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https://issues.apache.org/jira/browse/PDFBOX-2853?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14615383#comment-14615383
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Tilman Hausherr commented on PDFBOX-2853:
-----------------------------------------

I'm also in a difficult decision: there are plans to release 1.8.10 soon, so 
I'd like to hear a second opinion about that one, i.e. making the change in 
PDCCitt only.

> CCITT: Background is rendered as transparent color
> --------------------------------------------------
>
>                 Key: PDFBOX-2853
>                 URL: https://issues.apache.org/jira/browse/PDFBOX-2853
>             Project: PDFBox
>          Issue Type: Bug
>          Components: Rendering
>    Affects Versions: 1.8.9
>            Reporter: Jakob Pyttlik
>              Labels: easyfix
>         Attachments: ccittbug.png
>
>
> CCITT-Images with colorspace different from PDIndexed are created using 
> PDCCitt.java/getRGBImage:
> {code}
>  if (colorspace instanceof PDIndexed)
>         {
>            ...
>         }
>         else
>         {
>             byte[] map = new byte[] { (byte) 0x00, (byte) 0xFF };
>             colorModel = new IndexColorModel(1, map.length, map, map, map, 
> Transparency.OPAQUE);
>         }
> {code}
> 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.



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