[
https://issues.apache.org/jira/browse/PDFBOX-6155?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Tilman Hausherr updated PDFBOX-6155:
------------------------------------
Description:
bitmap-symbol-textrefine-customat.pdf has a garbled shape, however
bitmap-symbol-textrefine.pdf doesn't. The difference is that the problematic
one has 4 AT bytes.
[https://github.com/SerenityOS/serenity/blob/master/Tests/LibGfx/test-inputs/jbig2/json/bitmap-symbol-textrefine-customat.json]
{code:json}
"refinement_adaptive_template_pixels": [
10,
-1,
4,
15
],
{code}
After a lot of reading and searching I was able to trace it to
{{GenericRefinementRegion.updateOverride()}} which ignores AT bytes if they are
-1. However the specification says no such thing:
6.3.5.3 Fixed templates and adaptive templates
The AT pixel RA1 can be located anywhere in the field shown in Figure 7, not
including the current pixel. The AT pixel
RA2 can be located anywhere in the range (-128, -128) to (127, 127) in the
reference bitmap.
Just removing the two lines fixes the problem but ruins
bitmap-symbol-textrefine-negative-delta-width.pdf, which has all -1 so I'll
research that.
was:
bitmap-symbol-textrefine-customat.pdf has a garbled shape, however
bitmap-symbol-textrefine.pdf doesn't. The difference is that one has 4 AT bytes.
https://github.com/SerenityOS/serenity/blob/master/Tests/LibGfx/test-inputs/jbig2/json/bitmap-symbol-textrefine-customat.json
{code:json}
"refinement_adaptive_template_pixels": [
10,
-1,
4,
15
],
{code}
After a lot of reading and searching I was able to trace it to
{{GenericRefinementRegion.updateOverride()}} which ignores AT bytes if they are
-1. However the specification says no such thing:
6.3.5.3 Fixed templates and adaptive templates
The AT pixel RA1 can be located anywhere in the field shown in Figure 7, not
including the current pixel. The AT pixel
RA2 can be located anywhere in the range (-128, -128) to (127, 127) in the
reference bitmap.
Just removing the two lines fixes the problem but ruins
bitmap-symbol-textrefine-negative-delta-width.pdf, which has all -1 so I'll
research that.
> AT (Adaptive template pixels) -1 byte skipped
> ---------------------------------------------
>
> Key: PDFBOX-6155
> URL: https://issues.apache.org/jira/browse/PDFBOX-6155
> Project: PDFBox
> Issue Type: Sub-task
> Components: JBIG2
> Affects Versions: 3.0.4 JBIG2
> Reporter: Tilman Hausherr
> Assignee: Tilman Hausherr
> Priority: Major
> Attachments: bitmap-symbol-textrefine-customat.pdf,
> bitmap-symbol-textrefine-negative-delta-width.pdf,
> bitmap-symbol-textrefine.pdf
>
>
> bitmap-symbol-textrefine-customat.pdf has a garbled shape, however
> bitmap-symbol-textrefine.pdf doesn't. The difference is that the problematic
> one has 4 AT bytes.
> [https://github.com/SerenityOS/serenity/blob/master/Tests/LibGfx/test-inputs/jbig2/json/bitmap-symbol-textrefine-customat.json]
> {code:json}
> "refinement_adaptive_template_pixels": [
> 10,
> -1,
> 4,
> 15
> ],
> {code}
> After a lot of reading and searching I was able to trace it to
> {{GenericRefinementRegion.updateOverride()}} which ignores AT bytes if they
> are -1. However the specification says no such thing:
> 6.3.5.3 Fixed templates and adaptive templates
> The AT pixel RA1 can be located anywhere in the field shown in Figure 7, not
> including the current pixel. The AT pixel
> RA2 can be located anywhere in the range (-128, -128) to (127, 127) in the
> reference bitmap.
> Just removing the two lines fixes the problem but ruins
> bitmap-symbol-textrefine-negative-delta-width.pdf, which has all -1 so I'll
> research that.
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