' Changes resolution of Jpeg2000 page, saves Jpeg2000 file,
' checks that resolution has been changed correctly.
Public Shared Sub ChangeJpeg2000PageResolution(jpeg2000Filename As String, newResolution As Vintasoft.Imaging.Resolution)
    ' open an existing JPEG2000 file
    Using file As New Vintasoft.Imaging.Codecs.ImageFiles.Jpeg2000.Jpeg2000File(jpeg2000Filename, System.IO.FileMode.Open, System.IO.FileAccess.ReadWrite)
        Dim page As Vintasoft.Imaging.Codecs.ImageFiles.Jpeg2000.Jpeg2000Page = file.Page

        page.Resolution = newResolution

        file.SaveChanges()
    End Using

    ' check that resolution is saved correctly

    Using file As New Vintasoft.Imaging.Codecs.ImageFiles.Jpeg2000.Jpeg2000File(jpeg2000Filename, System.IO.FileMode.Open, System.IO.FileAccess.Read)
        Dim page As Vintasoft.Imaging.Codecs.ImageFiles.Jpeg2000.Jpeg2000Page = file.Page

        Dim resolution As Vintasoft.Imaging.Resolution = page.Resolution

        ' little difference is allowed
        If System.Math.Abs(resolution.Horizontal - newResolution.Horizontal) > 0.01 OrElse System.Math.Abs(resolution.Vertical - newResolution.Vertical) > 0.01 Then
            Throw New System.ApplicationException()
        End If
    End Using
End Sub

// Changes resolution of Jpeg2000 page, saves Jpeg2000 file,
// checks that resolution has been changed correctly.
public static void ChangeJpeg2000PageResolution(string jpeg2000Filename,
    Vintasoft.Imaging.Resolution newResolution)
{
    // open an existing JPEG2000 file
    using (Vintasoft.Imaging.Codecs.ImageFiles.Jpeg2000.Jpeg2000File file =
        new Vintasoft.Imaging.Codecs.ImageFiles.Jpeg2000.Jpeg2000File(
            jpeg2000Filename, System.IO.FileMode.Open, System.IO.FileAccess.ReadWrite))
    {
        Vintasoft.Imaging.Codecs.ImageFiles.Jpeg2000.Jpeg2000Page page = file.Page;

        page.Resolution = newResolution;

        file.SaveChanges();
    }

    // check that resolution is saved correctly

    using (Vintasoft.Imaging.Codecs.ImageFiles.Jpeg2000.Jpeg2000File file =
        new Vintasoft.Imaging.Codecs.ImageFiles.Jpeg2000.Jpeg2000File(
            jpeg2000Filename, System.IO.FileMode.Open, System.IO.FileAccess.Read))
    {
        Vintasoft.Imaging.Codecs.ImageFiles.Jpeg2000.Jpeg2000Page page = file.Page;

        Vintasoft.Imaging.Resolution resolution = page.Resolution;

        // little difference is allowed
        if (System.Math.Abs(resolution.Horizontal - newResolution.Horizontal) > 0.01 ||
            System.Math.Abs(resolution.Vertical - newResolution.Vertical) > 0.01)
        {
            throw new System.ApplicationException();
        }
    }
}