How to define a Ray ?

[FlashTang]

Hello Sir
How can I define a Ray ?
Like following image:

I know I can lengthen the segment with a long length
but maybe kld-intersections already has it's way to define easily ?

[thelonious]

Hi FlashTang,

Sorry, there's no "ray" shape in the library. When this was written, it was to be used with SVG shapes. SVG doesn't have rays, so this library doesn't either.

As an aside, any intersection that uses the line-line method could be made to support rays. The current code makes sure that the intersection point lies on both lines. If that check were modified (or even removed), then it would be checking rays instead of line segments. This may not help you, but your example image only uses line-line, so it could help with that case.

[FlashTang]

Hi FlashTang,

Sorry, there's no "ray" shape in the library. When this was written, it was to be used with SVG shapes. SVG doesn't have rays, so this library doesn't either.

As an aside, any intersection that uses the line-line method could be made to support rays. The current code makes sure that the intersection point lies on both lines. If that check were modified (or even removed), then it would be checking rays instead of line segments. This may not help you, but your example image only uses line-line, so it could help with that case.

@thelonious
Thanks for your reply and suggesting the solution
I need check both line-line and line-shapes, so I go for the solution: "extend the segment"
Just in case, if anyone interested, then here is the code :

Reference: https://stackoverflow.com/questions/7740507/extend-a-line-segment-a-specific-distance

function FakeRay(ax,ay,bx,by){
      var len = 99999;
      var lenAB = Math.sqrt(Math.pow(ax-bx,2),Math.pow(ay-by,2));
      var cx = bx + (bx - ax) / lenAB * len;
      var cy = by + (by - ay) / lenAB * len;
      return [ax,ay,cx,cy]; //return a new super-long segment
}
var ray = FakeRay(100,100,150,120);
var line = ShapeInfo.line([ray[0], ray[1]], [ray[2], ray[3]]);
var intersections = Intersection.intersect(otherShape, line);

Again, thanks for creating this library