Re: [css-compositing] Additional blend modes

On Fri, Sep 14, 2012 at 11:27 PM, Dean Jackson <dino@apple.com> wrote:

>
> On Sep 14, 2012, at 9:11 AM, Rik Cabanier <cabanier@gmail.com> wrote:
>
> We've been getting many requests from designers and web developers to add
> Photoshop's blend modes to the current working draft.
> They felt that these blending modes are commonly used and are needed to
> achieve certain effects.
>
> I propose that we extend the current list of blending modes with these
> values:
>
> Linear dodge
> Linear burn
> Vivid light
> Linear light
> Pin light
> Hard mix
> Divide
> Subtract
>
> These blend modes are not in the PDF spec. I checked the open source
> browsers (and Apple's CoreGraphics) and they don't have an implementation
> for them which may slow down their adoption.
> If there are no objections, I will update the spec with the blend formulas
> and example bitmaps.
>
>
> I'd like to know how often these are used in practice. My (limited)
> understanding is that the vast majority of cases use a small subset of
> blending operations. As you mention, we don't necessarily support these at
> the low-level, which complicates the implementation. I don't want to fill
> the list for completeness - I'd prefer to have more justification.
>

True. I don't know how often these are used either.
I talked to some people on the Photoshop team and they were also unsure of
their popularity. I didn't put them in at first because I had the same idea
as you: start small and add more later following user demands.

I will hold off on adding them for now.


>
> This is fairly similar to the idea of adding more canned filter effects -
> that represent the popular visual designs of today (not 1999 when the
> filters were first proposed). I'd love to suggest more, but I also want to
> wait to see how people use the small set we have given them, before being
> able to argue for expanding the feature.
>
> Thanks!
  Rik