Visual tool GraphicObjectTool.

In This Topic

The visual tool GraphicObjectTool allows to display static graphical objects in ImageViewer.

Graphical object.

GraphicObject class is a base class for static objects and allows to:

Create an object appearance using GraphicObject.DrawInObjectSpace or GraphicObject.DrawInViewerSpace method.
Change the coordinate space of object using GraphicObject.PointTransform property.
Change the object color using GraphicObject.Pen property.
Change the object background color using GraphicObject.Brush property.

Here is the list of standard static objects:

RectangularGraphicObject - a rectangular object.
EllipticalGraphicObject - an elliptical object.
TextGraphicObject - a rectangular object with text.
ImageGraphicObject - a rectangular object with image.
PathGraphicObject - an object based on graphics path.
GraphicObjectGroup - a group of graphical objects.

Here is C#/VB.NET code that demonstrates how to display a grid above the image:

/// <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

}

VB.NET

''' <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

Creating of object appearance.

VintaSoft Imaging .NET SDK allows to create a custom static object from scratch or modify an existing standard static object.

The object appearance can be created by overriding one of the following methods:

GraphicObject.DrawInObjectSpace - is called while drawing an object in the coordinate space of the object.
GraphicObject.DrawInViewerSpace - is called while drawing an object in the coordinate space of the image viewer. If the value of GraphicObject.PointTransform property is not set then the coordinate space of the image viewer will match the coordinate space of the object.

Here is C#/VB.NET code that demonstrates how to display a rotated text by overriding the GraphicObject.DrawInObjectSpace method:

/// <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

}

VB.NET

''' <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

Here is C#/VB.NET code that demonstrates how to display the name of loaded file, current zoom level and a bounding outline of image in the image viewer. The objects, responsible for displaying of the loaded file name and the zoom level, are located in the coordinate space of viewer, but the object, responsible for displaying of the bounding outline, is located in the coordinate space of image.

/// <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

}

VB.NET

''' <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

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