Dear ImGui

"Give someone state and they'll have a bug one day, but teach them how to represent state in two separate locations that have to be kept in sync and they'll have bugs for a lifetime." -ryg

_{(This library is available under a free and permissive license, but needs financial support to sustain its continued improvements. In addition to maintenance and stability there are many desirable features yet to be added. If your company is using Dear ImGui, please consider reaching out.)}

Businesses: support continued development and maintenance via invoiced sponsoring/support contracts:
  E-mail: contact @ dearimgui dot com
Individuals: support continued development and maintenance here. Also see Funding page.

The Pitch

Dear ImGui is a bloat-free graphical user interface library for C++. It outputs optimized vertex buffers that you can render anytime in your 3D-pipeline-enabled application. It is fast, portable, renderer agnostic, and self-contained (no external dependencies).

Dear ImGui is designed to enable fast iterations and to empower programmers to create content creation tools and visualization / debug tools (as opposed to UI for the average end-user). It favors simplicity and productivity toward this goal and lacks certain features commonly found in more high-level libraries. Among other things, full internationalization (right-to-left text, bidirectional text, text shaping etc.) and accessibility features are not supported.

Dear ImGui is particularly suited to integration in game engines (for tooling), real-time 3D applications, fullscreen applications, embedded applications, or any applications on console platforms where operating system features are non-standard.

• Minimize state synchronization.
• Minimize UI-related state storage on user side.
• Minimize setup and maintenance.
• Easy to use to create dynamic UI which are the reflection of a dynamic data set.
• Easy to use to create code-driven and data-driven tools.
• Easy to use to create ad hoc short-lived tools and long-lived, more elaborate tools.
• Easy to hack and improve.
• Portable, minimize dependencies, run on target (consoles, phones, etc.).
• Efficient runtime and memory consumption.
• Battle-tested, used by many major actors in the game industry.

Usage

The core of Dear ImGui is self-contained within a few platform-agnostic files which you can easily compile in your application/engine. They are all the files in the root folder of the repository (imgui*.cpp, imgui*.h). No specific build process is required: you can add all files into your existing project.

Backends for a variety of graphics API and rendering platforms are provided in the backends/ folder, along with example applications in the examples/ folder. You may also create your own backend. Anywhere where you can render textured triangles, you can render Dear ImGui.

C++20 users wishing to use a module may use the stripe2933/imgui-module third-party extension.

See the Getting Started & Integration section of this document for more details.

After Dear ImGui is set up in your application, you can use it from _anywhere_ in your program loop:

ImGui::Text("Hello, world %d", 123);
if (ImGui::Button("Save"))
    MySaveFunction();
ImGui::InputText("string", buf, IM_COUNTOF(buf));
ImGui::SliderFloat("float", &f, 0.0f, 1.0f);

// Create a window called "My First Tool", with a menu bar.
ImGui::Begin("My First Tool", &my_tool_active, ImGuiWindowFlags_MenuBar);
if (ImGui::BeginMenuBar())
{
    if (ImGui::BeginMenu("File"))
    {
        if (ImGui::MenuItem("Open..", "Ctrl+O")) { /* Do stuff */ }
        if (ImGui::MenuItem("Save", "Ctrl+S"))   { /* Do stuff */ }
        if (ImGui::MenuItem("Close", "Ctrl+W"))  { my_tool_active = false; }
        ImGui::EndMenu();
    }
    ImGui::EndMenuBar();
}

// Edit a color stored as 4 floats
ImGui::ColorEdit4("Color", my_color);

// Generate samples and plot them
float samples[100];
for (int n = 0; n < 100; n++)
    samples[n] = sinf(n * 0.2f + ImGui::GetTime() * 1.5f);
ImGui::PlotLines("Samples", samples, 100);

// Display contents in a scrolling region
ImGui::TextColored(ImVec4(1,1,0,1), "Important Stuff");
ImGui::BeginChild("Scrolling");
for (int n = 0; n < 50; n++)
    ImGui::Text("%04d: Some text", n);
ImGui::EndChild();
ImGui::End();

Dear ImGui allows you to create elaborate tools as well as very short-lived ones. On the extreme side of short-livedness: using the Edit&Continue (hot code reload) feature of modern compilers you can add a few widgets to tweak variables while your application is running, and remove the code a minute later! Dear ImGui is not just for tweaking values. You can use it to trace a running algorithm by just emitting text commands. You can use it along with your own reflection data to browse your dataset live. You can use it to expose the internals of a subsystem in your engine, to create a logger, an inspection tool, a profiler, a debugger, an entire game-making editor/framework, etc.

How it works

The IMGUI paradigm through its API tries to minimize superfluous state duplication, state synchronization, and state retention from the user's point of view. It is less error-prone (less code and fewer bugs) than traditional retained-mode interfaces, and lends itself to creating dynamic user interfaces. Check out the Wiki's About the IMGUI paradigm section for more details.

Dear ImGui outputs vertex buffers and command lists that you can easily render in your application. The number of draw calls and state changes required to render them is fairly small. Because Dear ImGui doesn't know or touch graphics state directly, you can call its functions anywhere in your code (e.g. in the middle of a running algorithm, or in the middle of your own rendering process). Refer to the sample applications in the examples/ folder for instructions on how to integrate Dear ImGui with your existing codebase.

A common misunderstanding is to mistake immediate mode GUI for immediate mode rendering, which usually implies hammering your driver/GPU with a bunch of inefficient draw calls and state changes as the GUI functions are called. This is NOT what Dear ImGui does. Dear ImGui outputs vertex buffers and a small list of draw calls batches. It never touches your GPU directly. The draw call batches are decently optimal and you can render them later, in your app or even remotely.

Releases & Changelogs

See Releases page for decorated Changelogs. Reading the changelogs is a good way to keep up to date with the things Dear ImGu