Slow Image Rendering

[HeavyMetalGeek]

I've been comparing some libraries for rendering multiple 4k camera feeds in Rust and C++. For some reason I am getting much worse performance from egui:

1. Qt : 20 fps
2. Raylib: 25 fps
3. Egui: 6-8 fps

Is image rendering a known weakness, or am I doing someting wrong?

    fn update(&mut self, ctx: &egui::Context, frame: &mut eframe::Frame) {
        self.frame_history
            .on_new_frame(ctx.input(|i| i.time), frame.info().cpu_usage);
        ctx.request_repaint();
        self.ui(ctx);
    }

    fn ui(&mut self, ctx: &egui::Context) {
        //...
        self.texture_handles = self
            .camera_buffers
            .iter()
            .enumerate()
            .filter_map(|(i, buf)| {
                if let Some(cam) = buf {
                    // Similar process in all testing
                    let xi_img: xiapi::Image<'_, u8> =
                        cam.next_image::<u8>(None).expect("Failed to get raw image");
                    let img = ColorImage::from_rgba_unmultiplied(
                        [xi_img.width() as usize, xi_img.height() as usize],
                        xi_img.data(),
                    );
                    Some(ctx.load_texture(i.to_string(), img, Default::default()))
                } else {
                    None
                }
            })
            .collect();
        //... use painter to paint image using texture handle ids
    }