Bug 44466 - XMLGraphics does not accept SAXSource'd images anymore after the latest image loaders changes [w-patch]
Summary: XMLGraphics does not accept SAXSource'd images anymore after the latest image...
Alias: None
Product: XMLGraphicsCommons - Now in Jira
Classification: Unclassified
Component: utilities (show other bugs)
Version: Trunk
Hardware: All All
: P2 major (vote)
Target Milestone: --
Assignee: XML Graphics Project Mailing List
Depends on:
Reported: 2008-02-21 11:09 UTC by Adam Strzelecki
Modified: 2008-02-23 03:24 UTC (History)
1 user (show)

Patch that detects if source is SAXSource and uses its stream. (2.72 KB, patch)
2008-02-21 11:10 UTC, Adam Strzelecki
Details | Diff

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Description Adam Strzelecki 2008-02-21 11:09:04 UTC
XMLmind XMLEditor is using custom URI resolver for FOPFactory, for all resolved URIs it is returning 
SAXSource rather than StreamSource.
Before 1.3 and latest FOP changes, images were loaded properly, but with latest trunk of FOP I started 
getting: [FOP Error] No ImagePreloader for ... and then Cannot open image (because URI was cached as 

After hours of digging I found out that URI resolver of XMLmind is returning always SAXSource, while src/java/org/apache/xmlgraphics/image/loader/impl/AbstractImageSessionContext.java @ newSource 
expects StreamSource. Also image loaders work only with ImageSource, that was created only from 
StreamSource, with generic Source they fail.

I'm attaching patch for AbstractImageSessionContext.java that checks also for SAXSource and allows 
using its inputSource's byte stream.

This makes XMLmind FOP addon again usable with latest FOP trunk.
Comment 1 Adam Strzelecki 2008-02-21 11:10:16 UTC
Created attachment 21575 [details]
Patch that detects if source is SAXSource and uses its stream.
Comment 2 Max Berger 2008-02-21 23:28:07 UTC

just to verify: Does xmleditor ALWAYS resolve to a SAXSource? I can understand
this on  xml-formatted images (such as SVG and MathML), but also for PNG, JPEG,

Because if that is the case then the real question is if this should be changed
in xmleditor rather than xmlgraphics: a SAXSource for JPEG images makes no
sense, where as support for SVG / MathML could be greatly simplified if the SAX
source is used directly. 

Comment 3 Adam Strzelecki 2008-02-22 01:14:48 UTC
Yes XMLMind is ALWAYS resolving to SAXSource, this is done because of some good reason stated in the 
source code :) I've forwarded this bug report to them.

However I can understand this some regression in here anyhow, because with FOP 0.94 and XMLGraphics 
1.2 it was working fine even with this SAXSource, but now it doesn't. So IMHO now matter how the 
underlaying code is written XMLGraphics shouldn't break with new release something that was working 
OK. (Also I think sthing is wrong with Java StreamSource & SAXSource inheritance, I'm not regular Java 
programmer though)
Comment 4 Jeremias Maerki 2008-02-23 03:24:41 UTC
Thanks for the patch, Adam. I have taken a slightly different approach than
you've taken in your patch to also properly handle Readers in SAXSources, for
example. I extended the helper methods in ImageUtil so they cover SAXSource,
too. Making use of that in AbstractImageSessionContext even helped simplify the
code. I've also added test cases for all sorts of scenarios (StreamSource,
SAXSource, DOMSource) so we're sure that the image plug-ins can deal with
whatever Source subclass they want.

Change in SVN: