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  1. XWiki Platform
  2. XWIKI-7623

Bad Image Scaling Quality

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Details

    • Improvement
    • Resolution: Fixed
    • Major
    • 8.4.4, 9.0-rc-1
    • 2.5 M2
    • Old Core
    • None
    • High
    • Medium
    • N/A

    Description

      Scaling an image (especially downscaling to less than half the size of the original image) produces quite bad results with very visible edges.

      This is a known problem of the normal Java2D scaled image drawing operations, described in this article: http://today.java.net/pub/a/today/2007/04/03/perils-of-image-getscaledinstance.html

      The article also provides a simple workaround that would greatly improve the image quality of down-scaled images with just a small increase in processing time. (if you use the example code from the article, plaase note that there's a bug with regard to upscaling images leading to an infinite loop, but that should be easy to fix).

      In my particular use case I'd like to produce a team list using the avatars stored with each account. And due to this bug the avatars of those who upload high-resolution pictures look worst in that list.

      Attachments

        1. activityStream.png
          activityStream.png
          50 kB
        2. comments.png
          comments.png
          62 kB
        3. userIndex.png
          userIndex.png
          56 kB
        4. userPicker.png
          userPicker.png
          34 kB

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              mflorea Marius Dumitru Florea
              jsauer Joachim Sauer
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              Dates

                Created:
                Updated:
                Resolved: