<div class="container">
    <span class="box">Test Test Test</span>
</div>

.container {
    width: 200px;
    height: 50px;
}

.box {
    display: inline;
    border: 2px solid black;
}

$('.container').draggable();

$('.container').resizable({
    handles: 'all',
    resize: function(evt, ui) {
        var width1 = parseInt(ui.element.css('width')),
            height1 = parseInt(ui.element.css('height'));
        ui.element.css({
            'font-size': (width1/10)+'px',
            'line-height': (height1/10)+'px'
        })
    }
});