Recently I've been trying to make some PDFs smaller by using better compression of JPEG pictures. I was happy to see that \externalfigure cheerfully accepts .jp2 (JPEG 2000) files. However, my understanding (and I could well be wrong, but I've seen it multiple places) is that JPEG 2000 *Part 2* files should have extension .jpx, not .jp2. By default, ConTeXt does not recognize .jpx. But if I rename a .jpx file to have a .jp2 extension, then ConTeXt properly processes the file and I see the picture in the PDF. Q: are there any plans to make ConTeXt recognize the .jpx extension? If not, can anyone suggest some ConTeXt code which allows me to tell ConTeXt to process a .jpx file as a .jp2 file? I have also been investigating the use to JPEG-XL files (.jxl). One of the interesting aspects of JXL files is that .jpg files can be **losslessly** compressed into .jxl files. (That is, you can recover the exact .jpg from the .jxl file if you want, so there is no further degradation of the image by doing this lossless compression.) I have been seeing 20% to 30% reduction in file sizes by converting JPGs into JXLs, which I would be happy to make use of in my PDFs, if possible. Bonus question: is there any plan to support JXL files in ConTeXt? Thanks. Jim
The recognised extensions are specified in a table in grph-inc.lmt, I don’t think you can alter that table runtime. But it is possible to do \externalfigure[method=jp2,file=….jpx] Untested, but should work. Best wishes, Taco
— Taco Hoekwater E: taco@bittext.nl genderfluid (all pronouns)
On Tue, Mar 5, 2024 at 15:18 (+0100), Taco Hoekwater wrote:
On 4 Mar 2024, at 15:30, Jim
wrote:
Recently I've been trying to make some PDFs smaller by using better compression of JPEG pictures.
The recognised extensions are specified in a table in grph-inc.lmt, I don’t think you can alter that table runtime.
But it is possible to do
\externalfigure[method=jp2,file=….jpx]
Untested, but should work.
Taco, I could not get that to work, but I did get \externalfigure[somefile.jpx][method=jp2] to work. Thanks very much for leading me to that solution. Jim
participants (3)
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Jim
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Taco Hoekwater
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Wolfgang Schuster