function boxLayout(orient, group, gap, maxWidth, maxHeight) {
    var x = 0;
    var y = 0;

    if (maxWidth == null) {
        maxWidth = Infinity;
    }
    if (maxHeight == null) {
        maxHeight = Infinity;
    }
    var currentLineMaxSize = 0;

    group.eachChild(function (child, idx) {
        var position = child.position;
        var rect = child.getBoundingRect();
        var nextChild = group.childAt(idx + 1);
        var nextChildRect = nextChild && nextChild.getBoundingRect();
        var nextX;
        var nextY;

        if (orient === 'horizontal') {
            var moveX = rect.width + (nextChildRect ? (-nextChildRect.x + rect.x) : 0);
            nextX = x + moveX;
            // Wrap when width exceeds maxWidth or meet a `newline` group
            // FIXME compare before adding gap?
            if (nextX > maxWidth || child.newline) {
                x = 0;
                nextX = moveX;
                y += currentLineMaxSize + gap;
                currentLineMaxSize = rect.height;
            }
            else {
                // FIXME: consider rect.y is not `0`?
                currentLineMaxSize = Math.max(currentLineMaxSize, rect.height);
            }
        }
        else {
            var moveY = rect.height + (nextChildRect ? (-nextChildRect.y + rect.y) : 0);
            nextY = y + moveY;
            // Wrap when width exceeds maxHeight or meet a `newline` group
            if (nextY > maxHeight || child.newline) {
                x += currentLineMaxSize + gap;
                y = 0;
                nextY = moveY;
                currentLineMaxSize = rect.width;
            }
            else {
                currentLineMaxSize = Math.max(currentLineMaxSize, rect.width);
            }
        }

        if (child.newline) {
            return;
        }

        position[0] = x;
        position[1] = y;

        orient === 'horizontal'
            ? (x = nextX + gap)
            : (y = nextY + gap);
    });
}
Parse position info.

@param {Object} positionInfo
@param {number|string} [positionInfo.left]
@param {number|string} [positionInfo.top]
@param {number|string} [positionInfo.right]
@param {number|string} [positionInfo.bottom]
@param {number|string} [positionInfo.width]
@param {number|string} [positionInfo.height]
@param {number|string} [positionInfo.aspect] Aspect is width / height
@param {Object} containerRect
@param {string|number} [margin]

@return {module:zrender/core/BoundingRect}