ICEpdf
  1. ICEpdf
  2. PDF-683

Improve DeviceGray image interpolation

          Details

          • Type: Bug Bug
          • Status: Closed
          • Priority: Major Major
          • Resolution: Fixed
          • Affects Version/s: 5.0.4
          • Fix Version/s: 5.0.5
          • Component/s: Core/Parsing
          • Labels:
            None
          • Environment:
            any
          • Salesforce Case Reference:

            Description

            We have had quite a few requests to improve the render quality of DeviceGray images. This requests usually falls into two different types; fax scans and small images used in type 3 fonts. When this type of document is viewed at the default zoom level the image can be difficult to read and or looks jagged.

            Turning on the following system properties helps a bit but the end result isn't as crisp as adobe.
            -Dorg.icepdf.core.target.dither=VALUE_DITHER_ENABLE
            -Dorg.icepdf.core.screen.render=VALUE_RENDER_QUALITY
            -Dorg.icepdf.core.screen.interpolation=VALUE_INTERPOLATION_BICUBIC
            -Dorg.icepdf.core.imageReference=smoothScaled

            This bug will capture changes to the smoothScaled image reference implementation to help improve image render quality.

              Activity

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              Patrick Corless added a comment -

              I've updated to the SmoothScaledImageReference class to scale DeviceGray images using a new recursive trilinear image scaling method tht significantly improves the readability of this type of images. There is a slight blurring at high zoom levels but overall I think this is a step forward.

              Show
              Patrick Corless added a comment - I've updated to the SmoothScaledImageReference class to scale DeviceGray images using a new recursive trilinear image scaling method tht significantly improves the readability of this type of images. There is a slight blurring at high zoom levels but overall I think this is a step forward.
              Hide
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              Patrick Corless added a comment -

              Applied enhancement trunk and 5.0.1 branch.

              Show
              Patrick Corless added a comment - Applied enhancement trunk and 5.0.1 branch.
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              Patrick Corless added a comment -

              Just wanted to state again that image interpolation will be significantly enahnced with the following properties:

              -Dorg.icepdf.core.target.dither=VALUE_DITHER_ENABLE
              -Dorg.icepdf.core.screen.render=VALUE_RENDER_QUALITY
              -Dorg.icepdf.core.screen.interpolation=VALUE_INTERPOLATION_BICUBIC
              -Dorg.icepdf.core.imageReference=smoothScaled

              Show
              Patrick Corless added a comment - Just wanted to state again that image interpolation will be significantly enahnced with the following properties: -Dorg.icepdf.core.target.dither=VALUE_DITHER_ENABLE -Dorg.icepdf.core.screen.render=VALUE_RENDER_QUALITY -Dorg.icepdf.core.screen.interpolation=VALUE_INTERPOLATION_BICUBIC -Dorg.icepdf.core.imageReference=smoothScaled
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              Patrick Corless added a comment -

              added some more test files to the support drive.

              Show
              Patrick Corless added a comment - added some more test files to the support drive.

                People

                • Assignee:
                  Patrick Corless
                  Reporter:
                  Patrick Corless
                • Votes:
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                  Dates

                  • Created:
                    Updated:
                    Resolved: