Is `overflow: hidden` changing the positioning of absolute children? - css

Question

I have an image gallery sliding images in an out only with css.
See http://codepen.io/anon/pen/xmhzE?editors=110 for the example or the attached code.
It works fine as long as the #images-div does not have overflow: hidden set. When overflow is set to hidden, the absolute positioning of the single images does not work anymore. When I use negative values for the left-property of the images it also works with overflow hidden.
Does overflow:hidden change the way how absolute children are layouted?
Does anyone has a solution to this problem?
Sources
index.html:
<div id="images">
<img id="image1" src="http://i.imgur.com/dL3io.jpg" />
<img id="image2" src="http://i.imgur.com/qASVX.jpg" />
<img id="image3" src="http://i.imgur.com/fLuHO.jpg" />
<img id="image4" src="http://i.imgur.com/5Sd3Q.jpg" />
</div>
<div id="slider">
1
2
3
4
</div>
base.css:
body {
text-align: center;
}
#images {
width: 400px;
height: 250px;
/*overflow: hidden; if this is set absolute positioning of images breaks*/
position: relative;
background-color: red;
margin: 20px auto;
}
#images img {
width: 400px;
height: 250px;
display: block;
position: absolute;
top: 0px;
left: 400px;
z-index: 1;
opacity: 0;
transition: all linear 500ms;
-o-transition: all linear 500ms;
-moz-transition: all linear 500ms;
-webkit-transition: all linear 500ms;
}
#images img:target {
top: 0px;
left: 0px;
z-index: 9;
opacity: 1;
}
#slider a {
text-decoration: none;
background: #E3F1FA;
border: 1px solid #C6E4F2;
padding: 4px 6px;
color: #222;
}
#slider a:hover {
background: #C6E4F2;
}

Answer 1

This puzzle kept me going. I just couldn't leave it be.
So last evening I was fiddling with it, but couldn't fix it (untill just yet :) ).
Testcase 1
While simplifying things I removed the opacity from the image-elements and left only 1 image and one link. I've set the image to 390px initially so that I can make sure that it is at that position (you can see just a little bit of the left of it).
http://codepen.io/anon/pen/tpCrc
Conclusion:
So what's important to notice is that fact that the image initially is there where it should be.
Then when clicking button 1 you can see it simply skips the transition.
So the browser doesn't change the position of the element, because of overflow:hidden (like the title of this post suggests). It goes to the position mentioned in the CSS (in the :target part), but without the transition.
Testcase 2
Then I got wondering why the browser would act that way and I kept thinking that maybe the focussing of the image element had something to do with it.
If you think about it: when clicking one of the buttons you add #target to the URL of the page and browser then tries to "scroll" to that element. To that, that element has to be visisble.
So I wondered: maybe the CSS has nothing to do with it. Let's try:
so I completely removed the :target-part and the transitions.
http://codepen.io/anon/pen/IvfBE
Conclusion:
Wow! What do we see there? When clicking one of the buttons the image still jumps to left:0 !!
I think we got a lead there.
Still though, I didn't know how to actually fix that. Still seems like a browser-bug to me.
The fix
Then - after a good night of sleep - I woke up with a fresh new idea.
What if we don't actually target the element we want to transition?
So I added a container to each image-element and target that instead.
<div id="images">
<div id="img1container"><img id="image1" src="http://i.imgur.com/dL3io.jpg" /></div>
<div id="img2container"><img id="image2" src="http://i.imgur.com/qASVX.jpg" /></div>
<div id="img3container"><img id="image3" src="http://i.imgur.com/fLuHO.jpg" /></div>
<div id="img4container"><img id="image4" src="http://i.imgur.com/5Sd3Q.jpg" /></div>
</div>
<div id="slider">
1
2
3
4
</div>
In the CSS the position of the image now has to be changed by "[parentElement]:target img" instead.
body {
text-align: center;
}
#images {
width: 400px;
height: 250px;
overflow: hidden; /* this did break it in the past ;) */
position: relative;
background-color: red;
margin: 20px auto;
}
#images img {
width: 400px;
height: 250px;
display: block;
position: absolute;
top: 0px;
left: 400px;
z-index: 1;
opacity: 0;
transition: all linear 500ms;
-o-transition: all linear 500ms;
-moz-transition: all linear 500ms;
-webkit-transition: all linear 500ms;
}
#images div:target img {
top: 0px;
left: 0px;
z-index: 9;
opacity: 1;
}
#slider a {
text-decoration: none;
background: #E3F1FA;
border: 1px solid #C6E4F2;
padding: 4px 6px;
color: #222;
}
#slider a:hover {
background: #C6E4F2;
}
And the working example:
http://codepen.io/anon/pen/lyzhi
Conclusion:
Yay!! Indeed, by not putting focus on the element you want to transition, it doesn't break.
So, you've got your fix there, but it still seems like a browser/engine-bug to me.
So I'd suggest you create a bugreport somewhere (if you've got time).
BTW: I've tested this in Chrome and IE - both the latest versions only. You might want to test this in Firefox and maybe some other browsers.