CSS3

As you may (or may not) know, I’m an Invited Expert on the CSS Working Group at W3C. Mostly I talk about specs. But today, I’m going to talk about testing.

W3C is working on test suites for the CSS specs, and I wanted us to have more web authors involved. Many of you have been frustrated with the inconsistent levels of CSS support across browsers, and I believe collaborative testing is one of the major ways we can improve the situation.

The annual W3C Technical Plenary / Advisory Committee (TPAC) meetings week took place last month bringing together the CSS Working Group, amongst others, for a series of face to face meetings in Santa Clara, California. Minutes from the meeting have now been made available online and promise progress for a number of CSS3 modules including CSS3 Selectors, Multicolumn Layout, Transitions, Transforms and Animations.

The CSS Working Group just published a Last Call for Comments Working Draft of CSS Backgrounds and Borders Level 3. Please review the draft and send your feedback. We’ll be accepting comments through 17 November 2009. (Note that feature requests are likely to be deferred to CSS4.) The best place for feedback is the CSSWG’s official mailing list www-style@w3.org, but we’ll also look at any comments posted (or linked to) here on CSS3.info.

There are a couple issues we’re specifically looking for feedback on:

Rounding vs. Scaling Down

The round option for background-repeat and border-image-repeat resizes images to fit the nearest whole number of tiles, rather than always scaling up or always scaling down. Rounding keeps closer to the intended size and, in the case where one dimension is fixed (e.g. in ‘border-image’), keeps the image closer to the intended aspect ratio. This is almost certainly the best solution for vector images and high-resolution raster images. However, if the given image is a low-resolution raster image, it will require interpolating pixels, which can look bad. See Rounding Extremes for illustrations.

The workaround is to specify a higher-resolution image (e.g. by shrinking from the original with background-size or border-image-width). Possible spec solutions include introducing a separate keyword that always scales down, and changing the algorithm so that we force scaling down whenever interpolation would be required for scaling up. So the options here are

1. Leave the spec as-is (always round to nearest): the workaround is good enough for me.
2. Trigger forced downscaling when interpolation is needed: avoiding interpolation is important to me and I don’t mind that the exact number of tiles is unpredictable and the resulting aspect ratio might skewed a little extra.
3. Default to rounding for round, but I want an extra keyword to force downscaling in all cases (including vector images) because [...].
4. Something else?

Please comment on what you prefer and why. (The more specific you can be “for example, this image that I would want to use [...]“, the easier it will be for us to understand your point.)

box-break naming

The previous draft included two properties for controlling behavior at box breaks (line breaks / column breaks / page breaks): border-break for controlling whether the border is drawn at the break, and background-break for controlling whether the background is drawn for each box individually or for the whole element as if it were broken after painting.

Hyatt suggested merging the two, so the current draft has a single box-break property instead. The two values mean, basically, “render backgrounds and borders for this box, and then slice it up” and “break the box and then render backgrounds and borders for each box individually”. The value names aren’t particularly clear, however, so we were wondering if anyone has better ideas.

Conclusion

So take a look at the new draft and send us your comments! This is your last chance to give feedback on this module: if all goes well, we’ll be publishing the Candidate Recommendation in time for Christmas, and given the state of experimental implementations right now, I expect things to move rapidly from there.

The W3C have released an updated working draft of the CSSOM View Module, edited by Anne van Kesteren.

Many of the features defined in the CSSOM View Module have been supported by most browsers for a long period of time, with many tracing their routes back to Microsoft’s Internet Explorer. The goal of this specification is therefore not to reinvent the wheel, but rather to define these features in such a way that they can be implemented by all browsers in an identical way.

The W3C today announced the release of two new working drafts; the flexible box layout module and images values module.

Perhaps foreshadowed by Google’s adoption of HTML 5, Jeffrey Zeldman pointed out late last week; the future of XHTML 2 is no more. Obviously the selectors we use in CSS 3 depend on the underlying markup we work with, so this news is very interesting and we think timely. As CSS 3 support inches forward with each browser release and as JavaScript libraries supplement poor browser behavior, the need for web developers and enthusiasts to be able to focus their attention has become a paramount concern.

News about developments in CSS 3 is hard to come by at the moment, so please forgive the slow rate of updates on the site in the last month. I attended the @media conference here in London last week and news on progress in CSS was noticeable by its absence, when even HTML 5 had its own session.

I see that Bert Bos has delivered a couple of presentations on the Template (formerly ‘Advanced’) Layout Module, but I can’t find slides of them anywhere. If anyone attended the talks and can send us copies, do please get in touch.

Other than that, the only news is that the CSS WG have released their list of expected module deliverables; the modules listed in the 2007 snapshot along with Media Queries look set to be Recommendations shortly, with many others to take on Candidate Recommendation status.

And that’s it. Sorry there isn’t more, or that it isn’t more exciting. I’m aiming to put together a load of new examples soon, so that should be more interesting!

Update: As mentioned in a comment below, no sooner do I say there’s not much going on than David Baron announces that the remaining CSS3 selectors have been implemented in a build of Mozilla (which will probably be seen in Firefox 3.1), and Media Queries are set to follow. That’s good news.

Over at Design Shack they’re four posts into the five-post Introduction to CSS3, which covers Borders, Text Effects, the User Interface and (coming soon) Multiple Columns. A nice intro to the subject if our own examples are too complicated for you :p

The new owners of the Fonts and Web Fonts modules, Jason Cranford Teague and John Daggett, say that only about 20% of the Web Fonts module is required for CSS (it is currently part of the SVG charter), and propose simplifying it before merging with the Fonts module. They hope to have a working draft of the new spec in August.

The closing date for letting the W3C know your priorities for CSS3 is Monday, March 10th. If you want to help shape the future of CSS, get over to webstandards.org and leave a comment now.

Is there ever a time when you wish CSS allowed you to apply style in ways that either are not currently possible, or require hacks and extra markup to make it possible? Well now is the chance to let the working group know exactly what you want. Bruce Lawson is collecting your feedback on the WaSP site. Go there and leave a comment outlining what effects you’d like to achieve. You can also leave feedback on the CSS3 Soapbox.

Remember that the Working Group want examples of what you are trying to achieve, so that they know if current proposals fit that need, or they can think about adding new functionality. Also state why you want to be able to do that, if it isn’t obvious. They are not looking for feedback on syntax, so just leaving a list of new properties you want added won’t be helpful. Also try to check the latest draft modules to see if your proposal is already possible. Things like rounded corners (border-radius) and striped tables (tr:nth-of-type(odd); or nth-child(even); etc.) are already possible. There may be things that you want to be able to do with a property that isn’t possible in the current spec (such as being able to have an inverted rounded corner using border-radius for an example off the top of my head). If this is the case then the suggestion will be very much worthwhile.

Also remember that there is no guarantee that things you suggest will be added to the spec, even if it makes sense, and is technically realistic to achieve.

We at CSS3.info are planning to have a wiki (or similar system) to collate feedback on CSS3 in one place, which can be referenced easier than a mailing list. We will include the most popular suggestions from the WaSP post (with full attribution) when the wiki is in place, and open it up to the public to edit. If suggestions get added to the spec, we can also include the syntax that will achieve that suggestion, and eventually a demo that will produce the same result, once it gets implemented.