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https://issues.apache.org/jira/browse/PDFBOX-825?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Timo Boehme updated PDFBOX-825:
-------------------------------
Description:
In class PDPixelMap used to decode images the handling of opacity for images
with color space PDIndexed is wrong.
Test PDF: http://onlinelibrary.wiley.com/doi/10.1002/ajh.21765/pdf
(or another PDF with image and color space /Indexed)
Picture Im2 at page 4 of the test PDF is empty (all pixels white).
The reason:
In PDPixelMap at line 205 (rev. 988513) an opacity variable is set depending on
first value of Decode parameter.
This parameter often is not specified (null) and default value is [0, 2^n-1].
Thus the code:
boolean isOpaque = (decode != null && decode.getInt(0) == 1) ? true : false;
sets isOpaque to false, resulting in all white pixel.
Exchanging 'true' and 'false' would help but I even can't imagine why a first
value of '1' should
be interpreted as an opacity parameter? Am I missing something (some kind of
workaround)?
If there are no good reasons for keeping the opaque parameter I would propose
removing it and setting alpha to 0xff in every case.
was:
In class PDPixelMap used to decode images the handling of opacity for images
with color space PDIndexed is wrong.
Test PDF:
http://onlinelibrary.wiley.com/store/10.1002/ajh.21765/asset/21765_ftp.pdf?v=1&t=gdwynpue&s=fefe3043eabbda71a925cb024b1e9731ea92a9b8
(or another PDF with image and color space /Indexed)
Picture Im2 at page 4 of the test PDF is empty (all pixels white).
The reason:
In PDPixelMap at line 205 (rev. 988513) an opacity variable is set depending on
first value of Decode parameter.
This parameter often is not specified (null) and default value is [0, 2^n-1].
Thus the code:
boolean isOpaque = (decode != null && decode.getInt(0) == 1) ? true : false;
sets isOpaque to false, resulting in all white pixel.
Exchanging 'true' and 'false' would help but I even can't imagine why a first
value of '1' should
be interpreted as an opacity parameter? Am I missing something (some kind of
workaround)?
If there are no good reasons for keeping the opaque parameter I would propose
removing it and setting alpha to 0xff in every case.
example PDF link did not work
> Wrong opacity for images with indexed color space
> --------------------------------------------------
>
> Key: PDFBOX-825
> URL: https://issues.apache.org/jira/browse/PDFBOX-825
> Project: PDFBox
> Issue Type: Bug
> Components: Parsing
> Affects Versions: 1.3.0
> Reporter: Timo Boehme
> Original Estimate: 0.25h
> Remaining Estimate: 0.25h
>
> In class PDPixelMap used to decode images the handling of opacity for images
> with color space PDIndexed is wrong.
> Test PDF: http://onlinelibrary.wiley.com/doi/10.1002/ajh.21765/pdf
> (or another PDF with image and color space /Indexed)
> Picture Im2 at page 4 of the test PDF is empty (all pixels white).
> The reason:
> In PDPixelMap at line 205 (rev. 988513) an opacity variable is set depending
> on first value of Decode parameter.
> This parameter often is not specified (null) and default value is [0, 2^n-1].
> Thus the code:
> boolean isOpaque = (decode != null && decode.getInt(0) == 1) ? true : false;
> sets isOpaque to false, resulting in all white pixel.
> Exchanging 'true' and 'false' would help but I even can't imagine why a first
> value of '1' should
> be interpreted as an opacity parameter? Am I missing something (some kind of
> workaround)?
> If there are no good reasons for keeping the opaque parameter I would propose
> removing it and setting alpha to 0xff in every case.
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