Forum 'VintaSoft Annotation .NET Plug-in Discussions'

• Using mouse events. In this case you need subscribe to necessary events and define logic in events.
• Using annotation builder. In this case you need create annotation builder - class that defines annotation building logic, and specify that annotation must be built using custom annotation builder.

Private Sub Button2_Click(sender As System.Object, e As System.EventArgs) Handles Button2.Click
    ' create text annotation data
    Dim textAnnoData As TextAnnotationData = New TextAnnotationData()
    ' specify that annotation size must be calculated automatically depending on text content
    textAnnoData.AutoSize = True
    ' specify annotation text
    textAnnoData.Text = "Hallo"
    ' specify annotation location
    textAnnoData.Location = New PointF(-1000, -1000)

    ' create text annotation view
    Dim textAnnoView As TextAnnotationView = New TextAnnotationView(textAnnoData)
    ' define custom builder for text annotation view
    textAnnoView.Builder = New MyTextAnnotationBuilder(textAnnoView)

    ' add annotation view to the first image in annotation viewer
    annotationViewer1.AddAndBuildAnnotation(textAnnoView)
End Sub

''' <summary>
''' Custom builder of text annotation.
''' </summary>
Public Class MyTextAnnotationBuilder
    Inherits RectangularAnnotationBuilder

    ' annotation width before transform
    Dim _widthBeforeTransform As Double
    ' annotation height before transform
    Dim _heightBeforeTransform As Double



    ''' <summary>
    ''' Initializes a new instance of the <see cref="MyTextAnnotationBuilder"/> class.
    ''' </summary>
    ''' <param name="annotation">The annotation.</param>
    Public Sub New(ByVal annotation As IRectangularInteractiveObject)
        MyBase.new(annotation)

        ' clear interaction areas of annotation
        InteractionAreaList.Clear()
        ' add new interaction area that has size equal to viewer size and interacts when mouse is hovered or moved over viewer
        InteractionAreaList.Add(New ImageViewerArea(InteractionAreaType.Hover Or InteractionAreaType.Movable))
    End Sub



    ''' <summary>
    ''' Performs the interaction with annotation.
    ''' </summary>
    Protected Overrides Sub PerformInteraction(args As Vintasoft.Imaging.UI.VisualTools.UserInteraction.InteractionEventArgs)
        Dim x0 As Double
        Dim y0 As Double
        Dim x1 As Double
        Dim y1 As Double

        ' if first user interaction with interaction area occurs
        If args.Action = InteractionAreaAction.Begin Then
            ' get bounding box of annotation
            InteractiveObject.GetRectangle(x0, y0, x1, y1)
            ' save annotation width and height
            _widthBeforeTransform = x1 - x0
            _heightBeforeTransform = y1 - y0

            ' if user moved mouse over interaction area
        ElseIf args.Action = InteractionAreaAction.Move Then
            ' calculate left-top point of annotation
            x0 = args.Location.X
            y0 = args.Location.Y
            ' calculate right-bottom point of annotation
            x1 = x0 + _widthBeforeTransform
            y1 = y0 + _heightBeforeTransform
            ' set bounding box of annotation
            InteractiveObject.SetRectangle(x0, y0, x1, y1)
            ' specify that interatcion occurs
            args.InteractionOccured(True)

            ' if user clicked on interaction area
        ElseIf args.Action = InteractionAreaAction.Click Then
            ' specify that interatcion is finished
            args.InteractionFinished = True

        End If
    End Sub

End Class