loops.cc

来自「手写识别是模式识别中研究得一个热点」· CC 代码 · 共 176 行

#include <SLList.h>
#include "HWRawDataC.hh"

#define MYDEBUG 0

#define MIN(A,B) (A<B?A:B)
#define MAX(A,B) (A>B?A:B)

float max4(float A, float B, float C, float D);
float min4(float A, float B, float C, float D);

// Returns 1 if line P1-P2 crosses point P3-P4. 
int DoCross(HWDataPointC P1, HWDataPointC P2, HWDataPointC P3, 
	    HWDataPointC P4);

int main(void)
{
  HWHeaderC Header;
  cin >> Header;
  cout << Header;

  SLList<HWDataPointC> Points;
  int PenUp = 1;
  while (1)
    {
      HWRawDataC ThisRecord;
      cin >> ThisRecord;
      if (!cin) break;
      cout << ThisRecord;
//      cerr << "Working on record: " << ThisRecord;
//      cerr << "List length = " << Points.length() << "\n";
      if (ThisRecord.Type == 1 || ThisRecord.Type == 2)
	{			// keep track if pen is up or down.
	  PenUp = ThisRecord.Type-1;
	} 
      if (PenUp) Points.clear();
      if (ThisRecord.Type == 0 && Points.length() > 3)
	{
	  for (Pix FirstPoint = Points.first(); ; Points.next(FirstPoint))
	    {
	      Pix SecPoint = FirstPoint;
	      Points.next(SecPoint);
	      Pix ThirdPoint = SecPoint;
	      Points.next(ThirdPoint);
	      if (ThirdPoint == 0) break;
	      if (DoCross(Points(FirstPoint), Points(SecPoint), 
			  Points.rear(), ThisRecord.DataPoint))
		{
		  cout << "6 0\n";
		  cerr << "Cross at: " << Points(FirstPoint) << " - " 
		    << Points(SecPoint) << " crosses " << Points.rear()
		      << " - " << ThisRecord.DataPoint << ".\n";
		}
	    }
	}
      if (ThisRecord.Type == 0) Points.append(ThisRecord.DataPoint);
    }

  return 0;
}


int DoCross(HWDataPointC P1, HWDataPointC P2, HWDataPointC P3, HWDataPointC P4)
{
  if (MYDEBUG)
    cerr << "Finding cross on " << P1 << "-" << P2 << " and " << P3 << "-" << P4 << ".\n";

    if (P1 == P2 || P3 == P4)
      {
	if (MYDEBUG)
	  cerr << "Ignoring line with no length.\n";
	return 0;
      }

  if (P1.XPos == P2.XPos && P3.YPos == P4.YPos)
    {
      if (MYDEBUG)
	cerr << "Doing special case cross.  P1/P2 is horizontal.\n";
      if (MIN(P3.XPos, P4.XPos) <= P1.XPos && P1.XPos <= MAX(P3.XPos, P4.XPos) &&
	  MIN(P1.YPos, P2.YPos) <= P3.YPos && P3.YPos <= MAX(P1.YPos, P2.YPos))
	return 1;
      else return 0;
    }

  if (P1.YPos == P2.YPos && P3.XPos == P4.XPos)
    {
      if (MYDEBUG)
	cerr << "Doing special case cross.  P1/P2 is vertical.\n";
      if (MIN(P1.XPos, P2.XPos) <= P3.XPos && P3.XPos <= MAX(P1.XPos, P2.XPos) &&
	  MIN(P3.YPos, P4.YPos) <= P1.YPos && P1.YPos <= MAX(P3.YPos, P4.YPos))
	return 1;
      else return 0;
    }
  
  float m1 = (float)(P2.YPos - P1.YPos) / (P2.XPos - P1.XPos);
  float m2 = (float)(P4.YPos - P3.YPos) / (P4.XPos - P3.XPos);

  float b1 = P1.YPos - m1*P1.XPos;
  float b2 = P3.YPos - m2*P3.XPos;
  
  float X,Y;
  if (P3.XPos == P4.XPos)
    {
      Y = m1*P3.XPos + b1;
      X = P3.XPos;
    }
  else if (P1.XPos == P2.XPos)
    {
      Y = m1*P1.XPos + b1;
      X = P1.XPos;
    }
  else if (P1.YPos == P2.YPos)
    {
      X = (P1.YPos-b2)/m2;
      Y = P1.YPos;
    }
  else if (P3.YPos == P4.YPos)
    {
      X = (P3.YPos-b1)/m1;
      Y = P3.YPos;
    }
  else 
    {
      Y = (b1-m1*b2/m2)/(1-m1/m2);
      X = (Y-b1)/m1;
    }
  
  if (MYDEBUG)
    {
      cerr << "Calculating intercept of " << P1 << "-" << P2 << " and " << P3 
	<< "-" << P4 << "\n";
      cerr << "m1 = " << m1 << ", m2 = " << m2 << ", b1 = " << b1 << ", b2 = "
	<< b2 << "\n";
      cerr << "intersect at " << X << ", " << Y << ".\n";
      
      cerr << "Output: " << 
	(MIN(P1.XPos, P2.XPos) <= X) <<
	(X <= MAX(P1.XPos, P2.XPos)) <<
	(MIN(P1.YPos, P2.YPos) <= Y) <<
	(Y <= MAX(P1.YPos, P2.YPos)) <<
	(MIN(P3.XPos, P4.XPos) <= X) <<
	(X <= MAX(P3.XPos, P4.XPos)) <<
	(MIN(P3.YPos, P4.YPos) <= Y) <<
	(Y <= MAX(P3.YPos, P4.YPos)) << "\n";
    }

  return 
    MIN(P1.XPos, P2.XPos) <= X &&
    X <= MAX(P1.XPos, P2.XPos) &&
    MIN(P1.YPos, P2.YPos) <= Y &&
    Y <= MAX(P1.YPos, P2.YPos) &&
    MIN(P3.XPos, P4.XPos) <= X &&
    X <= MAX(P3.XPos, P4.XPos) &&
    MIN(P3.YPos, P4.YPos) <= Y &&
    Y <= MAX(P3.YPos, P4.YPos);
    
}


float min4(float A, float B, float C, float D)
{
  float T1 = A<B?A:B;
  float T2 = T1<C?T1:C;
  float T3 = T2<D?T2:D;
  return T3;
}


float max4(float A, float B, float C, float D)
{
  float T1 = A>B?A:B;
  float T2 = T1>C?T1:C;
  float T3 = T2>D?T2:D;
  return T3;
}