/// <summary>
/// Displays grid over image in image viewer.
/// </summary>
/// <param name="viewer">The viewer.</param>
public static void DrawGridOverImageInImageViewer(Vintasoft.Imaging.UI.ImageViewer viewer)
{
    // create visual tool that can display static graphic objects in an image viewer
    Vintasoft.Imaging.UI.VisualTools.GraphicObjects.GraphicObjectTool tool = 
        new Vintasoft.Imaging.UI.VisualTools.GraphicObjects.GraphicObjectTool();
    // create graphic object that displays image grid
    GridGraphicObject grid = new GridGraphicObject(tool);
    // add graphic object to the visual tool
    tool.GraphicObjectCollection.Add(grid);
    // set visual tool as current visual tool of image viewer
    viewer.VisualTool = tool;
}


/// <summary>
/// Represents an image grid which can be displayed in image viewer.
/// </summary>
public class GridGraphicObject : 
    Vintasoft.Imaging.UI.VisualTools.GraphicObjects.GraphicObject
{

    #region Fields

    Vintasoft.Imaging.UI.VisualTools.VisualTool _tool;

    #endregion



    #region Constructors

    /// <summary>
    /// Initializes a new instance of the <see cref="GridGraphicObject"/> class.
    /// </summary>
    /// <param name="tool">The visual tool.</param>
    public GridGraphicObject(Vintasoft.Imaging.UI.VisualTools.VisualTool tool)
    {
        if (tool == null)
            throw new System.ArgumentNullException();
        _tool = tool;
        Pen = new System.Drawing.Pen(
            System.Drawing.Color.FromArgb(128, System.Drawing.Color.Lime), 1);
        PointTransform = 
            new Vintasoft.Imaging.UI.VisualTools.PixelsToImageViewerPointFTransform();
    }

    #endregion



    #region Properties

    System.Drawing.PointF _location = System.Drawing.PointF.Empty;
    /// <summary>
    /// Gets or sets the location of grid.
    /// </summary>
    /// <value>
    /// Default value is <b>(0,0)</b>.
    /// </value>
    public System.Drawing.PointF Location
    {
        get
        {
            return _location;
        }
        set
        {
            _location = value;
        }
    }

    System.Drawing.SizeF _cellSize = new System.Drawing.SizeF(1, 1);
    /// <summary>
    /// Gets or sets the size of the grid cell.
    /// </summary>
    /// <value>
    /// Default value is <b>(1,1)</b>.
    /// </value>
    public System.Drawing.SizeF CellSize
    {
        get
        {
            return _cellSize;
        }
        set
        {
            _cellSize = value;
        }
    }

    Vintasoft.Imaging.UnitOfMeasure _cellUnitOfMeasure = 
        Vintasoft.Imaging.UnitOfMeasure.Centimeters;
    /// <summary>
    /// Gets or sets the unit of measure of the grid cell.
    /// </summary>
    /// <value>
    /// Default value is <b>UnitOfMeasure.Centimeters</b>.
    /// </value>
    public Vintasoft.Imaging.UnitOfMeasure CellUnitOfMeasure
    {
        get
        {
            return _cellUnitOfMeasure;
        }
        set
        {
            _cellUnitOfMeasure = value;
        }
    }

    #endregion



    #region Methods

    /// <summary>
    /// Determines that point belongs the object.
    /// </summary>
    /// <param name="x">X coordinate of point in object space.</param>
    /// <param name="y">Y coordinate of point in object space.</param>
    /// <returns>
    /// <b>true</b> if point belongs the object;
    /// otherwise, <b>false</b>.
    /// </returns>
    public override bool IsPointOnObject(float x, float y)
    {
        if (_tool.ImageViewer.Image != null &&
            (Pen != null || Brush != null))
        {
            System.Drawing.RectangleF rect = GetRectangle(_location, _tool.ImageViewer.Image);
            return rect.Contains(x, y);
        }
        else
            return false;
    }

    /// <summary>
    /// Returns a bounding box of object, in object space.
    /// </summary>
    /// <returns>
    /// Bounding box of object, in object space.
    /// </returns>
    public override System.Drawing.RectangleF GetBoundingBox()
    {
        if (_tool.ImageViewer.Image != null)
            return GetRectangle(_location, _tool.ImageViewer.Image);
        else
            return System.Drawing.RectangleF.Empty;
    }

    /// <summary>
    /// Returns a drawing rectangle of object, in object space.
    /// </summary>
    /// <param name="viewer">An image viewer.</param>
    /// <returns>
    /// Drawing rectangle of object, in object space.
    /// </returns>
    public override System.Drawing.RectangleF GetDrawingBox(Vintasoft.Imaging.UI.ImageViewer viewer)
    {
        if (viewer.Image == null)
            return System.Drawing.RectangleF.Empty;

        System.Drawing.RectangleF rect = GetRectangle(_location, viewer.Image);
        if (Pen != null)
        {
            float penWidth = Pen.Width / 2.0f;
            rect.Inflate(penWidth, penWidth);
        }
        return rect;
    }

    /// <summary>
    /// Draws the object on specified <see cref="System.Drawing.Graphics" /> in the object space.
    /// </summary>
    /// <param name="viewer">An image viewer.</param>
    /// <param name="g">A graphics where the object must be drawn.</param>
    /// <remarks>
    /// This method draws object after the PointTransform is applied to
    /// the Graphics, specified by <i>g</i> parameter.<br /><br />
    /// By default this method does not do anything.
    /// </remarks>
    public override void DrawInObjectSpace(Vintasoft.Imaging.UI.ImageViewer viewer, System.Drawing.Graphics g)
    {
        if (viewer.Image == null)
            return;

        System.Drawing.RectangleF rect = GetRectangle(_location, viewer.Image);
        if (Brush != null)
            g.FillRectangle(Brush, rect);

        if (Pen != null && !CellSize.IsEmpty)
        {
            float cellHeight = 
                (float)Vintasoft.Imaging.Utils.UnitOfMeasureConverter.ConvertToPixels(CellSize.Height, CellUnitOfMeasure);
            int countRow = (int)System.Math.Ceiling(rect.Height / cellHeight);

            float cellWidth = 
                (float)Vintasoft.Imaging.Utils.UnitOfMeasureConverter.ConvertToPixels(CellSize.Width, CellUnitOfMeasure);
            int countColumn = (int)System.Math.Ceiling(rect.Width / cellWidth);

            if (countRow > 0 && countColumn > 0)
            {
                float x1 = rect.X;
                float y1 = rect.Y + cellHeight;
                float x2 = rect.Right;
                int i;

                for (i = 1; i < countRow; i++, y1 += cellHeight)
                    g.DrawLine(Pen, x1, y1, x2, y1);

                x1 += cellWidth;
                y1 = rect.Y;
                float y2 = rect.Bottom;
                for (i = 1; i < countColumn; i++, x1 += cellWidth)
                    g.DrawLine(Pen, x1, y1, x1, y2);
            }
        }
    }

    /// <summary>
    /// Creates a new WpfGridGraphicObject that is a copy of the current instance.
    /// </summary>
    /// <returns>
    /// A new WpfGridGraphicObject that is a copy of this instance.
    /// </returns>
    public override object Clone()
    {
        GridGraphicObject obj = new GridGraphicObject(_tool);
        CopyTo(obj);
        return obj;
    }

    /// <summary>
    /// Copies current WpfGridGraphicObject to the target WpfGridGraphicObject.
    /// </summary>
    /// <param name="obj">WpfGridGraphicObject to copy.</param>
    public override void CopyTo(Vintasoft.Imaging.UI.VisualTools.GraphicObjects.GraphicObject obj)
    {
        base.CopyTo(obj);

        GridGraphicObject gridObj = obj as GridGraphicObject;
        if (gridObj != null)
        {
            gridObj.Location = Location;
            gridObj.CellSize = CellSize;
            gridObj.CellUnitOfMeasure = CellUnitOfMeasure;
        }
    }

    /// <summary>
    /// Gets the rectangle of grid.
    /// </summary>
    /// <param name="location">The location.</param>
    /// <param name="image">The image.</param>
    private System.Drawing.RectangleF GetRectangle(
        System.Drawing.PointF location, 
        Vintasoft.Imaging.VintasoftImage image)
    {
        System.Drawing.RectangleF rect = new System.Drawing.RectangleF(
            _location.X, _location.Y,
            image.Width - _location.X, image.Height - _location.Y);
        return rect;
    }

    #endregion

}

''' <summary>
''' Displays grid over image in image viewer.
''' </summary>
''' <param name="viewer">The viewer.</param>
Public Shared Sub DrawGridOverImageInImageViewer(viewer As Vintasoft.Imaging.UI.ImageViewer)
    ' create visual tool that can display static graphic objects in an image viewer
    Dim tool As New Vintasoft.Imaging.UI.VisualTools.GraphicObjects.GraphicObjectTool()
    ' create graphic object that displays image grid
    Dim grid As New GridGraphicObject(tool)
    ' add graphic object to the visual tool
    tool.GraphicObjectCollection.Add(grid)
    ' set visual tool as current visual tool of image viewer
    viewer.VisualTool = tool
End Sub


''' <summary>
''' Represents an image grid which can be displayed in image viewer.
''' </summary>
Public Class GridGraphicObject
    Inherits Vintasoft.Imaging.UI.VisualTools.GraphicObjects.GraphicObject

    #Region "Fields"

    Private _tool As Vintasoft.Imaging.UI.VisualTools.VisualTool

    #End Region



    #Region "Constructors"

    ''' <summary>
    ''' Initializes a new instance of the <see cref="GridGraphicObject"/> class.
    ''' </summary>
    ''' <param name="tool">The visual tool.</param>
    Public Sub New(tool As Vintasoft.Imaging.UI.VisualTools.VisualTool)
        If tool Is Nothing Then
            Throw New System.ArgumentNullException()
        End If
        _tool = tool
        Pen = New System.Drawing.Pen(System.Drawing.Color.FromArgb(128, System.Drawing.Color.Lime), 1)
        PointTransform = New Vintasoft.Imaging.UI.VisualTools.PixelsToImageViewerPointFTransform()
    End Sub

    #End Region



    #Region "Properties"

    Private _location As System.Drawing.PointF = System.Drawing.PointF.Empty
    ''' <summary>
    ''' Gets or sets the location of grid.
    ''' </summary>
    ''' <value>
    ''' Default value is <b>(0,0)</b>.
    ''' </value>
    Public Property Location() As System.Drawing.PointF
        Get
            Return _location
        End Get
        Set
            _location = value
        End Set
    End Property

    Private _cellSize As New System.Drawing.SizeF(1, 1)
    ''' <summary>
    ''' Gets or sets the size of the grid cell.
    ''' </summary>
    ''' <value>
    ''' Default value is <b>(1,1)</b>.
    ''' </value>
    Public Property CellSize() As System.Drawing.SizeF
        Get
            Return _cellSize
        End Get
        Set
            _cellSize = value
        End Set
    End Property

    Private _cellUnitOfMeasure As Vintasoft.Imaging.UnitOfMeasure = Vintasoft.Imaging.UnitOfMeasure.Centimeters
    ''' <summary>
    ''' Gets or sets the unit of measure of the grid cell.
    ''' </summary>
    ''' <value>
    ''' Default value is <b>UnitOfMeasure.Centimeters</b>.
    ''' </value>
    Public Property CellUnitOfMeasure() As Vintasoft.Imaging.UnitOfMeasure
        Get
            Return _cellUnitOfMeasure
        End Get
        Set
            _cellUnitOfMeasure = value
        End Set
    End Property

    #End Region



    #Region "Methods"

    ''' <summary>
    ''' Determines that point belongs the object.
    ''' </summary>
    ''' <param name="x">X coordinate of point in object space.</param>
    ''' <param name="y">Y coordinate of point in object space.</param>
    ''' <returns>
    ''' <b>true</b> if point belongs the object;
    ''' otherwise, <b>false</b>.
    ''' </returns>
    Public Overrides Function IsPointOnObject(x As Single, y As Single) As Boolean
        If _tool.ImageViewer.Image IsNot Nothing AndAlso (Pen IsNot Nothing OrElse Brush IsNot Nothing) Then
            Dim rect As System.Drawing.RectangleF = GetRectangle(_location, _tool.ImageViewer.Image)
            Return rect.Contains(x, y)
        Else
            Return False
        End If
    End Function

    ''' <summary>
    ''' Returns a bounding box of object, in object space.
    ''' </summary>
    ''' <returns>
    ''' Bounding box of object, in object space.
    ''' </returns>
    Public Overrides Function GetBoundingBox() As System.Drawing.RectangleF
        If _tool.ImageViewer.Image IsNot Nothing Then
            Return GetRectangle(_location, _tool.ImageViewer.Image)
        Else
            Return System.Drawing.RectangleF.Empty
        End If
    End Function

    ''' <summary>
    ''' Returns a drawing rectangle of object, in object space.
    ''' </summary>
    ''' <param name="viewer">An image viewer.</param>
    ''' <returns>
    ''' Drawing rectangle of object, in object space.
    ''' </returns>
    Public Overrides Function GetDrawingBox(viewer As Vintasoft.Imaging.UI.ImageViewer) As System.Drawing.RectangleF
        If viewer.Image Is Nothing Then
            Return System.Drawing.RectangleF.Empty
        End If

        Dim rect As System.Drawing.RectangleF = GetRectangle(_location, viewer.Image)
        If Pen IsNot Nothing Then
            Dim penWidth As Single = Pen.Width / 2F
            rect.Inflate(penWidth, penWidth)
        End If
        Return rect
    End Function

    ''' <summary>
    ''' Draws the object on specified <see cref="System.Drawing.Graphics" /> in the object space.
    ''' </summary>
    ''' <param name="viewer">An image viewer.</param>
    ''' <param name="g">A graphics where the object must be drawn.</param>
    ''' <remarks>
    ''' This method draws object after the PointTransform is applied to
    ''' the Graphics, specified by <i>g</i> parameter.<br /><br />
    ''' By default this method does not do anything.
    ''' </remarks>
    Public Overrides Sub DrawInObjectSpace(viewer As Vintasoft.Imaging.UI.ImageViewer, g As System.Drawing.Graphics)
        If viewer.Image Is Nothing Then
            Return
        End If

        Dim rect As System.Drawing.RectangleF = GetRectangle(_location, viewer.Image)
        If Brush IsNot Nothing Then
            g.FillRectangle(Brush, rect)
        End If

        If Pen IsNot Nothing AndAlso Not CellSize.IsEmpty Then
            Dim cellHeight As Single = CSng(Vintasoft.Imaging.Utils.UnitOfMeasureConverter.ConvertToPixels(CellSize.Height, CellUnitOfMeasure))
            Dim countRow As Integer = CInt(Math.Truncate(System.Math.Ceiling(rect.Height / cellHeight)))

            Dim cellWidth As Single = CSng(Vintasoft.Imaging.Utils.UnitOfMeasureConverter.ConvertToPixels(CellSize.Width, CellUnitOfMeasure))
            Dim countColumn As Integer = CInt(Math.Truncate(System.Math.Ceiling(rect.Width / cellWidth)))

            If countRow > 0 AndAlso countColumn > 0 Then
                Dim x1 As Single = rect.X
                Dim y1 As Single = rect.Y + cellHeight
                Dim x2 As Single = rect.Right
                Dim i As Integer

                i = 1
                While i < countRow
                    g.DrawLine(Pen, x1, y1, x2, y1)
                    i += 1
                    y1 += cellHeight
                End While

                x1 += cellWidth
                y1 = rect.Y
                Dim y2 As Single = rect.Bottom
                i = 1
                While i < countColumn
                    g.DrawLine(Pen, x1, y1, x1, y2)
                    i += 1
                    x1 += cellWidth
                End While
            End If
        End If
    End Sub

    ''' <summary>
    ''' Creates a new WpfGridGraphicObject that is a copy of the current instance.
    ''' </summary>
    ''' <returns>
    ''' A new WpfGridGraphicObject that is a copy of this instance.
    ''' </returns>
    Public Overrides Function Clone() As Object
        Dim obj As New GridGraphicObject(_tool)
        CopyTo(obj)
        Return obj
    End Function

    ''' <summary>
    ''' Copies current WpfGridGraphicObject to the target WpfGridGraphicObject.
    ''' </summary>
    ''' <param name="obj">WpfGridGraphicObject to copy.</param>
    Public Overrides Sub CopyTo(obj As Vintasoft.Imaging.UI.VisualTools.GraphicObjects.GraphicObject)
        MyBase.CopyTo(obj)

        Dim gridObj As GridGraphicObject = TryCast(obj, GridGraphicObject)
        If gridObj IsNot Nothing Then
            gridObj.Location = Location
            gridObj.CellSize = CellSize
            gridObj.CellUnitOfMeasure = CellUnitOfMeasure
        End If
    End Sub

    ''' <summary>
    ''' Gets the rectangle of grid.
    ''' </summary>
    ''' <param name="location">The location.</param>
    ''' <param name="image">The image.</param>
    Private Function GetRectangle(location As System.Drawing.PointF, image As Vintasoft.Imaging.VintasoftImage) As System.Drawing.RectangleF
        Dim rect As New System.Drawing.RectangleF(_location.X, _location.Y, image.Width - _location.X, image.Height - _location.Y)
        Return rect
    End Function

    #End Region

End Class

/// <summary>
/// Represents a static rotated text which can be displayed in image viewer.
/// </summary>
public class RotatedTextGraphicObject : 
    Vintasoft.Imaging.UI.VisualTools.GraphicObjects.TextGraphicObject
{

    #region Properties

    float _textRotationAngle = 0.0f;
    /// <summary>
    /// Gets or sets the rotation angle, in degrees, of text.
    /// </summary>
    /// <value>
    /// Default value is <b>0.0</b>.
    /// </value>
    public float TextRotationAngle
    {
        get
        {
            return _textRotationAngle;
        }
        set
        {
            _textRotationAngle = value % 360.0f;
        }
    }

    #endregion



    #region Methods

    /// <summary>
    /// Draws the object on specified <see cref="System.Drawing.Graphics" />.
    /// </summary>
    /// <param name="viewer">An image viewer.</param>
    /// <param name="g">A graphics where the object must be drawn.</param>
    /// <remarks>
    /// This method draws object after the
    /// <see cref="Vintasoft.Imaging.UI.VisualTools.GraphicObjects.GraphicObject.PointTransform" /> is applied
    /// to the Graphics, specified by <i>g</i> parameter.
    /// </remarks>
    public override void DrawInObjectSpace(Vintasoft.Imaging.UI.ImageViewer viewer, 
        System.Drawing.Graphics g)
    {
        // save matrix of Graphics
        using (System.Drawing.Drawing2D.Matrix m = g.Transform)
        {
            // create matrix
            using (System.Drawing.Drawing2D.Matrix tmp = new System.Drawing.Drawing2D.Matrix())
            {
                // calculate center point of text
                System.Drawing.PointF center = new System.Drawing.PointF(
                    Rectangle.X + Rectangle.Width / 2.0f,
                    Rectangle.Y + Rectangle.Height / 2.0f);
                // rotate matrix
                tmp.RotateAt(_textRotationAngle, center);
                // multiply matrix
                g.MultiplyTransform(tmp);
            }

            // draw text
            base.DrawInObjectSpace(viewer, g);

            // restore matrix of Graphics
            g.Transform = m;
        }
    }

    #endregion

}

''' <summary>
''' Represents a static rotated text which can be displayed in image viewer.
''' </summary>
Public Class RotatedTextGraphicObject
    Inherits Vintasoft.Imaging.UI.VisualTools.GraphicObjects.TextGraphicObject

    #Region "Properties"

    Private _textRotationAngle As Single = 0F
    ''' <summary>
    ''' Gets or sets the rotation angle, in degrees, of text.
    ''' </summary>
    ''' <value>
    ''' Default value is <b>0.0</b>.
    ''' </value>
    Public Property TextRotationAngle() As Single
        Get
            Return _textRotationAngle
        End Get
        Set
            _textRotationAngle = value Mod 360F
        End Set
    End Property

    #End Region



    #Region "Methods"

    ''' <summary>
    ''' Draws the object on specified <see cref="System.Drawing.Graphics" />.
    ''' </summary>
    ''' <param name="viewer">An image viewer.</param>
    ''' <param name="g">A graphics where the object must be drawn.</param>
    ''' <remarks>
    ''' This method draws object after the
    ''' <see cref="Vintasoft.Imaging.UI.VisualTools.GraphicObjects.GraphicObject.PointTransform" /> is applied
    ''' to the Graphics, specified by <i>g</i> parameter.
    ''' </remarks>
    Public Overrides Sub DrawInObjectSpace(viewer As Vintasoft.Imaging.UI.ImageViewer, g As System.Drawing.Graphics)
        ' save matrix of Graphics
        Using m As System.Drawing.Drawing2D.Matrix = g.Transform
            ' create matrix
            Using tmp As New System.Drawing.Drawing2D.Matrix()
                ' calculate center point of text
                Dim center As New System.Drawing.PointF(Rectangle.X + Rectangle.Width / 2F, Rectangle.Y + Rectangle.Height / 2F)
                ' rotate matrix
                tmp.RotateAt(_textRotationAngle, center)
                ' multiply matrix
                g.MultiplyTransform(tmp)
            End Using

            ' draw text
            MyBase.DrawInObjectSpace(viewer, g)

            ' restore matrix of Graphics
            g.Transform = m
        End Using
    End Sub

    #End Region

End Class

/// <summary>
/// Visual tool that draws static text (filename, current zoom factor) over image in
/// image viewer and draws a frame around image in image viewer:
/// </summary>
public class GraphicObjectToolExample : 
    Vintasoft.Imaging.UI.VisualTools.GraphicObjects.GraphicObjectTool
{

    #region Fields

    /// <summary>
    /// The graphic object that draws a filename over the image in image viewer.
    /// </summary>
    Vintasoft.Imaging.UI.VisualTools.GraphicObjects.TextGraphicObject _fileNameGraphicObject = 
        new Vintasoft.Imaging.UI.VisualTools.GraphicObjects.TextGraphicObject();

    /// <summary>
    /// The graphic object that draws image zoom factor over the image in image viewer.
    /// </summary>
    Vintasoft.Imaging.UI.VisualTools.GraphicObjects.TextGraphicObject _zoomGraphicObject = 
        new Vintasoft.Imaging.UI.VisualTools.GraphicObjects.TextGraphicObject();

    /// <summary>
    /// The graphic object that draws a frame around image in image viewer.
    /// </summary>
    Vintasoft.Imaging.UI.VisualTools.GraphicObjects.RectangularGraphicObject _borderGraphicObject = 
        new Vintasoft.Imaging.UI.VisualTools.GraphicObjects.RectangularGraphicObject();

    #endregion



    #region Constructors

    /// <summary>
    /// Initializes a new instance of the <see cref="GraphicObjectToolExample"/> class.
    /// </summary>
    public GraphicObjectToolExample()
    {
        _fileNameGraphicObject.TextAnchor = Vintasoft.Imaging.AnchorType.Top;
        _fileNameGraphicObject.FontBrush = System.Drawing.Brushes.Salmon;
        _fileNameGraphicObject.Font = new System.Drawing.Font("Arial", 24);
        GraphicObjectCollection.Add(_fileNameGraphicObject);

        _zoomGraphicObject.TextAnchor = 
            Vintasoft.Imaging.AnchorType.Bottom | Vintasoft.Imaging.AnchorType.Right;
        _zoomGraphicObject.FontBrush = System.Drawing.Brushes.Lime;
        _zoomGraphicObject.Font = new System.Drawing.Font("Arial", 20);
        GraphicObjectCollection.Add(_zoomGraphicObject);

        _borderGraphicObject.PointTransform = 
            new Vintasoft.Imaging.UI.VisualTools.PixelsToImageViewerPointFTransform();
        _borderGraphicObject.Pen = new System.Drawing.Pen(
            System.Drawing.Color.FromArgb(128, System.Drawing.Color.Lime), 10);
        GraphicObjectCollection.Add(_borderGraphicObject);
    }

    #endregion



    #region Methods

    /// <summary>
    /// Raises the <see cref="Vintasoft.Imaging.UI.VisualTools.VisualTool.Activated" /> event.
    /// </summary>
    protected override void OnActivated(System.EventArgs e)
    {
        base.OnActivated(e);
        ImageViewer.ZoomChanged += 
            new System.EventHandler<Vintasoft.Imaging.UI.ZoomChangedEventArgs>(ImageViewer_ZoomChanged);
        ImageViewer.ClientSizeChanged += new System.EventHandler(ImageViewer_ClientSizeChanged);
        ImageViewer.ImageLoaded += 
            new System.EventHandler<Vintasoft.Imaging.ImageLoadedEventArgs>(ImageViewer_ImageLoaded);

        UpdateGraphicObjects();
    }

    /// <summary>
    /// Raises the <see cref="Vintasoft.Imaging.UI.VisualTools.VisualTool.Deactivated" /> event.
    /// </summary>
    protected override void OnDeactivated(System.EventArgs e)
    {
        base.OnDeactivated(e);

        ImageViewer.ZoomChanged -= ImageViewer_ZoomChanged;
        ImageViewer.ClientSizeChanged -= ImageViewer_ClientSizeChanged;
        ImageViewer.ImageLoaded -= ImageViewer_ImageLoaded;
    }

    /// <summary>
    /// Updates the graphic objects.
    /// </summary>
    void UpdateGraphicObjects()
    {
        _fileNameGraphicObject.Rectangle = ImageViewer.ClientRectangle;
        _zoomGraphicObject.Rectangle = ImageViewer.ClientRectangle;
        _zoomGraphicObject.Text = string.Format("Zoom: {0}", ImageViewer.Zoom);

        Vintasoft.Imaging.VintasoftImage image = ImageViewer.Image;
        if (image == null)
        {
            _fileNameGraphicObject.Text = string.Empty;
            _borderGraphicObject.Rectangle = System.Drawing.Rectangle.Empty;
        }
        else
        {
            Vintasoft.Imaging.ImageSourceInfo info = image.SourceInfo;
            if (string.IsNullOrEmpty(info.Filename))
                _fileNameGraphicObject.Text = string.Empty;
            else
            {
                string text = System.IO.Path.GetFileName(info.Filename);
                if (info.PageCount > 1)
                    text += string.Format(" (Page {0}/{1})", info.PageIndex + 1, info.PageCount);
                _fileNameGraphicObject.Text = text;
            }

            _borderGraphicObject.Rectangle = new System.Drawing.RectangleF(0, 0, image.Width, image.Height);
        }
    }

    /// <summary>
    /// Handles the ClientSizeChanged event of the ImageViewer control.
    /// </summary>
    void ImageViewer_ClientSizeChanged(object sender, System.EventArgs e)
    {
        UpdateGraphicObjects();
    }

    /// <summary>
    /// Handles the ZoomChanged event of the ImageViewer control.
    /// </summary>
    void ImageViewer_ZoomChanged(object sender, Vintasoft.Imaging.UI.ZoomChangedEventArgs e)
    {
        UpdateGraphicObjects();
    }

    /// <summary>
    /// Handles the ImageLoaded event of the ImageViewer control.
    /// </summary>
    void ImageViewer_ImageLoaded(object sender, Vintasoft.Imaging.ImageLoadedEventArgs e)
    {
        UpdateGraphicObjects();
    }

    #endregion

}

''' <summary>
''' Visual tool that draws static text (filename, current zoom factor) over image in
''' image viewer and draws a frame around image in image viewer:
''' </summary>
Public Class GraphicObjectToolExample
    Inherits Vintasoft.Imaging.UI.VisualTools.GraphicObjects.GraphicObjectTool

    #Region "Fields"

    ''' <summary>
    ''' The graphic object that draws a filename over the image in image viewer.
    ''' </summary>
    Private _fileNameGraphicObject As New Vintasoft.Imaging.UI.VisualTools.GraphicObjects.TextGraphicObject()

    ''' <summary>
    ''' The graphic object that draws image zoom factor over the image in image viewer.
    ''' </summary>
    Private _zoomGraphicObject As New Vintasoft.Imaging.UI.VisualTools.GraphicObjects.TextGraphicObject()

    ''' <summary>
    ''' The graphic object that draws a frame around image in image viewer.
    ''' </summary>
    Private _borderGraphicObject As New Vintasoft.Imaging.UI.VisualTools.GraphicObjects.RectangularGraphicObject()

    #End Region



    #Region "Constructors"

    ''' <summary>
    ''' Initializes a new instance of the <see cref="GraphicObjectToolExample"/> class.
    ''' </summary>
    Public Sub New()
        _fileNameGraphicObject.TextAnchor = Vintasoft.Imaging.AnchorType.Top
        _fileNameGraphicObject.FontBrush = System.Drawing.Brushes.Salmon
        _fileNameGraphicObject.Font = New System.Drawing.Font("Arial", 24)
        GraphicObjectCollection.Add(_fileNameGraphicObject)

        _zoomGraphicObject.TextAnchor = Vintasoft.Imaging.AnchorType.Bottom Or Vintasoft.Imaging.AnchorType.Right
        _zoomGraphicObject.FontBrush = System.Drawing.Brushes.Lime
        _zoomGraphicObject.Font = New System.Drawing.Font("Arial", 20)
        GraphicObjectCollection.Add(_zoomGraphicObject)

        _borderGraphicObject.PointTransform = New Vintasoft.Imaging.UI.VisualTools.PixelsToImageViewerPointFTransform()
        _borderGraphicObject.Pen = New System.Drawing.Pen(System.Drawing.Color.FromArgb(128, System.Drawing.Color.Lime), 10)
        GraphicObjectCollection.Add(_borderGraphicObject)
    End Sub

    #End Region



    #Region "Methods"

    ''' <summary>
    ''' Raises the <see cref="Vintasoft.Imaging.UI.VisualTools.VisualTool.Activated" /> event.
    ''' </summary>
    Protected Overrides Sub OnActivated(e As System.EventArgs)
        MyBase.OnActivated(e)
        AddHandler ImageViewer.ZoomChanged, New System.EventHandler(Of Vintasoft.Imaging.UI.ZoomChangedEventArgs)(AddressOf ImageViewer_ZoomChanged)
        AddHandler ImageViewer.ClientSizeChanged, New System.EventHandler(AddressOf ImageViewer_ClientSizeChanged)
        AddHandler ImageViewer.ImageLoaded, New System.EventHandler(Of Vintasoft.Imaging.ImageLoadedEventArgs)(AddressOf ImageViewer_ImageLoaded)

        UpdateGraphicObjects()
    End Sub

    ''' <summary>
    ''' Raises the <see cref="Vintasoft.Imaging.UI.VisualTools.VisualTool.Deactivated" /> event.
    ''' </summary>
    Protected Overrides Sub OnDeactivated(e As System.EventArgs)
        MyBase.OnDeactivated(e)

        RemoveHandler ImageViewer.ZoomChanged, AddressOf ImageViewer_ZoomChanged
        RemoveHandler ImageViewer.ClientSizeChanged, AddressOf ImageViewer_ClientSizeChanged
        RemoveHandler ImageViewer.ImageLoaded, AddressOf ImageViewer_ImageLoaded
    End Sub

    ''' <summary>
    ''' Updates the graphic objects.
    ''' </summary>
    Private Sub UpdateGraphicObjects()
        _fileNameGraphicObject.Rectangle = ImageViewer.ClientRectangle
        _zoomGraphicObject.Rectangle = ImageViewer.ClientRectangle
        _zoomGraphicObject.Text = String.Format("Zoom: {0}", ImageViewer.Zoom)

        Dim image As Vintasoft.Imaging.VintasoftImage = ImageViewer.Image
        If image Is Nothing Then
            _fileNameGraphicObject.Text = String.Empty
            _borderGraphicObject.Rectangle = System.Drawing.Rectangle.Empty
        Else
            Dim info As Vintasoft.Imaging.ImageSourceInfo = image.SourceInfo
            If String.IsNullOrEmpty(info.Filename) Then
                _fileNameGraphicObject.Text = String.Empty
            Else
                Dim text As String = System.IO.Path.GetFileName(info.Filename)
                If info.PageCount > 1 Then
                    text += String.Format(" (Page {0}/{1})", info.PageIndex + 1, info.PageCount)
                End If
                _fileNameGraphicObject.Text = text
            End If

            _borderGraphicObject.Rectangle = New System.Drawing.RectangleF(0, 0, image.Width, image.Height)
        End If
    End Sub

    ''' <summary>
    ''' Handles the ClientSizeChanged event of the ImageViewer control.
    ''' </summary>
    Private Sub ImageViewer_ClientSizeChanged(sender As Object, e As System.EventArgs)
        UpdateGraphicObjects()
    End Sub

    ''' <summary>
    ''' Handles the ZoomChanged event of the ImageViewer control.
    ''' </summary>
    Private Sub ImageViewer_ZoomChanged(sender As Object, e As Vintasoft.Imaging.UI.ZoomChangedEventArgs)
        UpdateGraphicObjects()
    End Sub

    ''' <summary>
    ''' Handles the ImageLoaded event of the ImageViewer control.
    ''' </summary>
    Private Sub ImageViewer_ImageLoaded(sender As Object, e As Vintasoft.Imaging.ImageLoadedEventArgs)
        UpdateGraphicObjects()
    End Sub

    #End Region

End Class