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  1. PDFBox
  2. PDFBOX-2853

CCITT: Background is rendered as transparent color

    Details

    • Type: Bug
    • Status: Closed
    • Priority: Major
    • Resolution: Fixed
    • Affects Version/s: 1.8.9
    • Fix Version/s: 1.8.10
    • Component/s: Rendering
    • Labels:
    • Flags:
      Patch

      Description

      CCITT-Images with colorspace different from PDIndexed are created using PDCCitt.java/getRGBImage:

       if (colorspace instanceof PDIndexed)
              {
                 ...
              }
              else
              {
                  byte[] map = new byte[] { (byte) 0x00, (byte) 0xFF };
                  colorModel = new IndexColorModel(1, map.length, map, map, map, Transparency.OPAQUE);
              }
      

      The value Transparency.OPAQUE (=1) is provided for the parameter "transparentIndex" - this creates an image, in which the white color is treated as transparent.

      This bug is especially annoying for some OCR-documents I had to work with (using PageDrawer). They consist of rendered text (as result of the OCR), that has the original content as image rendered on top, fully covering the text. When the white background is rendered as transparent, the rendered page gets messed up, because both texts can be seen,

      Proposed Fix/Patch
      Replace the value Transparency.OPAQUE with -1, so that no color is transparent.

        Attachments

        1. ccittbug.png
          17 kB
          Jakob Pyttlik

          Activity

            People

            • Assignee:
              tilman Tilman Hausherr
              Reporter:
              JPyttlik Jakob Pyttlik
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              Dates

              • Created:
                Updated:
                Resolved: