Javascript check Mouse clicked inside the Circle or Polygon

Question

Any one know how to check that wheter a mouse is clicked inside the circle or polygon. My problem is I want to check that if mouse has been clciked inside the circle or polygon. circle or polygon coordinates has been stored inside an array. Any help is really appreciated

Answer 1

As suggested by some other answers, I followed some links and found the c code here. Here is the JavaScript translation for finding whether a point is in a polygon

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function pnpoly( nvert, vertx, verty, testx, testy ) {
    var i, j, c = false;
    for( i = 0, j = nvert-1; i < nvert; j = i++ ) {
        if( ( ( verty[i] > testy ) != ( verty[j] > testy ) ) &&
            ( testx < ( vertx[j] - vertx[i] ) * ( testy - verty[i] ) / ( verty[j] - verty[i] ) + vertx[i] ) ) {
                c = !c;
        }
    }
    return c;
}

nvert - Number of vertices in the polygon. Whether to repeat the first vertex at the end is discussed below.
vertx, verty - Arrays containing the x- and y-coordinates of the polygon's vertices.
testx, testy - X- and y-coordinate of the test point.