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# include "appUtilConfig.h"
# include <stdio.h>
# include <string.h>
# include <stdlib.h>
# include <stddef.h>
# include <ctype.h>
# include <limits.h>
# include <math.h>
# include "geo2DInteger.h"
# include <appDebugon.h>
/************************************************************************/
/* */
/* Intersect two line segments. Use the algorithm from: */
/* */
/* Subject 1.03 in http://www.faqs.org/faqs/graphics/algorithms-faq. */
/* */
/* Arguments: */
/* */
/************************************************************************/
int geo2DIIntersectSegments( Point2DI * p1,
Point2DI * p2,
double * pXab1,
double * pXab2,
double * pXcd1,
double * pXcd2,
const Point2DI * ab,
const Point2DI * cd )
{
double numXab;
double xab;
double numXcd;
double xcd;
double divxxx;
double Ax= ab[0].p2diX;
double Ay= ab[0].p2diY;
double Bx= ab[1].p2diX;
double By= ab[1].p2diY;
double Cx= cd[0].p2diX;
double Cy= cd[0].p2diY;
double Dx= cd[1].p2diX;
double Dy= cd[1].p2diY;
if ( Ax == Bx && Ay == By )
{ FFDEB(Ax,Bx); FFDEB(Ay,By); return 0; }
if ( Cx == Dx && Cy == Dy )
{ FFDEB(Cx,Dx); FFDEB(Cy,Dy); return 0; }
numXab= ( Ay- Cy )* ( Dx- Cx )- ( Ax- Cx )* ( Dy- Cy );
numXcd= ( Ay- Cy )* ( Bx- Ax )- ( Ax- Cx )* ( By- Ay );
divxxx= ( Bx- Ax )* ( Dy- Cy )- ( By- Ay )* ( Dx- Cx );
if ( divxxx == 0 )
{
if ( numXab == 0 )
{
double C_AB;
double D_AB;
double A_CD;
double B_CD;
/*FFDEB(divxxx,numXab);*/
if ( Ax == Bx ) /* collinear and vertical */
{
C_AB= ( Cy- Ay )/ ( By- Ay );
D_AB= ( Dy- Ay )/ ( By- Ay );
A_CD= ( Ay- Cy )/ ( Dy- Cy );
B_CD= ( By- Cy )/ ( Dy- Cy );
}
else{
C_AB= ( Cx- Ax )/ ( Bx- Ax );
D_AB= ( Dy- Ay )/ ( By- Ay );
A_CD= ( Ax- Cx )/ ( Dx- Cx );
B_CD= ( Bx- Cx )/ ( Dx- Cx );
}
if ( C_AB < 0.0 && D_AB < 0.0 )
{ return 0; }
if ( C_AB > 1.0 && D_AB > 1.0 )
{ return 0; }
if ( D_AB > C_AB )
{
if ( D_AB == 0.0 )
{
p1->p2diX= Ax;
p1->p2diY= Ay;
*pXab1= 0.0;
*pXcd1= 1.0;
return 1;
}
if ( C_AB >= 0.0 )
{
p1->p2diX= Cx;
p1->p2diY= Cy;
*pXab1= C_AB;
*pXcd1= 0.0;
if ( C_AB == 1.0 )
{ return 1; }
}
else{
p1->p2diX= Ax;
p1->p2diY= Ay;
*pXab1= 0.0;
*pXcd1= A_CD;
}
if ( D_AB <= 1.0 )
{
p2->p2diX= Dx;
p2->p2diY= Dy;
*pXab2= D_AB;
*pXcd2= 1.0;
}
else{
p2->p2diX= Bx;
p2->p2diY= By;
*pXab2= 1.0;
*pXcd2= B_CD;
}
return 2;
}
else{
if ( C_AB == 0.0 )
{
p1->p2diX= Ax;
p1->p2diY= Ay;
*pXab1= 0.0;
*pXcd1= 0.0;
return 1;
}
if ( D_AB >= 0.0 )
{
p1->p2diX= Dx;
p1->p2diY= Dy;
*pXab1= D_AB;
*pXcd1= 1.0;
if ( D_AB == 1.0 )
{ return 1; }
}
else{
p1->p2diX= Ax;
p1->p2diY= Ay;
*pXab1= 0.0;
*pXcd1= A_CD;
}
if ( C_AB <= 1.0 )
{
p2->p2diX= Cx;
p2->p2diY= Cy;
*pXab2= C_AB;
*pXcd2= 0.0;
}
else{
p2->p2diX= Bx;
p2->p2diY= By;
*pXab2= 1.0;
*pXcd2= 1.0- B_CD;
}
return 2;
}
}
else{ return 0; }
}
xab= numXab/ divxxx;
xcd= numXcd/ divxxx;
if ( xab < 0.0 || xab > 1.0 )
{ return 0; }
if ( xcd < 0.0 || xcd > 1.0 )
{ return 0; }
p1->p2diX= p2->p2diX= Ax+ xab* ( Bx- Ax );
p1->p2diY= p2->p2diY= Ay+ xab* ( By- Ay );
*pXab1= xab;
*pXcd1= xcd;
/*
p1->p2diX= p2->p2diX= Cx+ xcd* ( Cx- Dx );
p1->p2diY= p2->p2diY= Cy+ xcd* ( Cy- Dy );
*/
return 1;
}
/************************************************************************/
/* */
/* Calculate the distance of point 'c' to the line through points 'a' */
/* and 'b'. */
/* */
/* Distances to the left are positive. */
/* */
/************************************************************************/
double geo2DIDistanceToLine( const Point2DI * ab,
const Point2DI * c )
{
double Ax= ab[0].p2diX;
double Ay= ab[0].p2diY;
double Bx= ab[1].p2diX;
double By= ab[1].p2diY;
double Cx= c[0].p2diX;
double Cy= c[0].p2diY;
double L2= ( Bx- Ax )* ( Bx- Ax )+ ( By- Ay )* ( By- Ay );
/*
double Dr= ( Cx- Ax )* ( Bx- Ax )+ ( Cy- Ay )* ( By- Ay );
double r;
*/
double Ds= ( Ay- Cy )* ( Bx- Ax )+ ( Ax- Cx )* ( By- Ay );
double s;
if ( Ax == Bx && Ay == By )
{ FFDEB(Ax,Bx); FFDEB(Ay,By); return 0; }
s= Ds/ L2;
return s* sqrt( L2 );
}
/************************************************************************/
/* */
/* Calculate the distance of the projection of point 'c' on the line */
/* through points 'a' and 'b' to point A. */
/* and 'b'. */
/* */
/* Distances in the direction of B are positive. */
/* */
/************************************************************************/
double geo2DIProjectionOnLine( const Point2DI * ab,
const Point2DI * c )
{
double Ax= ab[0].p2diX;
double Ay= ab[0].p2diY;
double Bx= ab[1].p2diX;
double By= ab[1].p2diY;
double Cx= c[0].p2diX;
double Cy= c[0].p2diY;
double L2= ( Bx- Ax )* ( Bx- Ax )+ ( By- Ay )* ( By- Ay );
double Dr= ( Cx- Ax )* ( Bx- Ax )+ ( Cy- Ay )* ( By- Ay );
double r;
/*
double Ds= ( Ay- Cy )* ( Bx- Ax )+ ( Ax- Cx )* ( By- Ay );
double s;
*/
if ( Ax == Bx && Ay == By )
{ FFDEB(Ax,Bx); FFDEB(Ay,By); return 0; }
r= Dr/ L2;
return r* sqrt( L2 );
}
/************************************************************************/
/* */
/* See whether a point is in a polygon. */
/* */
/* The number of intersections of the line to a point very far away is */
/* counted. It should be odd. */
/* */
/* 1) When the line is collinear with one of the sides of the */
/* polygon, another point far away it tried. */
/* 2) Skip zero length segments. */
/* 3) Intersect segment with segment to point far away. */
/* 4) If collinear, abort this attempt.. Another point far away is */
/* chosen below. */
/* */
/************************************************************************/
int geo2DIPointInPolygon( const Point2DI * p,
const Point2DI * points,
int pointCount )
{
Point2DI ab[2];
Point2DI p1;
Point2DI p2;
int attempts= 0;
ab[1]= ab[0]= *p;
ab[1].p2diX= INT_MAX;
/* 1 */
for (;;)
{
int i;
int res;
const Point2DI * vp;
int crossings= 0;
double xab1;
double xab2;
double xvp1;
double xvp2;
vp= points;
for ( i= 0; i < pointCount; vp++, i++ )
{
/* 2 */
if ( vp[0].p2diX == vp[1].p2diX &&
vp[0].p2diY == vp[1].p2diY )
{ continue; }
/* 3 */
res= geo2DIIntersectSegments( &p1, &p2,
&xab1, &xab2, &xvp1, &xvp2, ab, vp );
if ( res == 0 )
{ continue; }
/* 4 */
if ( res != 1 )
{ /*LDEB(res);*/ break; }
/* 5 */
if ( p1.p2diX == vp[0].p2diX &&
p1.p2diY == vp[0].p2diY )
{
if ( p1.p2diX == p->p2diX &&
p1.p2diY == p->p2diY )
{ return 1; }
/*FFDEB(p1.p2diX,p1.p2diY);*/
if ( attempts < 60 )
{ break; }
}
if ( p1.p2diX == vp[1].p2diX &&
p1.p2diY == vp[1].p2diY )
{
if ( p1.p2diX == p->p2diX &&
p1.p2diY == p->p2diY )
{ return 1; }
/*FFDEB(p1.p2diX,p1.p2diY);*/
if ( attempts < 60 )
{ break; }
}
if ( xvp1 < 0.001 || xvp1 > 0.999 ||
xvp2 < 0.001 || xvp2 > 0.999 )
{
if ( attempts < 60 )
{ break; }
}
crossings++;
}
if ( i < pointCount )
{ ab[1].p2diY += 100; attempts++; continue; }
if ( crossings % 2 )
{ return 1; }
else{ return 0; }
}
}
/************************************************************************/
/* */
/* Clip a line segment to a rectangle. */
/* */
/************************************************************************/
static int geo2DIFirstBorderIntersection(
Point2DI * pP,
double * pXp,
Point2DI p0,
Point2DI p1,
const DocumentRectangle * dr )
{
Point2DI pa;
Point2DI pb;
double xpa;
double xpb;
double xsa;
double xsb;
Point2DI p;
double xp= 2;
Point2DI vp[2];
Point2DI side[2];
vp[0]= p0;
vp[1]= p1;
side[0].p2diX= dr->drX0; side[0].p2diY= dr->drY0;
side[1].p2diX= dr->drX1; side[1].p2diY= dr->drY0;
if ( geo2DIIntersectSegments( &pa, &pb, &xpa, &xpb, &xsa, &xsb,
vp, side ) == 1 && xpa < xp )
{ p= pa; xp= xpa; }
side[0].p2diX= dr->drX0; side[0].p2diY= dr->drY1;
side[1].p2diX= dr->drX1; side[1].p2diY= dr->drY1;
if ( geo2DIIntersectSegments( &pa, &pb, &xpa, &xpb, &xsa, &xsb,
vp, side ) == 1 && xpa < xp )
{ p= pa; xp= xpa; }
side[0].p2diX= dr->drX0; side[0].p2diY= dr->drY0;
side[1].p2diX= dr->drX0; side[1].p2diY= dr->drY1;
if ( geo2DIIntersectSegments( &pa, &pb, &xpa, &xpb, &xsa, &xsb,
vp, side ) == 1 && xpa < xp )
{ p= pa; xp= xpa; }
side[0].p2diX= dr->drX1; side[0].p2diY= dr->drY0;
side[1].p2diX= dr->drX1; side[1].p2diY= dr->drY1;
if ( geo2DIIntersectSegments( &pa, &pb, &xpa, &xpb, &xsa, &xsb,
vp, side ) == 1 && xpa < xp )
{ p= pa; xp= xpa; }
if ( xp > 1 )
{ return 1; }
*pP= p; *pXp= xp; return 0;
}
static int geo2DILastBorderIntersection( Point2DI * pP,
double * pXp,
Point2DI p0,
Point2DI p1,
const DocumentRectangle * dr )
{
Point2DI pa;
Point2DI pb;
double xpa;
double xpb;
double xsa;
double xsb;
Point2DI p;
double xp= -1;
Point2DI vp[2];
Point2DI side[2];
vp[0]= p0;
vp[1]= p1;
side[0].p2diX= dr->drX0; side[0].p2diY= dr->drY0;
side[1].p2diX= dr->drX1; side[1].p2diY= dr->drY0;
if ( geo2DIIntersectSegments( &pa, &pb, &xpa, &xpb, &xsa, &xsb,
vp, side ) == 1 && xpa > xp )
{ p= pa; xp= xpa; }
side[0].p2diX= dr->drX0; side[0].p2diY= dr->drY1;
side[1].p2diX= dr->drX1; side[1].p2diY= dr->drY1;
if ( geo2DIIntersectSegments( &pa, &pb, &xpa, &xpb, &xsa, &xsb,
vp, side ) == 1 && xpa > xp )
{ p= pa; xp= xpa; }
side[0].p2diX= dr->drX0; side[0].p2diY= dr->drY0;
side[1].p2diX= dr->drX0; side[1].p2diY= dr->drY1;
if ( geo2DIIntersectSegments( &pa, &pb, &xpa, &xpb, &xsa, &xsb,
vp, side ) == 1 && xpa > xp )
{ p= pa; xp= xpa; }
side[0].p2diX= dr->drX1; side[0].p2diY= dr->drY0;
side[1].p2diX= dr->drX1; side[1].p2diY= dr->drY1;
if ( geo2DIIntersectSegments( &pa, &pb, &xpa, &xpb, &xsa, &xsb,
vp, side ) == 1 && xpa > xp )
{ p= pa; xp= xpa; }
if ( xp < 0 )
{ return 1; }
*pP= p; *pXp= xp; return 0;
}
int geo2DIClipSegmentToRectangle(
Point2DI vpChanged[2],
double * pXp0,
double * pXp1,
const Point2DI vp[2],
const DocumentRectangle * dr )
{
double xp0= 0.0;
double xp1= 1.0;
Point2DI p0= vp[0];
Point2DI p1= vp[1];
if ( ! geo2DIPointInBox( &(vp[0]), dr ) )
{
if ( geo2DIFirstBorderIntersection( &p0, &xp0, vp[0], vp[1], dr ) )
{ return 1; }
}
if ( ! geo2DIPointInBox( &(vp[1]), dr ) )
{
if ( geo2DILastBorderIntersection( &p1, &xp1, vp[0], vp[1], dr ) )
{ return 1; }
}
vpChanged[0]= p0; *pXp0= xp0;
vpChanged[1]= p1; *pXp1= xp1;
return 0;
}
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