Annotation data

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The AnnotationData class is intended for storing the base information about annotation.

The complete information about annotation is stored in a class derived from AnnotationData class.

Annotations, derived from AnnotationData class, are divided into 3 types:

Annotations based on rectangle (derived from RectangleAnnotationData class):
- RectangleAnnotationData - holds information about the annotation that displays rectangle.
- EllipseAnnotationData - holds information about the annotation that displays an ellipse.
- EmbeddedImageAnnotationData - holds information about the annotation that displays an embedded image.
- ReferencedImageAnnotationData - holds information about the annotation that displays a referenced image.
- HighlightAnnotationData - holds information about the annotation that highlights region of image.
- TextAnnotationData - holds information about the annotation that displays text which can be edited by the user.
- LinkAnnotationData - holds information about the annotation that displays a hypertext link.
- StampAnnotationData - holds information about the annotation that displays a text message with a rounded rectangle outline similar to a rubber stamp.
Annotations based on collection of points (derived from LineAnnotationDataBase class):
- LineAnnotationData - holds information about the annotation that displays a line.
- LinesAnnotationData - holds information about the annotation that displays lines.
- PolygonAnnotationData - holds information about the annotation that displays a polygon.
- RulerAnnotationData - holds information about the annotation that displays the single line and the length of line.
- RulersAnnotationData - holds information about the annotation that displays a series of lines and the total length of lines.
- AngleAnnotationData - holds information about the annotation that displays two lines, the angle between them and the total length of lines.
- LeaderLineAnnotationData - holds information about the annotation that displays a leader line.
Composite annotations (derived from CompositeAnnotationData class). These annotations are combining several annotations of any type.
- FreeTextAnnotationData - holds information about the annotation that displays an editable text area and a leader polyline used for pointing on the image.
- GroupAnnotationData - holds information about the annotation that displays a group of annotations.

Annotation location

The AnnotationData.Location property allows to get/set the annotation location.

Location of rectangle-based annotation always matches with center of annotation's rectangle.
Location of points-based annotation by default matches with its first point, unless the coordinates of the first point are changed.

Location is specified and stored in the image coordinate system with the beginning in the left upper corner. Unit of measure is 1 DIP (Device Independent Pixel) which equal 1/96 inch.

Annotation size

The AnnotationData.Size property allows to get/set the annotation size.

Size is specified and stored in the image coordinate system with the beginning in the left upper corner. Unit of measure is 1 DIP (Device Independent Pixel) which equal 1/96 inch.

Annotation rotation angle and center of rotation

The AnnotationData.Rotation property allows to get/set the annotation rotation in degrees.

Rotation center of annotation is the point in the image coordinate system, in regard to which the annotation is rotated when value of AnnotationData.Rotation property is changed.
The rotation center of any annotation can be calculated as follows:

first, calculate location of non rotated annotation using the AnnotationData.GetLocationWithoutRotation method
next, calculate the offset of annotation's rotation center relative to the location using the AnnotationData.GetCenterRelativeToLocation method
finally, move the point, which is specified by the first value, to the offset, which is specified by the second value

Annotation's rotation angle is the deviation angle from normal non-rotated state of annotation. It is specified and stored in degrees. Rotation angle has positive value when annotation is rotating clockwise and negative when counterclockwise.

Annotation bounding rectangle

The bounding rectangle of annotation is the minimum rectangle, which includes the annotation in whole and which sides are parallels to the image sides.
For rectangle-based annotation the bounding rectangle is the minimum rectangle, which includes all vertices of annotation's rectangle and its center always matches with center of annotation's rectangle.
For points-based annotation the bounding rectangle is the minimum rectangle, which includes all annotation's points.

AnnotationData.GetBoundingBox method calculates a bounding box of annotation.
Here is C#/VB.NET code that shows how to check if the annotation is inside the image boundaries:

bool IsAnnotationInsideImage(
    Vintasoft.Imaging.Annotation.AnnotationData annotation, 
    Vintasoft.Imaging.VintasoftImage image)
{
    // get the bounding box
    System.Drawing.RectangleF boundingBox = annotation.GetBoundingBox();
    // calculate image size in device independent pixels
    float imageWidthInDips = image.Width * 96f / (float)image.Resolution.Horizontal;
    float imageHeightInDips = image.Height * 96f / (float)image.Resolution.Vertical;
    System.Drawing.RectangleF imageRect = 
        new System.Drawing.RectangleF(0, 0, imageWidthInDips, imageHeightInDips);
    // check if image rectangle contains the bounding box
    return imageRect.Contains(boundingBox);
}

VB.NET

Private Function IsAnnotationInsideImage(annotation As Vintasoft.Imaging.Annotation.AnnotationData, image As Vintasoft.Imaging.VintasoftImage) As Boolean
    ' get the bounding box
    Dim boundingBox As System.Drawing.RectangleF = annotation.GetBoundingBox()
    ' calculate image size in device independent pixels
    Dim imageWidthInDips As Single = image.Width * 96F / CSng(image.Resolution.Horizontal)
    Dim imageHeightInDips As Single = image.Height * 96F / CSng(image.Resolution.Vertical)
    Dim imageRect As New System.Drawing.RectangleF(0, 0, imageWidthInDips, imageHeightInDips)
    ' check if image rectangle contains the bounding box
    Return imageRect.Contains(boundingBox)
End Function

AnnotationData.GetBoundingBox(PointF location, SizeF size, float rotation) method calculates the bounding box that annotation would have with location, size and rotation parameters passed as arguments of method.
Here is C#/VB.NET code that shows how to restrict the rotation angle of annotation to prevent it from overrunning the boundaries of the specified area:

System.Drawing.RectangleF _boundingArea;
Vintasoft.Imaging.Annotation.AnnotationData _annotation;

void SubscribeOnPropertyChanging()
{
    _annotation.PropertyChanging += 
        new System.EventHandler<Vintasoft.Imaging.ObjectPropertyChangingEventArgs>(annotation_PropertyChanging);
}

void annotation_PropertyChanging(object sender, Vintasoft.Imaging.ObjectPropertyChangingEventArgs e)
{
    if (e.PropertyName == "Rotation")
    {
        System.Drawing.RectangleF boundingBox = _annotation.GetBoundingBox(
            _annotation.Location, _annotation.Size, (float)e.NewValue);

        if (!_boundingArea.Contains(boundingBox))
        {
            e.Cancel = true;
        }
    }
}

VB.NET

Private _boundingArea As System.Drawing.RectangleF
Private _annotation As Vintasoft.Imaging.Annotation.AnnotationData

Private Sub SubscribeOnPropertyChanging()
    AddHandler _annotation.PropertyChanging, New System.EventHandler(Of Vintasoft.Imaging.ObjectPropertyChangingEventArgs)(AddressOf annotation_PropertyChanging)
End Sub

Private Sub annotation_PropertyChanging(sender As Object, e As Vintasoft.Imaging.ObjectPropertyChangingEventArgs)
    If e.PropertyName = "Rotation" Then
        Dim boundingBox As System.Drawing.RectangleF = _annotation.GetBoundingBox(_annotation.Location, _annotation.Size, CSng(e.NewValue))

        If Not _boundingArea.Contains(boundingBox) Then
            e.Cancel = True
        End If
    End If
End Sub

Annotation properties

AnnotationData class contains a set of properties divided into following groups:

information about annotation: AnnotationData.Guid, AnnotationData.Name
date-time/author/changes: AnnotationData.CreationTime, AnnotationData.ModifiedTime, AnnotationData.CreatedBy, AnnotationData.ModifiedBy
location/size/rotation: AnnotationData.Location, AnnotationData.Size, AnnotationData.Rotation
visual appearance: AnnotationData.Border, AnnotationData.Outline, AnnotationData.FillBrush, AnnotationData.ToolTip
visibility: AnnotationData.IsVisible
transforms: AnnotationData.HorizontalMirrored, AnnotationData.VerticalMirrored, AnnotationData.Resizeable, AnnotationData.Rotatable, AnnotationData.CanMove, AnnotationData.CanRotate, AnnotationData.CanResize, AnnotationData.CanMirror

Classes, which are derived from AnnotationData class, have additional properties, which specify annotation data. For example, the LineAnnotationDataBase class has Points property, which contains information about points of annotation.

Add comments to the annotation

Each annotation can be commented. The AnnotationData.Comment property returns the root comment for annotation (an instance of AnnotationComment class). The AnnotationComment.Replies property returns the comment collection (an instance of CommentCollection class), which contains replies to the comment.

Monitor changes in annotation properties

The AnnotationData class provides events, which allow to monitor changes in annotation properties:

AnnotationData.PropertyChanging event appears if any property of annotation is changing. The event provides the ability to change new property value or even cancel the change.
AnnotationData.PropertyChanged event appears if any property of annotation is changed.

Load and save annotation

AnnotationData class implements ISerializable interface. This allows to load/save annotations using any formatter, which implements IFormatter interface.

Initialize the annotation properties

The AnnotationData class implements ISupportInitialize interface.

The AnnotationData.BeginInit method allows to start initialization of annotation properties. The AnnotationData.BeginInit raises the AnnotationData.PropertyChanged event with the following properties: PropertyName="IsInitializing", NewValue=True.

The AnnotationData.EndInit method allows to stop initialization of annotation properties. The AnnotationData.BeginInit raises the AnnotationData.PropertyChanged event with the following properties: PropertyName="IsInitializing", NewValue=False.

The AnnotationData.BeginInit and AnnotationData.EndInit methods just generate additional AnnotationData.PropertyChanged events and does not change logic of calling AnnotationData.PropertyChanging and AnnotationData.PropertyChanged events of annotation.
The AnnotationData.BeginInit and AnnotationData.EndInit methods can be nested.

Clone annotation

The AnnotationData class implements ICloneable interface.

Here is C#/VB.NET code that shows how to clone single annotation from a collection and add cloned annotation into the same collection:

void CloneAndAdd(Vintasoft.Imaging.Annotation.AnnotationDataCollection annotationCollection, int index)
{
    // clone annotation at specified index
    Vintasoft.Imaging.Annotation.AnnotationData clonedAnnotation = 
        (Vintasoft.Imaging.Annotation.AnnotationData)annotationCollection[index].Clone();
    // add cloned annotation to the end of the collection
    annotationCollection.Add(clonedAnnotation);
}

VB.NET

Private Sub CloneAndAdd(annotationCollection As Vintasoft.Imaging.Annotation.AnnotationDataCollection, index As Integer)
    ' clone annotation at specified index
    Dim clonedAnnotation As Vintasoft.Imaging.Annotation.AnnotationData = DirectCast(annotationCollection(index).Clone(), Vintasoft.Imaging.Annotation.AnnotationData)
    ' add cloned annotation to the end of the collection
    annotationCollection.Add(clonedAnnotation)
End Sub

Annotation collection

The AnnotationDataCollection class is a collection of instances of AnnotationData class. The AnnotationDataCollection class provides the ability to add, remove, rearrange, sort elements, convert AnnotationData elements to array, subscribe to property changing/change events of each annotation.

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