Method ScaleWindowsInViewport

imgui_tiny_app/imgui/imgui.cpp:16763–16777

Scale all windows (position, size). Use when e.g. changing DPI. (This is a lossy operation!)

// Scale all windows (position, size). Use when e.g. changing DPI. (This is a lossy operation!)
void ImGui::ScaleWindowsInViewport(ImGuiViewportP* viewport, float scale)
{
    ImGuiContext& g = *GImGui;
    //IMGUI_DEBUG_LOG_VIEWPORT("[viewport] ScaleWindowsInViewport 0x%08X\n", viewport->ID);
    if (viewport->Window)
    {
        ScaleWindow(viewport->Window, scale);
    }
    else
    {
        for (ImGuiWindow* window : g.Windows)
            if (window->Viewport == viewport)
                ScaleWindow(window, scale);
    }
}

// If the backend doesn't support ImGuiBackendFlags_HasMouseHoveredViewport or doesn't honor ImGuiViewportFlags_NoInputs for it, we do a search ourselves.
// A) It won't take account of the possibility that non-imgui windows may be in-between our dragged window and our target window.