- From: fantasai <fantasai.lists@inkedblade.net>
- Date: Tue, 14 Sep 2010 11:32:09 -0700
- To: Brian Manthos <brianman@microsoft.com>
- CC: "Tab Atkins Jr." <jackalmage@gmail.com>, Sylvain Galineau <sylvaing@microsoft.com>, "www-style@w3.org" <www-style@w3.org>
On 09/14/2010 02:17 AM, Brian Manthos wrote: > What does > Background-position: left 17px center; > serialize out as? > > "left 17px 50%"? > > That seems to collide with > "If three or four values are given, then each<percentage> or<length> represents > an offset and must be preceded by a keyword, which specifies from which edge the offset is given." > > Or are you saying center sometimes becomes 50% when serialized out, and sometimes doesn't? > > Actually... > Background-position: center right 15px; > ...is a better example because with the left example below you can get away with "17px 50%". Let's take a look at the Computed Value section of the property definition: http://www.w3.org/TR/css3-background/#the-background-position It says: # If one or two values are specified, for a <length> the absolute length, # otherwise a percentage. If three or four values are specified, two # pairs of a keyword plus a length or percentage. Further down the definition of 'center' says: # Equivalent to ‘50%’ (‘left 50%’) for the horizontal position if the # horizontal position is not otherwise specified, or ‘50%’ (‘top 50%’) # for the vertical position if it is. So your first example would compute to "left 17px top 50%" and your second example would compute to "right 15px top 50%". ~fantasai
Received on Tuesday, 14 September 2010 18:32:46 UTC