fix: don't force 96 dpi

[Nerixyz]

Setting AA_Use96Dpi would fix fonts to a specific pixel/point size (usage in Qt). We want the fonts to scale and use the scale provided by the OS. I only tested this on Windows.

Fixes #5411.

Tests

The following tests should be done for each platform and configuration:

1. Dragging across screens of equal High-DPI scaling (if >1 screens) - are there issues or window size changes?
2. Saving on each screen - does the window appear at the same size when launched again?
3. Are the fonts reasonably sized compared to other apps?
4. Zooming in and out - does this look reasonable? Does saving work?

Platforms and Setups

• Windows
  • Single-monitor
    • 100% scale
    • >100% scale
  • Multi-monitor
    • all 100% scale
    • all >100% scale (but equal)
    • all >100% scale (different)
    • some 100%, some >100% scale
    • At least two setups from the linked issue (not sure what the exact cause is, probably the monitor)
• macOS
  • 100% scale
  • >100% scale (on a laptop)
• Linux
  • x11
    • 100% scale
    • >100% scale
  • Wayland
    • 100% scale
    • >100% scale

[pajlada]

Good catch!

Linux (Wayland w/ sway), 100% monitor

Text renders the same, icons render slightly different but only better from what I can tell

Linux (Wayland w/ sway), 150% monitor

Text is aliased differently, but I'm not 100% sure if this is due to screenshots scaling weirdly on sway. When I look at the monitor itself, everything looks very good still. Nothing has changed significantly in size.

macOS 200% monitor

Tab text size, Tab size, and chat text size are all smaller with this change. It's more in line with other texts (text input & chat header). Text still looks sharp. Overall I think this change is fine on macOS, but I could do more thorough testing in settings & menus to see if anything changes there.

macOS 100% monitor

Not tested yet

[karl-police]

I tested this on Windows with

set QT_SCALE_FACTOR_ROUNDING_POLICY=Round
chatterino.exe

And the Font Size in the chat was similar as commit Chatterino Nightly 2.4.6 (commit 4a5d4ef3) which is an older build, where things are "okay".

However, things that didn't scale with this, were badges and a lot of other things. But the badges were smaller compared to on the Twitch Website. Which is bad. It does fix the Tab widths though.

My LogPixels is at 120 on a laptop. I don't have multiple monitors to check other things.

Nightly 2.4.6

This build from this merge check artifact

On Twitch the badges actually scale slightly larger? They don't fit perfectly in the same "bar" as the font size of the username.

Turning Round off brings issues like these

which alter as you drag the window...

[Nerixyz]

But the badges were smaller compared to on the Twitch Website.

You only showed a screenshot from Chatterino.

This build from this merge check artifact

The badges in the second screenshot are 18x18 (original size) and in the first, they're 22x22, which is roughly $\frac{120}{96} \cdot 18 = 22.5$ We might need to look at the scaling there. Similar issues are likely with emote images.

Turning Round off brings issues like these
[...]
which alter as you drag the window...

This is a different issue - it's not the intention of this PR to fix this.

[karl-police]

Badge screenshot from website