Responsive Vertical Alignment of text inside an absolutely positioned div

Question

I'm creating a thumbnail image gallery. I'm having it where you hover over the image and you see the title and description. I want the title and description centred inside the hover div.

Because I have positioned the hover div as absolute, I'm having trouble using the usual table methods to vertically align. Whenever I resized the viewport, the text wouldn't be in the centre anymore.

Any help with this would be appreciated.

Here is the jsfiddle example: http://jsfiddle.net/Forresty/2snra4tL/1/

Here is the code:

HTML:

<a class="work_item_link" href="#">
    <div class="work_item">
        <img src="http://www.personal.psu.edu/ivs5030/plant.jpg" >                                
        <div class="item_hover">  
            <div class="item_description">
                <h4>Item Heading</h4>
                <p>ITEM DESCRIPTION</p>
            </div>
        </div>
    </div>
</a>

<a class="work_item_link" href="#">
    <div class="work_item">
        <img src="http://www.personal.psu.edu/ivs5030/plant.jpg">

        <div class="item_hover">   
            <div class="item_description">
                <h4>Item Heading</h4>
                <p>ITEM DESCRIPTION</p>
            </div>
        </div>
    </div>
</a>

<a class="work_item_link_no_margin" href="#">
    <div class="work_item">
        <img src="http://www.personal.psu.edu/ivs5030/plant.jpg">

        <div class="item_hover">
            <div class="item_description">
                <h4>Item Heading</h4>
                <p>ITEM DESCRIPTION</p>
            </div>
        </div>
    </div>
</a>

CSS:

.work_item_link {
    position: relative;
    width: 32%;
    height: auto;
    float: left;
    margin-right: 2%;
    //overflow: hidden;
    &:hover {
        .item_hover {
            opacity: 1;
        }
    }
    img {
        width: 100%;
        display: block;
    }
}
.work_item_link_no_margin {
    position: relative;
    width: 32%;
    height: auto;
    float: left;
    //overflow: hidden;
    &:hover {
        .item_hover {
            opacity: 1;
        }
    }
    img {
        width: 100%;
        display: block;
    }
}
.item_hover {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: red;
    opacity: 0;
    transition: all 1s;
}

Answer 1

fff...

im too late. i was hoping to be able to provide my first answer... i made a nice fiddle for you. my technique:

transform: translate(-50%, -50%);
top: 50%;
left: 50%;
position: relative;

Answer 2

I answered my own question.

The final code can be seen here: http://jsfiddle.net/Forresty/2snra4tL/4/

I added another div as a table containing the div that contains the text.

Thanks again.

HTML:

 <a class="work_item_link" href="#">
                            <div class="work_item">
                                <img src="http://www.personal.psu.edu/ivs5030/plant.jpg" >                                
                                <div class="item_hover">
                                    <div class="center">
                                    <div class="item_description">
                                        <h4>Item Heading</h4>
                                        <p>ITEM DESCRIPTION</p>
                                    </div>
                                    </div>
                                </div>
                            </div>
                        </a>
 <a class="work_item_link" href="#">
                            <div class="work_item">
                                <img src="http://www.personal.psu.edu/ivs5030/plant.jpg">

                                <div class="item_hover">
                                    <div class="center">
                                    <div class="item_description">
                                        <h4>Item Heading</h4>
                                        <p>ITEM DESCRIPTION</p>
                                    </div>
                                    </div>
                                </div>
                            </div>
                        </a>
 <a class="work_item_link_no_margin" href="#">
                            <div class="work_item">
                                <img src="http://www.personal.psu.edu/ivs5030/plant.jpg">

                                <div class="item_hover">
                                    <div class="center">
                                    <div class="item_description">
                                        <h4>Item Heading</h4>
                                        <p>ITEM DESCRIPTION</p>
                                    </div>
                                    </div>
                                </div>
                            </div>
                        </a>

SCSS:

.work_item_link {
    position: relative;
    width: 32%;
    height: auto;
    float: left;
    margin-right: 2%;
    &:hover {
        .item_hover {
            opacity: 1;
        }
    }
    img {
        width: 100%;
        display: block;
    }
}
.work_item_link_no_margin {
    position: relative;
    width: 32%;
    height: auto;
    float: left;
    &:hover {
        .item_hover {
            opacity: 1;
        }
    }
    img {
        width: 100%;
        display: block;
    }
}
.item_hover {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: red;
    opacity: 0;
    transition: all 1s;
}

.center{
    width: 100%;
    height: 100%;
    display: table;
    text-align: center;
}

.item_description{
    display: table-cell;
    vertical-align: middle;

    p, h4{
        margin: 0;
    }
}

Answer 3

Here is how you align your text:

Horizontally:

.item_description p,
.item_description h4{
  text-align:center;   
}

Vertically:

.item_description{
   position: relative;
   margin-top: 50%;
   -webkit-transform: translateY(-100%);
   -ms-transform: translateY(-100%);
   transform: translateY(-100%);    
}

Fixed Fiddle