ICEpdf
  1. ICEpdf
  2. PDF-289

Transparency grouping on colour space support

    Details

    • Type: Bug Bug
    • Status: Closed
    • Priority: Major Major
    • Resolution: Fixed
    • Affects Version/s: 6.0
    • Fix Version/s: 6.0.2
    • Component/s: Core/Parsing
    • Labels:
      None
    • Environment:
      any

      Description

      The pdf in question has an image that isn't properly clipped and obscures the underlying text. Normally this kind of issue falls under masking but in this case it's actually a transparency group issue.

      The Indexed colour space oft he image has transparency group definition which must be responsible for the transparency shown by acrobat.
      1. aging-asia.pdf
        244 kB
        Patrick Corless

        Issue Links

          Activity

          Hide
          Patrick Corless added a comment -

          sample file

          Show
          Patrick Corless added a comment - sample file
          Hide
          Patrick Corless added a comment -

          Moving to 4.3.

          Show
          Patrick Corless added a comment - Moving to 4.3.
          Hide
          Patrick Corless added a comment -

          Another example of transparency group issue.

          Show
          Patrick Corless added a comment - Another example of transparency group issue.
          Hide
          Patrick Corless added a comment -

          Moving target to 5.1 in the hope that we can tackle transparency groups for this release.

          Show
          Patrick Corless added a comment - Moving target to 5.1 in the hope that we can tackle transparency groups for this release.
          Hide
          Patrick Corless added a comment -

          Did a little more work on this issue/topic. I tried to apply a simple mask on the image in question using white as the transparency pixel. The PDF renders correctly but unfortunately there are other side effects in other documents. From what I can tell from the spec we should be treating each xForm in the group as a separate layer and in this case the back text would be used as a mask on the image. This may still be possible to implement but as of current, we need to save each layer as a buffered image and do the masking which is both memory intensive and results in a much lower quality render.

          Show
          Patrick Corless added a comment - Did a little more work on this issue/topic. I tried to apply a simple mask on the image in question using white as the transparency pixel. The PDF renders correctly but unfortunately there are other side effects in other documents. From what I can tell from the spec we should be treating each xForm in the group as a separate layer and in this case the back text would be used as a mask on the image. This may still be possible to implement but as of current, we need to save each layer as a buffered image and do the masking which is both memory intensive and results in a much lower quality render.
          Hide
          Patrick Corless added a comment -

          A lot of work has gone into improving our support for transparency groups particularly around various blending modes. As result this PDF is now correctly rendering using a multiply blend mode.

          Show
          Patrick Corless added a comment - A lot of work has gone into improving our support for transparency groups particularly around various blending modes. As result this PDF is now correctly rendering using a multiply blend mode.
          Hide
          Patrick Corless added a comment -

          Marking as fixed.

          Show
          Patrick Corless added a comment - Marking as fixed.

            People

            • Assignee:
              Patrick Corless
              Reporter:
              Patrick Corless
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              Dates

              • Created:
                Updated:
                Resolved: