< Windows samples

OptimizerTest - VB

The sample shows how to use 'pdftron.PDF.Optimizer' to reduce PDF file size by reducing the file size, removing redundant information, and compressing data streams using the latest in image compression technology. 'pdftron.PDF.Optimizer' is an optional Add-On to PDFNet Core SDK.

'
' Copyright (c) 2001-2018 by PDFTron Systems Inc. All Rights Reserved.
'

Imports System

Imports pdftron
Imports pdftron.Common
Imports pdftron.Filters
Imports pdftron.SDF
Imports pdftron.PDF

Module OptimizerTestVB
	Dim pdfNetLoader As PDFNetLoader = pdftron.PDFNetLoader.Instance()

	'---------------------------------------------------------------------------------------
    ' The following sample illustrates how to reduce PDF file size using 'pdftron.PDF.Optimizer'.
    ' The sample also shows how to simplify and optimize PDF documents for viewing on mobile devices 
    ' and on the Web using 'pdftron.PDF.Flattener'.
    '
    ' @note Both 'Optimizer' and 'Flattener' are separately licensable add-on options to the core PDFNet license.
    '
    ' ----
    '
    ' 'pdftron.PDF.Optimizer' can be used to optimize PDF documents by reducing the file size, removing 
    ' redundant information, and compressing data streams using the latest in image compression technology. 
    '
    ' PDF Optimizer can compress and shrink PDF file size with the following operations:
	' - Remove duplicated fonts, images, ICC profiles, and any other data stream. 
	' - Optionally convert high-quality or print-ready PDF files to small, efficient and web-ready PDF. 
	' - Optionally down-sample large images to a given resolution. 
	' - Optionally compress or recompress PDF images using JBIG2 and JPEG2000 compression formats. 
    ' - Compress uncompressed streams and remove unused PDF objects.
    ' ----
    '
    ' 'pdftron.PDF.Flattener' can be used to speed-up PDF rendering on mobile devices and on the Web by 
    ' simplifying page content (e.g. flattening complex graphics into images) while maintaining vector text 
    ' whenever possible.
    '
    ' Flattener can also be used to simplify process of writing custom converters from PDF to other formats. 
    ' In this case, Flattener can be used as first step in the conversion pipeline to reduce any PDF to a 
    ' very simple representation (e.g. vector text on top of a background image).
	'---------------------------------------------------------------------------------------
	Sub Main()
		PDFNet.Initialize()

		Dim input_path As String = "../../../../TestFiles/"
		Dim output_path As String = "../../../../TestFiles/Output/"
		Dim input_filename As String = "newsletter.pdf"

		'--------------------------------------------------------------------------------
		' Example 1) Simple optimization of a pdf with default settings. 
		'
		Try
			Using doc As PDFDoc = New PDFDoc(input_path  & input_filename)
				doc.InitSecurityHandler()
				Optimizer.Optimize(doc)
				doc.Save(output_path  & input_filename  & "_opt1.pdf", SDFDoc.SaveOptions.e_linearized)
			End Using
		Catch e As PDFNetException
			Console.WriteLine(e.Message)
		End Try

		'--------------------------------------------------------------------------------
		' Example 2) Reduce image quality and use jpeg compression for
		' non monochrome images.
		Try
			Using doc As PDFDoc = New PDFDoc(input_path  & input_filename)
				doc.InitSecurityHandler()

				Dim image_settings As New Optimizer.ImageSettings

				' low quality jpeg compression
				image_settings.SetCompressionMode(Optimizer.ImageSettings.CompressionMode.e_jpeg)
				image_settings.SetQuality(1)

				' Set the output dpi to be standard screen resolution
				image_settings.SetImageDPI(144, 96)

				' this option will recompress images not compressed with
				' jpeg compression and use the result if the new image
				' is smaller.
				image_settings.ForceRecompression(True)

				' this option is not commonly used since it can 
				' potentially lead to larger files.  It should be enabled
				' only if the output compression specified should be applied
				' to every image of a given type regardless of the output image size
				'image_settings.ForceChanges(true);

				' use the same settings for both color and grayscale images
				Dim opt_settings As New Optimizer.OptimizerSettings
				opt_settings.SetColorImageSettings(image_settings)
				opt_settings.SetGrayscaleImageSettings(image_settings)

				Optimizer.Optimize(doc, opt_settings)

				doc.Save(output_path  & input_filename  & "_opt2.pdf", SDFDoc.SaveOptions.e_linearized)
			End Using
		Catch e As PDFNetException
			Console.WriteLine(e.Message)
		End Try

		'--------------------------------------------------------------------------------
		' Example 3) Use monochrome image settings and default settings
		' for color and grayscale images. 
		Try
			Using doc As PDFDoc = New PDFDoc(input_path  & input_filename)
				doc.InitSecurityHandler()

				Dim mono_image_settings As New Optimizer.MonoImageSettings

				mono_image_settings.SetCompressionMode(Optimizer.MonoImageSettings.CompressionMode.e_jbig2)
				mono_image_settings.ForceRecompression(True)

				Dim opt_settings As New Optimizer.OptimizerSettings
				opt_settings.SetMonoImageSettings(mono_image_settings)

				Optimizer.Optimize(doc, opt_settings)

				doc.Save(output_path  & input_filename  & "_opt3.pdf", SDFDoc.SaveOptions.e_linearized)
			End Using
		Catch e As PDFNetException
			Console.WriteLine(e.Message)
		End Try

        '-------------------------------------------------------------------------------
        ' Example 4) Use Flattener to simplify content in this document
        ' using default settings
        Try
			Using doc As PDFDoc = New PDFDoc(input_path  & "TigerText.pdf")
				doc.InitSecurityHandler()

				Dim fl As New Flattener

				' The following lines can increase the resolution of background
				' images.
				'fl.SetDPI(300)
				'fl.SetMaximumImagePixels(5000000)

				' This line can be used to output Flate compressed background
				' images rather than DCTDecode compressed images which is the default
				'fl.SetPreferJPG(false)

				' In order to adjust thresholds for when text is Flattened
				' the following function can be used.
				'fl.SetThreshold(Flattener.Threshold.e_keep_most)

				' We use e_fast option here since it is usually preferable
				' to avoid Flattening simple pages in terms of size and 
				' rendering speed. If the desire is to simplify the 
				' document for processing such that it contains only text and
				' a background image e_simple should be used instead.
				fl.Process(doc, Flattener.FlattenMode.e_fast)

				doc.Save(output_path  & "TigerText_flatten.pdf", SDFDoc.SaveOptions.e_linearized)
			End Using
        Catch e As PDFNetException
            Console.WriteLine(e.Message)
        End Try

	End Sub
End Module