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From STAMPF Lukas <lukas.sta...@bat.at>
Subject AW: QR Image Detection Down 2.0.13 -> 2.0.14
Date Fri, 05 Apr 2019 16:14:26 GMT
Hi,

I guess the reason for that is that if you set a single RenderingHint, you need to provide
all of them or lose the rest from Default. 

By setting KEY_ANTIALIASING I essentially removed VALUE_RENDER_QUALITY and so it didn't work.

But now the interesting part: By setting VALUE_RENDER_QUALITY I kept that setting, but removed
the KEY_INTERPOLATION setting. 

I just checked: Setting KEY_RENDERING and KEY_ANTIALIASING and therefore removing KEY_INTERPOLATION
from the RenderingHints improved my situation on 2.0.14. Has something changed there?

Lukas

-----Urspr√ľngliche Nachricht-----
Von: Tilman Hausherr <THausherr@t-online.de> 
Gesendet: Freitag, 5. April 2019 17:55
An: users@pdfbox.apache.org
Betreff: Re: QR Image Detection Down 2.0.13 -> 2.0.14

Hi,

This is weird, RenderingHints.VALUE_RENDER_QUALITY is in the default settings?! See in the
source code, PDFRenderer.createDefaultRenderingHints().

antialiasing is off when bitonal destination.

Tilman


Am 05.04.2019 um 17:48 schrieb STAMPF Lukas:
> Thanks, seems like it wasn't the antialiasing. Turning it off and on didn't change the
results between 2.0.13 and 2.0.14. What did help however was
>                  hints.put(RenderingHints.KEY_RENDERING, 
> RenderingHints.VALUE_RENDER_QUALITY);
>
> Setting this on 2.0.14 seems to restore the 2.0.13 behavior. Could be coincidence though.
Need to verify it with a larger amount of documents first. Has something about this setting
changed between versions when rendering in BINARY mode?
>
> Lukas
>
> -----Urspr√ľngliche Nachricht-----
> Von: Tilman Hausherr <THausherr@t-online.de>
> Gesendet: Freitag, 5. April 2019 17:00
> An: users@pdfbox.apache.org
> Betreff: Re: QR Image Detection Down 2.0.13 -> 2.0.14
>
> Yes, PDFRenderer now allows to pass rendering hints.
>
> Tilman
>
> Am 05.04.2019 um 16:42 schrieb STAMPF Lukas:
>> Hi,
>>
>> I am using  PDFBox to generate BufferedImages  which I feed to ZXing 
>> 3.3.3 to do QR scanning. When I updated from 2.0.13 to 2.0.14 I 
>> noticed a severe reduction in scanning reliability. I guess its 
>> related to this change 
>> https://issues.apache.org/jira/browse/PDFBOX-4391
>>
>> This is the render command I use:
>>               bim = pdfRenderer.renderImageWithDPI(pageCounter, dpi, 
>> ImageType.BINARY);
>>
>> I try multiple dpi settings between 150 and 300, to increase my changes to find a
QR code.
>> Is there some flag I can set to test out if the antialiasing causes this?
>>
>> Kind regards
>>
>>
>
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