namespace UserGuide.Programming.Annotation
{
    class HowTo_RotatePdfPageWithAnnotations
    {
        /// <summary>
        /// Rotates current image, in annotation viewer, by a specified orthogonal angle.
        /// </summary>
        /// <param name="viewer">Annotation viewer.</param>
        /// <param name="angle">Rotation angle.</param>
        public static void RotateImageWithAnnotations(Vintasoft.Imaging.Annotation.UI.AnnotationViewer viewer, int angle)
        {
            if (angle % 90 != 0)
                throw new System.ArgumentOutOfRangeException();

            // if image is vector image (PDF)
            if (viewer.Image.SourceInfo.DecoderName == "Pdf")
                // rotate PDF page with annotation, without rastering PDF page,
                // by a specified orthogonal angle
                RotatePdfPageWithAnnotations(viewer.Image, viewer.AnnotationDataCollection, angle);
            // if image is raster image (not PDF)
            else
                // rotate a raster image
                viewer.AnnotationDataController.RotateImageWithAnnotations(viewer.Image, angle);
        }

        /// <summary>
        /// Rotate PDF page with annotation, without rastering PDF page,
        /// by a specified orthogonal angle.
        /// </summary>
        /// <param name="image">Image associated with PDF page.</param>
        /// <param name="annotations">Annotation data collection.</param>
        /// <param name="angle">Rotation angle.</param>
        public static void RotatePdfPageWithAnnotations(
            Vintasoft.Imaging.VintasoftImage image,
            Vintasoft.Imaging.Annotation.AnnotationDataCollection annotations,
            int angle)
        {
            if (angle % 90 != 0)
                throw new System.ArgumentOutOfRangeException();

            // get PDF page associated with image
            Vintasoft.Imaging.Pdf.Tree.PdfPage page = 
                Vintasoft.Imaging.Pdf.PdfDocumentController.GetPageAssociatedWithImage(image);
            if (page == null)
                throw new System.ArgumentException();


            // get width and height, in pixels, of not rotated image
            int notRotatedImageWidth = image.Width;
            int notRotatedImageHeight = image.Height;

            // rotate PDF page
            page.Rotate = (page.Rotate + angle) % 360;
            // reload image from PDF document
            image.Reload(true);


            // get width and height, in pixels, of rotated image
            int rotatedImageWidth = image.Width;
            int rotatedImageHeight = image.Height;

            // get scale factor for converting values from pixels to DIP (device independent pixels)
            float scalePixelsToDipX = 96f / (float)image.Resolution.Horizontal;
            float scalePixelsToDipY = 96f / (float)image.Resolution.Vertical;

            // calculate offset
            System.Drawing.PointF offset = new System.Drawing.PointF(
                ((rotatedImageWidth - notRotatedImageWidth) / 2f) * scalePixelsToDipX,
                ((rotatedImageHeight - notRotatedImageHeight) / 2f) * scalePixelsToDipY);

            // calcualte the rotation center
            System.Drawing.PointF rotationCenter = new System.Drawing.PointF(
                (notRotatedImageWidth / 2f) * scalePixelsToDipX,
                (notRotatedImageHeight / 2f) * scalePixelsToDipY);

            // rotate annotations
            RotateAnnotations(annotations, angle, offset, rotationCenter);
        }

        /// <summary>
        /// Rotates annotations by a specified angle.
        /// </summary>
        /// <param name="annotations">Annotation data collection.</param>
        /// <param name="angle">Rotation angle.</param>
        /// <param name="offset">Offset.</param>
        /// <param name="rotationCenter">Rotation center.</param>
        private static void RotateAnnotations(
            Vintasoft.Imaging.Annotation.AnnotationDataCollection annotations,
            float angle,
            System.Drawing.PointF offset,
            System.Drawing.PointF rotationCenter)
        {
            // gets annotation locations
            int annotationsCount = annotations.Count;
            if (annotationsCount == 0)
                return;

            System.Drawing.PointF[] points = new System.Drawing.PointF[annotationsCount];
            for (int i = 0; i < annotationsCount; i++)
                points[i] = annotations[i].Location;

            using (System.Drawing.Drawing2D.Matrix m = new System.Drawing.Drawing2D.Matrix())
            {
                // offset
                m.Translate(offset.X, offset.Y);

                // rotate at
                m.RotateAt(angle, rotationCenter);

                // execute transformation of annotations location
                m.TransformPoints(points);
            }

            // change annotation location and rotation property
            for (int i = 0; i < annotationsCount; i++)
            {
                annotations[i].Rotation += angle;
                annotations[i].Location = points[i];
            }
        }

    }
}

Namespace UserGuide.Programming.Annotation
    Class HowTo_RotatePdfPageWithAnnotations
        ''' <summary>
        ''' Rotates current image, in annotation viewer, by a specified orthogonal angle.
        ''' </summary>
        ''' <param name="viewer">Annotation viewer.</param>
        ''' <param name="angle">Rotation angle.</param>
        Public Shared Sub RotateImageWithAnnotations(viewer As Vintasoft.Imaging.Annotation.UI.AnnotationViewer, angle As Integer)
            If angle Mod 90 <> 0 Then
                Throw New System.ArgumentOutOfRangeException()
            End If

            ' if image is vector image (PDF)
            If viewer.Image.SourceInfo.DecoderName = "Pdf" Then
                ' rotate PDF page with annotation, without rastering PDF page,
                ' by a specified orthogonal angle
                RotatePdfPageWithAnnotations(viewer.Image, viewer.AnnotationDataCollection, angle)
            Else
                ' if image is raster image (not PDF)
                ' rotate a raster image
                viewer.AnnotationDataController.RotateImageWithAnnotations(viewer.Image, angle)
            End If
        End Sub

        ''' <summary>
        ''' Rotate PDF page with annotation, without rastering PDF page,
        ''' by a specified orthogonal angle.
        ''' </summary>
        ''' <param name="image">Image associated with PDF page.</param>
        ''' <param name="annotations">Annotation data collection.</param>
        ''' <param name="angle">Rotation angle.</param>
        Public Shared Sub RotatePdfPageWithAnnotations(image As Vintasoft.Imaging.VintasoftImage, annotations As Vintasoft.Imaging.Annotation.AnnotationDataCollection, angle As Integer)
            If angle Mod 90 <> 0 Then
                Throw New System.ArgumentOutOfRangeException()
            End If

            ' get PDF page associated with image
            Dim page As Vintasoft.Imaging.Pdf.Tree.PdfPage = Vintasoft.Imaging.Pdf.PdfDocumentController.GetPageAssociatedWithImage(image)
            If page Is Nothing Then
                Throw New System.ArgumentException()
            End If


            ' get width and height, in pixels, of not rotated image
            Dim notRotatedImageWidth As Integer = image.Width
            Dim notRotatedImageHeight As Integer = image.Height

            ' rotate PDF page
            page.Rotate = (page.Rotate + angle) Mod 360
            ' reload image from PDF document
            image.Reload(True)


            ' get width and height, in pixels, of rotated image
            Dim rotatedImageWidth As Integer = image.Width
            Dim rotatedImageHeight As Integer = image.Height

            ' get scale factor for converting values from pixels to DIP (device independent pixels)
            Dim scalePixelsToDipX As Single = 96F / CSng(image.Resolution.Horizontal)
            Dim scalePixelsToDipY As Single = 96F / CSng(image.Resolution.Vertical)

            ' calculate offset
            Dim offset As New System.Drawing.PointF(((rotatedImageWidth - notRotatedImageWidth) / 2F) * scalePixelsToDipX, ((rotatedImageHeight - notRotatedImageHeight) / 2F) * scalePixelsToDipY)

            ' calcualte the rotation center
            Dim rotationCenter As New System.Drawing.PointF((notRotatedImageWidth / 2F) * scalePixelsToDipX, (notRotatedImageHeight / 2F) * scalePixelsToDipY)

            ' rotate annotations
            RotateAnnotations(annotations, angle, offset, rotationCenter)
        End Sub

        ''' <summary>
        ''' Rotates annotations by a specified angle.
        ''' </summary>
        ''' <param name="annotations">Annotation data collection.</param>
        ''' <param name="angle">Rotation angle.</param>
        ''' <param name="offset">Offset.</param>
        ''' <param name="rotationCenter">Rotation center.</param>
        Private Shared Sub RotateAnnotations(annotations As Vintasoft.Imaging.Annotation.AnnotationDataCollection, angle As Single, offset As System.Drawing.PointF, rotationCenter As System.Drawing.PointF)
            ' gets annotation locations
            Dim annotationsCount As Integer = annotations.Count
            If annotationsCount = 0 Then
                Return
            End If

            Dim points As System.Drawing.PointF() = New System.Drawing.PointF(annotationsCount - 1) {}
            For i As Integer = 0 To annotationsCount - 1
                points(i) = annotations(i).Location
            Next

            Using m As New System.Drawing.Drawing2D.Matrix()
                ' offset
                m.Translate(offset.X, offset.Y)

                ' rotate at
                m.RotateAt(angle, rotationCenter)

                ' execute transformation of annotations location
                m.TransformPoints(points)
            End Using

            ' change annotation location and rotation property
            For i As Integer = 0 To annotationsCount - 1
                annotations(i).Rotation += angle
                annotations(i).Location = points(i)
            Next
        End Sub

    End Class
End Namespace