contrib/brl/bseg/brip/brip_line_generator.cxx Source File

Go to the documentation of this file.
00001 #include "brip_line_generator.h"
00002 
00003 #include <vcl_iostream.h>
00004 #include <vcl_cmath.h>
00005 
00006 bool brip_line_generator::generate(bool& init, float xs, float ys,
00007                                    float xe, float ye,
00008                                    float& x, float& y)
00009 {
00010   static float dx, dy, mag, xinc, yinc;
00011   static int x1, y1;
00012   if (init)
00013   {
00014     dx = xe-xs;
00015     dy = ye-ys;
00016     mag = (float)vcl_sqrt(dx*dx + dy*dy);
00017     if (mag<1)//Can't reach the next pixel under any circumstances
00018       return false;
00019     xinc = dx/mag;
00020     yinc = dy/mag;
00021     x1 = int(xe);
00022     y1 = int(ye);
00023     x = xs;
00024     y = ys;
00025     init = false;
00026 //  done = false;
00027     return true;
00028   }
00029 
00030   //Previous pixel location
00031   int xp = int(x);
00032   int yp = int(y);
00033   //Increment along the line until the motion is greater than one pixel
00034   for (int i = 0; i<5; i++)
00035   {
00036     x += (float)0.5*xinc;
00037     y += (float)0.5*yinc;
00038     //Check to see if we have finished the span
00039     int xc = int(x), yc = int(y);
00040     bool passed_xe = ((xinc>=0)&&(xc>x1))||((xinc<0)&&(xc<x1));
00041     bool passed_ye = ((yinc>=0)&&(yc>y1))||((yinc<0)&&(yc<y1));
00042     if (passed_xe||passed_ye)
00043       return false;
00044     //Check if we have advanced by at least 1 pixel
00045     if (vcl_fabs(static_cast<float>(xc-xp))>=1||vcl_fabs(static_cast<float>(yc-yp))>=1)
00046       return true;
00047   }
00048   vcl_cout << "In brip_line_generator: - shouldn't happen - "
00049            << "xs="<<xs<<" ys="<<ys<<" xe="<<xe<<" ye="<< ye << vcl_endl;
00050   return false;
00051 }