eeeps / content-dpr-explainer Goto Github PK

See my description of the problem and a bunch of ideas about potential solutions here: httpwg/http-extensions#1102

TL;DR:

• Rounding errors w/ Content-DPR will often cause small layout jumps, in transitions between a placeholder and a full-resolution image
• More precision would allow us to solve this in one dimension only. More precision could be achieved by splitting the header value into integer and fractional parts (Content-DPR: int=1, frac=234567), or into a rational (Content-DPR: a=1234567, b=1000000).
• Specifying exact target intrinsic dimensions would allow us to solve it in both dimensions (for instance Content-DPR: w=871, h=576 or even Content-DPR: 1.234567;w=871;h=576;).

For this particular use case, exact dimensions would be best; failing that, more precision would be good; failing that, the current limitations... might be acceptable? Some things I'm noodling on:

• Not sure if intrinsic dimensions are confusingly outside of the scope of the Content-DPR name, or still aligned with the other use cases, such that everything still fits under the same umbrella.
• Not sure if this use case is important enough to merit it's own syntax or header.
• Not sure if the existing behavior, with small layout jumps, is "good enough."
• Pretty sure it would be harder to integrate exact intrinsic dimensions into HTML (this is not a dealbreaker, just work)

Why? To avoid resampling!

• cropping to block boundaries
• not rescaling on the server at all, up to some threshold

@nhoizey gave a bunch of great feedback, here: https://docs.google.com/document/d/1CBR_y_UKImis0wm7BubvUEs07v4fQMzeuSdHjuWij9g/edit

@malchata, in private conversation, mentioned that not understanding terms like "density-corrected intrinsic size" was a big blocker to understanding this stuff, when he was figuring it out. Maybe have a human-readable glossary, in addition to the links out to the spec text.