function transformLocalCoord(out, elFrom, elTarget, inX, inY) {
    return transformCoordWithViewport(_calcOut$1, elFrom, inX, inY, true)
        && transformCoordWithViewport(out, elTarget, _calcOut$1[0], _calcOut$1[1]);
}
Transform "local coord" from `elFrom` to `elTarget`.
"local coord": the coord based on the input `el`. The origin point is at
    the position of "left: 0; top: 0;" in the `el`.

Support when CSS transform is used.

Having the `out` (that is, `[outX, outY]`), we can create an DOM element
and set the CSS style as "left: outX; top: outY;" and append it to `elTarge`
to locate the element.

For example, this code below positions a child of `document.body` on the event
point, no matter whether `body` has `margin`/`paddin`/`transfrom`/... :
```js
transformLocalCoord(out, container, document.body, event.offsetX, event.offsetY);
if (!eqNaN(out[0])) {
    // Then locate the tip element on the event point.
    var tipEl = document.createElement('div');
    tipEl.style.cssText = 'position: absolute; left:' + out[0] + ';top:' + out[1] + ';';
    document.body.appendChild(tipEl);
}
```

Notice: In some env this method is not supported. If called, `out` will be `[NaN, NaN]`.

@param {Array.<number>} out [inX: number, inY: number] The output..
       If can not transform, `out` will not be modified but return `false`.
@param {HTMLElement} elFrom The `[inX, inY]` is based on elFrom.
@param {HTMLElement} elTarget The `out` is based on elTarget.
@param {number} inX
@param {number} inY
@return {boolean} Whether transform successfully.