Replicate background-style:contain on img? - html

Question

Notice that I need to declare the img source from the html (this will be dynamic), so i dont use background here.
HTML
<div class='some-form'>
<form>
<button>...<button>
<img id="some-img" src="something"/>
<input id="some-input"/>
</form>
</div>
CSS
.some-form {
display: block;
position: relative;
}
.some-form #some-input {
background-color: rgba(255,255,255,0);
border: 1px solid #2F2F2F;
width: 300px;
color: #000;
opacity: 1;
}
.some-form #some-img {
position:absolute;
background-color: #FFF;
z-index: -1;
//background-size: contain; //this does not work
//background-position: center right 50px; //so this will not work
}
How can I get the image to act like contain so that I can align it the way i want?

Answer 1

Keep your code as-is, but change #some-img from an img to a div (and specify width and height as needed based on the image dimensions). It's not possible (at least not in a simple way) to make an img element behave as if it was using background-size and background-position properties since img elements are not backgrounds. So in order to do so, you instead make the image a div with a background-image.
Since you are dynamically populating the image src, you can instead use inline styles to define a background-image on the div, as this lets you call a PHP or other server-side function to echo the image url (which you can't do in a CSS file).
So for example, keep the CSS you have now (but add height/width or other styles to the #some-img div as needed) but replace <img id="some-img" src="something"/> with something like this:
<div style="background-image: url(<?php theDynamicImageURL(); ?>);"></div>
or equivalent in whatever language or method you are using to populate the image dynamically.
There are better ways to do this as inline CSS is generally something that should be avoided, but the use in this case is not too dangerous but it'll work in a pinch and most other methods would either be equally sloppy or a lot more work.

Answer 2

If you include jquery, you can write a script to cheat this:
<script type="text/javascript">
height = $('#some-img').height();
width = $('#some-img').width();
src = $('#some-img').attr('src');
$('#sime-img').wrap('<div id="contain"></div>');
$('#contain').height(height).width(width);
$('#contain').css('background',"url('" + src + "')");
$('#contain').css('background-sizing','contain');
$('#some-img').css('opacity','0');
</script>
It isn't nice. You can do the same thing w/o JQuery, I just used it for convenience.

Answer 3

If I understand correctly, you're looking to constrain an image to the size of its containing element and center it vertically and horizontally.
This will get you pretty close, but the image will only scale up to its actual size, no bigger.
HTML
<div class='some-form'>
<form>
<button></button>
<img id="some-img" src="http://lorempixel.com/300/200/sports"/>
<input id="some-input" />
</form>
</div>
CSS
.some-form {
display: block;
position: relative;
width:400px;
height:180px;
background: rgba(255,255,0,.1); /* for checking that it fits*/
}
.some-form #some-input {
background-color: rgba(255,255,255,0);
border: 1px solid #2F2F2F;
width: 300px;
color: #000;
opacity: 1;
}
.some-form #some-img {
position:absolute;
background-color: #FFF;
top:0;
bottom:0;
left:0;
right:0;
margin:auto auto;
max-width:100%;
max-height:100%;
z-index: -1;
}
fiddle: http://jsfiddle.net/XNR38/
Good luck!