Winnovative, PdfConverter Setting the Header and Footer height dynamicaly - asp.net

Question

I am using the Winnovative's PdfConverter to convert my HTML page to a PDF, i am able to get the PDF with header footer and all. But i have a requirement where i need to set the height of the Header and footer dynamically based on the content of the text that needs to be added. Below is the code i tried to achieve this but was not successful. Please can you help on what would i be missing here, or is there any other method i need to follow.
The PdfFooterOptions.FooterHeight is initially set to default 40px.
PdfConverter pdfConverter = new PdfConverter();
// set the converter options
pdfConverter.PdfDocumentOptions.PdfPageSize = PdfPageSize.A4;
pdfConverter.PdfDocumentOptions.PdfCompressionLevel = PdfCompressionLevel.Normal;
pdfConverter.PdfDocumentOptions.PdfPageOrientation = PdfPageOrientation.Portrait;
// set header and footer
pdfConverter.PdfDocumentOptions.ShowHeader = true;
pdfConverter.PdfDocumentOptions.ShowFooter = true;
//Add header and footer text
AddHeaderElements(pdfConverter, text);
AddFooterElements(pdfConverter, text);
// set the HTML content
pdfConverter.PdfDocumentOptions.FitWidth = true;
// set the embedded fonts option
pdfConverter.PdfDocumentOptions.EmbedFonts = true;
// set the live HTTP links option
pdfConverter.PdfDocumentOptions.LiveUrlsEnabled = true;
// set the JavaScript
pdfConverter.JavaScriptEnabled = true;
// set the images in PDF are compressed with JPEG to reduce the PDF document size
pdfConverter.PdfDocumentOptions.JpegCompressionEnabled = true;
// enable auto-generated bookmarks for a specified list of tags (e.g. H1 and H2)
pdfConverter.PdfBookmarkOptions.HtmlElementSelectors = new string[] { "H1", "H2" };
// Performs the conversion and get the pdf document bytes that can be further
// saved to a file or sent as response to browser
// The baseURL parameter helps the converter to get the CSS files and images
// referenced by a relative URL in the HTML string.
byte[] pdfValue = null;
pdfValue = pdfConverter.GetPdfBytesFromHtmlString(htmlCodeToConvert);
private void AddFooterElements(PdfConverter pdfConverter, string title)
{
//write the page number
TextElement footerText = new TextElement(550, pdfConverter.PdfFooterOptions.FooterHeight - 20,
string.Format(uiContentController.GetText("Aanvarag_Page"), "&p;", "&P;"),
new System.Drawing.Font(new System.Drawing.FontFamily("Tahoma"),
7, System.Drawing.GraphicsUnit.Point));
footerText.EmbedSysFont = true;
footerText.TextAlign = HorizontalTextAlign.Left;
pdfConverter.PdfFooterOptions.AddElement(footerText);
// set the footer HTML area
HtmlToPdfElement footerHtml = new HtmlToPdfElement(10, 0, 0,
0,
title, null, 1024, 0);
footerHtml.NavigationCompletedEvent += OnFooterHtmlNavigationCompleted;
pdfConverter.PdfFooterOptions.AddElement(footerHtml);
}
void OnFooterHtmlNavigationCompleted(NavigationCompletedParams eventParams)
{
// Get the header HTML width and height from event parameters
float footerHtmlWidth = eventParams.HtmlContentWidthPt;
float footerHtmlHeight = eventParams.HtmlContentHeightPt;
// Calculate the header width from coverter settings
float footerWidth = pdfConverter.PdfDocumentOptions.PdfPageSize.Width - pdfConverter.PdfDocumentOptions.LeftMargin -
pdfConverter.PdfDocumentOptions.RightMargin;
// Calculate a resize factor to fit the header width
float resizeFactor = 1;
if (footerHtmlWidth > footerWidth)
resizeFactor = footerWidth / footerHtmlWidth;
// Calculate the header height to preserve the HTML aspect ratio
float footerHeight = footerHtmlHeight * resizeFactor;
// Set the calculated header height
pdfConverter.PdfFooterOptions.FooterHeight = footerHeight;
}

Answer 1

There is a working example with source code for headers. For footers should be similar.
// Define the HTML to PDF converter object as a class member to make it accessible in the headerHtml_NavigationCompletedEvent handler
// where the header height will be automatically adjusted
private HtmlToPdfConverter htmlToPdfConverter;
// Indicates if a line should be drawn at the botom of the header
private bool drawHeaderLine = true;
protected void convertToPdfButton_Click(object sender, EventArgs e)
{
// Create a HTML to PDF converter object with default settings
htmlToPdfConverter = new HtmlToPdfConverter();
// Set license key received after purchase to use the converter in licensed mode
// Leave it not set to use the converter in demo mode
htmlToPdfConverter.LicenseKey = "fvDh8eDx4fHg4P/h8eLg/+Dj/+jo6Og=";
// Enable header in the generated PDF document
htmlToPdfConverter.PdfDocumentOptions.ShowHeader = true;
string headerHtmlUrl = Server.MapPath("~/DemoAppFiles/Input/HTML_Files/Header_HTML.html");
Document documentObject = null;
try
{
if (autoResizeHeaderRadioButton.Checked)
{
// Create a HTML element to be added in header
HtmlToPdfElement headerHtml = new HtmlToPdfElement(headerHtmlUrl);
// Install a handler where to set the automatically calculated header height
headerHtml.NavigationCompletedEvent += new NavigationCompletedDelegate(headerHtml_NavigationCompletedEvent);
// Add the HTML element to header
// When the element is rendered in header by converter, the headerHtml_NavigationCompletedEvent handler
// will be invoked and the header height will be automatically calculated
htmlToPdfConverter.PdfHeaderOptions.AddElement(headerHtml);
// Call the converter to produce a Document object
documentObject = htmlToPdfConverter.ConvertUrlToPdfDocumentObject(urlTextBox.Text);
// Uninstall the handler
headerHtml.NavigationCompletedEvent -= new NavigationCompletedDelegate(headerHtml_NavigationCompletedEvent);
// Draw a line at the header bottom
if (drawHeaderLine)
{
float headerWidth = documentObject.Header.Width;
float headerHeight = documentObject.Header.Height;
// Create a line element for the bottom of the header
LineElement headerLine = new LineElement(0, headerHeight - 1, headerWidth, headerHeight - 1);
// Set line color
headerLine.ForeColor = Color.Gray;
// Add line element to the bottom of the header
documentObject.Header.AddElement(headerLine);
}
// Save the PDF document in a memory buffer
byte[] outPdfBuffer = documentObject.Save();
// Send the PDF as response to browser
// Set response content type
Response.AddHeader("Content-Type", "application/pdf");
// Instruct the browser to open the PDF file as an attachment or inline
Response.AddHeader("Content-Disposition", String.Format("attachment; filename=Auto_Resize_Header_Footer.pdf; size={0}", outPdfBuffer.Length.ToString()));
// Write the PDF document buffer to HTTP response
Response.BinaryWrite(outPdfBuffer);
// End the HTTP response and stop the current page processing
Response.End();
}
else
{
// Create a HTML to PDF element to be added in header
HtmlToPdfElement headerHtml = new HtmlToPdfElement(headerHtmlUrl);
// Set a fixed header height in points
htmlToPdfConverter.PdfHeaderOptions.HeaderHeight = float.Parse(headerHeightTextBox.Text);
// Set the HTML element to fit the container height
headerHtml.FitHeight = true;
// Add HTML element to fit the fixed header height
htmlToPdfConverter.PdfHeaderOptions.AddElement(headerHtml);
// Draw a line at the header bottom
if (drawHeaderLine)
{
// Calculate the header width based on PDF page size and margins
float headerWidth = htmlToPdfConverter.PdfDocumentOptions.PdfPageSize.Width -
htmlToPdfConverter.PdfDocumentOptions.LeftMargin - htmlToPdfConverter.PdfDocumentOptions.RightMargin;
// Calculate header height
float headerHeight = htmlToPdfConverter.PdfHeaderOptions.HeaderHeight;
// Create a line element for the bottom of the header
LineElement headerLine = new LineElement(0, headerHeight - 1, headerWidth, headerHeight - 1);
// Set line color
headerLine.ForeColor = Color.Gray;
// Add line element to the bottom of the header
htmlToPdfConverter.PdfHeaderOptions.AddElement(headerLine);
}
// Convert the HTML page to a PDF document in a memory buffer
byte[] outPdfBuffer = htmlToPdfConverter.ConvertUrl(urlTextBox.Text);
// Send the PDF as response to browser
// Set response content type
Response.AddHeader("Content-Type", "application/pdf");
// Instruct the browser to open the PDF file as an attachment or inline
Response.AddHeader("Content-Disposition", String.Format("attachment; filename=Auto_Resize_Header_Footer.pdf; size={0}", outPdfBuffer.Length.ToString()));
// Write the PDF document buffer to HTTP response
Response.BinaryWrite(outPdfBuffer);
// End the HTTP response and stop the current page processing
Response.End();
}
}
finally
{
// Close the PDF document
if (documentObject != null)
documentObject.Close();
}
}
/// <summary>
/// This handler is called after the navigation to header HTML completed. The document header is resized in this event handler
/// </summary>
/// <param name="eventParams">The event parameter containing the HTML content size in pixels and points</param>
void headerHtml_NavigationCompletedEvent(NavigationCompletedParams eventParams)
{
// Get the header HTML width and height from event parameters
float headerHtmlWidth = eventParams.HtmlContentWidthPt;
float headerHtmlHeight = eventParams.HtmlContentHeightPt;
// Calculate the header width from coverter settings
float headerWidth = htmlToPdfConverter.PdfDocumentOptions.PdfPageSize.Width - htmlToPdfConverter.PdfDocumentOptions.LeftMargin -
htmlToPdfConverter.PdfDocumentOptions.RightMargin;
// Calculate a resize factor to fit the header width
float resizeFactor = 1;
if (headerHtmlWidth > headerWidth)
resizeFactor = headerWidth / headerHtmlWidth;
// Calculate the header height to preserve the HTML aspect ratio
float headerHeight = headerHtmlHeight * resizeFactor;
if (!(headerHeight < htmlToPdfConverter.PdfDocumentOptions.PdfPageSize.Height - htmlToPdfConverter.PdfDocumentOptions.TopMargin -
htmlToPdfConverter.PdfDocumentOptions.BottomMargin))
{
throw new Exception("The header height cannot be bigger than PDF page height");
}
// Set the calculated header height
htmlToPdfConverter.PdfDocumentOptions.DocumentObject.Header.Height = headerHeight;
}