Intro - Developer docs

This section is for developers willing to build and modify the imgui_bundle library. It covers topics such as building the library, updating dependencies, and adding new features or bindings.

Architecture Overview¶

ImGui Bundle implements a four-layer architecture:

1. Rendering Backends – GLFW/SDL + OpenGL/Metal/DirectX/Vulkan

2. Dear ImGui Core – immediate-mode widget system

3. Hello ImGui Framework – window lifecycle, docking, DPI handling, asset management

4. ImmApp Layer – simplified runner with automatic add-on initialization

Users can work at their preferred abstraction level, from raw ImGui calls to the high-level immapp.run() API.

Python Bindings¶

The bindings are auto-generated using litgen, a code generator that transforms C++ headers into:

• nanobind C++ code – the actual binding implementation

• .pyi type stubs – for IDE autocompletion and type checking

All 23+ C++ libraries compile into a single _imgui_bundle native extension, with submodules conditionally available based on build configuration.

Key Concepts¶

• Add-On System: ImmApp manages automatic context creation for optional libraries via AddOnsParams flags (with_implot, with_markdown, etc.)

• Cross-Platform: Same codebase deploys to desktop (Windows/macOS/Linux), mobile (iOS/Android), and web (Emscripten/Pyodide)

• DPI-Aware Sizing: Helper functions like EmToVec2() enable responsive layouts across high-DPI displays

More Resources¶

• DeepWiki - ImGui Bundle – AI-powered documentation explorer for in-depth architecture questions

• Litgen Documentation – the bindings generator used by this project

In This Section¶

• Repository Structure – folder organization

• Bindings Introduction – how the generator works

• Update Bindings – updating existing library bindings

• Add New Library – adding a new library to the bundle

• Debug Native C++ – debugging C++ code from Python