Template Class

The Template class represents content which is repeated on each page of the PDF document. The templates can be used to create headers and footers, watermarks or any other content that needs to be repeated on each page of the PDF document.

A Template class can render all the graphic elements (e.g HTML to PDF converter, texts, images, shapes) a PdfPage can render, but it cannot render interactive elements like PDF links, attachments, text notes. A Template class object can be instantiated using the AddTemplate interface of the Document class.

There two logical types of templates in PDF Creator: predefined templates like header and footer and custom templates. Both predefined and custom templates are instances of the Template class, but the predefined templates dimensions are considered when calculating the available client area in a PDF page.

Predefined Templates

The predefined templates are the document header, footer, left bar template and right bar template. The predefined templates are automatically docked to the corresponding side of the PDF page.

For example, the predefined header is automatically docked to the top of the PDF page, which means the header location is the top left corner and the width of the header template is the width of the page. Also if a predefined header was set, the available client area in PDF page will start right under the header. Similarly, if a predefined footer was set, it will be docked to the bottom of page and the available client area in PDF will end right above the footer template. It is recommended to set the predefined templates before starting to add elements to the document.

Below is a sample to code to add a footer to the PDF document. Another special element in the sample code below is the text element used to add page numbering. When adding a text element to a template, the &p; token will be replaced with the current page number and the &P; token will be replaced with the total number of pages of the PDF document. This is possible because the templates are rendered after the PDF document main layer was rendered.

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private void AddHtmlFooter(Document document, PdfFont footerPageNumberFont)
{
    string thisPageURL = HttpContext.Current.Request.Url.AbsoluteUri;
    string headerAndFooterHtmlUrl = thisPageURL.Substring(0, thisPageURL.LastIndexOf('/')) + "/HeaderAndFooterHtml.htm";

    //create a template to be added in the header and footer
    document.FooterTemplate = document.AddTemplate(document.Pages[0].ClientRectangle.Width, 60);
    // create a HTML to PDF converter element to be added to the header template
    HtmlToPdfElement footerHtmlToPdf = new HtmlToPdfElement(headerAndFooterHtmlUrl);
    document.FooterTemplate.AddElement(footerHtmlToPdf);

    // add page number to the footer
    TextElement pageNumberText = new TextElement(document.FooterTemplate.ClientRectangle.Width - 100, 30, "This is page &p; of &P; pages", footerPageNumberFont);
    document.FooterTemplate.AddElement(pageNumberText);
}

Private Sub AddHtmlFooter(document As Document, footerPageNumberFont As PdfFont)
    Dim thisPageURL As String = HttpContext.Current.Request.Url.AbsoluteUri
    Dim headerAndFooterHtmlUrl As String = thisPageURL.Substring(0, thisPageURL.LastIndexOf("/"C)) + "/HeaderAndFooterHtml.htm"

    'create a template to be added in the header and footer
    document.FooterTemplate = document.AddTemplate(document.Pages(0).ClientRectangle.Width, 60)
    ' create a HTML to PDF converter element to be added to the header template
    Dim footerHtmlToPdf As New HtmlToPdfElement(headerAndFooterHtmlUrl)
    document.FooterTemplate.AddElement(footerHtmlToPdf)

    ' add page number to the footer
    Dim pageNumberText As New TextElement(document.FooterTemplate.ClientRectangle.Width - 100, 30, "This is page &p; of &P; pages", footerPageNumberFont)
    document.FooterTemplate.AddElement(pageNumberText)
End Sub

Custom Templates

The custom templates can be used to add watermarks or any other content that must be repeated in the same position on each page. In the code sample below, taken from the ModifyExistingPdf sample, a watermark containing a text and an image is added to an existing document:

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protected void btnCreatePDF_Click(object sender, EventArgs e)
{
    string pdfToModify = textBoxPdfFilePath.Text.Trim();

    // create a PDF document
    Document document = new Document(pdfToModify);

    // get the first page the PDF document
    PdfPage firstPage = document.Pages[0];

    string logoImagePath = System.IO.Path.Combine(Server.MapPath("~"), @"img\logo.jpg");

    // display image in the available space in page and with a auto determined height to keep the aspect ratio
    ImageElement imageElement1 = new ImageElement(0, 0, logoImagePath);
    AddElementResult addResult = firstPage.AddElement(imageElement1);

    // add image border
    // add a border to watermark
    RectangleElement imageBorderRectangleElement = new RectangleElement(1, 1, addResult.EndPageBounds.Width, addResult.EndPageBounds.Height);
    firstPage.AddElement(imageBorderRectangleElement);

    System.Drawing.Image logoImg = System.Drawing.Image.FromFile(logoImagePath);

    // calculate the watermark location
    System.Drawing.SizeF imageSizePx = logoImg.PhysicalDimension;

    // transform from pixels to points
    float imageWidthPoints = UnitsConverter.PixelsToPoints(imageSizePx.Width);
    float imageHeightPoints = UnitsConverter.PixelsToPoints(imageSizePx.Height);

    float watermarkXLocation = (firstPage.ClientRectangle.Width - imageWidthPoints)/2;
    float watermarkYLocation = firstPage.ClientRectangle.Height / 4;

    // add a template watermark to the document repeated on each document page
    // the watermark size is equal to image size in points
    Template watermarkTemplate = document.AddTemplate(new System.Drawing.RectangleF(watermarkXLocation, watermarkYLocation, imageWidthPoints, imageHeightPoints + 20));

    // add a standard font to the document
    PdfFont watermarkTextFont = document.AddFont(StdFontBaseFamily.HelveticaBold);
    watermarkTextFont.Size = 10;

    // Add a text element to the watermark. You can add any other graphic element to a template
    TextElement watermarkTextElement = new TextElement(3, 0, "This is Watermark Text", watermarkTextFont);
    watermarkTextElement.ForeColor = System.Drawing.Color.Red;
    watermarkTextElement.Transparency = 100;
    watermarkTemplate.AddElement(watermarkTextElement);

    // add an image to the watermak
    ImageElement watermarkImageElement = new ImageElement(0, 20, logoImg);
    watermarkImageElement.Transparency = 100;
    watermarkTemplate.AddElement(watermarkImageElement);

    // add a border to watermark
    RectangleElement watermarkRectangleElement = new RectangleElement(0, 0, watermarkTemplate.ClientRectangle.Width, watermarkTemplate.ClientRectangle.Height);
    watermarkTemplate.AddElement(watermarkRectangleElement);

    // dispose the image
    logoImg.Dispose();

    // save the document on http response stream
    document.Save(Response, false, "Demo.pdf");
}

Protected Sub btnCreatePDF_Click(sender As Object, e As EventArgs)
    Dim pdfToModify As String = textBoxPdfFilePath.Text.Trim()

    ' create a PDF document
    Dim document As New Document(pdfToModify)

    ' get the first page the PDF document
    Dim firstPage As PdfPage = document.Pages(0)

    Dim logoImagePath As String = System.IO.Path.Combine(Server.MapPath("~"), "img\logo.jpg")

    ' display image in the available space in page and with a auto determined height to keep the aspect ratio
    Dim imageElement1 As New ImageElement(0, 0, logoImagePath)
    Dim addResult As AddElementResult = firstPage.AddElement(imageElement1)

    ' add image border
    ' add a border to watermark
    Dim imageBorderRectangleElement As New RectangleElement(1, 1, addResult.EndPageBounds.Width, addResult.EndPageBounds.Height)
    firstPage.AddElement(imageBorderRectangleElement)

    Dim logoImg As System.Drawing.Image = System.Drawing.Image.FromFile(logoImagePath)

    ' calculate the watermark location
    Dim imageSizePx As System.Drawing.SizeF = logoImg.PhysicalDimension

    ' transform from pixels to points
    Dim imageWidthPoints As Single = UnitsConverter.PixelsToPoints(imageSizePx.Width)
    Dim imageHeightPoints As Single = UnitsConverter.PixelsToPoints(imageSizePx.Height)

    Dim watermarkXLocation As Single = (firstPage.ClientRectangle.Width - imageWidthPoints) / 2
    Dim watermarkYLocation As Single = firstPage.ClientRectangle.Height / 4

    ' add a template watermark to the document repeated on each document page
    ' the watermark size is equal to image size in points
    Dim watermarkTemplate As Template = document.AddTemplate(New System.Drawing.RectangleF(watermarkXLocation, watermarkYLocation, imageWidthPoints, imageHeightPoints + 20))

    ' add a standard font to the document
    Dim watermarkTextFont As PdfFont = document.AddFont(StdFontBaseFamily.HelveticaBold)
    watermarkTextFont.Size = 10

    ' Add a text element to the watermark. You can add any other graphic element to a template
    Dim watermarkTextElement As New TextElement(3, 0, "This is Watermark Text", watermarkTextFont)
    watermarkTextElement.ForeColor = System.Drawing.Color.Red
    watermarkTextElement.Transparency = 100
    watermarkTemplate.AddElement(watermarkTextElement)

    ' add an image to the watermak
    Dim watermarkImageElement As New ImageElement(0, 20, logoImg)
    watermarkImageElement.Transparency = 100
    watermarkTemplate.AddElement(watermarkImageElement)

    ' add a border to watermark
    Dim watermarkRectangleElement As New RectangleElement(0, 0, watermarkTemplate.ClientRectangle.Width, watermarkTemplate.ClientRectangle.Height)
    watermarkTemplate.AddElement(watermarkRectangleElement)

    ' dispose the image
    logoImg.Dispose()

    ' save the document on http response stream
    document.Save(Response, False, "Demo.pdf")
End Sub