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Thread: [Qt 4.6.3] Retrieve JPEG quality

  1. #1
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    Default [Qt 4.6.3] Retrieve JPEG quality

    Hi 2 all !
    I have the next task: read a JPEG image from file, rotate it by 90 degrees, and save it in same quality as an original image.

    The question is: how can I get the JPEG quality ( 1..100 % ) from the JPEG-file.

    I tried QImageReader.quality() and the result is always -1.

    Thank you. Boris.

  2. #2
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    Default Re: [Qt 4.6.3] Retrieve JPEG quality

    for JPEG there are libraries around which provide lossless rotation. Google for "lossless rotate jpeg lib" or start reading at http://jpegclub.org/

  3. The following user says thank you to otternase for this useful post:

    borisbn (20th January 2011)

  4. #3
    Join Date
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    Default Re: [Qt 4.6.3] Retrieve JPEG quality

    otternase, thank you very much. After I read your post, googled for "lossless rotate jpeg lib" and read http://jpegclub.org/ I have no questions about this theme. Thank you once more.

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