How to set the font size for the code_view_ui for egui_extras

[vshashi01]

I want to be able to show a XML text file with some syntax highlighting through code_view_ui API from egui_extras but I also want to be able to resize the text font dynamically during run time. It is not super clear how this can be achieved.

Any guide will be helpful.

[rustbasic]

See code_editor in egui_demo_app.

[vshashi01]

Thanks for replying, I did read them through and tried to pass in a custom FontId to the TextEdit control, however, this would not result in the set font size for the texts at all. It seems to always use the default app font size when I build the app.

                           let mut layouter = |ui: &egui::Ui, string: &str, wrap_width: f32| {
                                let mut layout_job = egui_extras::syntax_highlighting::highlight(
                                    ui.ctx(),
                                    &CodeTheme::dark(),
                                    string,
                                    "xml",
                                );
                                layout_job.wrap.max_width = wrap_width;
                                ui.fonts(|f| {
                                    // f.row_height(&FontId::monospace(self.font_size));
                                    f.layout_job(layout_job)
                                })
                            };

                            let mut text = text_to_display.clone();

                            ui.add(
                                egui::TextEdit::multiline(&mut text)
                                    .font(FontId::monospace(400.0)) // for cursor height
                                    .desired_rows(10)
                                    .lock_focus(false)
                                    .desired_width(f32::INFINITY)
                                    .layouter(&mut layouter),
                            );

[rustbasic]

monospace(400.0) to 10.0 ~ 20.0

[rustbasic]

It's too complicated to explain everything.
I'll just give you a hint.

pub struct CodeTheme {
dark_mode: bool,
formats: enum_map::EnumMap<TokenType, egui::TextFormat>,
}

In store_in_memory(), you need to put the desired FontId into CodeTheme.formats(= self.formats).
There are several places where you need to make changes.

[RDMCz]

How do I access formats when it's not public?

[RDMCz]

I was able to make it work using the ui.scope in egui 0.33.3.

let font_size = 22.0;
let mut text = "ABCD";

ui.scope(|ui| {
    // In this UI scope we overwrite the font size
    ui.style_mut().text_styles.insert(
        egui::TextStyle::Monospace,
        egui::FontId::new(font_size, egui::FontFamily::Monospace),
    );

    // Set up the layouter
    let mut layouter =
        |ui: &egui::Ui, buf: &dyn egui::TextBuffer, wrap_width: f32| {
            let mut layout_job = egui_extras::syntax_highlighting::highlight(
                ui.ctx(),
                ui.style(),
                &CodeTheme::dark(0.0), // This number doesn't seem to change anything (?)
                buf.as_str(),
                "xml",
            );
            layout_job.wrap.max_width = wrap_width;
            ui.fonts_mut(|f| f.layout_job(layout_job))
        };

    // Add the textedit widget with the layouter
    ui.add(egui::TextEdit::multiline(&mut text).layouter(&mut layouter));
});