<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><title>Graphics.UI.Gtk.Misc.DrawingArea</title><link href="ocean.css" rel="stylesheet" type="text/css" title="Ocean" /><script src="haddock-util.js" type="text/javascript"></script><script type="text/javascript">//<![CDATA[
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</script></head><body><div id="package-header"><ul class="links" id="page-menu"><li><a href="src/Graphics-UI-Gtk-Misc-DrawingArea.html">Source</a></li><li><a href="index.html">Contents</a></li><li><a href="doc-index.html">Index</a></li></ul><p class="caption">gtk-0.12.0: Binding to the Gtk+ graphical user interface library.</p></div><div id="content"><div id="module-header"><table class="info"><tr><th>Portability</th><td>portable (depends on GHC)</td></tr><tr><th>Stability</th><td>provisional</td></tr><tr><th>Maintainer</th><td>gtk2hs-users@lists.sourceforge.net</td></tr></table><p class="caption">Graphics.UI.Gtk.Misc.DrawingArea</p></div><div id="table-of-contents"><p class="caption">Contents</p><ul><li><a href="#g:1">Detail
</a></li><li><a href="#g:2">Class Hierarchy
</a></li><li><a href="#g:3">Types
</a></li><li><a href="#g:4">Constructors
</a></li><li><a href="#g:5">Methods
</a></li></ul></div><div id="description"><p class="caption">Description</p><div class="doc"><p>A widget for custom user interface elements
</p></div></div><div id="synopsis"><p id="control.syn" class="caption expander" onclick="toggleSection('syn')">Synopsis</p><ul id="section.syn" class="hide" onclick="toggleSection('syn')"><li class="src short"><span class="keyword">data</span> <a href="#t:DrawingArea">DrawingArea</a> </li><li class="src short"><span class="keyword">class</span> <a href="Graphics-UI-Gtk-Abstract-Widget.html#t:WidgetClass">WidgetClass</a> o => <a href="#t:DrawingAreaClass">DrawingAreaClass</a> o </li><li class="src short"><a href="#v:castToDrawingArea">castToDrawingArea</a> :: <a href="/usr/share/doc/ghc/html/libraries/glib-0.12.0/System-Glib-GObject.html#t:GObjectClass">GObjectClass</a> obj => obj -> <a href="Graphics-UI-Gtk-Misc-DrawingArea.html#t:DrawingArea">DrawingArea</a></li><li class="src short"><a href="#v:gTypeDrawingArea">gTypeDrawingArea</a> :: <a href="Graphics-UI-Gtk-Abstract-Widget.html#t:GType">GType</a></li><li class="src short"><a href="#v:toDrawingArea">toDrawingArea</a> :: <a href="Graphics-UI-Gtk-Misc-DrawingArea.html#t:DrawingAreaClass">DrawingAreaClass</a> o => o -> <a href="Graphics-UI-Gtk-Misc-DrawingArea.html#t:DrawingArea">DrawingArea</a></li><li class="src short"><a href="#v:drawingAreaNew">drawingAreaNew</a> :: <a href="/usr/share/doc/ghc/html/libraries/base-4.3.1.0/System-IO.html#t:IO">IO</a> <a href="Graphics-UI-Gtk-Misc-DrawingArea.html#t:DrawingArea">DrawingArea</a></li><li class="src short"><a href="#v:drawingAreaGetDrawWindow">drawingAreaGetDrawWindow</a> :: <a href="Graphics-UI-Gtk-Misc-DrawingArea.html#t:DrawingArea">DrawingArea</a> -> <a href="/usr/share/doc/ghc/html/libraries/base-4.3.1.0/System-IO.html#t:IO">IO</a> <a href="Graphics-UI-Gtk-Gdk-DrawWindow.html#t:DrawWindow">DrawWindow</a></li><li class="src short"><a href="#v:drawingAreaGetSize">drawingAreaGetSize</a> :: <a href="Graphics-UI-Gtk-Misc-DrawingArea.html#t:DrawingArea">DrawingArea</a> -> <a href="/usr/share/doc/ghc/html/libraries/base-4.3.1.0/System-IO.html#t:IO">IO</a> (<a href="/usr/share/doc/ghc/html/libraries/base-4.3.1.0/Data-Int.html#t:Int">Int</a>, <a href="/usr/share/doc/ghc/html/libraries/base-4.3.1.0/Data-Int.html#t:Int">Int</a>)</li></ul></div><div id="interface"><h1 id="g:1">Detail
</h1><div class="doc"><p>The <code><a href="Graphics-UI-Gtk-Misc-DrawingArea.html#t:DrawingArea">DrawingArea</a></code> widget is used for creating custom user interface
elements. It's essentially a blank widget; you can draw on
the <code><a href="Graphics-UI-Gtk-Gdk-Drawable.html#t:Drawable">Drawable</a></code> returned by <code><a href="Graphics-UI-Gtk-Misc-DrawingArea.html#v:drawingAreaGetDrawWindow">drawingAreaGetDrawWindow</a></code>.
</p><p>After creating a drawing area, the application may want to connect to:
</p><ul><li> Mouse and button press signals to respond to input from the user.
</li><li> The <code><a href="Graphics-UI-Gtk-Abstract-Widget.html#v:realize">realize</a></code> signal to take any necessary actions when the widget is
instantiated on a particular display. (Create GDK resources in response to
this signal.)
</li><li> The <code><a href="Graphics-UI-Gtk-Abstract-Widget.html#v:configureEvent">configureEvent</a></code> signal to take any necessary actions when the
widget changes size.
</li><li> The <code><a href="Graphics-UI-Gtk-Abstract-Widget.html#v:exposeEvent">exposeEvent</a></code> signal to handle redrawing the contents of the
widget.
</li></ul><p>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; <code><a href="Graphics-UI-Gtk-Abstract-Widget.html#v:widgetQueueDrawArea">widgetQueueDrawArea</a></code> and
<code>windowInvalidateRect</code> are equally good ways to do this. You'll then get an
expose event for the invalid region.
</p><p>The available routines for drawing are documented on the GDK Drawing
Primitives page.
</p><p>To receive mouse events on a drawing area, you will need to enable them
with <code><a href="Graphics-UI-Gtk-Abstract-Widget.html#v:widgetAddEvents">widgetAddEvents</a></code>. To receive keyboard events, you will need to set the
<code><a href="Graphics-UI-Gtk-Abstract-Widget.html#v:widgetCanFocus">widgetCanFocus</a></code> attribute on the drawing area, and should probably draw some
user-visible indication that the drawing area is focused.
</p></div><h1 id="g:2">Class Hierarchy
</h1><div class="doc"><pre>
| <code><a href="/usr/share/doc/ghc/html/libraries/glib-0.12.0/System-Glib-GObject.html#t:GObject">GObject</a></code>
| +----<code><a href="Graphics-UI-Gtk-Abstract-Object.html#t:Object">Object</a></code>
| +----<code><a href="Graphics-UI-Gtk-Abstract-Widget.html#t:Widget">Widget</a></code>
| +----DrawingArea
</pre></div><h1 id="g:3">Types
</h1><div class="top"><p class="src"><span class="keyword">data</span> <a name="t:DrawingArea" class="def">DrawingArea</a> <a href="src/Graphics-UI-Gtk-Types.html#DrawingArea" class="link">Source</a></p><div class="subs instances"><p id="control.i:DrawingArea" class="caption collapser" onclick="toggleSection('i:DrawingArea')">Instances</p><div id="section.i:DrawingArea" class="show"><table><tr><td class="src"><a href="/usr/share/doc/ghc/html/libraries/base-4.3.1.0/Data-Eq.html#t:Eq">Eq</a> <a href="Graphics-UI-Gtk-Misc-DrawingArea.html#t:DrawingArea">DrawingArea</a></td><td class="doc empty"> </td></tr><tr><td class="src"><a href="/usr/share/doc/ghc/html/libraries/base-4.3.1.0/Data-Ord.html#t:Ord">Ord</a> <a href="Graphics-UI-Gtk-Misc-DrawingArea.html#t:DrawingArea">DrawingArea</a></td><td class="doc empty"> </td></tr><tr><td class="src"><a href="/usr/share/doc/ghc/html/libraries/glib-0.12.0/System-Glib-GObject.html#t:GObjectClass">GObjectClass</a> <a href="Graphics-UI-Gtk-Misc-DrawingArea.html#t:DrawingArea">DrawingArea</a></td><td class="doc empty"> </td></tr><tr><td class="src"><a href="Graphics-UI-Gtk-Misc-DrawingArea.html#t:DrawingAreaClass">DrawingAreaClass</a> <a href="Graphics-UI-Gtk-Misc-DrawingArea.html#t:DrawingArea">DrawingArea</a></td><td class="doc empty"> </td></tr><tr><td class="src"><a href="Graphics-UI-Gtk-Abstract-Widget.html#t:WidgetClass">WidgetClass</a> <a href="Graphics-UI-Gtk-Misc-DrawingArea.html#t:DrawingArea">DrawingArea</a></td><td class="doc empty"> </td></tr><tr><td class="src"><a href="Graphics-UI-Gtk-Abstract-Object.html#t:ObjectClass">ObjectClass</a> <a href="Graphics-UI-Gtk-Misc-DrawingArea.html#t:DrawingArea">DrawingArea</a></td><td class="doc empty"> </td></tr></table></div></div></div><div class="top"><p class="src"><span class="keyword">class</span> <a href="Graphics-UI-Gtk-Abstract-Widget.html#t:WidgetClass">WidgetClass</a> o => <a name="t:DrawingAreaClass" class="def">DrawingAreaClass</a> o <a href="src/Graphics-UI-Gtk-Types.html#DrawingAreaClass" class="link">Source</a></p><div class="subs instances"><p id="control.i:DrawingAreaClass" class="caption collapser" onclick="toggleSection('i:DrawingAreaClass')">Instances</p><div id="section.i:DrawingAreaClass" class="show"><table><tr><td class="src"><a href="Graphics-UI-Gtk-Misc-DrawingArea.html#t:DrawingAreaClass">DrawingAreaClass</a> <a href="Graphics-UI-Gtk-Display-Spinner.html#t:Spinner">Spinner</a></td><td class="doc empty"> </td></tr><tr><td class="src"><a href="Graphics-UI-Gtk-Misc-DrawingArea.html#t:DrawingAreaClass">DrawingAreaClass</a> <a href="Graphics-UI-Gtk-Misc-DrawingArea.html#t:DrawingArea">DrawingArea</a></td><td class="doc empty"> </td></tr></table></div></div></div><div class="top"><p class="src"><a name="v:castToDrawingArea" class="def">castToDrawingArea</a> :: <a href="/usr/share/doc/ghc/html/libraries/glib-0.12.0/System-Glib-GObject.html#t:GObjectClass">GObjectClass</a> obj => obj -> <a href="Graphics-UI-Gtk-Misc-DrawingArea.html#t:DrawingArea">DrawingArea</a><a href="src/Graphics-UI-Gtk-Types.html#castToDrawingArea" class="link">Source</a></p></div><div class="top"><p class="src"><a name="v:gTypeDrawingArea" class="def">gTypeDrawingArea</a> :: <a href="Graphics-UI-Gtk-Abstract-Widget.html#t:GType">GType</a><a href="src/Graphics-UI-Gtk-Types.html#gTypeDrawingArea" class="link">Source</a></p></div><div class="top"><p class="src"><a name="v:toDrawingArea" class="def">toDrawingArea</a> :: <a href="Graphics-UI-Gtk-Misc-DrawingArea.html#t:DrawingAreaClass">DrawingAreaClass</a> o => o -> <a href="Graphics-UI-Gtk-Misc-DrawingArea.html#t:DrawingArea">DrawingArea</a><a href="src/Graphics-UI-Gtk-Types.html#toDrawingArea" class="link">Source</a></p></div><h1 id="g:4">Constructors
</h1><div class="top"><p class="src"><a name="v:drawingAreaNew" class="def">drawingAreaNew</a> :: <a href="/usr/share/doc/ghc/html/libraries/base-4.3.1.0/System-IO.html#t:IO">IO</a> <a href="Graphics-UI-Gtk-Misc-DrawingArea.html#t:DrawingArea">DrawingArea</a><a href="src/Graphics-UI-Gtk-Misc-DrawingArea.html#drawingAreaNew" class="link">Source</a></p><div class="doc"><p>Creates a new drawing area.
</p></div></div><h1 id="g:5">Methods
</h1><div class="top"><p class="src"><a name="v:drawingAreaGetDrawWindow" class="def">drawingAreaGetDrawWindow</a> :: <a href="Graphics-UI-Gtk-Misc-DrawingArea.html#t:DrawingArea">DrawingArea</a> -> <a href="/usr/share/doc/ghc/html/libraries/base-4.3.1.0/System-IO.html#t:IO">IO</a> <a href="Graphics-UI-Gtk-Gdk-DrawWindow.html#t:DrawWindow">DrawWindow</a><a href="src/Graphics-UI-Gtk-Misc-DrawingArea.html#drawingAreaGetDrawWindow" class="link">Source</a></p><div class="doc"><p>See <code><a href="Graphics-UI-Gtk-Abstract-Widget.html#v:widgetGetDrawWindow">widgetGetDrawWindow</a></code>
</p></div></div><div class="top"><p class="src"><a name="v:drawingAreaGetSize" class="def">drawingAreaGetSize</a> :: <a href="Graphics-UI-Gtk-Misc-DrawingArea.html#t:DrawingArea">DrawingArea</a> -> <a href="/usr/share/doc/ghc/html/libraries/base-4.3.1.0/System-IO.html#t:IO">IO</a> (<a href="/usr/share/doc/ghc/html/libraries/base-4.3.1.0/Data-Int.html#t:Int">Int</a>, <a href="/usr/share/doc/ghc/html/libraries/base-4.3.1.0/Data-Int.html#t:Int">Int</a>)<a href="src/Graphics-UI-Gtk-Misc-DrawingArea.html#drawingAreaGetSize" class="link">Source</a></p><div class="doc"><p>See <code><a href="Graphics-UI-Gtk-Abstract-Widget.html#v:widgetGetSize">widgetGetSize</a></code>
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