Write Once, Ship Everywhere: Hello ImGui Makes Dear ImGui Apps Portable

You've got an idea for a tool, a prototype, or a full-blown application. You want to build it with Dear ImGui because it's fast, immediate-mode, and lets you focus on the interface rather than fighting a UI framework. But then reality hits: you need it to run on Windows, macOS, Linux, maybe iOS and Android, and the web too. Suddenly you're drowning in platform-specific build systems, backend configurations, and windowing library choices. Hello ImGui exists to make that problem mostly disappear.

What It Does

Hello ImGui is a library built on top of Dear ImGui that abstracts away the multiplatform boilerplate. The goal, as the README puts it, is to make multiplatform app development as simple as writing a "Hello World" program. You write your application logic and UI code once, and Hello ImGui handles the rest—window creation, platform backends, rendering backends, asset loading, and app lifecycle across desktop, mobile, and web targets.

Under the hood, it supports SDL2 and Glfw3 as platform backends, and OpenGL3, Metal, Vulkan, and DirectX as rendering backends. That means you're not locked into a single graphics API or windowing system. The library also handles asset embedding across all platforms with no code required, app icon and name customization for mobile and macOS, and a bunch of quality-of-life features that normally take significant effort to get right. The README points to a full documentation website and a PDF manual that you can even feed into an LLM if you want.

Why It's Cool

• One codebase, six platforms. Linux, Windows, macOS, iOS, Android, and Emscripten (web). The README claims minimal setup—literally one line of CMake code. If that holds up in practice, it's a massive reduction in friction compared to wiring up each platform manually.

• Backend flexibility without the pain. You can target OpenGL3, Metal, Vulkan, or DirectX for rendering, and SDL2 or Glfw3 for the platform layer. That's not just about choice—it means you can use Metal on macOS and iOS, DirectX on Windows, and OpenGL or Vulkan elsewhere, all from the same application code.

• Asset embedding and app customization with zero code. Loading fonts, images, or other resources across desktop, mobile, and web usually involves platform-specific paths and bundling. Hello ImGui handles this for you. Same with setting app icons and names on mobile—no code required.

• Power Save mode. This is a small feature that matters a lot in practice. It reduces FPS when the app is idle, which is great for battery life on mobile and laptops. It's the kind of thing you'd otherwise have to implement yourself.

• High DPI support that just works. Automatic UI scaling to match screen DPI on any platform. If you've ever shipped an app that looked tiny on a 4K monitor or blurry on a Retina display, you know why this is valuable.

• Dockable windows and multiple layouts. For complex UIs, you get enhanced layout handling out of the box. This is something that Dear ImGui supports at a lower level, but Hello ImGui makes it more accessible.

• Theme tweaking and advanced font support. An extensive list of additional themes, plus support for icons, emojis, and colored fonts. Again, these are things you can do with Dear ImGui directly, but having them ready to go saves time.

• Integration with ImGui Test Engine. You can automate and test your apps. This is a big deal for anything beyond a prototype—having a testing story built in makes the library suitable for serious projects.

• User settings persistence. Window position, layout, opened windows, theme, and custom settings are saved automatically. Your users won't have to reconfigure everything every time they launch your app.

• Custom 3D backgrounds. If you want to add visual polish, you can easily drop in a 3D background. It's a nice touch for demos or applications where presentation matters.

How to Try It

The README doesn't include install commands directly—it points to the documentation website for API, usage, and build instructions. Here's the general path:

1. Head to the Hello ImGui documentation website for full setup details.
2. Check out the GitHub repository to browse the source and examples.
3. If you prefer a single document, grab the full PDF manual. The README notes you can feed it into an LLM like ChatGPT if you want interactive help.
4. The README mentions a StarterTemplate workflow, so look for that in the repo if you want a quick starting point.
5. Once you're set up, the idea is that you write your Dear ImGui code as usual, and Hello ImGui handles the platform and backend layers for you.

The repository has CI badges for all the major platforms and backends—Windows, Mac, Linux, MinGW, iOS, Android, Emscripten, Metal, Vulkan, DirectX, plus TestEngine, Automate, and StarterTemplate workflows. That's a good sign that the project is actively tested across the matrix it claims to support.

Final Thoughts

Hello ImGui is for developers who want to build Dear ImGui applications without getting bogged down in multiplatform plumbing. If you're prototyping an internal tool, building a cross-platform utility, or even shipping a commercial app, the value proposition is clear: write your UI once, and let the library handle the rest. It's not trying to replace Dear ImGui—it's trying to make it easier to use in the real world, where "just build it for Windows" is rarely the whole story. If that sounds like your situation, it's worth a look.

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