0, x, y;
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int i = 0;
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for (i = 0; i < this->npoints; i++)
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{
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s += this->points[i].x * this->points[(i + 1) % this->npoints].y -
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this->points[(i + 1) % this->npoints].x * this->points[i].y;
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}
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return s * 0.5;
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// Trapezium rule for convex and non-convex polygons
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// S=abs(сумма{(x[i+1]-x[i])*(y[i+1]+y[i])/2})
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}
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static double __Polygon_max_diag (const Polygon *this)
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{
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double diag = 0.0,
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tmp = 0.0,
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tmp1 = 0.0,
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tmp2 = 0.0;
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int i = 0, j = 0;
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for (i = 0; i < this->npoints - 2; i++)
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{
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for (j = i + 2; j < this->npoints; j++)
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{
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tmp1 = (this->points[i].x - this->points[j].x);
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tmp2 = (this->points[i].y - this->points[j].y);
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tmp = sqrt (tmp1 * tmp1 + tmp2 * tmp2);
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if (diag < tmp)
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{
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diag = tmp;
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}
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}
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}
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return diag;
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}
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/* public */
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Polygon* Polygon_new (const struct point *points, int npoints)
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{
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Polygon *poly = g_new0 (Polygon, 1);
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Polygon_constructor (poly, points, npoints);
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return poly;
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}
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