-- -----------------------------------------------------------------------
--
-- $Source: /repository/uni/htk/menuitems/MenuCheckButton.hs,v $
--
-- HTk - a GUI toolkit for Haskell  -  (c) Universitaet Bremen
--
-- $Revision: 1.3 $ from $Date: 2001/12/17 20:54:55 $  
-- Last modification by $Author: ludi $
--
-- -----------------------------------------------------------------------

---
-- HTk's <strong>menu checkbutton</strong>.<br>
-- A simple checkbutton inside a menu associated with a polymorphic
-- variable.
module MenuCheckButton (

  HasIndicator(..),
  HasAccelerator(..),

  MenuCheckButton,
  createMenuCheckButton

) where

import Core
import Configuration
import Image
import BitMap
import Menu
import MenuItem
import Indicator
import Synchronized
import Computation
import TkVariables


-- -----------------------------------------------------------------------
-- MenuCascade type
-- -----------------------------------------------------------------------

---
-- The <code>MenuCheckButton</code> datatype.
newtype MenuCheckButton = MenuCheckButton GUIOBJECT


-- -----------------------------------------------------------------------
-- commands
-- -----------------------------------------------------------------------

---
-- Constructs a new menu checkbutton and returns a handler.
-- @param m       - the parent menu.
-- @param cnf     - the list of configuration options for this menu
--                  checkbutton.
-- @return result - A menu checkbutton.
createMenuCheckButton :: Menu -> [Config MenuCheckButton] ->
                         IO MenuCheckButton
createMenuCheckButton m cnf =
  createMenuItem m MENUCHECKBUTTON MenuCheckButton cnf


-- -----------------------------------------------------------------------
-- instances
-- -----------------------------------------------------------------------

---
-- A menu checkbutton is a menu item (any menu item instantiates the
-- abstract <code>class MenuItem</code>).
instance MenuItem MenuCheckButton

---
-- Internal.
instance Eq MenuCheckButton where
---
-- Internal.
  w1 == w2 = (toGUIObject w1) == (toGUIObject w2)

---
-- Internal.
instance GUIObject MenuCheckButton where 
---
-- Internal.
  toGUIObject (MenuCheckButton w) = w
---
-- Internal.
  cname _ = "MenuCheckButton"

---
-- You can synchronize on a menu checkbutton.
instance Synchronized MenuCheckButton where
---
-- Synchronizes on a menu checkbutton.
  synchronize = synchronize . toGUIObject

---
-- A menu checkbutton has an optional text to display as a reminder
-- about a keystroke binding.
instance HasAccelerator MenuCheckButton

---
-- A menu checkbutton can contain a bitmap (instead of text or an image).
instance HasBitMap MenuCheckButton

---
-- A menu checkbutton has a configureable border.
instance HasBorder MenuCheckButton

---
-- A menu checkbutton has a normal foreground and background colour and
-- an active/disabled foreground and background colour.
instance HasColour MenuCheckButton where 
---
-- Internal.
  legalColourID = buttonColours

---
-- A menu checkbutton is a stateful object, it can be enabled or
-- disabled.
instance HasEnable MenuCheckButton

---
-- You can specify the font of a menu checkbutton.
instance HasFont MenuCheckButton

---
-- A menu checkbutton has a configureable text justification.
instance HasJustify MenuCheckButton

---
-- You can display an indicator with a menu checkbutton.
instance HasIndicator MenuCheckButton

---
-- A menu checkbutton can contain an image (instead of text or a bitmap).
instance HasPhoto MenuCheckButton

---
-- You can specify the size of a menu checkbutton.
instance HasSize MenuCheckButton

---
-- A menu checkbutton can contain text (instead of an image or bitmap).
instance GUIValue v => HasText MenuCheckButton v where
---
-- Sets the text to display.
  text str w = cset w "label" str >> return w
---
-- Gets the displayed text.
  getText w = cget w "label"

---
-- You can set the index of a text character to underline.
instance HasUnderline MenuCheckButton

---
-- The polymorphic variable the menu checkbutton's value is associated
-- with.
instance HasVariable MenuCheckButton

---
-- A menu checkbutton has a value, that corresponds to a polymorphic
-- <code>TkVariable</code>.
instance GUIValue v => HasValue MenuCheckButton v

---
-- When a menu checkbutton is clicked, a corresponding event is invoked.
instance HasCommand MenuCheckButton