Java Utililty Methods Line Intersect

Point intersect(int xa, int ya, int xb, int yb, int xc, int yc, int xd, int yd)
intersect

double denom = (double) ((xb - xa) * (yd - yc) - (yb - ya) * (xd - xc));
double rnum = (double) ((ya - yc) * (xd - xc) - (xa - xc) * (yd - yc));
if (denom == 0.0D) {
 return rnum != 0.0D ? null
 : ((xa >= xb || xb >= xc && xb >= xd) && (xa <= xb || xb <= xc && xb <= xd) ? new Point(xa, ya)
 : new Point(xb, yb));
} else {
 double r = rnum / denom;
...

Point intersect(Point a, Point b, Point c, Point d)
intersect

float[] rv = intersect(new float[] { a.x, a.y, b.x, b.y, c.x, c.y, d.x, d.y });
if (rv == null)
 return null;
return new Point((int) rv[0], (int) rv[1]);

Area intersect(Shape shape1, Shape shape2)
Intersect 2 shapes and return result in an Area type shape.

final Area result = new Area(shape1);
result.intersect(new Area(shape2));
return result;

Shape intersectClip(final Graphics2D g2d, final Shape clip)
Setting clip Shape by taking old clip Shape into account

return intersectClip(g2d, clip, true);

Point2D intersection(Line2D a, Line2D b)
Computes the intersection between two lines.

double x1 = a.getX1(), y1 = a.getY1(), x2 = a.getX2(), y2 = a.getY2(), x3 = b.getX1(), y3 = b.getY1(),
 x4 = b.getX2(), y4 = b.getY2();
double d = (x1 - x2) * (y3 - y4) - (y1 - y2) * (x3 - x4);
if (d == 0) {
 return null;
double xi = ((x3 - x4) * (x1 * y2 - y1 * x2) - (x1 - x2) * (x3 * y4 - y3 * x4)) / d;
double yi = ((y3 - y4) * (x1 * y2 - y1 * x2) - (y1 - y2) * (x3 * y4 - y3 * x4)) / d;
...

Point2D intersection(Line2D lineA, Line2D lineB)
Computes the intersection between two lines.

Point2D lineAPt1 = lineA.getP1();
Point2D lineAPt2 = lineA.getP2();
Point2D lineBPt1 = lineB.getP1();
Point2D lineBPt2 = lineB.getP2();
double x1 = lineAPt1.getX();
double y1 = lineAPt1.getY();
double x2 = lineAPt2.getX();
double y2 = lineAPt2.getY();
...

Point2D.Double intersection(Point2D p1, Point2D p2, Point2D p3, Point2D p4)
Return the intersection point between infinite line A defined by points p1 & p2 and infinite line B defined by points p3 & p4.

double x1 = p1.getX();
double y1 = p1.getY();
double x2 = p2.getX();
double y2 = p2.getY();
double x3 = p3.getX();
double y3 = p3.getY();
double x4 = p4.getX();
double y4 = p4.getY();
...

Point2D intersectionPoint(final Line2D l1, final Line2D l2)
Calculates the intersection point where the two infinitely enlarged lines meet.

final double x1 = l1.getX1();
final double y1 = l1.getY1();
final double x2 = l1.getX2();
final double y2 = l1.getY2();
final double x3 = l2.getX1();
final double y3 = l2.getY1();
final double x4 = l2.getX2();
final double y4 = l2.getY2();
...

Point intersectionZJU(int x1, int y1, int x2, int y2, int x3, int y3, int x4, int y4)
intersection ZJU

long d = ((long) (y4 - y3)) * (x2 - x1) - ((long) (x4 - x3)) * (y2 - y1);
if (d == 0)
 return new Point(-1, -1); 
double a = (((long) (x4 - x3)) * (y1 - y3) - ((long) (y4 - y3)) * (x1 - x3)) * 1.0 / d;
int x = x1 + (int) (a * (x2 - x1));
int y = y1 + (int) (a * (y2 - y1));
if (x >= Math.min(x1, x2) && x <= Math.max(x1, x2) && x <= Math.max(x3, x4) && x >= Math.min(x3, x4)
 && y >= Math.min(y1, y2) && y <= Math.max(y1, y2) && y <= Math.max(y3, y4) && y >= Math.min(y3, y4)) 
...

Point intersectionZJU(int x1, int y1, int x2, int y2, int x3, int y3, int x4, int y4)
intersection ZJU

long d = ((long) (y4 - y3)) * (x2 - x1) - ((long) (x4 - x3)) * (y2 - y1);
if (d == 0)
 return new Point(-1, -1); 
double a = (((long) (x4 - x3)) * (y1 - y3) - ((long) (y4 - y3)) * (x1 - x3)) * 1.0 / d;
int x = x1 + (int) (a * (x2 - x1));
int y = y1 + (int) (a * (y2 - y1));
if (x >= Math.min(x1, x2) && x <= Math.max(x1, x2) && x <= Math.max(x3, x4) && x >= Math.min(x3, x4)
 && y >= Math.min(y1, y2) && y <= Math.max(y1, y2) && y <= Math.max(y3, y4) && y >= Math.min(y3, y4)) 
...