No fonts available until first call to Context::run()

Error message

No fonts available until first call to Context::run()

What it means

Error "No fonts available until first call to Context::run()" thrown in emilk/egui.

Source

Thrown at crates/egui/src/context.rs:1103

    ///
    /// This is swapped at the end of each pass.
    #[inline]
    pub(crate) fn prev_pass_state<R>(&self, reader: impl FnOnce(&PassState) -> R) -> R {
        self.write(move |ctx| reader(&ctx.viewport().prev_pass))
    }

    /// Read-only access to [`Fonts`].
    ///
    /// Not valid until first call to [`Context::run_ui()`].
    /// That's because since we don't know the proper `pixels_per_point` until then.
    #[inline]
    pub fn fonts<R>(&self, reader: impl FnOnce(&FontsView<'_>) -> R) -> R {
        self.write(move |ctx| {
            let pixels_per_point = ctx.pixels_per_point();
            reader(
                &ctx.fonts
                    .as_mut()
                    .expect("No fonts available until first call to Context::run()")
                    .with_pixels_per_point(pixels_per_point),
            )
        })
    }

    /// Read-write access to [`Fonts`].
    ///
    /// Not valid until first call to [`Context::run_ui()`].
    /// That's because since we don't know the proper `pixels_per_point` until then.
    #[inline]
    pub fn fonts_mut<R>(&self, reader: impl FnOnce(&mut FontsView<'_>) -> R) -> R {
        self.write(move |ctx| {
            let pixels_per_point = ctx.pixels_per_point();
            reader(
                &mut ctx
                    .fonts
                    .as_mut()
                    .expect("No fonts available until first call to Context::run()")

View on GitHub (pinned to d802a982ce)

When it happens

Trigger: Thrown at crates/egui/src/context.rs:1103 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of emilk/egui@d802a982ce (2026-08-16). Data as JSON: /api/errors/2026e2dd4fbb2365. Report an issue: GitHub.