[Bug 16349] backface-visibility underdefined

https://www.w3.org/Bugs/Public/show_bug.cgi?id=16349

--- Comment #2 from Aryeh Gregor <ayg@aryeh.name> 2012-03-14 17:21:53 UTC ---
Please say if Safari on Mac displays red in any of these cases, and if so, why
you think it's right:

Test-case 1:

data:text/html,<!DOCTYPE html>
<div style="height:100px;width:100px;background:lime">
  <div style="height:100px;width:100px;background:red;
  -webkit-transform:rotatex(180deg);-webkit-backface-visibility:hidden">
  </div>
</div>

Test-case 2:

data:text/html,<!DOCTYPE html>
<div style="height:100px;width:100px;background:lime;
-webkit-transform:rotatex(180deg)">
  <div style="height:100px;width:100px;background:red;
  -webkit-transform:rotatex(180deg);
  -webkit-backface-visibility:hidden"></div>
</div>

Test-case 3:

data:text/html,<!DOCTYPE html>
<div style="height:100px;width:100px;background:lime">
  <div style="-webkit-transform:rotatex(60deg);
  -webkit-transform-style:preserve-3d">
    <div style="height:100px;width:100px;background:red;
    -webkit-transform:rotatex(60deg);-webkit-backface-visibility:hidden">
    </div>
  </div>
</div>

Test-case 4:

data:text/html,<!DOCTYPE html>
<style>div { width: 100px; height: 100px }</style>
<div style="-webkit-transform: rotateX(180deg); background: red">
  <div style="-webkit-backface-visibility: hidden; background: lime">
  </div>
</div>

Test-case 5:

data:text/html,<!DOCTYPE html>
<style>div { width: 100px; height: 100px }</style>
<div style="-webkit-transform: rotateX(180deg);
-webkit-transform-style: preserve-3d; background: lime">
  <div style="-webkit-backface-visibility: hidden; background: red">
  </div>
</div>

Test-case 6:

data:text/html,<!DOCTYPE html>
<style>div { height: 100px; width: 100px }</style>
<div style="background: lime">
  <div style="background: red; -webkit-backface-visibility: hidden;
  -webkit-transform: scaleZ(-1)"></div>
</div>

WebKit nightly on Windows 8 displays red in test-case 5, which I think is a
bug.  (It gets all the rest right.)  In support of the fact that this is a bug,
adding -webkit-transform: scale(1) to the inner div in that test-case makes
both the WebKit nightly and Chrome-with-GPU-acceleration display green. 
Firefox had this bug too until version 13; the problem is that it was assuming
that since there was no transform specified on the element, it didn't have to
pay attention to 3D rendering separately from the parent, so it didn't look at
backface-visibility.

If Safari on Mac gets all of these test-cases right, then it probably matches
my proposed spec change too.

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Received on Wednesday, 14 March 2012 17:22:00 UTC