Определение принадлежности точки многоугольнику

wwsplit_polygon.zip   

 inpoly.zip

Совершенно ничего интересного. Нарыл в инете метод, разработанный для серверов, определяющих попадание мышки в географическую карту. Вызвал - он заработал.

reloadView

-(void) reloadView:(CGPoint )theTouchPoint
{
 unsigned int theGernamyPlat[18][2] = {
  {600, 175},
  {625, 175},
  {670, 200},
  {705, 180},
  {730, 205},
  {755, 300},
  {750, 320},
  {685, 350},
  {735, 400},
  {715, 450},
  {640, 465},
  {565, 460},
  {585, 405},
  {540, 385},
  {530, 320},
  {535, 290},
  {565, 225},
  {610, 215}
 };
 int bInner; bInner = inPolygon(theGernamyPlat, 18, theTouchPoint.x, theTouchPoint.y);
 
 UIImage *imageCombine = nil;
 if(bInner == 1){
  UIImage *imageMask = [UIImage imageNamed:@"Europe_Germany_mask.png"];
  UIImage *imageFull = [UIImage imageNamed:@"Europe_Full.png"];
  UIImage *imageGermany = [self maskImage:imageFull withMask:imageMask];
  UIImage *imageGray = [UIImage imageNamed:@"Europe_Gray.png"]; 
  imageCombine = [self concatImage: imageGray withMask:imageGermany]; 
 }
 else imageCombine = [UIImage imageNamed:@"Europe_Gray.png"];  
 
 
 if(imageView != nil){
  [imageView removeFromSuperview];
  [imageView release];
 }
 imageView = [[UIImageView alloc] initWithImage:imageCombine];
 [scrollView addSubview:imageView];
}

INPOLY.C

/***************************************************************************
 *                                                                         *
 *   INPOLY.C                                                              *
 *                                                                         *
 *   Copyright (c) 1995-1996 Galacticomm, Inc.  Freeware source code.      *
 *                                                                         *
 *   Please feel free to use this source code for any purpose, commercial  *
 *   or otherwise, as long as you don't restrict anyone else's use of      *
 *   this source code.  Please give credit where credit is due.            *
 *                                                                         *
 *   Point-in-polygon algorithm, created especially for World-Wide Web     *
 *   servers to process image maps with mouse-clickable regions.           *
 *                                                                         *
 *   http://www.visibone.com/inpoly/inpoly.c                               *
 *                                                                         *
 *                                       6/19/95 - Bob Stein & Craig Yap   *
 *                                       stein@visibone.com                *
 *                                       craig@cse.fau.edu                 *
 *                                                                         *
 ***************************************************************************/
 
int                                /*   1=inside, 0=outside                */
inpoly(                            /* is target point inside a 2D polygon? */
unsigned int poly[][2],            /*   polygon points, [0]=x, [1]=y       */
int npoints,                       /*   number of points in polygon        */
unsigned int xt,                   /*   x (horizontal) of target point     */
unsigned int yt)                   /*   y (vertical) of target point       */
{
     unsigned int xnew,ynew;
     unsigned int xold,yold;
     unsigned int x1,y1;
     unsigned int x2,y2;
     int i;
     int inside=0;
 
     if (npoints < 3) {
          return(0);
     }
     xold=poly[npoints-1][0];
     yold=poly[npoints-1][1];
     for (i=0 ; i < npoints ; i++) {
          xnew=poly[i][0];
          ynew=poly[i][1];
          if (xnew > xold) {
               x1=xold;
               x2=xnew;
               y1=yold;
               y2=ynew;
          }
          else {
               x1=xnew;
               x2=xold;
               y1=ynew;
               y2=yold;
          }
          if ((xnew < xt) == (xt <= xold)         /* edge "open" at left end */
           && ((long)yt-(long)y1)*(long)(x2-x1)
            < ((long)y2-(long)y1)*(long)(xt-x1)) {
               inside=!inside;
          }
          xold=xnew;
          yold=ynew;
     }
     return(inside);
}