imgui-kmp

Kotlin Multiplatform bindings for Dear ImGui and the ecosystem around it: ImPlot, ImPlot3D, imgui-node-editor, ImGuiFileDialog, ImGuiColorTextEdit (TextEditor + extras + event hooks), imgui_markdown, the imgui_club extensions (memory editor, multi-context compositor, threaded rendering) and SDL3 platform/renderer backends. The bindings wrap the C++ code from the includes/ submodules through a C API, a JNI bridge (JVM/Android) and Kotlin/Native cinterop (all native targets).

Android has two independent APIs: the JVM API (an AAR with per-ABI JNI .so files, loaded via System.loadLibrary) and the Kotlin/Native API (androidNative* targets, linked as a static library into your libmain.so). Use the JVM API from an Android app written in Kotlin/JVM; use the native API when your Android app is Kotlin/Native (e.g. via sdl-kmp's libmain.so), since a JVM .so and a native libmain.so cannot be loaded side by side.

Kotlin Multiplatform / Android / native:

implementation("cn.enaium.imgui:imgui-kmp:1.0.6")

JVM: the right native binary is resolved automatically — the imgui-kmp-jvm artifact pulls in the matching :jni-jvm-* sibling on the classpath:

• imgui-kmp-jni-jvm-linux-x86_64
• imgui-kmp-jni-jvm-linux-aarch64
• imgui-kmp-jni-jvm-darwin-x86_64
• imgui-kmp-jni-jvm-darwin-aarch64
• imgui-kmp-jni-jvm-windows-x86_64

NativeLoader detects os.name/os.arch at runtime, extracts the matching binary from the classpath to a temp directory, and System.loads it. No java.library.path setup is required for downstream JVM consumers. On Android the .so is loaded from the AAR's jniLibs via System.loadLibrary.

import cn.enaium.imgui.ImGui
import cn.enaium.imgui.ImVec2
import cn.enaium.imgui.extensions.implot.ImPlot

fun main() {
    // 1. Create the imgui context and set up the IO
    val context = ImGui.createContext()
    val io = ImGui.getIO()
    io.displaySize = ImVec2(1280f, 800f)   // set from your window every frame
    io.deltaTime = 1f / 60f

    // 2. ImPlot needs an explicit context bound to the imgui context
    ImPlot.setImGuiContext(context)
    val plotContext = ImPlot.createContext()

    // 3. One frame: build the UI, then render the draw data with your backend
    ImGui.newFrame()
    if (ImGui.begin("Hello")) {
        ImGui.text("Hello, imgui-kmp!")
        if (ImPlot.beginPlot("Sine")) {
            ImPlot.setupFinish()
            val xs = FloatArray(100) { it.toFloat() }
            val ys = FloatArray(100) { kotlin.math.sin(it / 10.0).toFloat() }
            ImPlot.plotLine("sin", xs, ys)
            ImPlot.endPlot()
        }
    }
    ImGui.end()
    ImGui.render()

    // 4. ImGui.getDrawData() -> draw the meshes with your renderer
    val drawData = ImGui.getDrawData()

    ImPlot.destroyContext(plotContext)
    ImGui.destroyContext(context)
}

The draw data is plain vertex/index buffers (20 bytes per vertex: pos, uv, color), so it can be fed into any renderer. The examples directory holds six modules written in Kotlin on top of sdl-kmp:

• examples/common — the shared demo UI (DemoUi), the SDL platform backend (ImGuiSdlBackend) and the reusable SdlRendererApp frame-loop bootstrap used by the renderer-based examples.
• examples/android-sdl — the vendored org.libsdl.app Android glue (SDLActivity, ...) shared by every example Android app.
• examples/sdl_renderer — SDL renderer (ImGuiSdlRendererBackend), mirrors imgui_impl_sdlrenderer3.cpp using SDL_RenderGeometry.
• examples/sdl_gpu — SDL GPU (ImGuiSdlGpuBackend), mirrors imgui_impl_sdlgpu3.cpp using the SDL3 GPU API with the precompiled SPIR-V/MSL shaders shipped with Dear ImGui.
• examples/node_editor — a blueprints-style node graph on the imgui-node-editor bindings: draggable typed pins, link creation, deletion and context menus.
• examples/club — the imgui_club bindings: the MemoryEditor hex editor and the MultiContextCompositor stacking a second ImGui context over the main UI in one window, with cross-context drag & drop (drag a swatch from the main window onto the overlay — a different ImGui context — and the compositor delivers the payload there).
• examples/implot3d — ImPlot3D 3D plots in a ShowDemoWindow-style layout: line/scatter/surface/mesh demos, box scale & rotation, markers & text, NaN handling.
• examples/filedialog — ImGuiFileDialog: open/save/directory dialogs with filter collections, per-extension file styles and selection reporting.
• examples/colortextedit — ImGuiColorTextEdit: a syntax-highlighted text editor with language/palette switching, find/replace, markers and view toggles, plus the extras (TrieAutoComplete, notifications) and event hooks for language-server integration.
• examples/markdown — imgui_markdown rendered directly into a window (headings, lists, code, clickable links with tooltips).

Run them headless or with a window:

# JVM (SDL renderer)
SDL_VIDEO_DRIVER=dummy ./gradlew :examples:sdl_renderer:jvmRun --args="--frames 120"

# JVM (SDL GPU, needs a real display)
./gradlew :examples:sdl_gpu:jvmRun --args="--frames 120"

# Native macOS (headless)
SDL_VIDEO_DRIVER=dummy IMGUI_KMP_FRAMES=120 ./examples/sdl_renderer/build/bin/macosArm64/debugExecutable/sdl_renderer.kexe

# JVM (node editor)
SDL_VIDEO_DRIVER=dummy ./gradlew :examples:node_editor:jvmRun --args="--frames 120"

# JVM (imgui_club: memory editor + multi-context compositor)
SDL_VIDEO_DRIVER=dummy ./gradlew :examples:club:jvmRun --args="--frames 120"

# JVM (implot3d / filedialog / colortextedit / markdown)
SDL_VIDEO_DRIVER=dummy ./gradlew :examples:implot3d:jvmRun --args="--frames 120"
SDL_VIDEO_DRIVER=dummy ./gradlew :examples:filedialog:jvmRun --args="--frames 120"
SDL_VIDEO_DRIVER=dummy ./gradlew :examples:colortextedit:jvmRun --args="--frames 120"
SDL_VIDEO_DRIVER=dummy ./gradlew :examples:markdown:jvmRun --args="--frames 120"

The examples consume :imgui-kmp as a project dependency, so they always build against the local source. (Standalone consumers use cn.enaium.imgui:imgui-kmp:1.0.6 from Maven Central or Maven Local.)

The binding mirrors the C++ API closely. Widgets take mutable arrays for out-parameters (like BooleanArray for checkbox), matching the pointer semantics of Dear ImGui:

val value = FloatArray(1) { 0.5f }
if (ImGui.sliderFloat("value", value, 0f, 1f)) { /* value[0] changed */ }

val checked = BooleanArray(1) { true }
ImGui.checkbox("checked", checked)

val current = IntArray(1)
ImGui.combo("fruit", current, arrayOf("Apple", "Banana", "Cherry"))

val text = ImGui.inputText("name", "hello")  // returns the buffer content

Style colors and flags are exposed as constants:

ImGui.pushStyleColor(ImGuiCol.BUTTON, ImVec4(0.4f, 0.2f, 0.6f, 1f))
ImGui.popStyleColor()

ImGui.begin("window", flags = ImGuiWindowFlags.NO_SAVED_SETTINGS)

Plot items accept an ImPlotSpec for per-item styling:

ImPlot.plotScatter("points", xs, ys, ImPlotSpec(marker = ImPlotMarker.CIRCLE, markerSize = 4f))
ImPlot.plotBars("bars", values, barSize = 0.6)
ImPlot.plotHistogram("distribution", values)
ImPlot.pushColormap(ImPlotColormap.PLASMA)

The complete demo UI (menu bar, tabs, tables, popups, plots, the built-in showDemoWindow / ImPlot.showDemoWindow) lives in examples/common/src/commonMain/kotlin/cn/enaium/imgui/example/common/DemoUi.kt.

The Dear ImGui, ImPlot, ImPlot3D, imgui-node-editor, ImGuiFileDialog, ImGuiColorTextEdit, imgui_markdown and imgui_club sources are git submodules under includes/:

git submodule update --init --recursive

• jni/ — CMake build of the static library (libimgui.a) and the JNI bridge, plus the per-OS/arch JVM JNI artifact projects.
• jni/c_api/ — the C API consumed by both the JNI bridge and the cinterop bindings.
• imgui-kmp/ — the multiplatform module: cn.enaium.imgui for ImGui, cn.enaium.imgui.extensions.implot for ImPlot, ...extensions.implot3d for ImPlot3D, ...extensions.nodeeditor for imgui-node-editor, ...extensions.filedialog for ImGuiFileDialog, ...extensions.colortextedit for ImGuiColorTextEdit (TextEditor + TrieAutoComplete + Notifications + event hooks), ...extensions.markdown for imgui_markdown and ...extensions.memoryeditor / ...extensions.mcc / ...extensions.threadedrendering for imgui_club, plus the SDL backends under cn.enaium.imgui.backends.sdl.
• examples/ — the shared demo UI (examples/common), the shared SDL Android glue (examples/android-sdl) and the SDL renderer (examples/sdl_renderer), SDL GPU (examples/sdl_gpu), node editor (examples/node_editor), imgui_club (examples/club), ImPlot3D (examples/implot3d), file dialog (examples/filedialog), text editor (examples/colortextedit) and Markdown (examples/markdown) demos, shared across JVM, desktop native and Android native targets.

./gradlew :imgui-kmp:jvmTest          # JVM tests (uses the host JNI artifact)
./gradlew :imgui-kmp:macosArm64Test   # native tests
./gradlew :imgui-kmp:buildAndroidJniLibs  # all four Android ABI .so files
./gradlew :imgui-kmp:publishToMavenLocal # publish everything to Maven Local

MIT, see LICENSE. All bundled libraries (Dear ImGui, ImPlot, imgui-node-editor, ImGuiFileDialog, imgui_club) are MIT-licensed as well.