gif to tiff with compression

[VBAHole22]

I have a simple routine that converts gif images to tiffs like so

 

 
If fi.Name.Substring(fi.Name.Length - 4, 4).ToUpper = ".GIF" Then
                   Dim img As Image = Image.FromFile(fi.FullName)
                   Dim tifName As String
                   tifName = Path.GetDirectoryName(fi.FullName)
                   tifName = tifName & "\" & Path.GetFileNameWithoutExtension(fi.Name) & ".tif"
                   img.Save(tifName, ImageFormat.Tiff)
                   i += 1
                   Me.txtResults.Text = Me.txtResults.Text & System.Environment.NewLine & i & " Saved " & tifName
               Else
                   MessageBox.Show("Something is messed up this is not a gif file")
               End If

 

Really very simple.

 

But is there a way that I can control the compression of the tiff that results?

I have tried looking into the EncoderParameters but there is scare info out there about this stuff.

Any suggestions?

[Folle_Invasato]

try to give a look at:

http://www.bobpowell.net

[VBAHole22]

Yeah, I have come across that site during my searches.

He does have a routine for JPEG compression but not gif or tiff.

He uses the EncoderParameters and literal strings like

 

codec.MimeType=="image/jpeg")

 

I'm wondering where this stuff is cataloged? How does one find out about the collections and how to use them?

[Folle_Invasato]

You can find a list of MIME types in your Windows registry, under the key

 

HKEY_CLASSES_ROOT\MIME\Database\Content Type

[Nerseus]

Doing a search on "tiff compression EncoderParameter" in Google turned up a number of good hits. No direct sample code to do exactly what you want, but very close (including getting the parameters needed for each mime type when using the EncoderParameter object).

 

-ner

[VBAHole22]

Okay, I made small progress on this one. I managed to get the encoder parameters working for LZW and No Compression but there are other options (CCIT3, CCIT4, RLE). None of these options will work for me. They all throw errors. What's up with that?

 

I would like to use RLE but can't figure out how.

 

I am also interested in doing gif to tif with no compression but I want to reduce the colors from 256 to 16. Anyone know how to do that?

 

I gotta say, working with images like this in .NET is not fun or easy. Why is it so complicated and how come there is so little code out there? Is everyone just using photoshop or some 3rd party tool? Can you program those to run batch?

 

Any suggestions will be greatly appreciated.