Method BeginMenuEx

KBotExt/imgui/imgui_widgets.cpp:7137–7332

}

bool ImGui::BeginMenuEx(const char* label, const char* icon, bool enabled)
{
	ImGuiWindow* window = GetCurrentWindow();
	if (window->SkipItems)
		return false;

	ImGuiContext& g = *GImGui;
	const ImGuiStyle& style = g.Style;
	const ImGuiID id = window->GetID(label);
	bool menu_is_open = IsPopupOpen(id, ImGuiPopupFlags_None);

	// Sub-menus are ChildWindow so that mouse can be hovering across them (otherwise top-most popup menu would steal focus and not allow hovering on parent menu)
	// The first menu in a hierarchy isn't so hovering doesn't get across (otherwise e.g. resizing borders with ImGuiButtonFlags_FlattenChildren would react), but top-most BeginMenu() will bypass that limitation.
	ImGuiWindowFlags window_flags = ImGuiWindowFlags_ChildMenu | ImGuiWindowFlags_AlwaysAutoResize | ImGuiWindowFlags_NoMove | ImGuiWindowFlags_NoTitleBar | ImGuiWindowFlags_NoSavedSettings | ImGuiWindowFlags_NoNavFocus;
	if (window->Flags & ImGuiWindowFlags_ChildMenu)
		window_flags |= ImGuiWindowFlags_ChildWindow;

	// If a menu with same the ID was already submitted, we will append to it, matching the behavior of Begin().
	// We are relying on a O(N) search - so O(N log N) over the frame - which seems like the most efficient for the expected small amount of BeginMenu() calls per frame.
	// If somehow this is ever becoming a problem we can switch to use e.g. ImGuiStorage mapping key to last frame used.
	if (g.MenusIdSubmittedThisFrame.contains(id))
	{
		if (menu_is_open)
			menu_is_open = BeginPopupEx(id, window_flags); // menu_is_open can be 'false' when the popup is completely clipped (e.g. zero size display)
		else
			g.NextWindowData.ClearFlags();          // we behave like Begin() and need to consume those values
		return menu_is_open;
	}

	// Tag menu as used. Next time BeginMenu() with same ID is called it will append to existing menu
	g.MenusIdSubmittedThisFrame.push_back(id);

	ImVec2 label_size = CalcTextSize(label, NULL, true);

	// Odd hack to allow hovering across menus of a same menu-set (otherwise we wouldn't be able to hover parent without always being a Child window)
	// This is only done for items for the menu set and not the full parent window.
	const bool menuset_is_open = IsRootOfOpenMenuSet();
	if (menuset_is_open)
		PushItemFlag(ImGuiItemFlags_NoWindowHoverableCheck, true);

	// The reference position stored in popup_pos will be used by Begin() to find a suitable position for the child menu,
	// However the final position is going to be different! It is chosen by FindBestWindowPosForPopup().
	// e.g. Menus tend to overlap each other horizontally to amplify relative Z-ordering.
	ImVec2 popup_pos, pos = window->DC.CursorPos;
	PushID(label);
	if (!enabled)
		BeginDisabled();
	const ImGuiMenuColumns* offsets = &window->DC.MenuColumns;
	bool pressed;

	// We use ImGuiSelectableFlags_NoSetKeyOwner to allow down on one menu item, move, up on another.
	const ImGuiSelectableFlags selectable_flags = ImGuiSelectableFlags_NoHoldingActiveID | ImGuiSelectableFlags_NoSetKeyOwner | ImGuiSelectableFlags_SelectOnClick | ImGuiSelectableFlags_DontClosePopups;
	if (window->DC.LayoutType == ImGuiLayoutType_Horizontal)
	{
		// Menu inside an horizontal menu bar
		// Selectable extend their highlight by half ItemSpacing in each direction.
		// For ChildMenu, the popup position will be overwritten by the call to FindBestWindowPosForPopup() in Begin()
		popup_pos = ImVec2(pos.x - 1.0f - IM_FLOOR(style.ItemSpacing.x * 0.5f), pos.y - style.FramePadding.y + window->MenuBarHeight());