How do I unskew background image in skewed layer (CSS)? - css

Question

I'm trying to display a profile photo like this / - / (the slashes represent slants using skewX, the hyphen represents a horizontally-aligned background image).
The problem is that this code also skews the background image:
.photo {
transform: skewX(35deg);
-ms-transform: skewX(35deg); /* IE 9 */
-webkit-transform: skewX(35deg); /* Safari and Chrome */
width: 100px;
height: 92px;
border-right: 1px solid black;
border-left: 1px solid black;
background-image: url('silhouette.png');
background-repeat: no-repeat;
background-position: top left;
}
...
<div class="photo"></div>
I've tried to reverse the background skew like this:
.photo {
transform: skewX(35deg);
-ms-transform: skewX(35deg); /* IE 9 */
-webkit-transform: skewX(35deg); /* Safari and Chrome */
width: 100px;
height: 92px;
border-right: 1px solid black;
border-left: 1px solid black;
}
.photo div {
transform: skewX(-35deg);
-ms-transform: skewX(-35deg); /* IE 9 */
-webkit-transform: skewX(-35deg); /* Safari and Chrome */
width: 100%;
height: 100%;
background-image: url('silhouette.png');
background-repeat: no-repeat;
background-position: top left;
}
...
<div class="photo"><div></div></div>
...but I get / [-] / (the background doesn't fit flush to the slants).
I've been at this all day, please can you help me? I've got coder's bock!

Answer 1

I'd rather use a pseudo element that's holding the background-image. The key to the solution is using transform-origin:
Example
.photo {
transform: skewX(35deg);
-ms-transform: skewX(35deg); /* IE 9 */
-webkit-transform: skewX(35deg); /* Safari and Chrome */
width: 100px;
height: 92px;
border-right: 1px solid black;
border-left: 1px solid black;
/* new styles */
position: relative;
overflow: hidden;
-webkit-transform-origin: top left;
-ms-transform-origin: top left;
transform-origin: top left;
}
.photo::before {
content: "";
transform: skewX(-35deg);
-ms-transform: skewX(-35deg); /* IE 9 */
-webkit-transform: skewX(-35deg); /* Safari and Chrome */
background-image: url('http://placekitten.com/200/200');
background-repeat: no-repeat;
background-position: top left;
/* new styles */
position: absolute;
-webkit-transform-origin: top left;
-ms-transform-origin: top left;
transform-origin: top left;
width: 1000%; /* something ridiculously big */
height: 1000%; /* something ridiculously big */
}