moonbit-community/imgui

MoonBit bindings for Dear ImGui on the native backend.

The top-level moonbit-community/imgui package provides a scoped API for building immediate-mode UI from MoonBit. It is designed for application code: windows, menus, tabs, popups, tables, and widgets are used through trailing callbacks, and matching Dear ImGui scope close calls are handled automatically.

Example

let context = @imgui.Context::create()
defer context.destroy()

fn render_ui(state : State) -> Unit raise @imgui.ImGuiError {
  let ui = @imgui.ui()
  ui.window(
    "MoonBit Dear ImGui",
    flags=[@imgui.WindowFlag::MenuBar],
    style=[Rounding(6.0), Text(White)],
  ) <| ui => {
    ui.menu_bar() <| ui => {
      ui.menu_item("Increment counter") <| () => {
        state.counter = state.counter + 1
      }
    }

    ui.text("Hello from MoonBit")
    ui.checkbox("Enabled", state.enabled) <| value => {
      state.enabled = value
    }
    ui.slider_float("Value", state.value, 0.0, 1.0) <| value => {
      state.value = value
    }
    ui.button(
      "Run",
      style=[Background(Blue), HoveredBg(Cyan), ActiveBg(Green), Rounding(4.0)],
    ) <| () => {
      state.counter = state.counter + 1
    }
  }
}

try! @imgui.new_frame()
try! render_ui(state)
ignore(try! @imgui.render())

Scoped UI

• ui.window(...) <| ui => { ... } opens a window and closes it automatically.
• ui.main_menu_bar(...), ui.menu_bar(...), ui.tab_bar(...), ui.table(...), ui.popup(...), ui.popup_modal(...), ui.popup_context_item(...), ui.tooltip(...), ui.item_tooltip(...), ui.combo(...), ui.group(...), ui.disabled(...), ui.with_id(...), and ui.tree_node(...) close their scopes automatically.
• Widgets with values pass the updated value directly to the callback: checkbox(...) <| value => { ... }, slider_float4(...) <| value => { ... }, drag_int_range2(...) <| value => { ... }, input_text(...) <| value => { ... }, and color_edit4(...) <| value => { ... }.
• Buttons and menu items run their callback only when activated.
• Composable flags are passed as enum arrays, for example flags=[@imgui.WindowFlag::MenuBar, @imgui.WindowFlag::NoSavedSettings].
• Scoped style sheets are passed as enum arrays, for example style=[Text(White), Background(Hex("#223344")), SelectedBg(Cyan), CollapsedBg(Gray), Rounding(6.0)]. Use Slot(StyleColor, Color) only when a precise color slot is needed.

Packages

• moonbit-community/imgui: user-facing API.
• moonbit-community/imgui/bindings/glfw: GLFW platform backend bindings.
• moonbit-community/imgui/bindings/opengl3: OpenGL3 renderer backend bindings.

The low-level generated binding package is available as moonbit-community/imgui/bindings for advanced users who need direct access to Dear ImGui C API symbols.

Run The Window Example

Initialize submodules first:

git submodule update --init --recursive

Install GLFW. On macOS with Homebrew:

brew install glfw

Then run the GLFW/OpenGL3 example:

moon run examples/glfw_opengl3 --target native

The example opens a native window and renders MoonBit-authored interactive UI: checkboxes, scalar and multi-component sliders, drag controls, text inputs, color editors, popups, a modal, context menus, menus, tabs, tables, columns, item/window state queries, and a secondary window.

Validate

moon check --target native
moon test --target native

Dear ImGui source is MIT licensed. Dear Bindings is MIT licensed. The MoonBit wrapper code in this repository is Apache-2.0 licensed.