[Geoserver-users] WMS fails in SVG but works in other formats

Hi list, and happy new year to the geoserver users and developers !

I have a wms request that works fine when the output format is set to either PDF (application/pdf) or PNG (image/png), but fails when trying to set the output format to SVG (image/svg).

Any idea of what might be causing this ?
Geoserver version is 2.14.0.
Stack trace is here : https://pastebin.com/EHq0Lmau

Regards
--
Arnaud

Is this the case for all your layers or just one?

Ian

···

Ian Turton

Looking at the code, it's a rendering error, but the stack trace isn't
really that informative.

Do you have a specific case that reproduces this? Any chance that you can
debug it to find out the specific rendering exception that occurs (probably
in Batik, maybe in GeoTools)?

Brad

-----Original Message-----
From: Arnaud L. <arnaud.listes@anonymised.com>
Sent: Wednesday, 9 January 2019 7:28 PM
To: GeoServer Mailing List List <geoserver-users@lists.sourceforge.net>
Subject: [Geoserver-users] WMS fails in SVG but works in other formats

Hi list, and happy new year to the geoserver users and developers !

I have a wms request that works fine when the output format is set to either
PDF (application/pdf) or PNG (image/png), but fails when trying to set the
output format to SVG (image/svg).

Any idea of what might be causing this ?
Geoserver version is 2.14.0.
Stack trace is here : https://pastebin.com/EHq0Lmau

Regards
--
Arnaud

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Hi list, and happy new year to the geoserver users and developers !

I have a wms request that works fine when the output format is set to
either PDF (application/pdf) or PNG (image/png), but fails when trying
to set the output format to SVG (image/svg).

Any idea of what might be causing this ?

This is like saying “If I go to work by car or bike everything works, but using the train, something breaks, any idea what might be causing this?”.
The code writing out the format is very different in these three formats, PNG writes using Java2D, PDF using iText and SVG using Batik.

Geoserver version is 2.14.0.
Stack trace is here : https://pastebin.com/EHq0Lmau

From the trace I see:

  1. Caused by: java.lang.NullPointerException

  2. at org.apache.batik.svggen.ImageHandlerBase64Encoder.encodeImage(ImageHandlerBase64Encoder.java:157)

  3. at org.apache.batik.svggen.ImageHandlerBase64Encoder.handleHREF(ImageHandlerBase64Encoder.java:133)

  4. at org.apache.batik.svggen.DefaultImageHandler.handleImage(DefaultImageHandler.java:91)

  5. at org.apache.batik.svggen.SimpleImageHandler.handleImage(SimpleImageHandler.java:126)

  6. at org.apache.batik.svggen.SVGGraphics2D.drawRenderedImage(SVGGraphics2D.java:1023)

  7. at org.geotools.renderer.lite.StyledShapePainter.renderImage(StyledShapePainter.java:747)

Making a guess, maybe the style is pointing to an image that cannot be located, and SVG will throw an NPE instead
of silently skipping it? Or, if this is the actual code (lines number might not match, but it seems they do) it could be
that for some reason Batik is not finding a PNG encoder (the writer variable), but I would not know why or how:

https://github.com/apache/batik/blob/trunk/batik-svggen/src/main/java/org/apache/batik/svggen/ImageHandlerBase64Encoder.java#L152

This would need someone running a debugger inside the Batik encoding (and possibly initialization of that registry) and figure out
what happened. A first step would be to open a bug report on Jira with reproducible steps (including data and style needed).
Also, make sure you’ve tried the generation on the latest stable version (2.14.1) as we have been upgrading Batik a few times recently.

Cheers
Andrea

···

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Hi Ian, thanks for your answer

Le 09/01/2019 à 09:42, Ian Turton a écrit :

Is this the case for all your layers or just one?

All layers with external png images as symbolizers apparently.

Regards
--
Arnaud

Hi Brad, and thanks for your answer

Le 09/01/2019 à 09:43, bradh@anonymised.com a écrit :

Looking at the code, it's a rendering error, but the stack trace isn't
really that informative.

Do you have a specific case that reproduces this? Any chance that you can
debug it to find out the specific rendering exception that occurs (probably
in Batik, maybe in GeoTools)?

I can reproduce this by trying to render any layer that has a visible png symbolizer.
I don't know much (almost nothing, actually) about java coding/debugging, so it's not an easy task for me.

I'll be glad to dig into this when I have some spare time though (but this is not the cas at the moment unfortunatelly).

Regards
--
Arnaud

Hi Andrea, thanks for your answer !

Le 09/01/2019 à 09:43, Andrea Aime a écrit :

This is like saying "If I go to work by car or bike everything works, but using the train, something breaks, any idea what might be causing this?".
The code writing out the format is very different in these three formats, PNG writes using Java2D, PDF using iText and SVG using Batik.

I gave a stack trace, so I feel I did a little bit more than that...

Making a guess, maybe the style is pointing to an image that cannot be located, and SVG will throw an NPE instead
of silently skipping it?

The png files are there (I checked them all, they were not many) and are rendered fine with the other encoders.

Or, if this is the actual code (lines number might not match, but it seems they do) it could be
that for some reason Batik is not finding a PNG encoder (the writer variable), but I would not know why or how:
https://github.com/apache/batik/blob/trunk/batik-svggen/src/main/java/org/apache/batik/svggen/ImageHandlerBase64Encoder.java#L152

Maybe, but this is definitively beyond my knowledge.

This would need someone running a debugger inside the Batik encoding (and possibly initialization of that registry) and figure out
what happened. A first step would be to open a bug report on Jira with reproducible steps (including data and style needed).
Also, make sure you've tried the generation on the latest stable version (2.14.1) as we have been upgrading Batik a few times recently.

Yes, I'll do this ASAP.
I'll first upgrade to 2.14.1 to make sure this is not something that has already been fixed.

Thanks for your help !

Regards
--
Arnaud