imgui resize problems.

[Gh0stBlade]

Version/Branch of Dear ImGui:

Version: latest Branch: docking

Back-end/Renderer/Compiler/OS

Back-ends: imgui_impl_win32.cpp + imgui_impl_dx11.cpp.

Compiler: MSVC 2019 Operating System: Windows

My Issue/Question:

Hi, I created a gui for my editor but it appears that when I resize the window it completely messed up the mouse click position (it is offset) and the entire gui is also not stretched to fit the new OS window size.

I have tried calling:

ImGui::SetNextWindowPos(viewport->Pos);
ImGui::SetNextWindowSize(viewport->Size);
ImGui::SetNextWindowViewport(viewport->ID);

On the master window which holds a docking widget. Sadly when I resize the window it makes no difference the actual size is not properly updated.

Screenshots/Video

Before Resize:

After Resize (Maximise) Right side is cut off:

After Resize (smaller window) Right side is black completely:

Standalone, minimal, complete and verifiable example:

ImGuiViewport* viewport = ImGui::GetMainViewport();

ImGui::SetNextWindowPos(viewport->Pos);
ImGui::SetNextWindowSize(viewport->Size);
ImGui::SetNextWindowViewport(viewport->ID);

if (ImGui::Begin("Master Window", NULL, ImGuiWindowFlags_NoTitleBar | ImGuiWindowFlags_NoCollapse | ImGuiWindowFlags_NoResize | ImGuiWindowFlags_NoMove | ImGuiWindowFlags_NoBringToFrontOnFocus | ImGuiWindowFlags_NoNavFocus | ImGuiWindowFlags_AlwaysAutoResize))
{
    ImGui::Spacing();
    ImGui::Spacing();
    ImGui::Spacing();
}

ImGuiID dockSpaceId = ImGui::GetID("MyDockspace");
ImGui::DockSpace(dockSpaceId, ImVec2(0.0f, 0.0f), ImGuiDockNodeFlags_PassthruCentralNode);

[ocornut]

This doesn't look related to dear imgui, you are probably not resizing your DX11 framebuffer properly, or not updating something.

if you run the equivalent examples/example_win32_directx11/ you'll notice you don't have that problem. Follow the main.cpp code of that example and find what the code is doing that your app is not doing.

You can ask on Discord for further support. When you find the cause of your issue it would be good to post it here for future reference for other users.