[RESOLVED] (VB6)How to Read Values under Character Codes?

[amolt]

Hi All my friends,

This is the Characters from an Tiff Image File I Want to read :

II*   þ 





 

 






 @ Þ 







 
 @ Þ


Î 

Ö 


(

 )
  –
–
Þ Þ‚ Þ
Þ‚
Þ Þ‚ Þ Þ‚ Þ Þ‚ Þ Þ‚ Þ Þ‚ Þ Þ‚ Þ Þ‚ Þ Þ‚ Þ
Þ‚
Þ Þ‚ Þ Þ‚ Þ
Þ‚
Þ Þ‚ Þ Þ‚ Þ Þ‚ Þ Þ‚ Þ Þ‚ Þ Þ‚ Þ Þ‚ Þ Þ‚ Þ Þ‚ Þ Þ‚ Þ Þ‚ Þ Þ‚ Þ Þ‚ Þ Þ‚ Þ Þ‚ Þ Þ‚ Þ Þ‚ Þ Þ‚ € € € € € € € € € € € € € € € € € € € € € € € € € € € € € € € € € € € € € € € € € € € € € € € € € € € € € € € € € € € € € € € € œºœº ¹ ¹œº˜¹˜¹'¹ä¹Ù¸
¹3¸3¸‡¸¡¹Ý¹
º
º¶¹‡¹¹¹@¹º¸ºNº?ºí¹ò¹š¹’� �²¹†¹‡¹b¹¹…¹¿¹«¹]¹¹,¹_¹x¹h¹¼¹o¹K¹B¹i¹Ë¹ª¹°¹“¹Ê¹Ä¹ º¥¹|¹8¹e¹í¹ƒº¿ºÒºß¹Í¹g¹¨¹I¹x¹y¹*¹Ò¹d¹!¹6¹]¹›¹n¹K¹2¹Y¹ž¹³¹¹c¹’¹¹¹x¹ ¹ë¸$¹1¹a¹p¹Z¹b¹–¹î¹Ð¹¹¹3¹è¹ºÐ¹‹¹4¹¹¸¹G¹,¹ð¸W¹k¹ƒ¹-¹
¹æ¸L¹+¹M¹l¹F¹–¹“¹œ¹‡¹l¹¹ ¹õ¸¹9¹¹¹¹E¹6¹¹¹Ñ¸ê¸S¸

Could some one tell me how to recognise the data hidden under these characters,
this line is the header information from TIFF image file, as it consists of Tags and Values for that tags. Is there any method without using APIs to convert these values to its original ones.

In VB though after reading this file in binary mode, the original values cant get visible.
Or I am missing something.

My Code :

Const Buffer=2
Dim strData As String

Open txtPath.Text For Binary Access Read As nHandle
lSize = LOF(nHandle)
If nHandle = 0 Then
Close nHandle
End If
ReDim Chunk(lSize - 1)
Get nHandle, , Chunk

For i = 1 To UBound(Chunk)
' Need to Print the Original Value
' either it may be String or a Numeric Value
' As XResolution: 1024
strData = Chr(Chunk(i))
Debug.Print strData
Next
Close nHandle

As Converting to Chr() again prints its Character Code ; I got really confounded to get exact results.

Looking for quick help....


Thanks in advance

[tatkosmurff]

Since this is a header of an image file, try searching the format description.
Reading is as binary won't do it. It just seems to get some meaningless data.

What you are trying is to open a binary file stored with some user defined type,
and reading it byte by byte to decode.

You may try creating a binary file of your own and reading it the same way you try to read the .Tiff image header(assume you don't know what is in the file) . The result will be almost the same.

[Milk]

If you want to read a *.tif then you have to know how its structured. Your first stop should be a *.tif developer reference like the one at adobe.
This might help to get you started....

Option Explicit
Const TIF_LITTLE_ENDIAN = &H4949
Const TIF_BIG_ENDIAN = &H4D4D

Private Type tTiffFileHeader
    ByteOrder As Integer
    Is42 As Integer
    IFDOffset As Long
End Type

Private Type tTiffDirectoryEntry
    Tag As Integer
    Type As Integer
    Count As Long
    ValueOffset As Long
End Type

Private Type tTiffImageFileDirectory
    Count As Integer
    Entrys() As tTiffDirectoryEntry
    IFDOffset As Long
End Type

Private Sub Command1_Click()
Dim TifIDF() As tTiffImageFileDirectory, i As Long, ii As Long
    TifIDF = TiffInfo(App.Path & "/test.tif")
    For i = 0 To UBound(TifIDF)
        With TifIDF(i)
            Debug.Print "Image " & i,
            Debug.Print .Count & " entrys"
            Debug.Print "No", "tag", "type", "count", "value / offset"
            For ii = 0 To .Count - 1
                With .Entrys(ii)
                    Debug.Print ii + 1, .Tag, .Type, .Count, .ValueOffset
                End With
            Next ii
        End With
    Next i
End Sub


Private Function TiffInfo(filename As String) As tTiffImageFileDirectory()
Dim FF As Integer
Dim H As tTiffFileHeader
Dim IDF() As tTiffImageFileDirectory
Dim IDFub As Long
Dim NextOffset As Long
Dim i As Long

    IDFub = -1
    
    If LenB(Dir(filename)) Then
        'On Error GoTo eh:
        FF = FreeFile
        Open filename For Binary As #FF
            
            Get #FF, , H
            If H.ByteOrder = TIF_LITTLE_ENDIAN Then
                If H.Is42 = 42 Then
                    NextOffset = H.IFDOffset + 1

                    Do While NextOffset
                        IDFub = IDFub + 1
                        ReDim Preserve IDF(IDFub)
                        With IDF(IDFub)
                            Get #FF, NextOffset, .Count
                            If .Count > 0 Then
                                ReDim .Entrys(.Count - 1)
                                Get #FF, , .Entrys
                                Get #FF, , .IFDOffset
                                NextOffset = .IFDOffset + 1
                            End If
                        End With
                    Loop
                    
                End If
            End If

        Close #FF
    End If

eh:
    If IDFub < 0 Then
        ReDim TiffInfo(-1 To -1) 'to show a fail
    Else
        TiffInfo = IDF()
    End If
End Function

[amolt]

Hello Milk ,,
and very sorry to post feedback after long time .....

Thanks for u r Code which lead me towards initial steps of reading a Tiff format file .... I go through the Tiff file format specification and though was successful in reading a tiff file for my application purpose.

Thanks again to both of u ...

Regds,,

[Milk]

I thought I might have scared you off

I ended up writing a small class that enumerates and navigates tags, it might be useful to you....
http://www.vbforums.com/showthread.p...29#post3322529