gtk-0.12.2: Binding to the Gtk+ graphical user interface library.

Portability | portable (depends on GHC)
Stability | provisional
Maintainer | gtk2hs-users@lists.sourceforge.net

Graphics.UI.Gtk.Misc.DrawingArea

Contents

- Detail
- Class Hierarchy
- Types
- Constructors
- Methods

Description

A widget for custom user interface elements

Synopsis

- data DrawingArea
- class WidgetClass o => DrawingAreaClass o
- castToDrawingArea :: GObjectClass obj => obj -> DrawingArea
- gTypeDrawingArea :: GType
- toDrawingArea :: DrawingAreaClass o => o -> DrawingArea
- drawingAreaNew :: IO DrawingArea
- drawingAreaGetDrawWindow :: DrawingArea -> IO DrawWindow
- drawingAreaGetSize :: DrawingArea -> IO (Int, Int)

# 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

data DrawingArea

Instances

Eq DrawingArea |
Ord DrawingArea |
GObjectClass DrawingArea |
DrawingAreaClass DrawingArea |
WidgetClass DrawingArea |
ObjectClass DrawingArea |

class WidgetClass o => DrawingAreaClass o

Instances

DrawingAreaClass Spinner |
DrawingAreaClass DrawingArea |

castToDrawingArea :: GObjectClass obj => obj -> DrawingArea

gTypeDrawingArea :: GType

toDrawingArea :: DrawingAreaClass o => o -> DrawingArea

# Constructors

drawingAreaNew :: IO DrawingArea

Creates a new drawing area.

# Methods

drawingAreaGetDrawWindow :: DrawingArea -> IO DrawWindow

See `widgetGetDrawWindow`

drawingAreaGetSize :: DrawingArea -> IO (Int, Int)

See `widgetGetSize`