Iced GUI Library

Iced is inspired by The Elm Architecture, which requires splitting your user interface into four distinct, interacting concepts:

1. State: The data representing the current condition of your application.
2. Messages: An enumeration of user interactions or meaningful events (e.g., button clicks).
3. View logic: A function that transforms your State into a layout of widgets. These widgets are configured to produce Messages when interacted with.
4. Update logic: A function that receives Messages and modifies the State accordingly.

When you run an Iced application, the runtime handles the lifecycle: it executes the view logic to layout widgets, processes system events to produce messages, and triggers the update logic to keep the state in sync with the UI.

// 1. State
struct Counter {
    value: i32,
}

// 2. Messages
enum Message {
    Increment,
    Decrement,
}

// 3. View logic
impl Counter {
    pub fn view(&self) -> Column<'_, Message> {
        column![
            button("+").on_press(Message::Increment),
            text(self.value).size(50),
            button("-").on_press(Message::Decrement),
        ]
    }

    // 4. Update logic
    pub fn update(&mut self, message: Message) {
        match message {
            Message::Increment => self.value += 1,
            Message::Decrement => self.value -= 1,
        }
    }
}

// Execution
fn main() -> iced::Result {
    iced::run("A cool counter", Counter::update, Counter::view)
}

For users preferring Nix Flakes, you can use a flake.nix to create a dev shell. This method supports multiple systems and provides a consistent environment for Iced development.

To activate the environment, run:

nix develop

{
  inputs = {
    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
    systems.url = "github:nix-systems/default";
  };

  outputs = { nixpkgs, systems, ... }: 
    let
      eachSystem = nixpkgs.lib.genAttrs (import systems);
      pkgsFor = nixpkgs.legacyPackages;
    in {
      devShells = eachSystem (system: 
        let
          pkgs = pkgsFor.${system};
          dlopenLibraries = with pkgs; [
            libxkbcommon

            # GPU backend
            vulkan-loader
            # libGL

            # Window system
            wayland
            # xorg.libX11
            # xorg.libXcursor
            # xorg.libXi
          ];
        in {
          default = pkgs.mkShell {
            nativeBuildInputs = with pkgs; [
              cargo
              rustc
            ];

            # additional libraries that your project
            # links to at build time, e.g. OpenSSL
            buildInputs = [];

            env.RUSTFLAGS = "-C link-arg=-Wl,-rpath,${nixpkgs.lib.makeLibraryPath dlopenLibraries}";
          };
        });
    };