- From: Alan Gresley <alan@css-class.com>
- Date: Tue, 12 Apr 2011 04:36:36 +1000
- To: fantasai <fantasai.lists@inkedblade.net>
- CC: Simon Fraser <smfr@me.com>, Boris Zbarsky <bzbarsky@mit.edu>, Andrew Fedoniouk <news@terrainformatica.com>, Andrew Fedoniouk <andrew.fedoniouk@live.com>, www-style list <www-style@w3.org>
On 12/04/2011 3:36 AM, fantasai wrote: > On 04/11/2011 08:54 AM, Simon Fraser wrote: >> >> My proposal is to not have z-index applied to transformed elements. Please bare in mind that there are two things. The first is a 'stacking context' (some referred to as a stacking or painting layer) [1] and the second is a 'z-index or new stacking context' with a value that is not 'auto' [2]. Here are some details. | <integer> | This integer is the stack level of the generated box in the | current stacking context. The box also establishes a new | stacking context. | auto | The stack level of the generated box in the current stacking | context is '0'. The box does not establish a new stacking | context unless it is the root element. >> I'll work >> with Ted to propose some new wording for the spec. > > If you apply "position: relative" to the element, will z-index then apply? > > ~fantasai Opera, IE9 and Firefox are already painting the transforms as if they already had 'position relative' in respect to painting layer. If transforms cause a default behavior of 'position relative' then this would establish a new containing block. Do we want this? This is similar to the issue we faced a few years ago with box-shadow and text-shadow. Source order alone (normal painting behavior) was adopted as the spec for box-shadow and text-shadow. I think that we should step wisely with this. Here is a test case that shows how transforms are painted above a float when transitioning. Before and after the transition has taken place, the float is painted higher. http://css-class.com/test/temp/transform-transition-painting.htm The second example has 'position relative' on the float. This is strange for me since as a CSS author, I usually use to using 'position relative' to promote the painting layer (paint over), not de-promote a layer (paint under). [1] http://www.w3.org/TR/CSS21/visuren.html#x40 [2] http://www.w3.org/TR/CSS21/visuren.html#propdef-z-index -- Alan http://css-class.com/ Armies Cannot Stop An Idea Whose Time Has Come. - Victor Hugo
Received on Monday, 11 April 2011 18:37:10 UTC