Thank you for considering Aspose.
The barcode label size depends upon a lot of factors that are discussed in below linked technical article.
One of the main factor is the amount of data that you are trying to encode. Be default, the barcode label adjusts it’s size automatically according to the encoded data. But you can force BarCodeBuilder not to shrink or expand barcode size by setting BarCodeBuilder.AutoSize to false.
Please check the below sample source for your reference,
Dim bb As Aspose.BarCode.BarCodeBuilder = New Aspose.BarCode.BarCodeBuilder
'Set the Code text for the barcode
bb.CodeText = “test”
'Set the symbology type to Code39Standard
bb.SymbologyType = Aspose.BarCode.Symbology.Code128
'Set AutoSize to False
bb.AutoSize = False
'Set GraphicsUnit to Pixel
bb.GraphicsUnit = GraphicsUnit.Pixel
'Set image size
bb.ImageHeight = 50
bb.ImageWidth = 50
In case you have further queries or comments, please feel free to write back.