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The Gimp

Rotating JPG Images Without Losing Data? 14

Posted by Cliff from the avoiding-the-decompress-rotate-compress-phase dept.
Another voiciferous Anonymous Coward asks: "Is there a such thing as a loss-less JPEG rotator? I want to rotate 90 degrees w/o the decompress recompress cycle which chews up jpegs. Supposedly there are some for windows, but I haven't found any for Linux. The GIMP opens and resaves and from what I can tell so does ImageMagik."
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Rotating JPG Images Without Losing Data? More

Rotating JPG Images Without Losing Data?

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  • Compupic [photodex.com] over at photodex.com is a great program which does this and so much more. There's a free Linux version that works great . . . the only drawback is that after so many days the GIF and TIFF "license" expires. At that point you just delete your ~/.compupic/ directory and restart. ;-)

    --

  • jpegtran (Score:3)

    by Daffy Duck ( 17350 ) on Monday September 18, 2000 @02:58PM (#770817) Homepage
    The Independent JPEG Group's standard tool package includes "jpegtran" which will do exactly what you want. In fact, depending on your distribution, it might already be sitting on your Linux box.

    If not, here's one [uni-erlangen.de] of many links that came up on Google.

  • Tryy "jpegtran", distributed with libjpeg. (Score:1)

    by Anonymous Coward
    It does various rotates, flips, conversions to progressive, etc., all directly on the compressed form, so there's no quality change. (Um, the picture has to be a multiple of 8 pixels on a side for perfect invertibility.)

    Written by the Independent JPEG Group [ijg.org].

  • Oops, look before you link (Score:4)

    by Daffy Duck ( 17350 ) on Monday September 18, 2000 @03:02PM (#770819) Homepage
    Sorry, the link above is for an old version of the software that doesn't do rotation. Here [uu.net] is a link to a more recent version.
  • IANALU, but I use Corel Photopaint 8 for my Windows PC, and that doesn't have any perceptible loss. I only mention this because I'm pretty sure it's available for Linux, since Corel makes it. Good software, I HIGHLY reccommend it. (Also, IMHO, while it might cost as much as Adobe Photoshop, it's ten times better because of one reason: its interface.)

    -Forager.

  • You forgot a " there, dude. What I think you meant was..

    ... haven't found any for Linux. The GIMP [gimp.org] opens and resaves and from what I can tell so does ImageMagik [dupont.com]

    Remember kids, use that preview button.

  • Huh? To rotate a JPEG, you will have to decompress the huffman codes, swap the DCT coefficients and possibly do a sign change, swap corresponding quantization values then re-apply huffman compression. Sure it's lossless, but that's hardlly "rotating while compressed" A better phrase is "rotating without using inverse discrete cosine transforms." And this only works for 90 degree rotations! Besides, why sweat JPEG when JPEG 2000 is around the corner.
  • Could it be because the source material that he has is in JPEG format, and converting formats (such as to an uncompressed bitmap and back to JPEG) incurs loss? JPEG 2000 is dragging its feet while the work he needs to do is here and now.
  • photopaint for linux just sucked. it managed to crash my system few times, occasionally crashed only my X, and took amazing amount of harddrive space. it just sucks. btw, i suspect it was just a wine port, since there was huge amount of winelib rpm's that had to be installed. if they would've thinked twice what they were going to do, they would have done it properly. somebody might even use it if it worked.

  • Freeware:
    jpegcrop [sylvana.net]
    jpeg wizard [jpg.com]
    IrfanView [irfanview.com]
  • Pick up your monitor, and rotate it exactly 90 degrees, how easy is that?

    I hope you remembered to file a patent application prior to posting this idea.
  • How is this Redundant? Who else said this before me? BEsides, it was just a joke
  • Amazing how many people would rather "ask slashdot" then just ask jeeves :) ...
  • I use Corel Photopaint 8 for my Windows PC, and that doesn't have any perceptible loss.

    Sure, for high quality JPEG, if you have to decompress and recompress, you wont see a noticeable loss, no matter what S/W you use.

    But for a low quality JPEG, you'll have to recompress at a high quality rate in order to maintain the picture quality of the original with moderate safety.

    If you have a low quality JPEG, which you want to rotate, and then maintain as a low quality JPEG, you're doomed.

    Of course, this is all assuming your software will automatically re-compress on save, which is why the original question...

    --

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