using Spire.Pdf;
using Spire.Pdf.Graphics;

// Main call
static void AddHeader(PdfPageBase page, string left, string center, string right)
{
    var state = page.Canvas.Save();
    RotatePage(page);
    AddHeaderWithRotatedPage(page, left, center, right);
    page.Canvas.Restore(state);
}

static void RotatePage(PdfPageBase page)
{
    var width = page.ActualSize.Width;
    var height = page.ActualSize.Height;

    switch (page.Rotation)
    {
        case PdfPageRotateAngle.RotateAngle0:
            break;
        case PdfPageRotateAngle.RotateAngle90:
            page.Canvas.TranslateTransform(0, height);
            page.Canvas.RotateTransform(360 - 90);
            break;
        case PdfPageRotateAngle.RotateAngle180:
            page.Canvas.TranslateTransform(width, height);
            page.Canvas.RotateTransform(360 - 180);
            break;
        case PdfPageRotateAngle.RotateAngle270:
            page.Canvas.TranslateTransform(width, 0);
            page.Canvas.RotateTransform(360 - 270);
            break;
        default:
            break;
    }
}

static void AddHeaderWithRotatedPage(PdfPageBase page, string left, string center, string right)
{
    var width = page.Rotation == PdfPageRotateAngle.RotateAngle90 || page.Rotation == PdfPageRotateAngle.RotateAngle270
        ? page.ActualSize.Height
        : page.ActualSize.Width;

    var font = new PdfFont(PdfFontFamily.TimesRoman, 14f);
    if (!string.IsNullOrEmpty(left))
        page.Canvas.DrawString(left, font, PdfBrushes.Black, width / 2, 5, new PdfStringFormat(PdfTextAlignment.Left));
    if (!string.IsNullOrEmpty(center))
        page.Canvas.DrawString(center, font, PdfBrushes.Black, width / 2, 5, new PdfStringFormat(PdfTextAlignment.Center));
    if (!string.IsNullOrEmpty(right))
        page.Canvas.DrawString(right, font, PdfBrushes.Black, width - 50, 5, new PdfStringFormat(PdfTextAlignment.Right));
}