'
' PDFNet Copyright (c) 2001-2008 by PDFTron Systems Inc. All Rights Reserved.
'

Imports System
Imports System.Drawing
Imports System.Drawing.Imaging

Imports pdftron
Imports pdftron.Common
Imports PDFTRON.SDF
Imports pdftron.PDF

Module Module1

	'-----------------------------------------------------------------------------------
	' This sample illustrates one approach to PDF image extraction 
	' using PDFNet.
	' 
	' Note: Besides direct image export, you can also convert PDF images 
	' to GDI+ Bitmap, or extract uncompressed/compressed image data directly 
	' using element.GetImageData() (as illustrated in ElementReaderAdv 
	' sample project).
	'-----------------------------------------------------------------------------------

	Dim image_counter As Integer = 0

	' Relative path to the folder containing test files.
	Dim input_path As String = "../../../TestFiles/"
	Dim output_path As String = "../../../TestFiles/Output/"


	Sub ImageExtract(ByRef reader As ElementReader)
		Dim element As Element = reader.Next()
		While (Not IsNothing(element))		 ' Read page contents
			Dim type As Element.Type = element.GetType()

			If type = element.Type.e_image Or type = element.Type.e_inline_image Then
				image_counter = image_counter + 1
				Console.WriteLine("--> Image: {0}", image_counter)
				Console.WriteLine("    Width: {0}", element.GetImageWidth())
				Console.WriteLine("    Height: {0}", element.GetImageHeight())
				Console.WriteLine("    BPC: {0}", element.GetBitsPerComponent())

				Dim ctm As Matrix2D = element.GetCTM()
				Dim x2 As Double = 1
				Dim y2 As Double = 1
				ctm.Mult(x2, y2)
				Console.WriteLine("    Coords: x1={0}, y1={1}, x2={2}, y2={3}", ctm.m_h, ctm.m_v, x2, y2)

				If element.GetType() = element.Type.e_image Then
					Dim fname As String = output_path + "image_extract1_" + image_counter.ToString()
					Dim image As PDFTRON.PDF.Image = New PDFTRON.PDF.Image(element.GetXObject())
					image.Export(fname)					' or ExporAsPng() or ExporAsTiff() ...

					' Convert PDF bitmap to GDI+ Bitmap...
					' Dim bmp As Bitmap = element.GetBitmap()
					' bmp.Save(fname, ImageFormat.Png)
					' bmp.Dispose()

					' Instead of converting PDF images to a Bitmap, you can also extract 
					' uncompressed/compressed image data directly using element.GetImageData() 
					' as illustrated in ElementReaderAdv sample project.
				End If
			ElseIf type = element.Type.e_form Then
				reader.FormBegin()				   ' Process form XObjects
				ImageExtract(reader)
				reader.End()
			End If

			element = reader.Next()
		End While
	End Sub

	Sub Main()

		PDFNet.Initialize()
		PDFNet.SetResourcesPath("../../../../resources")

		' Example 1: 
		' Extract images by traversing the display list for 
        ' every page. With this approach it is possible to obtain 
		' image positioning information and DPI.
		Try
			Dim doc As PDFDoc = New PDFDoc(input_path + "newsletter.pdf")
			doc.InitSecurityHandler()

			Dim reader As ElementReader = New ElementReader

            Dim itr As PageIterator = doc.GetPageIterator()
            While itr.HasNext()
                reader.Begin(itr.Current())
                ImageExtract(reader)
                reader.End()
                itr.Next()
            End While

            doc.Close()
            Console.WriteLine("Done.")
        Catch ex As PDFNetException
			Console.WriteLine(ex.Message)
		Catch ex As Exception
			MsgBox(ex.Message)
		End Try

		' Example 2: 
		' Extract images by scanning the low-level document.
		Try
			Dim doc As PDFDoc = New PDFDoc(input_path + "newsletter.pdf")
			doc.InitSecurityHandler()
			image_counter = 0

            Dim cos_doc As SDFDoc = doc.GetSDFDoc()
			Dim num_objs As Integer = cos_doc.XRefSize()

			For i As Integer = 1 To num_objs - 1
				Dim obj As Obj = cos_doc.GetObj(i)
				If Not (obj Is Nothing Or obj.IsFree()) Then
					' Process only images
					If obj.IsStream() Then
						Dim itr As DictIterator = obj.Find("Type")
                        If itr.HasNext() Then
                            If itr.Value().GetName() = "XObject" Then
                                itr = obj.Find("Subtype")
                                If itr.HasNext() Then
                                    If itr.Value().GetName() = "Image" Then
                                        Dim image As PDFTRON.PDF.Image = New PDFTRON.PDF.Image(obj)

                                        image_counter = image_counter + 1
                                        Console.WriteLine("--> Image: {0}", image_counter)
                                        Console.WriteLine("    Width: {0}", image.GetImageWidth())
                                        Console.WriteLine("    Height: {0}", image.GetImageHeight())
                                        Console.WriteLine("    BPC: {0}", image.GetBitsPerComponent())

                                        Dim fname As String = output_path + "image_extract2_" + image_counter.ToString()
                                        image.Export(fname)        ' or ExporAsPng() or ExporAsTiff() ...

                                        ' Convert PDF bitmap to GDI+ Bitmap...
                                        ' Dim bmp As Bitmap = element.GetBitmap()
                                        ' bmp.Save(fname, ImageFormat.Png)
                                        ' bmp.Dispose()

                                        ' Instead of converting PDF images to a Bitmap, you can also extract 
                                        ' uncompressed/compressed image data directly using element.GetImageData() 
                                        ' as illustrated in ElementReaderAdv sample project.
                                    End If
                                End If
                            End If
                        End If
                    End If
				End If
			Next

			doc.Close()
			Console.WriteLine("Done.")
		Catch ex As PDFNetException
			Console.WriteLine(ex.Message)
		Catch ex As Exception
			MsgBox(ex.Message)
		End Try

		PDFNet.Terminate()
	End Sub
End Module