GtkSharp/doc/en/Gnome/CanvasItem.xml

<Type Name="CanvasItem" FullName="Gnome.CanvasItem">
  <TypeSignature Language="C#" Value="public class CanvasItem : Gtk.Object, IWrapper, IDisposable" Maintainer="auto" />
  <AssemblyInfo>
    <AssemblyName>gnome-sharp</AssemblyName>
    <AssemblyVersion>0.0.0.0</AssemblyVersion>
    <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>Base class for all canvas items</summary>
    <remarks>
      <para>
        This is the base class for all canvas items. Canvas items are
        the drawing elements of a GnomeCanvas. Example items include
        lines, ellipses, polygons, images, text, curves and even
        arbitrary GTK+ widgets.
      </para>
      <para>
        Canvas items use the GObject property system to query and set
        parameters. Properties are inherited so, for example, a
        <see cref="P:Gnome.CanvasPolygon" /> has a
        <see cref="P:Gnome.CanvasPolygon.FillColor" /> property that is
        inherited from its parent class object
        <see cref="P:Gnome.CanvasShape" />. So be
        sure to check the parent classes of
        <see cref="T:Gnome.CanvasItem" /> objects
        when looking for item properties.
      </para>
      <para>
        To create a new canvas item use the
        <see cref="C:Gnome.CanvasItem" /> constructor which
        takes a parent <see cref="T:Gnome.CanvasGroup" />,
        <see cref="T:GLib.Type" /> of the item to create,
        and a <see langword="null" /> terminated list of name/value GObject properties to
        set for the new item.
      </para>
      <para>
        There are several methods to change the drawing stacking
        order of an item. Call <see cref="M:Gnome.CanvasItem.Raise" /> to raise an
        item a specified number of positions or
        <see cref="M:Gnome.CanvasItem.Lower" /> to lower it. To raise an item to the
        top call <see cref="M:Gnome.CanvasItem.RaiseToTop" />. The
        <see cref="M:Gnome.CanvasItem.LowerToBottom" /> methods will put it at
        the bottom.
      </para>
      <para>
        To show an item call <see cref="M:Gnome.CanvasItem.Show" />. Note that
        canvas item's are shown by default and so do not need to be
        explicitly shown after creation (contrary to GTK+ widget
        behavior). Call <see cref="M:Gnome.CanvasItem.Hide" /> to hide an item.
      </para>
      <para>
        To move an item relative to its current position (item
        coordinates) call <see cref="M:Gnome.CanvasItem.Move" /> or
        <see cref="M:Gnome.CanvasItem.AffineRelative" /> for more complex
        transforms. <see cref="M:Gnome.CanvasItem.AffineAbsolute" /> can be used to
        set an item's transform to specific values (not offsets).
      </para>
      <para>
        To convert between world and item coordinate systems call
        <see cref="M:Gnome.CanvasItem.W2i" />, and to convert in the other direction
        call <see cref="M:Gnome.CanvasItem.I2w" />. To get the transform for
        converting from item to world coordinates use
        <see cref="M:Gnome.CanvasItem.I2wAffine" /> or for converting item to
        canvas coordinates, <see cref="M:Gnome.CanvasItem.I2cAffine" />.
      </para>
      <para>
        Handling user input for interactive items is accomplished
        through a few functions and the <see cref="E:Gnome.CanvasItem.CanvasEvent" /> signals. To grab the
        mouse cursor call <see cref="M:Gnome.CanvasItem.Grab" />, it can be
        ungrabbed with <see cref="M:Gnome.CanvasItem.Ungrab" /> (see
        <see cref="M:Gdk.Pointer.Grab" /> of the GTK+ library for details). To grab
        keyboard focus call <see cref="M:Gnome.CanvasItem.GrabFocus" />. Received
        events will be signaled via the "event" signal.
      </para>
      <para>
        Some other useful functions include a reparenting routine,
        <see cref="M:Gnome.CanvasItem.Reparent" />, and a function to query the
        bounding box of an item (a minumum rectangular area containing
        all parts of the item), <see cref="M:Gnome.CanvasItem.Getbounds" />.</para>
    </remarks>
  </Docs>
  <Base>
    <BaseTypeName>Gtk.Object</BaseTypeName>
  </Base>
  <Interfaces>
    <Interface>
      <InterfaceName>GLib.IWrapper</InterfaceName>
    </Interface>
    <Interface>
      <InterfaceName>System.IDisposable</InterfaceName>
    </Interface>
  </Interfaces>
  <Attributes />
  <Members>
    <Member MemberName="AffineRelative">
      <MemberSignature Language="C#" Value="public void AffineRelative (out double [] affine);" />
      <MemberType>Method</MemberType>
      <ReturnValue>
        <ReturnType>System.Void</ReturnType>
      </ReturnValue>
      <Parameters>
        <Parameter Name="affine" Type="System.Double []&amp;" RefType="out" />
      </Parameters>
      <Docs>
        <summary>
          Combines the specified affine transformation matrix with the
          item's current transformation.
        </summary>
        <param name="affine">Return value for an affine transformation matrix.</param>
        <remarks></remarks>
      </Docs>
    </Member>
    <Member MemberName="Lower">
      <MemberSignature Language="C#" Value="public void Lower (int positions);" />
      <MemberType>Method</MemberType>
      <ReturnValue>
        <ReturnType>System.Void</ReturnType>
      </ReturnValue>
      <Parameters>
        <Parameter Name="positions" Type="System.Int32" />
      </Parameters>
      <Docs>
        <summary>
          Lowers the item in its parent's stack by the specified
          number of positions. If the number of positions is greater
          than the distance to the bottom of the stack, then the item
          is put at the bottom.
        </summary>
        <param name="positions">Number of steps to lower the item.</param>
        <remarks></remarks>
      </Docs>
    </Member>
    <Member MemberName="Show">
      <MemberSignature Language="C#" Value="public void Show ();" />
      <MemberType>Method</MemberType>
      <ReturnValue>
        <ReturnType>System.Void</ReturnType>
      </ReturnValue>
      <Parameters />
      <Docs>
        <summary>Shows a canvas item. If the item was already shown, then no action is taken.</summary>
        <remarks></remarks>
      </Docs>
    </Member>
    <Member MemberName="RequestRedrawSvp">
      <MemberSignature Language="C#" Value="public void RequestRedrawSvp (Art.SVP svp);" />
      <MemberType>Method</MemberType>
      <ReturnValue>
        <ReturnType>System.Void</ReturnType>
      </ReturnValue>
      <Parameters>
        <Parameter Name="svp" Type="Art.SVP" />
      </Parameters>
      <Docs>
        <summary>Request redraw of <paramref name="svp" /> if in aa mode, or the entire item in in xlib mode.</summary>
        <param name="svp">The svp that needs to be redrawn</param>
        <remarks>
          <para>
            This item must contain <paramref name="svp" />.
          </para>
        </remarks>
      </Docs>
    </Member>
    <Member MemberName="GrabFocus">
      <MemberSignature Language="C#" Value="public void GrabFocus ();" />
      <MemberType>Method</MemberType>
      <ReturnValue>
        <ReturnType>System.Void</ReturnType>
      </ReturnValue>
      <Parameters />
      <Docs>
        <summary>
          Makes the specified item take the keyboard focus, so all
          keyboard events will be sent to it. If the canvas widget
          itself did not have the focus, it grabs it as well.
        </summary>
        <remarks></remarks>
      </Docs>
    </Member>
    <Member MemberName="LowerToBottom">
      <MemberSignature Language="C#" Value="public void LowerToBottom ();" />
      <MemberType>Method</MemberType>
      <ReturnValue>
        <ReturnType>System.Void</ReturnType>
      </ReturnValue>
      <Parameters />
      <Docs>
        <summary>Lowers an item to the bottom of its parent's stack.</summary>
        <remarks></remarks>
      </Docs>
    </Member>
    <Member MemberName="Hide">
      <MemberSignature Language="C#" Value="public void Hide ();" />
      <MemberType>Method</MemberType>
      <ReturnValue>
        <ReturnType>System.Void</ReturnType>
      </ReturnValue>
      <Parameters />
      <Docs>
        <summary>Hides a canvas item. If the item was already hidden, then no action is taken.</summary>
        <remarks></remarks>
      </Docs>
    </Member>
    <Member MemberName="RaiseToTop">
      <MemberSignature Language="C#" Value="public void RaiseToTop ();" />
      <MemberType>Method</MemberType>
      <ReturnValue>
        <ReturnType>System.Void</ReturnType>
      </ReturnValue>
      <Parameters />
      <Docs>
        <summary>Raises an item to the top of its parent's stack.</summary>
        <remarks></remarks>
      </Docs>
    </Member>
    <Member MemberName="W2i">
      <MemberSignature Language="C#" Value="public void W2i (ref double x, ref double y);" />
      <MemberType>Method</MemberType>
      <ReturnValue>
        <ReturnType>System.Void</ReturnType>
      </ReturnValue>
      <Parameters>
        <Parameter Name="x" Type="System.Double&amp;" RefType="ref" />
        <Parameter Name="y" Type="System.Double&amp;" RefType="ref" />
      </Parameters>
      <Docs>
        <summary>Converts a coordinate pair from world coordinates to item-relative coordinates.</summary>
        <param name="x">X coordinate to convert (input/output value).</param>
        <param name="y">Y coordinate to convert (input/output value).</param>
        <remarks>
          <para>
            The parameters <paramref name="x" /> and <paramref name="y" />
            are used as both in and out parameters.
          </para>
        </remarks>
      </Docs>
    </Member>
    <Member MemberName="UpdateSvp">
      <MemberSignature Language="C#" Value="public void UpdateSvp (Art.SVP p_svp, Art.SVP new_svp);" />
      <MemberType>Method</MemberType>
      <ReturnValue>
        <ReturnType>System.Void</ReturnType>
      </ReturnValue>
      <Parameters>
        <Parameter Name="p_svp" Type="Art.SVP" />
        <Parameter Name="new_svp" Type="Art.SVP" />
      </Parameters>
      <Docs>
        <summary>Sets the svp to the new value, requesting repaint on what's changed</summary>
        <param name="p_svp">the existing SVP</param>
        <param name="new_svp">the new SVP</param>
        <remarks></remarks>
      </Docs>
    </Member>
    <Member MemberName="UpdateSvpClip">
      <MemberSignature Language="C#" Value="public void UpdateSvpClip (Art.SVP p_svp, Art.SVP new_svp, Art.SVP clip_svp);" />
      <MemberType>Method</MemberType>
      <ReturnValue>
        <ReturnType>System.Void</ReturnType>
      </ReturnValue>
      <Parameters>
        <Parameter Name="p_svp" Type="Art.SVP" />
        <Parameter Name="new_svp" Type="Art.SVP" />
        <Parameter Name="clip_svp" Type="Art.SVP" />
      </Parameters>
      <Docs>
        <summary>Sets the svp to the new value, clipping if necessary, and requesting repaint on what's changed.</summary>
        <param name="p_svp">the old SVP</param>
        <param name="new_svp">the new SVP</param>
        <param name="clip_svp">a clip path</param>
        <remarks></remarks>
      </Docs>
    </Member>
    <Member MemberName="GetBounds">
      <MemberSignature Language="C#" Value="public void GetBounds (out double x1, out double y1, out double x2, out double y2);" />
      <MemberType>Method</MemberType>
      <ReturnValue>
        <ReturnType>System.Void</ReturnType>
      </ReturnValue>
      <Parameters>
        <Parameter Name="x1" Type="System.Double&amp;" RefType="out" />
        <Parameter Name="y1" Type="System.Double&amp;" RefType="out" />
        <Parameter Name="x2" Type="System.Double&amp;" RefType="out" />
        <Parameter Name="y2" Type="System.Double&amp;" RefType="out" />
      </Parameters>
      <Docs>
        <summary>
          Queries the bounding box of a canvas item. The bounds are
          returned in the coordinate system of the item's
          parent.
        </summary>
        <param name="x1">Return value for the leftmost edge of the bounding box</param>
        <param name="y1">Return value for the upper edge of the bounding box</param>
        <param name="x2">Return value for the rightmost edge of the bounding box</param>
        <param name="y2">Return value for the lower edge of the bounding box</param>
        <remarks></remarks>
      </Docs>
    </Member>
    <Member MemberName="AffineAbsolute">
      <MemberSignature Language="C#" Value="public void AffineAbsolute (out double [] affine);" />
      <MemberType>Method</MemberType>
      <ReturnValue>
        <ReturnType>System.Void</ReturnType>
      </ReturnValue>
      <Parameters>
        <Parameter Name="affine" Type="System.Double []&amp;" RefType="out" />
      </Parameters>
      <Docs>
        <summary>
          Makes the item's affine transformation matrix be equal to
          the specified matrix.
        </summary>
        <param name="affine">Return value for an affine transformation matrix.</param>
        <remarks></remarks>
      </Docs>
    </Member>
    <Member MemberName="Reparent">
      <MemberSignature Language="C#" Value="public void Reparent (Gnome.CanvasGroup new_group);" />
      <MemberType>Method</MemberType>
      <ReturnValue>
        <ReturnType>System.Void</ReturnType>
      </ReturnValue>
      <Parameters>
        <Parameter Name="new_group" Type="Gnome.CanvasGroup" />
      </Parameters>
      <Docs>
        <summary>
          Changes the parent of the specified item to be the new
          group. The item keeps its group-relative coordinates as for
          its old parent, so the item may change its absolute position
          within the canvas.
        </summary>
        <param name="new_group">A canvas group.</param>
        <remarks></remarks>
      </Docs>
    </Member>
    <Member MemberName="I2wAffine">
      <MemberSignature Language="C#" Value="public void I2wAffine (out double [] affine);" />
      <MemberType>Method</MemberType>
      <ReturnValue>
        <ReturnType>System.Void</ReturnType>
      </ReturnValue>
      <Parameters>
        <Parameter Name="affine" Type="System.Double []&amp;" RefType="out" />
      </Parameters>
      <Docs>
        <summary>Gets the affine transform that converts from the item's coordinate system to world coordinates.</summary>
        <param name="affine">Return value for an affine transformation matrix</param>
        <remarks></remarks>
      </Docs>
    </Member>
    <Member MemberName="Ungrab">
      <MemberSignature Language="C#" Value="public void Ungrab (uint etime);" />
      <MemberType>Method</MemberType>
      <ReturnValue>
        <ReturnType>System.Void</ReturnType>
      </ReturnValue>
      <Parameters>
        <Parameter Name="etime" Type="System.UInt32" />
      </Parameters>
      <Docs>
        <summary>Ungrabs the item, which must have been grabbed in the canvas, and ungrabs the mouse.</summary>
        <param name="etime">The timestamp for ungrabbing the mouse.</param>
        <remarks></remarks>
      </Docs>
    </Member>
    <Member MemberName="I2cAffine">
      <MemberSignature Language="C#" Value="public void I2cAffine (out double [] affine);" />
      <MemberType>Method</MemberType>
      <ReturnValue>
        <ReturnType>System.Void</ReturnType>
      </ReturnValue>
      <Parameters>
        <Parameter Name="affine" Type="System.Double []&amp;" RefType="out" />
      </Parameters>
      <Docs>
        <summary>Gets the affine transform that converts from item-relative coordinates to canvas pixel coordinates.</summary>/
        <param name="affine">Return value for an affine transformation matrix (return value).</param><remarks></remarks></Docs>
    </Member>
    <Member MemberName="Raise">
      <MemberSignature Language="C#" Value="public void Raise (int positions);" />
      <MemberType>Method</MemberType>
      <ReturnValue>
        <ReturnType>System.Void</ReturnType>
      </ReturnValue>
      <Parameters>
        <Parameter Name="positions" Type="System.Int32" />
      </Parameters>
      <Docs>
        <summary>
          Raises the item in its parent's stack by the specified
          number of positions. If the number of positions is greater
          than the distance to the top of the stack, then the item is
          put at the top.
        </summary>
        <param name="positions">Number of steps to raise the item.</param>
        <remarks></remarks>
      </Docs>
    </Member>
    <Member MemberName="I2w">
      <MemberSignature Language="C#" Value="public void I2w (ref double x, ref double y);" />
      <MemberType>Method</MemberType>
      <ReturnValue>
        <ReturnType>System.Void</ReturnType>
      </ReturnValue>
      <Parameters>
        <Parameter Name="x" Type="System.Double&amp;" RefType="ref" />
        <Parameter Name="y" Type="System.Double&amp;" RefType="ref" />
      </Parameters>
      <Docs>
        <summary>Converts a coordinate pair from item-relative coordinates to world coordinates.</summary>
        <param name="x">X coordinate to convert (input/output value).</param>
        <param name="y">Y coordinate to convert (input/output value).</param>
        <remarks>
          <para>
            The parameters <paramref name="x" /> and <paramref name="y" />
            are used as both in and out parameters.
          </para>
        </remarks>
      </Docs>
    </Member>
    <Member MemberName="Move">
      <MemberSignature Language="C#" Value="public void Move (double dx, double dy);" />
      <MemberType>Method</MemberType>
      <ReturnValue>
        <ReturnType>System.Void</ReturnType>
      </ReturnValue>
      <Parameters>
        <Parameter Name="dx" Type="System.Double" />
        <Parameter Name="dy" Type="System.Double" />
      </Parameters>
      <Docs>
        <summary>
          Moves a canvas item by creating an affine transformation
          matrix for translation by using the specified values. This
          happens in item local coordinate system, so if you have
          nontrivial transform, it most probably does not do, what you
          want.
        </summary>
        <param name="dx">Horizontal offset.</param>
        <param name="dy">Vertical offset.</param>
        <remarks></remarks>
      </Docs>
    </Member>
    <Member MemberName="RequestUpdate">
      <MemberSignature Language="C#" Value="public void RequestUpdate ();" />
      <MemberType>Method</MemberType>
      <ReturnValue>
        <ReturnType>System.Void</ReturnType>
      </ReturnValue>
      <Parameters />
      <Docs>
        <summary>To be used only by item implementations. Requests that the canvas queue an update for the specified item.</summary>
        <remarks></remarks>
      </Docs>
    </Member>
    <Member MemberName="ResetBounds">
      <MemberSignature Language="C#" Value="public void ResetBounds ();" />
      <MemberType>Method</MemberType>
      <ReturnValue>
        <ReturnType>System.Void</ReturnType>
      </ReturnValue>
      <Parameters />
      <Docs>
        <summary>Resets the bounding box of a canvas item to an empty rectangle.</summary>
        <remarks></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 CanvasItem (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 CanvasItem, 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="protected CanvasItem ();" />
      <MemberType>Constructor</MemberType>
      <ReturnValue />
      <Parameters />
      <Docs>
        <summary>To be added</summary>
        <returns>To be added: an object of type 'Gnome.CanvasItem'</returns>
        <remarks>To be added</remarks>
      </Docs>
    </Member>
    <Member MemberName="GType">
      <MemberSignature Language="C#" Value="public static uint GType { get; };" />
      <MemberType>Property</MemberType>
      <ReturnValue>
        <ReturnType>System.UInt32</ReturnType>
      </ReturnValue>
      <Docs>
        <summary>The GLib Type for Gnome.CanvasItem</summary>
        <returns>The GLib Type for the Gnome.CanvasItem class.</returns>
        <remarks />
      </Docs>
    </Member>
    <Member MemberName="Canvas">
      <MemberSignature Language="C#" Value="public Gnome.Canvas Canvas { get; };" />
      <MemberType>Property</MemberType>
      <ReturnValue>
        <ReturnType>Gnome.Canvas</ReturnType>
      </ReturnValue>
      <Docs>
        <summary>To be added</summary>
        <returns>To be added: an object of type 'Gnome.Canvas'</returns>
        <remarks>To be added</remarks>
      </Docs>
    </Member>
    <Member MemberName="Parent">
      <MemberSignature Language="C#" Value="public Gnome.CanvasItem Parent { set; get; };" />
      <MemberType>Property</MemberType>
      <ReturnValue>
        <ReturnType>Gnome.CanvasItem</ReturnType>
      </ReturnValue>
      <Parameters></Parameters>
      <Docs>
        <summary>The parent item</summary>
        <param name="value">the parent item</param>
        <returns>the parent item</returns>
        <remarks></remarks>
      </Docs>
    </Member>
    <Member MemberName="CanvasEvent">
      <MemberSignature Language="C#" Value="public event GnomeSharp.CanvasEventHandler CanvasEvent;" />
      <MemberType>Event</MemberType>
      <ReturnValue>
        <ReturnType>GnomeSharp.CanvasEventHandler</ReturnType>
      </ReturnValue>
      <Parameters />
      <Docs>
        <summary>
          Signals mouse button clicks, motion, enter/leave, and key
          press events on canvas items. Use this to create user
          interactive items. The x and y coordinates in the
          <see cref="F:GtkSharp.CanvasEventArgs.Event" />
          field have been converted to canvas world coordinates.
        </summary>
        <remarks></remarks>
      </Docs>
    </Member>
    <Member MemberName=".ctor">
      <MemberSignature Language="C#" Value="protected CanvasItem (GLib.Type gtype);" />
      <MemberType>Constructor</MemberType>
      <ReturnValue />
      <Parameters>
        <Parameter Name="gtype" Type="GLib.Type" />
      </Parameters>
      <Docs>
        <summary>Internal constructor</summary>
        <param name="gtype">GLib type for the type</param>
        <returns>Creates a new instance of CanvasItem, using the GLib-provided type</returns>
        <remarks>
          <para>This is a constructor used by derivative types of <see cref="T:Gnome.CanvasItem" /> that would have their own GLib type assigned to it.  This is not typically used by C# code.</para>
        </remarks>
      </Docs>
    </Member>
    <Member MemberName=".ctor">
      <MemberSignature Language="C#" Value="public CanvasItem (Gnome.CanvasGroup group, uint type);" />
      <MemberType>Constructor</MemberType>
      <ReturnValue />
      <Parameters>
        <Parameter Name="group" Type="Gnome.CanvasGroup" />
        <Parameter Name="type" Type="System.UInt32" />
      </Parameters>
      <Docs>
        <summary>To be added</summary>
        <param name="group">a <see cref="T:Gnome.CanvasGroup" /></param>
        <param name="type">a <see cref="T:System.UInt32" /></param>
        <returns>a <see cref="T:Gnome.CanvasItem" /></returns>
        <remarks>To be added</remarks>
      </Docs>
    </Member>
  </Members>
</Type>