Font Weights

[John Hendrikx]

On 29/05/2025 18:23, Dirk Lemmermann wrote:
> Hi everyone,
>
> Is there any chance we can get font weight working properly so that I can use a font with medium boldness and use it by declaring: -fx-font-weight: bolder; or by declaring -fx-font-weight: 600;? I know I can work around it by using the font family name, e.g. „Rubik Medium“ but this makes it impossible to replace the font at runtime, which is a requirement I am facing right now in order to support users with dyslexia. I was also considering using a variable but this is not supported for font family names (e,g, „-my-font; „Rubik Medium“).
Just curious, how would a variable help here for the problem having the
font selectable at runtime?
> Any other work arounds I am missing?

I don't have any easy solutions here, and I'm unsure what is involved in
actually making -fx-font-weight work better.

So, all I can offer is something very ugly like having the user select a
font, then generating a CSS file, and setting that on the root node; if
you keep the styles for font selection separate it may be doable as
you'd probably could get away with just replacing a single stylesheet
then (ie. mark a TextField with ".font-large" specifically and define
what that means in the custom CSS file).  This is a bit anti-CSS as
you'd prefer to mark such nodes only with their intended function, and
determine a suitable font based on that, but styles in FX don't compose.

If you're willing to go in the direction of generating all CSS files
based on LESS or SCSS (at runtime mind you, I hate doing this during a
build), more is possible:

What I've been doing myself (although I don't allow runtime selection)
is to allow users to modify CSS files; using LESS or SCSS one can neatly
pack all font related stuff into a single file, so I've sort of solved
this by having a `fonts.less` (see below).  I then mark styles with one
of the custom styles (.light, .regular, etc) to indicate what final font
they'll be using.  However, to make this work even at run time, I'd have
to regenerate all derived CSS files (but as I said, I can do this at
runtime anyway) -- so the effort is in then primarily in auto-generating
a base fonts CSS file given some user selection, then replacing all
stylesheets that were set throughout the application (or just restarting
the application).

For now a user could do this manually by only editing `fonts.less` and
then (re)starting the application.

Here is the fonts.less file I was talking about (note: there is also a
Linux variant as fonts work differently on different platforms as
well... perhaps MacOS needs a modified one also, but I never tried there)

fonts.less:

/*

* The Noto Sans font supports many variations. To get the correct variation

* in JavaFX, select them as follows:

*

* - Black = Noto Sans Blk

* - Bold = Noto Sans + font-weight: bold

* - Semi Bold = Noto Sans SemBd

* - Medium = Noto Sans Med

* - Regular = Noto Sans + font-weight: normal

* - Light = Noto Sans Light

*

* Note that these names are for Windows. Other platforms can use

* slightly different names.

*/

.light {

-fx-font-family: "Noto Sans Light";

-fx-font-weight: normal;

}

.regular {

-fx-font-family: "Noto Sans";

-fx-font-weight: normal;

}

.medium {

-fx-font-family: "Noto Sans Med";

-fx-font-weight: bold;

}

.semi-bold {

-fx-font-family: "Noto Sans SemBd";

-fx-font-weight: bold;

}

.bold {

-fx-font-family: "Noto Sans";

-fx-font-weight: bold;

}

.black {

-fx-font-family: "Noto Sans Blk";

-fx-font-weight: bold;

}

fonts-linux.less:

.light { -fx-font-family: "Noto Sans Light"; -fx-font-weight: normal; }
.regular { -fx-font-family: "Noto Sans"; -fx-font-weight: normal; }
.medium { -fx-font-family: "Noto Sans Medium"; -fx-font-weight: normal;
} .semi-bold { -fx-font-family: "Noto Sans SemiBold"; -fx-font-weight:
normal; } .bold { -fx-font-family: "Noto Sans"; -fx-font-weight: bold; }
.black { -fx-font-family: "Noto Sans Black"; -fx-font-weight: normal; }
And using it for some arbitrary style is then done (also with LESS) like:

.style-p3-extra-light {

-fx-font-size: 15;

.light;

}

Not what you hoped for I think :)

--John

>
> Dirk
>
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