GtkSharp/doc/en/Gdk/PixbufLoader.xml

<Type Name="PixbufLoader" FullName="Gdk.PixbufLoader">
  <TypeSignature Language="C#" Value="public class PixbufLoader : GLib.Object, IWrapper, IDisposable" Maintainer="auto" />
  <AssemblyInfo>
    <AssemblyName>gdk-sharp</AssemblyName>
    <AssemblyPublicKey>
    </AssemblyPublicKey>
    <AssemblyVersion>0.0.0.0</AssemblyVersion>
    <AssemblyCulture>neutral</AssemblyCulture>
    <Attributes />
  </AssemblyInfo>
  <ThreadSafetyStatement>Gtk# is thread aware, but not thread safe; See the <link location="node:gtk-sharp/programming/threads">Gtk# Thread Programming</link> for details.</ThreadSafetyStatement>
  <Docs>
    <summary>
      <para>PixbufLoader is a 'passive' pixbuf loader. It's not actively read pix buf data, but 'listen' for incoming data instead. It's useful in a case where you want to read the image data in small chunks. Typical use of PixbufLoader is when you want to read a very large image data or reading image from a slow media (such as a slow network connection).</para>
      <para>
You can see the "Images" section of GtkDemo to learn how to use PixbufLoader.
</para>
    </summary>
    <remarks>
      <example>
        <code lang="C#">
using System;
using System.IO;
using Gtk;
using Gdk;
                                                                                
namespace GtkDemo
{
        public class PixbufLoaderSample : Gtk.Window
        {
                static Gdk.PixbufLoader pixbufLoader;
                private uint timeout_id;
                private static Gtk.Image progressiveImage;
                private VBox vbox;
                BinaryReader imageStream;
 
                static void Main ()
                {
                        Application.Init ();
                        new PixbufLoaderSample ();
                        Application.Run ();
                }
 
                public PixbufLoaderSample () : base ("images")
                {
                        this.DeleteEvent += new DeleteEventHandler (WindowDelete);
                        this.BorderWidth = 8;
 
                        vbox = new VBox (false, 8);
                        vbox.BorderWidth = 8;
                        this.Add (vbox);
 
                        Label label = new Gtk.Label ("Progressive image loading");
                        label.UseMarkup = true;
                        vbox.PackStart (label);
 
                        Gtk.Frame frame = new Gtk.Frame ();
                        frame.ShadowType = ShadowType.In;
 
                        Alignment alignment = new Alignment (0.5f, 0.5f, 0f, 0f);
                        alignment.Add (frame);
                        vbox.PackStart (alignment, false, false, 0);
 
                        // Create an empty image for now; the progressive loader
                        // will create the pixbuf and fill it in.
                        progressiveImage = new Gtk.Image ();
                        frame.Add (progressiveImage);
 
                        StartProgressiveLoading ();
 
                        this.ShowAll ();
                }
 
                private void WindowDelete (object o, DeleteEventArgs args)
                {
                        this.Hide ();
                        this.Destroy ();
                        args.RetVal = true;
                }
 
                private void StartProgressiveLoading ()
                {
                /* This is obviously totally contrived (we slow down loading
                 * on purpose to show how incremental loading works).
                 * The real purpose of incremental loading is the case where
                 * you are reading data from a slow source such as the network.
                 * The timeout simply simulates a slow data source by inserting
                 * pauses in the reading process.
                 */
                        timeout_id = GLib.Timeout.Add (150, new GLib.TimeoutHandler (ProgressiveTimeout));
                }
 
                private  bool ProgressiveTimeout ()
                {
                        if (imageStream == null) {
                                // note you need to provide your own image
                                // at that location to run this sample
                                imageStream = new BinaryReader (new StreamReader ("images/alphatest.png").BaseStream);
                                pixbufLoader = new Gdk.PixbufLoader ();
                                pixbufLoader.AreaPrepared += new EventHandler (ProgressivePreparedCallback);
                                pixbufLoader.AreaUpdated += new AreaUpdatedHandler (ProgressiveUpdatedCallback);
                        }
 
                        if (imageStream.PeekChar () != -1) {
                                byte[] bytes = imageStream.ReadBytes (256);
                                pixbufLoader.Write (bytes, (uint) bytes.Length);
                                return true; // leave the timeout active
                        }
                        else {
                                imageStream.Close ();
                                return false; // removes the timeout
                        }
                }
 
                static void ProgressivePreparedCallback (object obj, EventArgs args)
                {
                        Gdk.Pixbuf pixbuf = pixbufLoader.Pixbuf;
                        pixbuf.Fill (0xaaaaaaff);
                        progressiveImage.FromPixbuf = pixbuf;
                }
 
                static void ProgressiveUpdatedCallback (object obj, AreaUpdatedArgs args)
                {
                        progressiveImage.QueueDraw ();
                }
        }
}
  </code>
      </example>
    </remarks>
  </Docs>
  <Base>
    <BaseTypeName>GLib.Object</BaseTypeName>
  </Base>
  <Interfaces>
    <Interface>
      <InterfaceName>GLib.IWrapper</InterfaceName>
    </Interface>
    <Interface>
      <InterfaceName>System.IDisposable</InterfaceName>
    </Interface>
  </Interfaces>
  <Attributes />
  <Members>
    <Member MemberName="Write">
      <MemberSignature Language="C#" Value="public bool Write (byte [] buf, uint count);" />
      <MemberType>Method</MemberType>
      <ReturnValue>
        <ReturnType>System.Boolean</ReturnType>
      </ReturnValue>
      <Parameters>
        <Parameter Name="buf" Type="System.Byte []" />
        <Parameter Name="count" Type="System.UInt32" />
      </Parameters>
      <Docs>
        <summary>Parses the next count bytes of image data from buffer buf.</summary>
        <param name="buf">array of bytes buffer to parse.</param>
        <param name="count">number of bytes to parse.</param>
        <returns>returns true if data was parsed and loaded succesfully.</returns>
        <remarks>
          <para>If the return value is false, the PixbufLoader will be closed.</para>
        </remarks>
      </Docs>
    </Member>
    <Member MemberName="Close">
      <MemberSignature Language="C#" Value="public bool Close ();" />
      <MemberType>Method</MemberType>
      <ReturnValue>
        <ReturnType>System.Boolean</ReturnType>
      </ReturnValue>
      <Parameters />
      <Docs>
        <summary>Closes the loader.</summary>
        <returns>returns true on successful close and false on error.</returns>
        <remarks>During the close, PixbufLoader will parse any data that has not been parsed. If the data is incomplete or corrupted, this method will return false.</remarks>
      </Docs>
    </Member>
    <Member MemberName="Finalize">
      <MemberSignature Language="C#" Value="protected override void Finalize ();" />
      <MemberType>Method</MemberType>
      <ReturnValue>
        <ReturnType>System.Void</ReturnType>
      </ReturnValue>
      <Parameters />
      <Docs>
        <summary>Disposes the resources associated with the object.</summary>
        <remarks />
      </Docs>
    </Member>
    <Member MemberName=".ctor">
      <MemberSignature Language="C#" Value="public PixbufLoader (IntPtr raw);" />
      <MemberType>Constructor</MemberType>
      <ReturnValue />
      <Parameters>
        <Parameter Name="raw" Type="System.IntPtr" />
      </Parameters>
      <Docs>
        <summary>Internal constructor</summary>
        <param name="raw">Pointer to the C object.</param>
        <returns>An instance of PixbufLoader, wrapping the C object.</returns>
        <remarks>
          <para>This is an internal constructor, and should not be used by user code.</para>
        </remarks>
      </Docs>
    </Member>
    <Member MemberName=".ctor">
      <MemberSignature Language="C#" Value="public PixbufLoader ();" />
      <MemberType>Constructor</MemberType>
      <ReturnValue />
      <Parameters />
      <Docs>
        <summary>Default constructor</summary>
        <returns>an object of type <see cref="T:Gdk.PixbufLoader" /></returns>
        <remarks />
      </Docs>
    </Member>
    <Member MemberName="Pixbuf">
      <MemberSignature Language="C#" Value="public Gdk.Pixbuf Pixbuf { get; };" />
      <MemberType>Property</MemberType>
      <ReturnValue>
        <ReturnType>Gdk.Pixbuf</ReturnType>
      </ReturnValue>
      <Docs>
        <summary>The Pixbuf that is being loaded.</summary>
        <returns>an object of type <see cref="T:Gdk.Pixbuf" /></returns>
        <remarks />
      </Docs>
    </Member>
    <Member MemberName="Animation">
      <MemberSignature Language="C#" Value="public Gdk.PixbufAnimation Animation { get; };" />
      <MemberType>Property</MemberType>
      <ReturnValue>
        <ReturnType>Gdk.PixbufAnimation</ReturnType>
      </ReturnValue>
      <Docs>
        <summary>To be added</summary>
        <returns>an object of type <see cref="T:Gdk.PixbufAnimation" /></returns>
        <remarks>To be added</remarks>
      </Docs>
    </Member>
    <Member MemberName="AreaPrepared">
      <MemberSignature Language="C#" Value="public event EventHandler AreaPrepared;" />
      <MemberType>Event</MemberType>
      <ReturnValue>
        <ReturnType>System.EventHandler</ReturnType>
      </ReturnValue>
      <Parameters />
      <Docs>
        <summary>Emitted when the area of the PixbufLoader is prepared.</summary>
        <remarks />
      </Docs>
    </Member>
    <Member MemberName="AreaUpdated">
      <MemberSignature Language="C#" Value="public event Gdk.AreaUpdatedHandler AreaUpdated;" />
      <MemberType>Event</MemberType>
      <ReturnValue>
        <ReturnType>Gdk.AreaUpdatedHandler</ReturnType>
      </ReturnValue>
      <Parameters />
      <Docs>
        <summary>Emitted when the area of the PixbufLoader is updated with data.</summary>
        <remarks />
      </Docs>
    </Member>
    <Member MemberName="Closed">
      <MemberSignature Language="C#" Value="public event EventHandler Closed;" />
      <MemberType>Event</MemberType>
      <ReturnValue>
        <ReturnType>System.EventHandler</ReturnType>
      </ReturnValue>
      <Parameters />
      <Docs>
        <summary>Emitted when the PixbufLoader is closed.</summary>
        <remarks />
      </Docs>
    </Member>
    <Member MemberName="Format">
      <MemberSignature Language="C#" Value="public Gdk.PixbufFormat Format { get; };" />
      <MemberType>Property</MemberType>
      <ReturnValue>
        <ReturnType>Gdk.PixbufFormat</ReturnType>
      </ReturnValue>
      <Docs>
        <summary>To be added</summary>
        <returns>a <see cref="T:Gdk.PixbufFormat" /></returns>
        <remarks>To be added</remarks>
      </Docs>
    </Member>
    <Member MemberName="SizePrepared">
      <MemberSignature Language="C#" Value="public event Gdk.SizePreparedHandler SizePrepared;" />
      <MemberType>Event</MemberType>
      <ReturnValue>
        <ReturnType>Gdk.SizePreparedHandler</ReturnType>
      </ReturnValue>
      <Parameters />
      <Docs>
        <summary>Emitted when the PixbufLoader has prepared its size.</summary>
        <remarks />
      </Docs>
    </Member>
    <Member MemberName="SetSize">
      <MemberSignature Language="C#" Value="public void SetSize (int width, int height);" />
      <MemberType>Method</MemberType>
      <ReturnValue>
        <ReturnType>System.Void</ReturnType>
      </ReturnValue>
      <Parameters>
        <Parameter Name="width" Type="System.Int32" />
        <Parameter Name="height" Type="System.Int32" />
      </Parameters>
      <Docs>
        <summary>Set the size of the image that will be loaded.</summary>
        <param name="width">a <see cref="T:System.Int32" /></param>
        <param name="height">a <see cref="T:System.Int32" /></param>
        <remarks />
      </Docs>
    </Member>
    <Member MemberName="GType">
      <MemberSignature Language="C#" Value="public static GLib.GType GType { get; };" />
      <MemberType>Property</MemberType>
      <ReturnValue>
        <ReturnType>GLib.GType</ReturnType>
      </ReturnValue>
      <Parameters />
      <Docs>
        <summary>GType Property.</summary>
        <returns>a <see cref="T:GLib.GType" /></returns>
        <remarks>Returns the native <see cref="T:GLib.GType" /> value for <see cref="T:Gdk.PixbufLoader" />.</remarks>
      </Docs>
    </Member>
    <Member MemberName="OnClosed">
      <MemberSignature Language="C#" Value="protected virtual void OnClosed ();" />
      <MemberType>Method</MemberType>
      <ReturnValue>
        <ReturnType>System.Void</ReturnType>
      </ReturnValue>
      <Parameters />
      <Docs>
        <summary>Default handler for the <see cref="M:Gdk.PixbufLoader.Closed" /> event.</summary>
        <remarks>Override this method in a subclass to provide a default handler for the <see cref="M:Gdk.PixbufLoader.Closed" /> event.</remarks>
      </Docs>
    </Member>
    <Member MemberName="OnSizePrepared">
      <MemberSignature Language="C#" Value="protected virtual void OnSizePrepared (int width, int height);" />
      <MemberType>Method</MemberType>
      <ReturnValue>
        <ReturnType>System.Void</ReturnType>
      </ReturnValue>
      <Parameters>
        <Parameter Name="width" Type="System.Int32" />
        <Parameter Name="height" Type="System.Int32" />
      </Parameters>
      <Docs>
        <summary>Default handler for the <see cref="M:Gdk.PixbufLoader.SizePrepared" /> event.</summary>
        <param name="width">a <see cref="T:System.Int32" /></param>
        <param name="height">a <see cref="T:System.Int32" /></param>
        <remarks>Override this method in a subclass to provide a default handler for the <see cref="M:Gdk.PixbufLoader.SizePrepared" /> event.</remarks>
      </Docs>
    </Member>
    <Member MemberName="OnAreaUpdated">
      <MemberSignature Language="C#" Value="protected virtual void OnAreaUpdated (int x, int y, int width, int height);" />
      <MemberType>Method</MemberType>
      <ReturnValue>
        <ReturnType>System.Void</ReturnType>
      </ReturnValue>
      <Parameters>
        <Parameter Name="x" Type="System.Int32" />
        <Parameter Name="y" Type="System.Int32" />
        <Parameter Name="width" Type="System.Int32" />
        <Parameter Name="height" Type="System.Int32" />
      </Parameters>
      <Docs>
        <summary>Default handler for the <see cref="M:Gdk.PixbufLoader.AreaUpdated" /> event.</summary>
        <param name="x">a <see cref="T:System.Int32" /></param>
        <param name="y">a <see cref="T:System.Int32" /></param>
        <param name="width">a <see cref="T:System.Int32" /></param>
        <param name="height">a <see cref="T:System.Int32" /></param>
        <remarks>Override this method in a subclass to provide a default handler for the <see cref="M:Gdk.PixbufLoader.AreaUpdated" /> event.</remarks>
      </Docs>
    </Member>
    <Member MemberName="OnAreaPrepared">
      <MemberSignature Language="C#" Value="protected virtual void OnAreaPrepared ();" />
      <MemberType>Method</MemberType>
      <ReturnValue>
        <ReturnType>System.Void</ReturnType>
      </ReturnValue>
      <Parameters />
      <Docs>
        <summary>Default handler for the <see cref="M:Gdk.PixbufLoader.AreaPrepared" /> event.</summary>
        <remarks>Override this method in a subclass to provide a default handler for the <see cref="M:Gdk.PixbufLoader.AreaPrepared" /> event.</remarks>
      </Docs>
    </Member>
    <Member MemberName=".ctor">
      <MemberSignature Language="C#" Value="protected PixbufLoader (GLib.GType gtype);" />
      <MemberType>Constructor</MemberType>
      <ReturnValue />
      <Parameters>
        <Parameter Name="gtype" Type="GLib.GType" />
      </Parameters>
      <Docs>
        <summary>Protected Constructor.</summary>
        <param name="gtype">a <see cref="T:GLib.GType" /></param>
        <returns>a <see cref="T:Gdk.PixbufLoader" /></returns>
        <remarks>Chain to this constructor if you have manually registered a native <see cref="T:GLib.GType" /> value for your subclass.</remarks>
      </Docs>
    </Member>
    <Member MemberName="Write">
      <MemberSignature Language="C#" Value="public bool Write (byte [] bytes);" />
      <MemberType>Method</MemberType>
      <ReturnValue>
        <ReturnType>System.Boolean</ReturnType>
      </ReturnValue>
      <Parameters>
        <Parameter Name="bytes" Type="System.Byte[]" />
      </Parameters>
      <Docs>
        <summary>Parses the bytes into the image data.</summary>
        <param name="bytes">a <see cref="T:System.Byte" /></param>
        <returns>a <see cref="T:System.Boolean" /></returns>
        <remarks>This is an overload to <see cref="M:Gdk.PixbufLoader.Write(System.Byte[],System.UInt32)" />, which determines the length automatically.</remarks>
      </Docs>
    </Member>
    <Member MemberName="NewWithMimeType">
      <MemberSignature Language="C#" Value="public static Gdk.PixbufLoader NewWithMimeType (string mime_type);" />
      <MemberType>Method</MemberType>
      <ReturnValue>
        <ReturnType>Gdk.PixbufLoader</ReturnType>
      </ReturnValue>
      <Parameters>
        <Parameter Name="mime_type" Type="System.String" />
      </Parameters>
      <Docs>
        <summary>To be added</summary>
        <param name="mime_type">a <see cref="T:System.String" /></param>
        <returns>a <see cref="T:Gdk.PixbufLoader" /></returns>
        <remarks>To be added</remarks>
      </Docs>
    </Member>
    <Member MemberName="NewWithType">
      <MemberSignature Language="C#" Value="public static Gdk.PixbufLoader NewWithType (string image_type);" />
      <MemberType>Method</MemberType>
      <ReturnValue>
        <ReturnType>Gdk.PixbufLoader</ReturnType>
      </ReturnValue>
      <Parameters>
        <Parameter Name="image_type" Type="System.String" />
      </Parameters>
      <Docs>
        <summary>To be added</summary>
        <param name="image_type">a <see cref="T:System.String" /></param>
        <returns>a <see cref="T:Gdk.PixbufLoader" /></returns>
        <remarks>To be added</remarks>
      </Docs>
    </Member>
  </Members>
</Type>