#allcomplex>div{
  margin-bottom: 10px;
  display:block;
}

.complexmem{
    width: 40vw;
    height:10vw;
    background-color: yellowgreen;
    display: table-cell;
    vertical-align: middle;
}

.complexmem>a>img{
    width: 7vw;
    height: 7vw;
    background-color: red;
}

.complexmem>img{
    width: 12vw;
    height: 7vw;
    background-color: blue;
}

.complexmem>.autotext{
    width: 20vw;
    height: 7vw;
    display:inline;
    color:white;
    background-color: green;
}

<div id="allcomplex">

    <div class="complexmem">

        <a href="#">
        <img src="http://science-all.com/images/magnifying-glass-clipart/magnifying-glass-clipart-13.jpg">
        </a>

        <img src="http://upload.wikimedia.org/wikipedia/commons/thumb/2/26/Microchip_PIC24HJ32GP202.jpg/220px-Microchip_PIC24HJ32GP202.jpg">

        <div class="autotext">
        <span>Computer Center Complex of microchip</span>
        </div>

    </div>

    <div class="complexmem">

        <a href="#">
        <img src="http://science-all.com/images/magnifying-glass-clipart/magnifying-glass-clipart-13.jpg">
        </a>

        <img src="http://upload.wikimedia.org/wikipedia/commons/thumb/f/f8/PIC16CxxxWIN.JPG/220px-PIC16CxxxWIN.JPG">

        <div class="autotext">
        <span>Laptop Center</span>
        </div>

    </div>

</div>

function resizeFont(parElem, ratio) {

    var parW = parElem.width();
    ratio = ratio || 7;

    parElem.find('span').each(function () {

        console.log($(this).width());
        console.log(parW);
        console.log(ratio);

        $(this).css('font-size',
        parW / $(this).width() * ratio + 'px');

    })
}

resizeFont($(".autotext"));