Image performance egui

[AlbinSjoegren]

Hey!

I am importing an image like so:

fn image_background(frame: &mut epi::Frame<'_>) -> egui::TextureId {
    let image_data_bkg = include_bytes!("data/images/Carina_Nebula_Detail.png");
    let image_bkg = image::load_from_memory(image_data_bkg).expect("Failed to load image");
    let image_buffer_bkg = image_bkg.to_rgba8();
    let size_bkg = (5200 as usize, 2500 as usize);
    let pixels_bkg = image_buffer_bkg.into_vec();
    let pixels_bkg: Vec<_> = pixels_bkg
        .chunks_exact(4)
        .map(|p| egui::Color32::from_rgba_unmultiplied(p[0], p[1], p[2], p[3]))
        .collect();
    // Allocate a texture:
    let texture_bkg = frame
        .tex_allocator()
        .alloc_srgba_premultiplied(size_bkg, &pixels_bkg);

    return texture_bkg;
}

and then displaying it in a central panel like so:

egui::containers::Frame {
                margin: Vec2::new(-20., -20.),
                corner_radius: 0.,
                ..Default::default()
            }
            .show(ui, |ui| {
                ui.image(image_background(frame), [2600.0, 1250.0]);
            });

When doing that the performance tanks so hard that every action (even hover) has a 2-second delay.
Is there any good way to run the decoder on program startup instead of every frame?
Thanks!
/Albin

[emilk]

There are many ways to do so. You can load it in App::setup. Or you can store an Option<TextureId> and fill it in when you notice it is None.

[AlbinSjoegren]

Used the App::setup method and it solved the lag problem, thanks!