ICEpdf
  1. ICEpdf
  2. PDF-577

PDF clarity is poor

          Details

          • Type: Bug Bug
          • Status: Closed
          • Priority: Major Major
          • Resolution: Fixed
          • Affects Version/s: 5.0
          • Fix Version/s: 5.0.3
          • Component/s: None
          • Labels:
            None
          • Environment:
            -
          • Salesforce Case Reference:

            Description

            The attached pdf's clarity is not as good as Adobe. The pdf is poor quality to being with. We've tried setting -Dorg.icepdf.core.imageReference=scaled along with 'mipmap' but see no improvement. Patrick suspects that we may need to write a custom ImageReference implementation for this type of file.

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              Pepijn Van Eeckhoudt added a comment - - edited

              MipMappedImageReference was (I assume) ported from a patch I submitted some time ago to improve image scaling quality. Unfortunately, the ported version does not implement the scaling in a way that actually improves quality. The javadoc even states (incorrectly) that

              The main idea here is that small images are painted at smaller zoom levels which in theory speeds up the image paint time.

              This was in fact not the main purpose. The main purpose was improved rendering quality of downscaled images. The original version derived each lower-res mipmap level from the previous level, scaling by a factor of two each time. The ported version always scales directly from the initial source image. This is potentially slower and defintely results in poorer image quality due to how Java2D implements image scaling.
              See https://today.java.net/pub/a/today/2007/04/03/perils-of-image-getscaledinstance.html for details.

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              Pepijn Van Eeckhoudt added a comment - - edited MipMappedImageReference was (I assume) ported from a patch I submitted some time ago to improve image scaling quality. Unfortunately, the ported version does not implement the scaling in a way that actually improves quality. The javadoc even states (incorrectly) that The main idea here is that small images are painted at smaller zoom levels which in theory speeds up the image paint time. This was in fact not the main purpose. The main purpose was improved rendering quality of downscaled images. The original version derived each lower-res mipmap level from the previous level, scaling by a factor of two each time. The ported version always scales directly from the initial source image. This is potentially slower and defintely results in poorer image quality due to how Java2D implements image scaling. See https://today.java.net/pub/a/today/2007/04/03/perils-of-image-getscaledinstance.html for details.
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              Patrick Corless added a comment -

              Thanks for checking back in Pepijn, I'll revisit the patch. Thanks for you feedback.

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              Patrick Corless added a comment - Thanks for checking back in Pepijn, I'll revisit the patch. Thanks for you feedback.
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              Patrick Corless added a comment -

              I've revisited the MIP maps implementation and changed the scaling to incremental scale the same image as suggested above. This combine with fixes to the the image proxy should improve the overall image quality of such pdfs.

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              Patrick Corless added a comment - I've revisited the MIP maps implementation and changed the scaling to incremental scale the same image as suggested above. This combine with fixes to the the image proxy should improve the overall image quality of such pdfs.
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              Patrick Corless added a comment -

              Closing, the images should look better when mipmap scaling is used, awaiting feedback from the client when 5.0.3 is released.

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              Patrick Corless added a comment - Closing, the images should look better when mipmap scaling is used, awaiting feedback from the client when 5.0.3 is released.

                People

                • Assignee:
                  Patrick Corless
                  Reporter:
                  Tyler Johnson
                • Votes:
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                  Watchers:
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                  Dates

                  • Created:
                    Updated:
                    Resolved: