[Bug]: Interface including fonts and viewports doesn’t scale properly on Mac OS with retina display

[dpk]

Version of OpenTTD

OpenTTD 13.1, also current nightly (20230415-master), Mac OS 13.3 (ARM)

Expected result

Opening OpenTTD on a Mac with a retina display and setting interface scaling to 2x should cause everything, including fonts, to scale. Only the margins around the fonts changes. The scale of the actual game is also too small, including in the startup screen.

Actual result

1x scaling, everything ‘correct’ in terms of proportions but too small to be seen on a high-resolution screen:

2x scaling, margins around interface elements increased but nothing else, and everything still too small to comfortably read:

If I enable ‘Auto-detect size’, it just changes to 2x scaling and looks exactly the same as when I select that manually.

Steps to reproduce

Open OpenTTD 13.1 on Mac OS. Fiddle with the Interface scale option in Game Options.

I’m using the original_windows graphics set, if that might make a difference. @LordAro suggested this might also be helpful info:

[glx22]

Sprite font is not resizable, but you can set a TrueType font with the font command.

[LordAro]

That's not true, it resizes for me on Linux

[dpk]

To show this is a regression at some point, this is what it looked like on the last version of OpenTTD I played before trying again today, 1.9.0 from 2019 (under Rosetta):

I consider this to be the correct behaviour in all regards. (The ‘interface size’ option is set to ‘normal’.)

[PeterN]

This happens if you've changed the max sprite zoom setting to be 1x instead of 4x

[2TallTyler]

Related issue of that setting changing things it probably shouldn't: #8873

[PeterN]

Hmm, that one is even worse as those gui sprites are handled in the same way as viewport sprites, and some sprites are drawn in both viewport and gui. At least fonts is an easier case to deal with :)

[dpk]

This happens if you've changed the max sprite zoom setting to be 1x instead of 4x

I assume you mean this setting:

As you can see, I have it set to 4x and the wrong result is the one I get. (Changing it doesn’t seem to affect anything at all, at least on the startup screen.)

[PeterN]

Ah, not that one, "Maximum zoom in level".

[dpk]

I have that set to ‘Normal’ (and the corresponding zoom out to 8x). As far as I know, I’ve never touched these settings.

[PeterN]

Change it to 4x. 4x is the default value, normal means 1x. The context is a bit wrong for how it ends up being used here...

You'll also need to tweak the interface scale again to make it reload after this change (or just restart the game.)

[dpk]

Aha, that did indeed fix it!

So I think there are two usability issues here:

1. I’m pretty sure I was using the default setting for this, but if not, it was something taken over from an older version of OpenTTD which worked and made sense there, but the same setting caused broken scaling on 13.1. If it was just an issue to do with interpretations of legacy values of an equivalent setting, maybe it’s not worth doing anything about.
2. I actually tried changing the setting when you pointed out which one but I assumed it didn’t work because nothing changed when I changed that setting alone. Changing that setting should probably cause a total interface redraw at the intended scale.

[PeterN]

You are right, this setting didn't previously affect font sprites before 13.0.