Error parsing TTF/OTF font file: InvalidFont on every font I try to load.

[Levitanus]

This is the piece of code, that loads font now:

let font_path = p
    .join("Font Awesome 6 Free-Regular-400.otf")
    .display()
    .to_string();
debug!("font path is: {:?}", font_path);
let mut fonts = FontDefinitions::default();
fonts.font_data.insert(
    "icons".to_owned(),
    FontData::from_owned(font_path.into_bytes()),
);
fonts
    .families
    .entry(egui::FontFamily::Proportional)
    .or_default()
    .push("icons".to_owned());
// self.data.fonts = fonts;
context.set_fonts(fonts);

But it ends up with the error: Error parsing "icons" TTF/OTF font file: InvalidFont wherever font I load. Can not find the same problem on the web, and also can not go further with it.

[rustbasic]

Make sure you check where the font file is located.

Please check the following to see if you can find something helpful.

pub fn setup_file_fonts(content: &mut Content, ctx: &egui::Context) {
    let font_filename = content.screen.font_filename.clone();

    if font_filename == content.screen.preload_fontfilename {
        // --------------------------------------
        // Default Fonts
        // --------------------------------------
        setup_preload_fonts(content, ctx);
        return;
    }

    if let Ok(font_data) = std::fs::read(&font_filename) {
        content.screen.font_filename = font_filename.clone();
        get_font_list(content);

        let mut fonts = egui::FontDefinitions::default();
        fonts.font_data.insert(
            "my_font".to_owned(),
            egui::FontData::from_owned(font_data).tweak(FontTweak {
                scale: content.screen.font_scale, // make it smaller or taller
                y_offset_factor: content.screen.font_y_offset_factor, // move it down(+) or up(-)
                y_offset: content.screen.font_y_offset,
                baseline_offset_factor: -0.0333, // makes the default fonts look more centered in buttons and such
            }),
        );

        fonts
            .families
            .entry(egui::FontFamily::Monospace)
            .or_default()
            .push("my_font".to_owned());

        fonts
            .families
            .entry(egui::FontFamily::Proportional)
            .or_default()
            .push("my_font".to_owned());

        ctx.set_fonts(fonts);
    } else {
        // --------------------------------------
        // Default Fonts
        // --------------------------------------
        setup_preload_fonts(content, ctx);
    }

    content.fontbook = Default::default();
}

[Levitanus]

Thank you a lot! It took time to get, that my first mistake was using filename instead of full font-family file, loaded to the variable.
Now I have a different type of problem, that font is still not rendered properly, and I see squares instead of icon glyphs.

The loading is now rewritten:

let font_path = p
    .join("Font Awesome 6 Free-Regular-400.otf")
    .display()
    .to_string();
debug!("font path is: {:?}", font_path);
if let Ok(font_data) = std::fs::read(&font_path) {
    let mut fonts = FontDefinitions::default();
    fonts
        .font_data
        .insert("icons".to_owned(), FontData::from_owned(font_data));
    fonts.families.insert(
        egui::FontFamily::Name("icons".into()),
        vec!["icons".to_owned()],
    );
    // debug!("{:#?}", fonts);
    context.set_fonts(fonts);
    // warn!("The font section should be rewritten");
}

And it, at least, does not complain on this.
And, when applied in the RichText, it also does not complain on anything, but still renders squares. I tested the same Unicode points in Inkscape, and the Glyphs were on the place.

let icons_font = egui::FontId::new(10.0, egui::FontFamily::Name("icons".into()));
if ui
    .button(RichText::new("").font(icons_font.clone()))
    .on_hover_text("remove")
    .clicked()
{
    remove_idx = Some(idx);
}

[rustbasic]

Usually, a square is rendered because there is no character corresponding to the font you are using. Check out FontBook in egui_demo_app.

I haven't checked your source code because I don't have time to check other people's source code.