1900 - Transparent background on HTML element causes undefined background

Status: VERIFIED FIXED

(Core :: CSS Parsing and Computation, defect, P2)

Description

[Hixie (not reading bugmail)]

What happens is that the following:

   HTML { background: transparent; }

...fails to draw the background, thus leaving an undefined mess.

See CSS1 spec for details on what exactly should happen.

Comment 1

[Hixie (not reading bugmail)]

Actually, it turns out that this behaviour is not against the spec.
See   http://www.w3.org/TR/REC-CSS1#the-canvas
...which says:

> If the 'background' value of the 'HTML' element is different
> from 'transparent' then use it, else use the 'background'
> value of the 'BODY' element. If the resulting value is
> 'transparent', the rendering is undefined.

...which is is!

I suggest reading "undefined" as "UA dependant" in non-strict-parsing
mode, and using the default window colour from the operating system.
As per "background-color:window;" from CSS2 - see
  http://www.w3.org/TR/REC-CSS2/ui.html#system-colors
for more details.

In strict-parsing mode, I would simply say
 "Cannot render document. Canvas color undefined."

Comment 2

[troy]

This is fixed now and we paint the background. We now have a root frame whose
child is the frame for the document element (in this case the HTML element). The
root frame draws its background using the default color.

Note we still have a problem mentioned below with the HTML element not using the
BODY's background if it has a value of 'transparent'. That's covered by bug
#2054