You need to reduce the number of colors to two after you have read the image to be able to save the image at 1 bit depth.
I have also figured out why setting anti-alias is ignored. But to fix this I will have to make a big change to the code of ImageMagick that will take around two days to complete. And since we have to do that in our spare time it might take a while before this is done.
There is however a work around for your situation. Since all your barcode images have the same size you can create an MagickImage with a fixed size and use the Drawable classes to draw your text on the image. I could post an example but you might want to give it a try yourself first.
I have also figured out why setting anti-alias is ignored. But to fix this I will have to make a big change to the code of ImageMagick that will take around two days to complete. And since we have to do that in our spare time it might take a while before this is done.
There is however a work around for your situation. Since all your barcode images have the same size you can create an MagickImage with a fixed size and use the Drawable classes to draw your text on the image. I could post an example but you might want to give it a try yourself first.