The customer reports: We have been using the ghostscript jpeg device to generate JPEG’s from postscript. In the transition from version 8.64 to 9.0 the quality of large text sizes have diminished – as the anti-aliasing automatically turns off at some pixel size of the characters. The attached postscript file illustrates the problem. The attached jpeg’s were generated by ghostscript using the options: -dSAFER -dBATCH -dNOPAUSE -dEPSCrop -sDEVICE=jpeg -dJPEGQ=100 -dGraphicsAlphaBits=4 -dTextAlphaBits=4 -r132.0
Ken took a look at this and reports: With -dDisableFAPI=true the text is always anti-aliased regardless of point size. With FAPI enabled the text is anti-aliased up to a point (~84.6975), presumably where the glyphs grow so large we stop caching them, and from then on is not anti-aliased. I'm not sure why not caching should cause the problem, but it does seem to be FAPI related. While we will want to fix the problem, you could suggest using -dDisableFAPI=true as a temporary work-around.
fixed in r12369. The patch can be seen here (it is fairly simple): http://www.ghostscript.com/pipermail/gs-cvs/2011-April/012645.html