Jewel — IntelliJ Platform

Jewel is JetBrains' design system for the IntelliJ Platform. The Nucleus Jewel toolkit styles DecoratedWindow with Jewel colors and metrics, so the title bar and window chrome match the IntelliJ look on macOS, Windows, and Linux. It runs on the Tao backend behind the same API (the AWT backend is also supported, but deprecated).

Add the dependency

dependencies {
    implementation("dev.nucleusframework:nucleus.nucleus-application:2.0.7")
    implementation("dev.nucleusframework:nucleus.decorated-window-tao:2.0.7")
    implementation("dev.nucleusframework:nucleus.decorated-window-jewel:2.0.7")
    implementation("dev.nucleusframework:nucleus.darkmode-detector:2.0.7")
    // A Jewel theme module — pick the one that matches your target IDE build.
    implementation("org.jetbrains.jewel:jewel-int-ui-standalone-243:<version>")
}

The toolkit depends on decorated-window-core and a backend module. Pair it with -tao for the Rust-native windowing backend; the -jbr / -jni AWT modules are deprecated.

Create a Jewel-styled window

Wrap the window content in a Jewel theme, then open a JewelDecoratedWindow:

import androidx.compose.foundation.layout.Box
import androidx.compose.foundation.layout.fillMaxSize
import androidx.compose.ui.Modifier
import dev.nucleusframework.application.nucleusApplication
import dev.nucleusframework.darkmodedetector.isSystemInDarkMode
import dev.nucleusframework.window.jewel.JewelDecoratedWindow
import dev.nucleusframework.window.jewel.JewelTitleBar
import org.jetbrains.jewel.intui.standalone.theme.IntUiTheme

fun main() = nucleusApplication {
    IntUiTheme(isDark = isSystemInDarkMode()) {
        JewelDecoratedWindow(
            onCloseRequest = ::exitApplication,
            title = "Tools",
        ) {
            JewelTitleBar { /* title bar content */ }
            Box(Modifier.fillMaxSize()) {
                // Jewel widgets go here
            }
        }
    }
}

The window reads the current Jewel theme and derives its title bar and chrome from it, so switching isDark flips the whole window between the light and dark IntelliJ palettes.

How it works

JewelDecoratedWindow is a Composable wrapper around DecoratedWindow. It reads JewelTheme.globalColors, derives a DecoratedWindowStyle and a TitleBarStyle from the active Jewel theme, and installs them through NucleusDecoratedWindowTheme before opening the window. Inside the window you compose regular Jewel widgets — Text, DefaultButton, OutlinedButton, lazy lists, and the rest.

There are two overloads. The one on NucleusApplicationScope — used above inside nucleusApplication { } — is backend-agnostic and works on both the Tao and AWT backends from the same call site. The overload on Compose's ApplicationScope is AWT-backed (JBR/JNI) and is meant for a plain application { } entry point.

rememberJewelWindowStyle() and rememberJewelTitleBarStyle() expose the derived styles directly. Use them when you build your own wrapper — for example, a single composable that switches between Jewel and another toolkit at runtime.

API reference

Open a window or dialog

• JewelDecoratedWindow(...) — a Jewel-styled window. Available on NucleusApplicationScope (backend-agnostic) and on ApplicationScope (AWT-backed).
• JewelDecoratedDialog(...) — the modal dialog variant. A top-level function is AWT-backed; the NucleusApplicationScope overload is backend-agnostic.

Add a title bar

• DecoratedWindowScope.JewelTitleBar(...) — the title bar slot for a window.
• DecoratedDialogScope.JewelDialogTitleBar(...) — the title bar slot for a dialog.

Read the derived styles

• rememberJewelWindowStyle(): DecoratedWindowStyle — the window chrome style derived from the active Jewel theme.
• rememberJewelTitleBarStyle(): TitleBarStyle — the title bar style derived from the active Jewel theme.

What's next

• Material toolkit — Material 2 and Material 3 styling for DecoratedWindow.
• DecoratedWindow — the underlying window and title bar API.
• Backends — Tao and the deprecated AWT backend.