- From: Dirk Schulze <dschulze@adobe.com>
- Date: Fri, 3 Oct 2014 17:15:56 +0000
- To: Tab Atkins Jr. <jackalmage@gmail.com>
- CC: www-style list <www-style@w3.org>
On Oct 3, 2014, at 6:25 PM, Tab Atkins Jr. <jackalmage@gmail.com> wrote: > On Fri, Oct 3, 2014 at 2:58 AM, Dirk Schulze <dschulze@adobe.com> wrote: >> >> On Oct 2, 2014, at 10:57 PM, Tab Atkins Jr. <jackalmage@gmail.com> wrote: >> >>> Currently, the image-set() function forbids more image-set()s from >>> nested inside of it, either directly or inside of other <image> values >>> (like nesting within a cross-fade()). >>> >>> On the call two weeks ago, I said that I don't think this restriction >>> is actually needed. It was originally added due to the complexity of >>> handling fallback across nested things, but we removed the fallback >>> ability so that we could later produce a well-tuned fallback() >>> function or something similar that handled all the fallback properly. >>> >>> Now, though, it shouldn't be hard. Nesting them is still *weird*, and >>> there's no reason to do so, but there's no reason to *restrict* it, >>> which requires additional code to detect and enforce. >>> >>> (I don't currently properly define how the resolution change actually >>> gets applied to the image; however I define it, some answer will fall >>> out for what nesting them means. The actual answer isn't important, >>> because there's no use-case for nesting them.) >> >> Would it be harmful to investigate in a later version of the spec? In general I like the idea but think that browser need to catch up first. Deep nesting can be tricky. What about a MAY in the spec that turns into a MUST later? > > What do you think might be tricky about deep nesting? You just > process at the top level based on the information at that level > (<resolution>), and make a choice. If that choice is a function, you > turn that into an image somehow; this might involve processing a > second image-set(). Eventually you bottom out into either a url or a > generated image, along with an intrinsic resolution override. It happens quite often that “just” turns out to be trickier than expected. Greetings, Dirk > > ~TJ
Received on Friday, 3 October 2014 17:16:26 UTC