Merge PDFs with page numbers in Xojo with MBS DynaPDF Plugin

You can use DynaPDFMBS class in MBS Xojo DynaPDF Plugin for a lot of PDF operations. Create PDF from scratch, add content like text, tables, vector graphics, images and place existing PDF content as templates. You can merge, split, encrypt, decrypt, optimize and print PDF documents.
Let’s show you how to do merge in DynaPDF with the following method snippet:

Sub Merge()
	Dim pdf As New DynapdfMBS
	pdf.SetLicenseKey "Lite" // For this example you can use a Lite, Pro or Enterprise License
	Dim outFile As folderitem = GetSaveFolderItem(MyFileTypes.Pdf, "Merge.pdf")
	If outFile = Nil Then Return // cancelled
	Call pdf.CreateNewPDF(outFile)
	// we import all content and as pages
	Dim flags As Integer = Bitwise.BitOr(pdf.kifImportAsPage, pdf.kifImportAll)
	Call pdf.SetImportFlags(flags)
	// loop over list to import all files there
	Dim c As Integer = List.ListCount-1
	For i As Integer = 0 To c
		// we store folderitems for file references in the CellTag here.
		Dim file As FolderItem = List.CellTag(i, 0)
		// open file
		Dim FileHandle As Integer = pdf.OpenimportFile(file, pdf.kptopen, "")
		If FileHandle >= 0 Then
			// import all pages
			Call pdf.ImportPDFFile(pdf.GetPageCount+1, 1.0, 1.0)
			// alternatively with Pro license, import individual pages
			'Call pdf.ImportPDFPage(1)
			Call pdf.CloseImportFile
		End If
	// optional edit all pages to have new text for page numbers
	If CheckPageNumbers.Value Then
		AddPageNumbers pdf
	End If
	Call pdf.CloseFile
	// open in preview
End Sub

As you see, we import all pages from all PDF documents and on the end do the page numbers, if a checkbox is clicked. Let’s take a look on how we edit pages to add page numbers:

Sub AddPageNumbers(pdf as DynaPDFMBS)
	Const FontStyle = pdf.kfsNone
	Const FontSize = 20
	// we add pages on bottom, so we can use Bottom Up coordinates
	Call pdf.SetPageCoords(pdf.kpcBottomUp)
	// loop over pages
	Dim c As Integer = pdf.GetPageCount
	For i As Integer = 1 To c
		// we try to edit each page
		If pdf.EditPage(i) Then
			Dim PageText As String = "Page "+Str(i)+" of "+Str(c)
			// draw white rectangle to overdraw existing page numbers
			Call pdf.SetFillColor(pdf.RGB(255, 255, 255)) // white color
			Call pdf.Rectangle(pdf.GetPageWidth-250, 40-FontSize-5, 200, FontSize+8, pdf.kfmFill )
			// setup font and color
			Call pdf.SetFont("Helvetica", FontStyle, FontSize)
			Call pdf.SetFillColor(0) // black color
			Call pdf.SetStrokeColor(0)
			// and write text into a right aligned text box on bottom of page with some margin
			Call pdf.WriteFTextEx(pdf.GetPageWidth-250, 40, 200, 40, pdf.ktaRight, PageText )
			// save page
			Call pdf.EndPage
		End If
End Sub

As you see we did some extra steps with drawing a rectangle over the area to wipe out any text there. We could use ExtractRect with the rectangle to look if there is existing text and then maybe use the other half of the page.
Let us know if you have questions. The example project will be included in next version as “Merge PDF documents with page numbers”. Please do not hesitate to contact us if you have questions.

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