Finding the GIF transparency colour through code

[RMS001]

Hi - Using good old VB6, is it possible to read in a GIF file and decode the header to find out the transparency value. I would then be able to pop it onto a form or user control and set the transparent value of the parent to allow the GIF edges to show through...

 

[strongm]

I'm not sure that I'm with you. VB already knows how to correctly display transparent gifs

 

[RMS001]

Hi strongm - I have found a potential solution. The header has byte 7, 8 as width, 9, 10 as height and bytes 14, 15, 16 are the background color:

Private Sub Form_Load()
Dim nFileNum As Integer
nFileNum = FreeFile
Dim iInput(1 To 16) As Byte
Dim sFile As String
sFile = "C:\Data\Image\GIF\starburst.gif"
Open sFile For Binary Access Read Lock Read Write As #nFileNum

Dim i As Integer
For i = 1 To 16
Get #nFileNum, i, iInput(i)
Debug.Print i & vbTab & iInput(i)
Next
Close #nFileNum

lblDimensions(7) = iInput(7)
lblDimensions(8) = iInput(8)
lblDimensions(9) = iInput(9)
lblDimensions(10) = iInput(10)

lblFinal = iInput(7) + iInput(8) * 256 & " x " & iInput(9) + iInput(10) * 256

Shape1.BackColor = RGB(iInput(14), iInput(15), iInput(16))

End Sub

The reason is - I put the gif in the picture and maskpicture properties of a user control, resize it and update the control with the correspondingly resized image. The activeX responds best when the mask colour matches the gif trans color. - Ron

P.S. This is done to get the image to float and overlap over several other pictureboxes etc. which of course the image control won't do.