- From: Dael Jackson <daelcss@gmail.com>
- Date: Mon, 13 Feb 2017 20:20:50 -0500
- To: www-style@w3.org
=========================================
These are the official CSSWG minutes.
Unless you're correcting the minutes,
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with an appropriate subject line.
=========================================
CSS Color
---------
- The issue of what happens to rgb() etc with Working Color Spaces
will be moved to another day when ChrisL & dino are available.
- RESOLVED: Add color computation section to color spec.
- The resolution of currentColor for color property will change
from used value time to computed value time.
- Florian will test border-color:transparent to see if
implementation is different from the spec.
- RESOLVED: Add that if you transition to/from current color use
numeric value
- Before the Color spec can include a reference to DCI P3 Chris
will need to investigate how to get it to comply to the W3C's
normative reference policy.
===== FULL MINUTES BELOW ======
Agenda: https://wiki.csswg.org/planning/seattle-2017
Scribe: nainar
Summary of morning
==================
[There was a brief summary of topics covered during the morning
breakout. See parts I through III of 2017-01-11 minutes.]
CSS Color
=========
What happens to rgb() etc with Working Color Spaces?
----------------------------------------------------
<nainar> https://github.com/w3c/csswg-drafts/issues/481
dino: The rgb function defines srgb values
dino: Change the core function like name/color ...
<dino> we do blending in non-linear sRGB
<dino> keeping the rgb() things in sRGB is going to be a pain for
the user
<dino> they'll have to convert everything
<dino> If the working color space is only for blending, then I
don't expect it to be useful. What's more important to
blending is whether you do linear or not. Microsoft had
some thoughts on this.
<dino> Note that colors won't change on existing documents. This
is only for documents that explicitly say "Hey, I want to
use AdobeRGB"
<dino> And I think there is a difference between the working color
space and the way you do blending of transparent colors.
For example, we technically don't do it right in sRGB at
the moment (we = CSS)
Florian: Color interpolation will be calculated according to color
space.
Florian: If you want to do outside of gamut you want to use color
space.
dino: You already have to address color outside the gamut.
dino: Authoring tools set a working color space - anything in the
space requires you to set all the colors.
Florian: If you set color in p3 > sgb and your working space is
srgb - you will have a problem.
dino: Exactly what we have today.
Florian: Everything collapses to srgb.
dino: we draw them like ???
dino: apple hardware - retina/iMac - displays that support more
than srgb
Florian: What you are doing is having the working color space be
the output device color space.
SteveZ: There is a fusion between what author see and
implementation sees.
SteveZ: dino is talking about color space sees.
Florian: I am speaking of space in which you do color math.
Florian: Putting two transparent colors over each other - that is
the working color space.
<smfr> https://drafts.csswg.org/css-color/#working-color-space
smfr: Working color space - author of doc says I want color space
to be p3 - then uses rgb color - the component is
interpreted in working color space.
Florian: What if you don't define it?
smfr: It means that things specified in srgb will be rendered in
srgb
Florian: What if you have a semi transparent color over srgb?
which space do you calculate in?
smfr: We will use the display color space.
Florian: In non linear - which is not specified outside srgb gamut.
smfr: On mac we will use something ??? p3, on iOS we use unclipped
sRGB - allowed to go below 0 and greater than 1.
Florian: The working color space is the output in that case - and
I want to preserve that - so that if you specify p3 -
they continue to use srgb space.
Florian: One reason I am thinking is consistency, and other reason
is if you want to switch color space - it is prettier if
you want to work in the math space, keeping legacy color
notation as always in srgb is better to me.
smfr: That's not how authoring tools work - you choose outside of
srgb then you automatically want to use srgb space.
smfr: We have asked adobe in the past about what they think
authoring tools should use.
Florian: Is this good authoring practice - don't get that from
adobe input.
Florian: If you mix stylesheets from origin - switching rules in
one style sheet messes with the other stylesheet which is
not nice.
Florian: Can we really have this discussion without Chris Lilley?
SteveZ: Legacy color was defined to be srgb - changing now will
have unfortunate consequences - people don't expect that.
SteveZ: If you could specify the color space - you wouldn't use
unless you wanted srgb.
Florian: Our current function doesn't have the s ahead of rgb().
astearns: Come back when we have dino and Chris Lilley.
Computed and used values for <color> values
-------------------------------------------
<nainar> https://github.com/w3c/csswg-drafts/pull/871
Florian: Came out of parallel discussion - color values aren't
used in color property only.
Florian: We want these places to do computed/used values the same
way.
Florian: We have defined this for color property not color value
type - caretColor asks that you do the same as color
property with changes.
Florian: Define in one place how color works - inherit/non inherit.
Florian: Pull request has proposed definition.
Florian: Current color boils to current color - at used value time
- same as parent, case of everything else (other than
color) - used value is same value as used value property.
dbaron: Move from way it was done till now.
dbaron: looking at old spec its clear.
Florian: Is this way of trying to define the behavior the way to
go? Seem sane to have section in css color space that
defines computed and used value?
dbaron: Reasonable to have section.
RESOLVED: Add color computation section to color spec.
Florian: At computed time color value becomes inherited for the
color property.
astearns: Section would say here is how color values work, and
color property would refer to it except for exceptions.
Florian: Hard to observe given that computedStyle gives you used
value at serialization time.
Florian: We use this for animation purposes, color value is a
keyword but we still interpolate from number value.
dbaron: Let's specify for color value, as better than current
color walking up the tree to look up the color property.
Florian: I'll take that feedback in - left undefined with issues
serialization for all the new values will be.
Florian: rgb/rgba/named colors/ hls? - documented the
interoperable behavior.
Florian: One thing where we don't have interop is when you
serialize color that is transparent and has value other
than 0 in rgb channels.
Florian: Gecko serializes transparent as transparent the keyword.
fremy: Difference between 0,0,0,1 and 0,0,0,0.
Florian: They behave the same except for gradients - for
transition we are fully interoperable - gradients safari
disagrees.
Florian: We want to be able to opt in to be different good thing
is with serialization is different.
dbaron: If you want 0,0,0,0 -> serialize as transparent
Florian: No one serializes that as transparent other than Gecko.
Florian: Talking about computed style not used style serialization.
zcorpan: The spec says to serialize as rgb or rgba.
Florian: We might need to errata color-3.
astearns: New section goes into color-4?
Florian: Yes and then see what needs to go as errata in 3.
<zcorpan> https://drafts.csswg.org/cssom/#serialize-a-css-component-value
zcorpan: The css spec will use rgb or rgba.
Florian: Is this computed value serialization?
zcorpan: It's used for both computed and specified value, I think
... depending on context.
Florian: The OM spec seems to be specifying string level, once you
are in rgb tells you where to put spaces not when to use
rgb.
<dbaron> https://bugzilla.mozilla.org/show_bug.cgi?id=347912
dbaron: Serialization principles I described to you yesterday -
serialize to most compatible form between old and new
syntax.
dbaron: border-color: transparent goes back to CSS1, and I didn't
want to suddenly start serializing that as rgba(0, 0, 0,
0).
fremy: If you write transparent - we serialize as transparent,
otherwise we return rgb if specified so
fremy: because of devtools.
zcorpan: Fair enough.
ACTION Florian change from used value time to computed value time
the resolution of current color for color property only.
<trackbot> Created ACTION-811
ACTION Florian reread old OM spec to see what to take from it
<trackbot> Created ACTION-812
zcorpan: For color the om spec differentiates between specified
value and other
zcorpan: <reads spec>
<dbaron> border-color: transparent goes back to CSS2, not CSS1:
https://www.w3.org/TR/1998/REC-CSS2-19980512/box.html#border-color-properties
<dbaron> but it's still older than css3-color
ACTION florian test border-color:transparent to see if its
different
<trackbot> Created ACTION-813
Florian: Once I have adjusted my stuff for OM - do we have section
in both color and OM spec?
Florian: OM doesn't look like the correct place to specify that.
astearns: For new things like shape function there is a
serialization in Shapes spec.
Florian: Use hooks into CSSOM and put the prose in the color spec?
zcorpan: File issues for each case?
Florian: By PR try to fix the OM spec OR migrate it to color spec
and pull out of OM spec
Interpolating between color spaces
----------------------------------
<nainar> https://github.com/w3c/csswg-drafts/issues/883
smfr: Interpolation between color p3 and blue/rgb something.
Florian: This is what the working color space - in which you do
color interpolation.
smfr: Not the same as implementation may pick a color space that
is different.
surma: Is the question the bigger color space easy to answer?
many people: No.
Florian: Come back after ChrisL has written it up - and then be ok
with or file issues on it
Animating to/from currentColor
------------------------------
<nainar> https://github.com/w3c/csswg-drafts/issues/873]
Florian: We are all interoperable - in transition/animation -
currentColor you can transition to and from - probably
should specify this.
dbaron: This is what we thought we were ok with breaking when we
decided to change currentColor to a computed value - no
one was ok with breaking it.
Florian: We should add sentence to the transition spec where you
define how to interpolate on color.
Florian: If you transition to/from current color use numeric value.
fremy: Doesn't work in edge
fremy: unless you use transparent.
dbaron: Bug maybe?
dbaron: Color is special because currentColor means inherit.
border-color is most interesting because currentColor is
the initial value.
fremy: probably a bug?
<fremy> xbody { color: rgba(300, 100, 100, 0.5); } xbody { color:
transparent; } body { color: rgba(0,0,0,0); }
<fremy> https://jsfiddle.net/byuusg4w/
<smfr> https://jsfiddle.net/1pt1qzwg/
<fremy> https://jsfiddle.net/byuusg4w/1/
gregwhitworth: Maybe our assumption of the usage of currentColor
is different from the way it is actually used.
fremy: Implicit works, specifying currentColor doesn't work.
gregwhitworth: smfr on yours ours works.
Florian: The spec doesn't say - and should say something.
Florian: If you transition to/from current color use numeric value.
astearns: Are there concerns about interoperability - everyone ok
with changing to this behavior?
Florian: If not what other behavior should we considered.
RESOLVED: Add that if you transition to/from current color use
numeric value.
Specification for DCI P3
------------------------
<astearns> https://github.com/w3c/csswg-drafts/issues/294
tantek: This is a problem with color we had before - what if
something normatively references a standard - subsequent
to that organizations like w3c have specified what they
mean by open standard.
tantek: No spec to reference that complies with open standard
principles - the w3c has a policy of what we should/
shouldn't reference.
Florian: Chris meant that there is not that there is no spec to
point to, but that a ??? spec doesn't exist to.
tantek: You mean a delta spec?
Florian: Who owns that spec? DCIP3
<tantek> FYI: https://open-stand.org/
<tantek> FYI: W3C Normative Reference Policy
https://www.w3.org/2013/09/normative-references
astearns: Proposal to reach out to them to see if some doc could
be given to w3c as member submission?
Florian: What Chris has written in github can we inline this?
tantek: Not doable unless you have read that spec.
dbaron: What he is talking about is the delta from the DCI p3?
tantek: I'm taking Chris's word for it.
dbaron: Has he read it?
astearns: Who in w3c will be go between?
tantek: Who owns it? Are they w3c memebrs?
???: Who presented this at TPAC?
dbaron: That's the person Chris mentions talking to at TPAC
astearns: Not listed as a member.
dbaron: Maybe it's another membership organization and there are
???
tantek: Unless you are a member you can't submit it.
astearns: We cant figure this out here - something that Chris
needs to work through with w3c management.
tantek: Specially if to implement that keyword you need to
normatively reference that.
astearns: That's all we can get to know, thanks for headsup - talk
to Chris
tantek: Crossed my radar - apple announced in 2016? the P3 stuff
and then raised the threshold that this might take off.
tantek: There was a blog post by cofounder of instagram that they
will support this - which is a wrap around webview
tantek: Once you had people using this supporting this becomes our
issue.
gsnedders: They had no plan to support this on their website.
Florian: Yeah but people will take images and reference the colors.
ACTION astearns to work with Chris to figure out what to do with
the epc for DCI p3
<trackbot> Created ACTION-814
smfr: This is supported in Safari review not behind a flag.
astearns: Safari doesn't pick up everything in the preview.
tantek: But web devs can experiment with by downloading the
preview.
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Received on Tuesday, 14 February 2017 01:21:56 UTC