Converting Background of a Image to transparent Using imagemagick programaticaly

Question

I am trying to Convert all the white background of a Image (generated from Html using a plugin) to transparent so that I can use it as a stamp

Using image As MagickImage = New MagickImage(filenamelocation)
                    image.Alpha(AlphaOption.Set)
                    image.ColorFuzz = New Percentage(40)
                    image.Settings.BackgroundColor = MagickColors.Transparent
                    image.Settings.FillColor = MagickColors.White
                    image.FloodFill(MagickColors.Transparent, 0, 0)   
                    image.Write(Path.Combine(Server.MapPath("~/Uploads/attachment/"), "stampimagename.png"))
                End Using

Iam using ImageMagick nuget package for doing the same and needs to convert all the white to transparent Only blue Color items shows remain ,Can somebody advice what I am doing wrong

score 0 · Accepted Answer · answered Jun 24 '20 at 15:23

I don't think you're supposed to declare the background as transparent then flood fill a white (not really sure what that means anyway..)

As I understand it from reading the command line operations that do this (and translating to VB; it seems that mostly the command line and VB are similar) you're just supposed to load the image, declare that white is the transparency color, with some fuzz factor maybe, and then save it as a format that supports transparency:

Using image As MagickImage = New MagickImage(filenamelocation)

    image.ColorFuzz = new Percentage(10) 'declare a lower fuzz factor
    img.Transparent(MagickColors.White) 'declare that the transparency should apply to anything that is white 
    img.Write("image.png") 'save as a format that support transparency. jpg does not

End Using

Converting Background of a Image to transparent Using imagemagick programaticaly

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