Oversampling, or scaling down

Posted Nov 14, 2014 10:04 UTC (Fri) by roc (subscriber, #30627)
In reply to: Oversampling, or scaling down by epa
Parent article: High-DPI displays and Linux

I mean Firefox scales arbitrary Web pages by fractional scales and they almost always look fine. Those Web pages use complex layouts and generally were not tested over a range of scale factors.

Oversampling, or scaling down

Posted Nov 18, 2014 5:32 UTC (Tue) by quotemstr (subscriber, #45331) [Link] (4 responses)

Thank you. It's frustrating how some people say that "$X is impossible!", and then when confronted with an existence proof of $X, just reiterate the claim that "$X is impossible!".

Fractional scaling in practice works fine; thanks for implementing it in Firefox. I hope the Wayland people come around: for some hardware (like mine), fractional scaling is precisely the right thing. Not everyone owns a Macbook.

If the Wayland developers persist in supporting only integer scaling factors, I suspect desktop environments will just hardcode 1x scaling and make toolkits do fractional scaling, which will be a mess all around.

Oversampling, or scaling down

Posted Nov 19, 2014 9:28 UTC (Wed) by epa (subscriber, #39769) [Link] (3 responses)

I think the point is that there's an existence proof of many legacy programs from the 2000s and 1990s which produce a nasty-looking mess when asked to scale by 3/2 (let alone, say, 4/3). That does not negate the existence of a large body of carefully written programs (of which Firefox is one) which handle arbitrary scaling perfectly. But it is (I presume) the reason why Apple chose to scale by an integer factor and then resize in the GPU if necessary. I quite agree, if starting from scratch then arbitrary dpi need to be supported.

On Linux, the legacy programs may often be ones using X11 server-side fonts. Currently X ships with 75dpi and 100dpi bitmap fonts. If it included 150dpi and 200dpi sets, programs like xterm could use those and so scale up nicely.

Oversampling, or scaling down

Posted Nov 20, 2014 21:48 UTC (Thu) by quotemstr (subscriber, #45331) [Link] (2 responses)

Firefox manages to render plenty of legacy websites that were not designed to be resolution-independent and scale them by fractional values. *That's* the point.

Oversampling, or scaling down

Posted Nov 20, 2014 22:16 UTC (Thu) by dlang (guest, #313) [Link]

HTML is designed to be resolution independent

A lot of web designers have been working hard ever since to undermine this design, but they have had limited success

Oversampling, or scaling down

Posted Nov 21, 2014 11:26 UTC (Fri) by epa (subscriber, #39769) [Link]

An HTML document is not a computer program and does not contain code for scaling glyphs or icons to a particular size. Firefox is, and contains well-written code for those tasks. You may as well say that plenty of legacy Microsoft Word documents can be scaled by fractional values when viewed in Microsoft Word.

Grab a PC running Windows 7 box and set it to 150% font scaling, then try a random assortment of third party software written before 2010. You will see the mess I am talking about - and I assume the situation with older Mac OS X programs is the same.

It is great that Firefox scales well and I quite agree it proves that scaling by an arbitrary factor is *not difficult*. That has very little bearing on whether existing programs, which exist in binary only form and cannot be modified, implement non-integer scaling reasonably. Even if 90% do so, ten per cent do not.