function transformDirection(direction, transform, invert$$1) {

    // Pick a base, ensure that transform result will not be (0, 0).
    var hBase = (transform[4] === 0 || transform[5] === 0 || transform[0] === 0)
        ? 1 : Math.abs(2 * transform[4] / transform[0]);
    var vBase = (transform[4] === 0 || transform[5] === 0 || transform[2] === 0)
        ? 1 : Math.abs(2 * transform[4] / transform[2]);

    var vertex = [
        direction === 'left' ? -hBase : direction === 'right' ? hBase : 0,
        direction === 'top' ? -vBase : direction === 'bottom' ? vBase : 0
    ];

    vertex = applyTransform$1(vertex, transform, invert$$1);

    return Math.abs(vertex[0]) > Math.abs(vertex[1])
        ? (vertex[0] > 0 ? 'right' : 'left')
        : (vertex[1] > 0 ? 'bottom' : 'top');
}
Return `true` if the given line (line `a`) and the given polygon
are intersect.
Note that we do not count colinear as intersect here because no
requirement for that. We could do that if required in future.

@param {number} a1x
@param {number} a1y
@param {number} a2x
@param {number} a2y
@param {Array.<Array.<number>>} points Points of the polygon.
@return {boolean}