function updateTextLocation(tspan, textAlign, x, y) {
    // Consider different font display differently in vertial align, we always
    // set vertialAlign as 'middle', and use 'y' to locate text vertically.
    attr(tspan, 'dominant-baseline', 'middle');
    attr(tspan, 'text-anchor', TEXT_ALIGN_TO_ANCHRO[textAlign]);
    attr(tspan, 'x', x);
    attr(tspan, 'y', y);
}
Manages elements that can be defined in <defs> in SVG,
e.g., gradients, clip path, etc.

@class
@param {number}          zrId      zrender instance id
@param {SVGElement}      svgRoot   root of SVG document
@param {string|string[]} tagNames  possible tag names
@param {string}          markLabel label name to make if the element
                                   is used