Crate egui_software_backend 

CPU software render backend for egui

Basic example usage:

use egui_software_backend::{BufferMutRef, ColorFieldOrder, EguiSoftwareRender};
let buffer = &mut vec![[0u8; 4]; 512 * 512];
let mut buffer_ref = BufferMutRef::new(buffer, 512, 512);
let ctx = egui::Context::default();
let mut demo = egui_demo_lib::DemoWindows::default();
let mut sw_render = EguiSoftwareRender::new(ColorFieldOrder::Bgra);

let out = ctx.run(egui::RawInput::default(), |ctx| {
   demo.ui(ctx);
});

let primitives = ctx.tessellate(out.shapes, out.pixels_per_point);

sw_render.render(
   &mut buffer_ref,
   &primitives,
   &out.textures_delta,
   out.pixels_per_point,
);

Usage with optional winit backend:

#[cfg(all(feature = "std", feature = "winit"))]
mod example {
   use egui::vec2;
   use egui_software_backend::{SoftwareBackend, SoftwareBackendAppConfiguration};

   struct EguiApp {}

   impl EguiApp {
       fn new(context: egui::Context) -> Self {
           egui_extras::install_image_loaders(&context);
           EguiApp {}
       }
   }

   impl egui_software_backend::App for EguiApp {
       fn update(&mut self, ctx: &egui::Context, _backend: &mut SoftwareBackend) {
           egui::CentralPanel::default().show(ctx, |ui| {
               ui.label("Hello World!");
           });
       }
   }

   fn main() {
       let settings = SoftwareBackendAppConfiguration::new()
           .inner_size(Some(vec2(500.0, 300.0)))
           .title(Some("Simple example".to_string()));

       egui_software_backend::run_app_with_software_backend(settings, EguiApp::new)
           //Can fail if winit fails to create the window
           .expect("Failed to run app")
   }
}

Performance will be very poor without compiler optimizations. Run in release or use (Cargo.toml):

# Enable high optimizations for dependencies
[profile.dev.package."*"]
opt-level = 3

Structs

BufferMutRef

A mutable reference to a slice of image buffer data and corresponding image extents.

BufferRef

A reference to a slice of image buffer data and corresponding image extents.

CachedPrimitive

A region of cached rendered image data that corresponds to a ClippedPrimitive.

EguiSoftwareRender

Software render backend for egui.

SoftwareBackend

This struct contains statistics as well as possible interactions with the software renderer.

SoftwareBackendAppConfiguration

Used to initialize the software render backend app, renderer, and winit configuration.

Enums

ColorFieldOrder

Used to define the color swizzle order. Some backends require Rgba and others require Bgra. The renderer swizzles textures as they are loaded so they can later be rasterized directly onto the frame buffer.

Traits

App

Implement this trait to write apps using the optional winit backend similarly to eframe’s App.

Functions

run_app_with_software_backend

Starts the app.