Button font is rendered incorrectly when using pixel art TTF font

[boruok]

Godot version

v4.0.beta.custom_build [dcb3754]

System information

Ubuntu 22.10, GTX1060, Vulkan

Issue description

tried to use pixel-art .ttf font on my project. Looks like Button font renders incorrectly compared to other buttons (checkbutton, link...)

below is how it looks, from top to bottom Button, CheckButton, LinkButton, MenuButton. All have same font with same size. Only Button glitched

Steps to reproduce

1. open attachment
2. try to change button text

Minimal reproduction project

New Game Project.zip

[Calinou]

I can confirm this on v4.0.beta.custom_build [b6e0603] (Linux).

The issue doesn't occur if font size is decreased from 7 to 6 on the Button:

On the other hand, the other 3 nodes are using a font size of 7, not 6. The "u" also looks different on the Button compared to the other nodes.

There seems to be a off-by-one error in general: Button needs a font size that is 1 pixel smaller to look similar to other nodes' font sizes. Here's an example with Button's font size set to 13, and CheckButton/LinkButton/MenuButton set to 14:

All screenshots above were taken with a zoom of 200% (integer scaling) to avoid any artifacts.

cc @bruvzg

[bruvzg]

Button style box or/and text alignment is likely resulting in a non integer horizontal offset, which is in general fine.

Disable subpixel positioning in the font import settings and reimport the font, it's not suitable for pixel art fonts (but can improve rendering of the small sizes of the usual vector fonts).

[bruvzg]

Since the particular font in the MRP is a vector font, but with all vertices aligned to the pixel grid and only line segments, it's not possible to detect if it's a pixel art font automatically. But we probably should auto disable subpixel positioning for true fixed size bitmap TTFs.

[boruok]

@bruvzg thanks! solved.

[Calinou]

Reopening, as this needs to be documented on Using fonts.