Transparent BMP's

[guiledotNET]

Is it possible to change the alpha colour on a transparent BMP, in VB .NET?

The reason is, when I load a transparent image, and store it in an image list with transparency, and then save that image from there, it gives it a black background… which is not what I want.

[PT Exorcist]

i have the feeling BMP format doesnt support transparency...i think u are talking about WMF or PNG or GIF right?

[guiledotNET]

Scan the image for transparent pixels, and convert them to a colour.

        Dim x As Integer, y As Integer
        For x = 0 To Img.Width - 1
            For y = 0 To Img.Height - 1
                If Img.GetPixel(x, y).ToArgb = 0 Then Img.SetPixel(x, y, Color.FromArgb(0, 0, 255, 0))
            Next
        Next

[guiledotNET]

If you load a BMP into a picture box, or image list, etc, it does support transparency. However, when you save it to disk, the transparent layer is issued a colour – I don’t know how and why it works like this… it just does. My solution is above.

[MrPolite]

Originally posted by guiledotNET
Scan the image for transparent pixels, and convert them to a colour.

        Dim x As Integer, y As Integer
        For x = 0 To Img.Width - 1
            For y = 0 To Img.Height - 1
                If Img.GetPixel(x, y).ToArgb = 0 Then Img.SetPixel(x, y, Color.FromArgb(0, 0, 255, 0))
            Next
        Next

that would be quite inefficient dont have my book with me now, otherwise I would post something better ...

[guiledotNET]

If you are able to, later, I would appreciate it.