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Graphics.UI.GLUT.Menu

Portability | portable
Stability | stable
Maintainer | sven.panne@aedion.de

Description
GLUT supports simple cascading pop-up menus. They are designed to let a user select various modes within a program. The functionality is simple and minimalistic and is meant to be that way. Do not mistake GLUT's pop-up menu facility with an attempt to create a full-featured user interface.
Synopsis

newtype Menu = Menu [MenuItem]

data MenuItem

= MenuEntry String MenuCallback
| SubMenu String Menu

type MenuCallback = IO ()
attachMenu :: MouseButton -> Menu -> IO ()
numMenuItems :: GettableStateVar Int

Documentation
newtype Menu

A menu is simply a list of menu items.
Constructors

Menu [MenuItem] |

data MenuItem

A single item within a menu can either be a plain menu entry or a sub-menu entry, allowing for arbitrarily deep nested menus.
Constructors

MenuEntry String MenuCallback | A plain menu entry with an associated callback, which is triggered when the user selects the entry
SubMenu String Menu | A sub-menu, which is cascaded when the user selects the entry, allowing sub-menu entries to be selected

type MenuCallback = IO ()
attachMenu :: MouseButton -> Menu -> IO ()

Create a new pop-up menu for the current window, attaching it to the given mouse button. A previously attached menu (if any), is detached before and won't receive callbacks anymore.

It is illegal to call `attachMenu` while any (sub-)menu is in use, i.e. popped up.

X Implementation Notes: If available, GLUT for X will take advantage of overlay planes for implementing pop-up menus. The use of overlay planes can eliminate display callbacks when pop-up menus are deactivated. The `SERVER_OVERLAY_VISUALS` convention is used to determine if overlay visuals are available.

numMenuItems :: GettableStateVar Int
Contains the number of menu items in the current menu.
Produced by Haddock version 0.8