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https://issues.apache.org/jira/browse/PDFBOX-4306?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16599636#comment-16599636
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Daniel Persson commented on PDFBOX-4306:
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Well, if it's a rounding error when drawing elements then I feel that you
should ensure to increase the precision instead of changing the image ratio.
With this solution we create images that are 1 pixel narrower than the same
produced by Poppler. Then again that might not be the correct resolution.
The thing that worries me is that when you create a spread of multiple images
you could introduce a jagged edge between the images if one pixel is missing.
Best regards
Daniel
> Image clipping area rounding error
> ----------------------------------
>
> Key: PDFBOX-4306
> URL: https://issues.apache.org/jira/browse/PDFBOX-4306
> Project: PDFBox
> Issue Type: Bug
> Reporter: Daniel Persson
> Priority: Major
> Labels: rendering
> Attachments: page-1.pdf, page-2.pdf, patch.diff, patch2.diff, test.jpg
>
>
> Creating images with PDFBox and merging them together when you have two pages
> that connect will create a white line between the images.
> We have looked into the issue and tried to fix it and found that the clipping
> area is a bit to tight so the images will not be rendered correctly. My guess
> is that this is due to a rounding error when using floats.
> Most of the graphics functions in java use double precision and PDFBox uses
> floats so when using layer upon layer of bounding boxes intersecting the
> clipping area it might get skewed to a bad bounding box.
> I've added a patch to this issue with the code we use as a workaround today.
> It's by no means the final solution to the problem but it resolves the white
> line issue.
> To be sure that you get the error when generating the images use the
> following command
> ```
> java -jar pdfbox-app-3.0.0-SNAPSHOT.jar PDFToImage -dpi 150 -quality 0.95
> -format jpg page-1.pdf
> ```
> We run java 8 on our machines.
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