Support Requests item #4319, was opened at 2010-11-06 18:18

Status: Closed Priority: 3 Submitted By: Boris Okun (okun) Assigned to: Nobody (None) Summary: jbig2 resolution Category: None Group: None Resolution: Invalid

Initial Comment: When including a jbig2enc generated file, the x,y-resolutions seem to be completely off. I think the problem is with the lines 701-702 in writejbig2.c img_xres(img) = (int) (pip->xres * 0.0254 + 0.5); img_yres(img) = (int) (pip->yres * 0.0254 + 0.5); The file has resolution set to 600dpi, according to my hex browser, if I manually change it to 600/0.0254=2362, I get the expected output. Or, perhaps, I and/or jbig2enc misunderstand the format of jbig2 files. Thanks, Boris ---------------------------------------------------------------------- Comment By: Boris Okun (okun) Date: 2010-11-10 01:43 Message: Hartmut, Thank you for the exhaustive explanation. It looks like a bug in jbig2enc. Boris ---------------------------------------------------------------------- Comment By: Hartmut Henkel (hhenkel) Date: 2010-11-09 20:59 Message: The parameters img_xres(img) and img_yres(img) are handled in pixels/inch within pdftex (see also calculations for PNG ang JPG images). The JBIG2 standard (file fcd14492.pdf) specifies in section 7.4.8.3 and 7.4.8.4 that the resolution must be stated in pixels/meter (not inch!). You expect your JBIG2 file to have a resolution of 600 dpi; when you divide by 0.0254, you get pixels/meter. So in your JBIG2 file there should indeed be 23622 as resolution, not 600. It looks as if there is some calculation bug when generating the JBIG2 file. ---------------------------------------------------------------------- Comment By: Boris Okun (okun) Date: 2010-11-08 14:14 Message: I am attaching: original: tetra.tiff compressed: jbig2 -s tetra.tiff > tetra.jbig2 tex: tetra.tex Thanks for looking into this, Boris ---------------------------------------------------------------------- Comment By: The Thanh Han (hanthethanh) Date: 2010-11-08 12:26 Message: can you please attach the image? Regards, Thanh ---------------------------------------------------------------------- You can respond by visiting: http://sarovar.org/tracker/?func=detail&atid=494&aid=4319&group_id=106