std::vector<IntResult> SimpleIntersector::LineArcIntersect(FastLine* line, FastArc* arc)
{
std::vector<IntResult> ret;
double dx = line->B.X() - line->A.X();
double dy = line->B.Y() - line->A.Y();
double a = dx*dx + dy*dy;
double b = 2 * ((line->B.X() - line->A.X()) * (line->A.X() - arc->C.X()) + (line->B.Y() - line->A.Y()) * (line->A.Y() - arc->C.Y()));
double c = arc->C.X() * arc->C.X() + arc->C.Y() * arc->C.Y() + line->A.X()*line->A.X() + line->A.Y()*line->A.Y() - 2*(arc->C.X() * line->A.X() + arc->C.Y() * line->A.Y()) - arc->rad * arc->rad;
double det = b * b - 4 * a * c;
if(det<-tol)
return ret;
if(det<0)
det = 0;
if(det > -tol && det < tol)
{
//single intersection
double u = (-b + sqrt(det)) / (2 * a);
ret.push_back(LineArcIntersect(line,arc,u));
return ret;
}
//These u's are for the line
double u1 = (-b + sqrt(det)) / (2 * a);
double u2 = (-b - sqrt(det)) / (2 * a);
ret.push_back(LineArcIntersect(line,arc,u1));
ret.push_back(LineArcIntersect(line,arc,u2));
return ret;
}
std::vector<IntResult> SimpleIntersector::Intersects(FastCurve* curve1, FastCurve* curve2)
{
std::vector<IntResult> ret;
bool swap=false;
FastLine* line1 = dynamic_cast<FastLine*>(curve1);
if(line1)
{
FastLine* line2 = dynamic_cast<FastLine*>(curve2);
if(line2)
ret = LinesIntersect((FastLine*)curve1,(FastLine*)curve2);
else
{
FastArc* arc2 = dynamic_cast<FastArc*>(curve2);
if(arc2)
{
ret = LineArcIntersect(line1,arc2);
}
}
}
else
{
FastArc* arc1 = dynamic_cast<FastArc*>(curve1);
if(arc1)
{
FastLine* line2 = dynamic_cast<FastLine*>(curve2);
if(line2)
{
ret = LineArcIntersect(line2,arc1);
swap = true;
}
else
{
FastArc* arc2 = dynamic_cast<FastArc*>(curve2);
ret = ArcsIntersect(arc1,arc2);
}
}
}
if(swap)
{
for(unsigned int i=0; i < ret.size(); i++)
{
ret[i].Swap();
}
}
return ret;
}
static int
drcArc_callback (const BoxType * b, void *cl)
{
ArcTypePtr arc = (ArcTypePtr) b;
struct drc_info *i = (struct drc_info *) cl;
if (!TEST_FLAG (FOUNDFLAG, arc) && LineArcIntersect (i->line, arc))
longjmp (i->env, 1);
return 1;
}
/* ---------------------------------------------------------------------------
* checks if an arc crosses a square
*/
bool
IsArcInRectangle (Coord X1, Coord Y1, Coord X2, Coord Y2, ArcTypePtr Arc)
{
LineType line;
/* construct a set of dummy lines and check each of them */
line.Thickness = 0;
line.Flags = NoFlags ();
/* upper-left to upper-right corner */
line.Point1.Y = line.Point2.Y = Y1;
line.Point1.X = X1;
line.Point2.X = X2;
if (LineArcIntersect (&line, Arc))
return (true);
/* upper-right to lower-right corner */
line.Point1.X = line.Point2.X = X2;
line.Point1.Y = Y1;
line.Point2.Y = Y2;
if (LineArcIntersect (&line, Arc))
return (true);
/* lower-right to lower-left corner */
line.Point1.Y = line.Point2.Y = Y2;
line.Point1.X = X1;
line.Point2.X = X2;
if (LineArcIntersect (&line, Arc))
return (true);
/* lower-left to upper-left corner */
line.Point1.X = line.Point2.X = X1;
line.Point1.Y = Y1;
line.Point2.Y = Y2;
if (LineArcIntersect (&line, Arc))
return (true);
return (false);
}
