Point Inside a Polygon //JavaScript Function

jonasraoni (Jonas Raoni Soares Silva) — Sun, 30 Mar 2008 16:57:56 GMT

Checks whether a point is inside a polygon.
Adapted from: [http://www.ecse.rpi.edu/Homepages/wrf/Research/Short_Notes/pnpoly.html]

[UPDATED CODE AND HELP CAN BE FOUND HERE: Point Inside a Polygon]



//+ Jonas Raoni Soares Silva

//@ http://jsfromhell.com/classes/is-point-in-poly [v1.0]



function isPointInPoly(poly, pt){

	for(var c = false, i = -1, l = poly.length, j = l - 1; ++i < l; j = i)

		((poly[i].y <= pt.y && pt.y < poly[j].y) || (poly[j].y <= pt.y && pt.y < poly[i].y))

		&& (pt.x < (poly[j].x - poly[i].x) * (pt.y - poly[i].y) / (poly[j].y - poly[i].y) + poly[i].x)

		&& (c = !c);

	return c;

}

Example

HitTest //JavaScript Function

jonasraoni (Jonas Raoni Soares Silva) — Thu, 24 Nov 2005 18:55:27 GMT

With this it's possible to correct the "SELECT over DIV" IE bug as i showed in the example bellow

it checks one element (or an array of them) against another one and returns the itens that matched the hit test (if the element superposes the other one in any place)

[UPDATED CODE AND HELP CAN BE FOUND HERE]

code



//+ Jonas Raoni Soares Silva

//@ http://jsfromhell.com/geral/hittest [v1.0]



hitTest = function(o, l){

	function getOffset(o){

		for(var r = {l: o.offsetLeft, t: o.offsetTop, r: o.offsetWidth, b: o.offsetHeight};

			o = o.offsetParent; r.l += o.offsetLeft, r.t += o.offsetTop);

		return r.r += r.l, r.b += r.t, r;

	}

	for(var b, s, r = [], a = getOffset(o), j = isNaN(l.length), i = (j ? l = [l] : l).length; i;

		b = getOffset(l[--i]), (a.l == b.l || (a.l > b.l ? a.l <= b.r : b.l <= a.r))

		&& (a.t == b.t || (a.t > b.t ? a.t <= b.b : b.t <= a.b)) && (r[r.length] = l[i]));

	return j ? !!r.length : r;

};

usage









    





    

    DIV x SELECT

DZone Snippets: hit code

Point Inside a Polygon //JavaScript Function

HitTest //JavaScript Function