GUI: Enable aspect ratio correction by default

[rootfather]

Currently, the aspect ratio correction option is disabled by default.

In my opinion, this option should be enabled by default instead, since probably most users tick it anyway and those that are not aware that such an option even exists will get the best gaming experience by default.

[csnover]

I think this is a good idea, and ties into the work that criezy was planning to do with improving the communication of pixel aspect ratios from the engines to the system (​PR#929). Once engines can communicate their correct PARs then we can invert this option to be some disabled by default thing labelled “Ignore pixel aspect ratio” instead.

[rsn8887]

I want to emphasize that two of my favorite games, Beneath a Steel Sky and Dreamweb, should have aspect correction disabled. There's also a discussion about pros and cons of aspect correction here: ​http://forums.scummvm.org/viewtopic.php?t=14460

Amiga versions of Lucasarts adventures also had big black bars on the bottom. They ran without aspect correction, and filled only 320*200 pixels on a 320*256 screen on the Amiga.

But since it is a user choice anyways, maybe a default state of ON is fine.

[csnover]

I think you’re confusing AR correction with the broken implementation of AR correction in ScummVM today.

The only technical problem with AR correction right now is that the engines can’t communicate the correct PAR to OSystem, and criezy is working on this. The correct PAR for DreamWeb (and a few SCUMM game versions) is 1:1. The correct PAR for almost all the 320x200 VGA games—and this is where the aspect ratio correction functions correctly—is 5:6. The NES version of Maniac Mansion is different than both of these and has a PAR of something like 8:7. This isn’t a “pros and cons” thing, unless you’re talking about how low-DPI monitors can’t interpolate without visible smearing. By default, AR correction fixes more games than it breaks now, and once PAR is communicated, turning AR correction off will result in image distortion 100% of the time. Given this, it makes way more sense for it to be on by default than off.

[sev-]

It is already happening, at least for OpenGL backend