Re: [compositing] Various small fixes for Compositing & Blending Level 1

Thanks for your feedback Amelia!

On Fri, Mar 6, 2015 at 12:02 PM, Amelia Bellamy-Royds <
amelia.bellamy.royds@gmail.com> wrote:

> 1) Examples and figures don't match
>
> A number of the examples in the Compositing & Blending Level 1 spec use
> the color keyword `green` (#080) in the code, but the figures are clearly
> using `lime` (#0F0):
>
>    - Example 1 (either the code or the figure could be changed)
>    - Example 2 (to get the primary/secondary color effect, you really
>    need to use #0F0)
>
> Fixed


> Also for Example 2, to create the figure as shown, the code should include
>
> svg { isolation: isolate; }
>
>
During the last TPAC, it was decided that the <svg> element creates a
stacking context. Previously, the spec called out this element as not
causing isolation but people felt that consistency was more important.
So, the special case was dropped and someone was going to update (or
create?) a spec to clearly say what causes stacking contexts.

Currently only Firefox is following this rule.


> As it is, screen mode applied to the default white page background results
> in all white.  (If browsers are supposed to treat the root element canvas
> as transparent black, then that needs to be stated somewhere and
> implementations need to update their behavior.)
>
> Alternately, since Example 2 comes before the discussion of the
> `isolation` property, it might be easier to simply add the rule
>
> svg { background-color: black }
>
>
> And update the figure accordingly.
>
> See http://fiddle.jshell.net/cghv8k0j/ in a browser that implements the
> blending spec.
>
> 2) There is some mangled markup in the spec.
>
> The most serious effect is that the `background-blend-mode` property is
> not being correctly listed in the table of contents.  This is showing up in
> both the Editor's Draft and the published spec.
>

Fixed


> 3)  `background-blend-mode` is a CSS property, not only for HTML
>
> The table for  `background-blend-mode`  says "Applies to:All HTML
> elements".  However, it could apply to any XML content that uses a CSS
> layout model.  That includes a top-level inline SVG element; in practice
> (and probably in SVG 2) it would also include a root <svg> element.
>
> A more useful and future-proof description would be "Applies to: Any
> element that renders the `background-image` property".  Another way to make
> the same distinction is to use the language from the Transforms spec
> is "elements with (or without) associated CSS layout box".
>

That would be a normative change which would push the spec back.
Maybe we can address this in level 2?