Controlling Intersection of CSS 3D Transformed Elements - css

Have been experimenting with CSS 3D transforms and am confused why I'm not getting the expected results in browsers other than Safari.
Basically I have 2 sibling elements that are on top of one another (on the same z-index). If I put a transform: rotateX(xdeg) on one and leave the other untouched I would expect to see one half of the transformed element hidden behind the untouched element and the other side to be sticking out.
HTML:
<div class="container">
<div class="outer"></div>
<div class="inner"></div>
</div>
CSS:
.container{
position: relative;
margin: 100px;
-webkit-perspective: 30em;
perspective: 30em;
}
.outer{
-webkit-transform: rotateX(45deg);
transform: rotateX(45deg);
position: absolute;
top: 0;
left:0;
width: 100px;
height: 100px;
box-sizing: border-box;
-moz-box-sizing: border-box;
border:5px black solid;
}
.inner{
position: absolute;
top: 5px;
left: 5px;
background: orange;
width: 90px;
height: 90px;
transform: rotate
}
http://jsfiddle.net/jaredkhan/4VRTb/3/
The fiddle uses the same code.
The bottom of the transformed element is not displayed in front of the element that is untouched despite theoretically being closer in 3D space. This does however, work as I would expect in Safari. Am I missing something? I've tried explicitly putting them both on the same z-index and even nesting the inner one, nothing seems to be working. It's likely I'm just being dumb but please help.
Thanks

Children are rendered one by one onto the plane of the parent element. You need to set transform-style: preserve-3d on the parent to prevent this (fiddle):
.container{
...
-webkit-transform-style: preserve-3d;
transform-style: preserve-3d;
}
More info on MDN: https://developer.mozilla.org/en-US/docs/Web/CSS/transform-style
(I'm not sure whether this even existed back in 2014 when you asked the question, but it works now in 2019.)

Related

Z-index not working with position:fixed pseudo-elements

I've researched a lot on the topic and generally most problems of this matter are solved by specifying of changing the position attribute. However, the situation is different when dealing with pseudo-elements. The following CSS is the reduced test case.
#div {
background: #f5f;
height: 80vw;
width: 80vw;
max-height: 50px;
max-width: 50px;
position: fixed;
top: 50%;
left: 50%;
transform: translate(-50%, -50%);
}
#div:before {
content: '';
background: #000;
height: 100vw;
width: 100vw;
max-height: 100px;
max-width: 100px;
position: fixed;
top: 50%;
left: 50%;
transform: translate(-50%, -50%);
z-index: -1;
}
HTML
<div id="div">hi!</div>
Fiddle
Pseudo elements belongs to the element itself. So the z-index will work in all pseudo "childrens", but not in the parent because is not in the same stack.
It's like when you want to change the z-index to put a div over another div but first is the parent of the second:
div {position:relative;}
.parent {z-index:10; background:red; padding: 5px;}
.children {z-index:5; background:blue;}
<div class="parent">
I need this more z-index than his children
<div class="children">
I need this less z-index than his parent
</div>
</div>
It doesn't work obviously. That's the same case.
To avoid this, you need to change your HTML and convert the pseudo element in a normal element with the propper stack.
EDIT
In your case, you can solve if you change the fixed positioning to the relative positioning:
http://jsfiddle.net/Kq2PY/166/
But this is a particular case because the parent is fixed positioning, and it works going out of the normal flow (fixed elements are attached to the document, not the parent element). So avoid to make this kind of things when you can make with another ways.

Z-index on a element with fixed position

I have a left panel with fixed position(it's always on the left side, nomatter how much you scroll) and also few elements in that left panel. On a certain event a mask appears(it goes over everything because position:fixed; z-index: 102).
My goal is when X event fires and the mask come up, to show up the holder element over the mask.
Here is a fiddle showing my problem: JSFIDDLE
Here is my HTML:
<div class="leftpanel">
<div class="just-random-elem" style="height: 30px;">just an element to move the holder abit down</div>
<div class="holder">asdasdas</div>
</div>
<div class="mask"></div>
<div style="height: 9999px;">Just to make sure both mask and leftpanel are with fixed positions.</div>
 and here's the CSS:
.mask {
opacity: 0.85;
position: fixed;
top: 0px;
left: 0px;
width: 100%;
height: 100%;
z-index: 101;
background-color: #000;
}
.leftpanel {
width: 250px;
height: 100%;
position: fixed;
top: 0px;
left: 0px;
background-color: red;
padding: 15px;
}
.holder {
width: 230px;
height: 90px;
background-color: #fff;
z-index: 99999; <<<<<<<<<< This is NOT working!
}
Your .holder element is no positioned, so z-index simply has no effect on it. You need to add a position value different from the default static – relative will do.
http://jsfiddle.net/DJA5F/4 works that way in every browser I tested – except Chrome. Can’t spontaneously say if Chrome is handling stacking contexts correct here and the others are not – or if it’s the other way around.
Works in Chrome as well if you put #mask into .leftpanel: http://jsfiddle.net/DJA5F/5 – might not be the nicest workaround, but since it’s postioned fixed, it does not actually matter, since the orientation for fixed is the viewport.

Off by one pixel issue in IE CSS transform

I am using transform: skew to create the effect of a down arrow on my banner image using both the :before and :after tags. The result should look like the following:
However, in IE 9-11 there seems to be a rounding issue. At some heights there is one pixel from the background image that shows below the skewed blocks resulting in the following:
In my case, the banner is a percentage of the total height of the window. Here is the some sample code which should be able to reproduce the problem:
HTML
<div id="main">
<div id="banner"></div>
<section>
<h1>...</h1>
<p>...</p>
</section>
</div>
CSS
#banner {
position: relative;
background-color: green;
width: 100%;
height: 75%;
overflow: hidden;
}
#banner:before,
#banner:after {
content: '';
display: block;
position: absolute;
bottom: 0;
width: 50%;
height: 1.5em;
background-color: #FFFFF9;
transform: skew(45deg);
transform-origin: right bottom;
}
#banner:after {
right: 0;
transform: skew(-45deg);
transform-origin: left bottom;
}
body {
background-color: #333;
position: absolute;
width: 100%;
height: 100%;
}
#main {
max-width: 40em;
margin: 0 auto;
background-color: #FFFFF9;
position: relative;
height: 100%;
}
section {
padding: 0 1em 5em;
background-color: #FFFFF9;
}
And here a working example.
Yes, seems to be a rounding issue – and I don’t know of anything that one could do to fix this. It’s in the nature of percentage values that they don’t always result in full pixel values – and how rounding is done in those cases is up to the browser vendor, I’m afraid.
I can only offer you a possible workaround (resp. “cover up”) that seems to work – if the layout really is as simple as this, and the main content area has a white background, and no transparency or background-image gets involved there.
Pull the section “up” over the banner by a negative margin of -1px (eliminated top margin of h1 here as well, otherwise it adjoins with the top margin of the section – countered by a padding-top), so that its background simply covers up that little glitch:
section {
padding: 1em 1em 5em;
background-color: #FFFFF9;
position:relative;
margin-top:-1px;
}
section h1:first-child { margin-top:0; }
Well, if you look closely, that makes the corner of triangle look slightly “cut off” (by one pixel) in those situations where the rounding glitch occurs – if you can live with that (and your desired layout allows for it), then take it :-) (And maybe serve it to IE only by some means). If not – then sorry, can’t help you there.

z-index is canceled by setting transform(rotate)

Using transform property, z-index is canceled and appeared in the front.
(When commenting out -webkit-transform, z-index is properly working in below code)
.test {
width: 150px;
height: 40px;
margin: 30px;
line-height: 40px;
position: relative;
background: white;
-webkit-transform: rotate(10deg);
}
.test:after {
width: 100px;
height: 35px;
content: "";
position: absolute;
top: 0;
right: 2px;
-webkit-box-shadow: 0 5px 5px #999;
/* Safari and Chrome */
-webkit-transform: rotate(3deg);
/* Safari and Chrome */
transform: rotate(3deg);
z-index: -1;
}
<html>
<head>
<title>transform</title>
<link rel="stylesheet" type="text/css" href="transformtest.css">
</head>
<body>
<div class="test">z-index is canceled.</div>
</body>
</html>
How do transform and z-index work together?
Let's walk through what is occurring. To start, note that z-index on positioned elements and transform by itself create new "stacking contexts" on elements. Here's what's going on:
Your .test element has transform set to something other than none, which gives it its own stacking context.
You then add a .test:after pseudo-element, which is a child of .test. This child has z-index: -1, setting the stack level of .test:after within the stacking context of .test Setting z-index: -1 on .test:after does not place it behind .test because z-index only has meaning within a given stacking context.
When you remove -webkit-transform from .test it removes its stacking context, causing .test and .test:after to share a stacking context (that of <html>) and making .test:after go behind .test. Note that after removing .test's -webkit-transform rule you can, once again, give it its own stacking context by setting a new z-index rule (any value) on .test (again, because it is positioned)!
So how do we solve your problem?
To get z-index working the way you expect, make sure that .test and .test:after share the same stacking context. The problem is that you want .test rotated with transform, but to do so means creating its own stacking context. Fortunately, placing .test in a wrapping container and rotating that will still allow its children to share a stacking context while also rotating both.
Here's what you started with: http://jsfiddle.net/fH64Q/
And here's a way you can get around the stacking-contexts and keep
the rotation (note that the shadow gets a bit cut off because of .test's white background):
.wrapper {
-webkit-transform: rotate(10deg);
}
.test {
width: 150px;
height: 40px;
margin: 30px;
line-height: 40px;
position: relative;
background: white;
}
.test:after {
width: 100px;
height: 35px;
content: "";
position: absolute;
top: 0;
right: 2px;
-webkit-box-shadow: 0 5px 5px #999; /* Safari and Chrome */
-webkit-transform: rotate(3deg); /* Safari and Chrome */
transform: rotate(3deg);
z-index: -1;
}
<div class="wrapper">
<div class="test">z-index is canceled.</div>
</div>
There are other ways to do this, better ways even. I would probably make the "post-it" background the containing element and then put the text inside, that would probably be the easiest method and would reduce the complexity of what you have.
Check out this article for more details about z-index and stacking order, or the working W3C CSS3 spec on stacking context
Set the div you want to stay on top to position:relative
Had a similar problem where siblings were being transform: translate()'d and z-index wouldn't work.
Most straightforward solution is to set position: relative on all siblings, then z-index would work again.
Quick fix: You could just rotate the other element by 0 degrees as well.
For those who still looking for the solution, I found this article how to solve issue with transform and z-index here
Simple usage of it is by doing this:
.parent { transform-style: preserve-3d; }
.parent:before { transform: translateZ(-1em); }
I was facing the similar problem.
What i did was, I added a wrapper div around the test and gave the transform property to the wrapper div.
.wrapper{
transform: rotate(10deg);
}
here is the fiddle http://jsfiddle.net/KmnF2/16/
Set the div you want to stay on top to position:absolute

div slanted in 2 directions

Is it possible to create the following shape as a DIV in CSS.
The browser support is not important.
You cannot skew an element like this directly, you'll need to use two elements (or generated content) and hide certain overflow to make the flat bottom edge:
http://jsfiddle.net/6DQUY/1/
#skew {
height: 240px;
overflow: hidden;
}
.skew {
background: #000;
display: inline-block;
height: 300px;
width: 500px;
margin-top: 100px;
transform: skew(-8deg, -8deg);
}
Note: I removed the cross browser definitions for better readability.
UPDATE: This would be a more fluid example which resizes in set dimensions: http://jsfiddle.net/6DQUY/3/. Note the padding-bottom on the wrapper which defines the ratio. You may have to play around with the percentage amounts.
#skew {
padding-bottom: 20%;
overflow: hidden;
position: relative;
}
.skew {
background: #000;
position: absolute;
top: 30%;
right: 8%;
left: 8%;
height: 100%;
transform: skew(-8deg, -8deg);
}
Using SVG:
Below is a sample using SVG polygon which can also be scaled easily. Text (if required) can be absolutely positioned on top of the shape.
.shape-svg {
position: relative;
height: 100px;
width: 300px;
}
svg {
position: absolute;
top: 0px;
left: 0px;
height: 100%;
width: 100%;
}
polygon {
fill: black;
}
/* Just for demo*/
.shape-svg{
transition: all 1s;
}
.shape-svg:hover {
height: 200px;
width: 600px;
}
<div class="shape-svg">
<svg viewBox='0 0 100 100' preserveAspectRatio='none'>
<polygon points='5,35 100,0 95,100 0,100' />
</svg>
</div>
The shape can be created using SVG clip path also instead of polygon.
Using CSS and Single Element:
The same shape can be achieved with CSS using only one element also. The key is to set the transform-origin as the side that is required to be straight.
.shape{
height: 100px;
width: 300px;
margin-top: 50px;
background: black;
transform-origin: 0% bottom;
transform: perspective(300px) rotateY(-15deg) skewX(-10deg);
transition: all 1s;
}
.shape:hover{
width: 350px;
height: 150px;
transform: perspective(450px) rotateY(-15deg) skewX(-10deg);
}
<script src="https://cdnjs.cloudflare.com/ajax/libs/prefixfree/1.0.7/prefixfree.min.js"></script>
<div class="shape"></div>
The shape achieved using this method can also be scaled. However as the height of the shape increases, the right side becomes taller and pushes the top-right corner even more higher. So, either the rotation angle needs to be decreased (or) the perspective needs to be increased (shape needs to be moved farther away) for the height of the right side to remain small enough and be within the viewing area. Or else, the margin-top should be increased.
Below is an explanation on why this happens:
Consider a rectangle positioned 300px in front of the viewer's eye. It is being rotated towards to the viewer and as the rotation happens, the side which is getting closer to the user will appear taller than the other side.
We have fixed the transform origin's x coordinate as 0% and so the height of the left side of the shape would be constant and that of the right side would keep increasing based on the rotation angle.
Because the transform origin's y coordinate is bottom, the bottom side of the shape would be kept straight and any height increase on the right side of the element would be projected upwards resulting in the shape going outside of the screen.
There is no such problem if only the width increases because the rotation angle is too minimal and so the shape's right side will never get anywhere close enough to the viewer to look very tall.
The shape in question is not an exact duplicate of the one discussed here but you can get some more ideas by looking at it :)
You could look into CSS transformations (transform) I have created a JsFiddle with a quick example.
HTML
<div class="skew"></div>
CSS
/* Skew the container one way */
.skew {
background: #000;
display: inline-block;
height: 50px;
width: 500px;
margin-top: 100px;
-webkit-transform: skewY(-5deg);
-moz-transform: skewY(-5deg);
-ms-transform: skewY(-5deg);
-o-transform: skewY(-5deg);
transform: skewY(-5deg);
}
NOTE:
You may need to include other transformations to get the unbalanced look.
--EDIT--
Here is another solution but using :before and :after CSS. JsFiddle.

Resources