Q: I am experiencing some aliasing on lines which is an issue for barcodes.
If I turn down the gamma the lines get better but the text really suffers.
Do you have path hinting enabled? I suspect the anti-aliasing is coming from the rectangles not being fully aligned with
On the left, path hinting is off and the bar code is anti-aliased; on the right, at the same resolution, path hinting is on and no anti-aliasing is present. In general,though a barcode may be an image, and the path hinting setting will do nothing for images. In this case you just need to render the image at a higher resolution that would be acceptable for the bar code reader.