Javascript 检查鼠标在圆或多边形内单击

Question

任何人都知道如何检查是否在圆或多边形内单击了鼠标。我的问题是我想检查鼠标是否在圆圈或多边形内被点击。圆或多边形坐标已存储在数组中。非常感谢任何帮助

Answer 1

根据 some other answers 的建议, 我点击了一些链接和 found the c code here . 这是用于查找点是否在多边形中的 JavaScript 翻译

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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.