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|
-- -*-haskell-*-
-- GIMP Toolkit (GTK) Widget DrawingArea
--
-- Author : Axel Simon
--
-- Created: 22 September 2002
--
-- Copyright (C) 1999-2005 Axel Simon
--
-- This library is free software; you can redistribute it and/or
-- modify it under the terms of the GNU Lesser General Public
-- License as published by the Free Software Foundation; either
-- version 2.1 of the License, or (at your option) any later version.
--
-- This library is distributed in the hope that it will be useful,
-- but WITHOUT ANY WARRANTY; without even the implied warranty of
-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
-- Lesser General Public License for more details.
--
-- |
-- Maintainer : gtk2hs-users@lists.sourceforge.net
-- Stability : provisional
-- Portability : portable (depends on GHC)
--
-- A widget for custom user interface elements
--
module Graphics.UI.Gtk.Misc.DrawingArea (
-- * Detail
--
-- | The 'DrawingArea' widget is used for creating custom user interface
-- elements. It's essentially a blank widget; you can draw on
-- the 'Drawable' returned by 'drawingAreaGetDrawWindow'.
--
-- After creating a drawing area, the application may want to connect to:
--
-- * Mouse and button press signals to respond to input from the user.
--
-- * The 'realize' signal to take any necessary actions when the widget is
-- instantiated on a particular display. (Create GDK resources in response to
-- this signal.)
--
-- * The 'configureEvent' signal to take any necessary actions when the
-- widget changes size.
--
-- * The 'exposeEvent' signal to handle redrawing the contents of the
-- widget.
--
-- Expose events are normally delivered when a drawing area first comes
-- onscreen, or when it's covered by another window and then uncovered
-- (exposed). You can also force an expose event by adding to the \"damage
-- region\" of the drawing area's window; 'widgetQueueDrawArea' and
-- 'windowInvalidateRect' are equally good ways to do this. You\'ll then get an
-- expose event for the invalid region.
--
-- The available routines for drawing are documented on the GDK Drawing
-- Primitives page.
--
-- To receive mouse events on a drawing area, you will need to enable them
-- with 'widgetAddEvents'. To receive keyboard events, you will need to set the
-- 'widgetCanFocus' attribute on the drawing area, and should probably draw some
-- user-visible indication that the drawing area is focused.
-- * Class Hierarchy
-- |
-- @
-- | 'GObject'
-- | +----'Object'
-- | +----'Widget'
-- | +----DrawingArea
-- @
-- * Types
DrawingArea,
DrawingAreaClass,
castToDrawingArea, gTypeDrawingArea,
toDrawingArea,
-- * Constructors
drawingAreaNew,
-- * Methods
drawingAreaGetDrawWindow,
drawingAreaGetSize
) where
import Control.Monad (liftM)
import System.Glib.FFI
import Graphics.UI.Gtk.Abstract.Object (makeNewObject)
{#import Graphics.UI.Gtk.Types#}
import Graphics.UI.Gtk.General.Structs (widgetGetDrawWindow, widgetGetSize)
-- to make haddock happy:
import Graphics.UI.Gtk.Abstract.Widget
{# context lib="gtk" prefix="gtk" #}
--------------------
-- Constructors
-- | Creates a new drawing area.
--
drawingAreaNew :: IO DrawingArea
drawingAreaNew =
makeNewObject mkDrawingArea $
liftM (castPtr :: Ptr Widget -> Ptr DrawingArea) $
{# call unsafe drawing_area_new #}
-- | See 'widgetGetDrawWindow'
--
drawingAreaGetDrawWindow :: DrawingArea -> IO DrawWindow
drawingAreaGetDrawWindow = widgetGetDrawWindow
{-# DEPRECATED drawingAreaGetDrawWindow "use widgetGetDrawWindow instead" #-}
-- | See 'widgetGetSize'
--
drawingAreaGetSize :: DrawingArea -> IO (Int, Int)
drawingAreaGetSize = widgetGetSize
{-# DEPRECATED drawingAreaGetSize "use widgetGetSize instead" #-}
|
