CODEWITHSUNDEEP
c++imgui
Sleepi
Sleepi

Reputation: 31

ImGui without Window?

Is it possible to create an ImGui screen without a background or window? It would just be the ImGui window that can be dragged across the screen. It would looks something like this, but instead of a blue background, you'd just see the application that is under it.

Upvotes: 2

Views: 11593

Answers (2)

Adam Henault
Adam Henault

Reputation: 63

I know the topic is pretty old but it can useful for some people.

You can't really display an ImGui without creating a window, but you can use the docking version of ImGui (link here). This version allow the ImGui interface to "live" outside of the window. So, you can easily have only the ImGui interface displayed.

To do that you can use the sample code from ImGui and modify the window creation like this :

ImGui_ImplWin32_EnableDpiAwareness();
const WNDCLASSEX wc = { sizeof(WNDCLASSEX), CS_CLASSDC, WndProc, 0L, 0L, GetModuleHandle(nullptr), nullptr, nullptr, nullptr, nullptr, _T("ImGui Standalone"), nullptr };
::RegisterClassEx(&wc);
const HWND hwnd = ::CreateWindow(wc.lpszClassName, _T("ImGui Standalone"), WS_OVERLAPPEDWINDOW, 100, 100, 50, 50, NULL, NULL, wc.hInstance, NULL);

if (!CreateDeviceD3D(hwnd))
{
    CleanupDeviceD3D();
    ::UnregisterClass(wc.lpszClassName, wc.hInstance);
    return;
}

::ShowWindow(hwnd, SW_HIDE);
::UpdateWindow(hwnd);

When you are calling the ShowWindow function you have to pass the SW_HIDE parameter to hide the window and only keep the ImGui interface.

You can find a complete project here.

Demo Screenshot

Upvotes: 4

Naveen
Naveen

Reputation: 519

In case of GLFW backend, the below window hint with a glclear color can help

glfwWindowHint(GLFW_TRANSPARENT_FRAMEBUFFER, GLFW_TRUE);

Render Loop:

{
    ...
    glfwGetFramebufferSize(window, &app_width, &app_height);
    glViewport(0, 0, app_width, app_height);
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
    glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
    
    //render
    ...
}

Upvotes: 1

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