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https://issues.apache.org/jira/browse/PDFBOX-6155?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=18074016#comment-18074016
]
Maruan Sahyoun edited comment on PDFBOX-6155 at 4/16/26 3:04 PM:
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[~tilman] I changed GenericRefinementRegion.updateOverride() to
{code}
case 0:
if (grAtX[0] != -1 || grAtY[0] != -1)
{
grAtOverride[0] = true;
override = true;
}
if (grAtX[1] != -1 || grAtY[1] != -1)
{
grAtOverride[1] = true;
override = true;
}
break;
{code}
as I think the {{&&}} was wrong here as if I'm not mistaken it's about the AT
not being in it's default position. Now excluding
{{bitmap-symbol-textrefine-customat.jbig2}} from the ignores
{code}
if (name.equals("bitmap-refine-template1-tpgron.jbig2") ||
name.equals("bitmap-symbol-context-reuse.jbig2") ||
name.equals("bitmap-symbol-symhuffrefine-textrefine.jbig2")) //
||
// name.equals("bitmap-symbol-textrefine-customat.jbig2"))
{
{code}
the tests still pass - WDYT?
maybe we should code it in the form {{if (!(grAtX[i] == -1 && grAtY[i] ==
-1))}} because, although it has the same result the meaning is clearer at least
from my understanding of the code which is to check if the AT is at it's
default position.
was (Author: msahyoun):
[~tilman] I changed GenericRefinementRegion.updateOverride() to
{code}
case 0:
if (grAtX[0] != -1 || grAtY[0] != -1)
{
grAtOverride[0] = true;
override = true;
}
if (grAtX[1] != -1 || grAtY[1] != -1)
{
grAtOverride[1] = true;
override = true;
}
break;
{code}
as I think the {{&&}} was wrong here as if I'm not mistaken it's about the AT
not being in it's default position. Now excluding
{{bitmap-symbol-textrefine-customat.jbig2}} from the ignores
{code}
if (name.equals("bitmap-refine-template1-tpgron.jbig2") ||
name.equals("bitmap-symbol-context-reuse.jbig2") ||
name.equals("bitmap-symbol-symhuffrefine-textrefine.jbig2")) //
||
// name.equals("bitmap-symbol-textrefine-customat.jbig2"))
{
{code}
the tests still pass - WDYT?
> 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 and trying 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.
> See also figure 7 earlier in the specification, which has (-1,-1) values.
> 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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