[CSS2.1] background-position poorly defined

Background-position is defined by example, not by rule:

   # <percentage>  <percentage>
   #    With a value pair of '0% 0%', the upper left corner
   #    of the image is aligned with the upper left corner of
   #    the box's padding edge. A value pair of '100% 100%'
   #    places the lower right corner of the image in the
   #    lower right corner of padding area. With a value pair
   #    of '14% 84%', the point 14% across and 84% down the
   #    image is to be placed at the point 14% across and 84%
   #    down the padding area.
   # <length> <length>
   #    With a value pair of '2cm 1cm', the upper left corner
   #    of the image is placed 2cm to the right and 1cm below
   #    the upper left corner of the padding area.

0% 0%, 100% 100%, and 14% 84% are defined but other percentage
pairs technically are not. I suggest adding some text to fix
this, maybe:

   <percentage> <percentage>
      A percentage pair X% Y% aligns the point of the image X%
      across the image (from the left) and Y% down the image
      (from the top) with the point X% across the element's
      padding box and Y% down the element's padding box.
      ... current examples ...

   <length> <length>
      A length pair X Y places the top left corner of the image
      a distance X to the right and a distance Y below the top
      left corner of the element's padding box.
      ... current examples ...

~fantasai

Received on Monday, 9 April 2007 20:43:28 UTC