Method NavUpdateWindowing

tutorials/common/imgui/imgui.cpp:11494–11676

Windowing management mode Keyboard: CTRL+Tab (change focus/move/resize), Alt (toggle menu layer) Gamepad: Hold Menu/Square (change focus/move/resize), Tap Menu/Square (toggle menu layer)

// Keyboard: CTRL+Tab (change focus/move/resize), Alt (toggle menu layer)
// Gamepad:  Hold Menu/Square (change focus/move/resize), Tap Menu/Square (toggle menu layer)
static void ImGui::NavUpdateWindowing()
{
    ImGuiContext& g = *GImGui;
    ImGuiIO& io = g.IO;

    ImGuiWindow* apply_focus_window = NULL;
    bool apply_toggle_layer = false;

    ImGuiWindow* modal_window = GetTopMostPopupModal();
    bool allow_windowing = (modal_window == NULL);
    if (!allow_windowing)
        g.NavWindowingTarget = NULL;

    // Fade out
    if (g.NavWindowingTargetAnim && g.NavWindowingTarget == NULL)
    {
        g.NavWindowingHighlightAlpha = ImMax(g.NavWindowingHighlightAlpha - io.DeltaTime * 10.0f, 0.0f);
        if (g.DimBgRatio <= 0.0f && g.NavWindowingHighlightAlpha <= 0.0f)
            g.NavWindowingTargetAnim = NULL;
    }

    // Start CTRL+Tab or Square+L/R window selection
    const bool nav_gamepad_active = (io.ConfigFlags & ImGuiConfigFlags_NavEnableGamepad) != 0 && (io.BackendFlags & ImGuiBackendFlags_HasGamepad) != 0;
    const bool nav_keyboard_active = (io.ConfigFlags & ImGuiConfigFlags_NavEnableKeyboard) != 0;
    const bool keyboard_next_window = allow_windowing && g.ConfigNavWindowingKeyNext && Shortcut(g.ConfigNavWindowingKeyNext, ImGuiKeyOwner_None, ImGuiInputFlags_Repeat | ImGuiInputFlags_RouteAlways);
    const bool keyboard_prev_window = allow_windowing && g.ConfigNavWindowingKeyPrev && Shortcut(g.ConfigNavWindowingKeyPrev, ImGuiKeyOwner_None, ImGuiInputFlags_Repeat | ImGuiInputFlags_RouteAlways);
    const bool start_windowing_with_gamepad = allow_windowing && nav_gamepad_active && !g.NavWindowingTarget && IsKeyPressed(ImGuiKey_NavGamepadMenu, 0, ImGuiInputFlags_None);
    const bool start_windowing_with_keyboard = allow_windowing && !g.NavWindowingTarget && (keyboard_next_window || keyboard_prev_window); // Note: enabled even without NavEnableKeyboard!
    if (start_windowing_with_gamepad || start_windowing_with_keyboard)
        if (ImGuiWindow* window = g.NavWindow ? g.NavWindow : FindWindowNavFocusable(g.WindowsFocusOrder.Size - 1, -INT_MAX, -1))
        {
            g.NavWindowingTarget = g.NavWindowingTargetAnim = window->RootWindow;
            g.NavWindowingTimer = g.NavWindowingHighlightAlpha = 0.0f;
            g.NavWindowingAccumDeltaPos = g.NavWindowingAccumDeltaSize = ImVec2(0.0f, 0.0f);
            g.NavWindowingToggleLayer = start_windowing_with_gamepad ? true : false; // Gamepad starts toggling layer
            g.NavInputSource = start_windowing_with_keyboard ? ImGuiInputSource_Keyboard : ImGuiInputSource_Gamepad;
        }

    // Gamepad update
    g.NavWindowingTimer += io.DeltaTime;
    if (g.NavWindowingTarget && g.NavInputSource == ImGuiInputSource_Gamepad)
    {
        // Highlight only appears after a brief time holding the button, so that a fast tap on PadMenu (to toggle NavLayer) doesn't add visual noise
        g.NavWindowingHighlightAlpha = ImMax(g.NavWindowingHighlightAlpha, ImSaturate((g.NavWindowingTimer - NAV_WINDOWING_HIGHLIGHT_DELAY) / 0.05f));

        // Select window to focus
        const int focus_change_dir = (int)IsKeyPressed(ImGuiKey_GamepadL1) - (int)IsKeyPressed(ImGuiKey_GamepadR1);
        if (focus_change_dir != 0)
        {
            NavUpdateWindowingHighlightWindow(focus_change_dir);
            g.NavWindowingHighlightAlpha = 1.0f;
        }

        // Single press toggles NavLayer, long press with L/R apply actual focus on release (until then the window was merely rendered top-most)
        if (!IsKeyDown(ImGuiKey_NavGamepadMenu))
        {
            g.NavWindowingToggleLayer &= (g.NavWindowingHighlightAlpha < 1.0f); // Once button was held long enough we don't consider it a tap-to-toggle-layer press anymore.
            if (g.NavWindowingToggleLayer && g.NavWindow)