Theme lookup in Godot 4.2

Question

Trying to understand how theme lookup works in Godot 4.2. Suppose a Control node script has the following two lines in it:

print(get_theme_font_size("normal_font_size", "RichTextLabel"))
print(theme.get_font_size("normal_font_size", "RichTextLabel"))

Can it ever happen that these two calls print different output? And if so, how?

Answer 1

These are, indeed, different.

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First of all, your Control might not have a Theme, and thus the line:

print(theme.get_font_size("normal_font_size", "RichTextLabel"))

Is an error (trying to call a method on a null value).

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But more importantly, using get_theme_font_size et.al. will have in consideration the theme overrides that might be set on the Control, while accessing the theme directly will not.

Note that different Control classes offer different theme overrides.

And yes, theme overrides are available even without a Theme.

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Addendum:

It is worth noting that it is intended that you set the Theme at the root of your UI, and all children Controls will use that same Theme, so you do not have to set the theme of every Control.

To be clear, the theme property is the Theme explicitly set on a Control. But a Theme might be applied on a Control because it is set on its theme property or on the theme property of one of its ancestors on the scene tree.

On the same logic, get_theme_font_size and similar methods will pick up the Theme that is applied to the Control, which might or might be set on the theme on the same Control or an ancestor.

By the way, theme overrides are specific of the Control. They do not propagate on the same manner.