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Posted to fop-dev@xmlgraphics.apache.org by bu...@apache.org on 2010/02/12 05:21:15 UTC
DO NOT REPLY [Bug 48733] New: Extend Line Break algorithm to support
non-standard configuration
https://issues.apache.org/bugzilla/show_bug.cgi?id=48733
Summary: Extend Line Break algorithm to support non-standard
configuration
Product: Fop
Version: 0.95
Platform: PC
OS/Version: Windows XP
Status: NEW
Severity: enhancement
Priority: P2
Component: general
AssignedTo: fop-dev@xmlgraphics.apache.org
ReportedBy: alex_watson@standardandpoors.com
The current line breaking algorithm in FOP 0.95 uses two static classes
LineBreakStatus and LineBreakUtils to implement the standard Unicode line
breaking algorithm (UTR 14).
In particular, this handles currency expressions such as $US150 and $A250 to
prevent line breaks within each number.
However, my company uses a different convention of putting the country before
the currency symbol (eg. US$150 and A$250). Unfortunately, this allows a line
break between the country and the currency symbol.
I have checked the UTR14 spec and I know this is non-standard. It prohibits
breaks between (PR,AL) but allows breaks between (AL,PR).
My enhancement request is for a way to override the default line-break pairs at
runtime. This is not currently possible because the LineBreakStatus and
LineBreakUtils classes are static with private members.
The simplest change would be to make the LineBreakUtils class public, change
the PAIR_TABLE to non-final and then add a method setLineBreakPairProperty(int,
int, byte). This would not break any existing unittests or functionality, but
would allow me to write something like this when I create my FopFactory:
LineBreakUtils.setLineBreakPairProperty(
LineBreakUtils.LINE_BREAK_PROPERTY_AL,
LineBreakUtils.LINE_BREAK_PROPERTY_PR,
LineBreakUtils.PROHIBITED_BREAK);
However, as LineBreakUtils is a generated java file I have an alternate patch
for LineBreakStatus that would achieve the same thing (but is a little more
work).
Please advise if there is a way to achieve this with current FOP functionality,
or if my suggested code enhancements are appropriate. I can provide PATCH code
for either approach if requested.
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DO NOT REPLY [Bug 48733] Extend Line Break algorithm to support
non-standard configuration
Posted by bu...@apache.org.
https://issues.apache.org/bugzilla/show_bug.cgi?id=48733
Vincent Hennebert <vh...@gmail.com> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|NEW |RESOLVED
Resolution| |INVALID
--- Comment #2 from Vincent Hennebert <vh...@gmail.com> 2010-02-12 10:39:10 UTC ---
Hi,
Like Manuel said, the appropriate way to deal with such special case is to
insert Word Joiner (U+2060) or otherwise Zero Width Space (U+200B) at the right
places in the text. In your case: US⁠$150, A⁠$250. Have a look at
chapter 16 of the Unicode Standard 5.2
(http://www.unicode.org/versions/Unicode5.2.0/). This is much more flexible as
that allows you to alter the algorithm's behaviour only locally; it's also more
practical than modifying FOP's source code.
If you have any further question feel free to ask on the fop-users list:
http://xmlgraphics.apache.org/fop/maillist.html#fop-user
HTH,
Vincent
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DO NOT REPLY [Bug 48733] Extend Line Break algorithm to support
non-standard configuration
Posted by bu...@apache.org.
https://issues.apache.org/bugzilla/show_bug.cgi?id=48733
--- Comment #1 from Manuel Mall <ma...@apache.org> 2010-02-12 06:50:00 UTC ---
(In reply to comment #0)
>
> However, my company uses a different convention of putting the country before
> the currency symbol (eg. US$150 and A$250). Unfortunately, this allows a line
> break between the country and the currency symbol.
>
The usual solution for special cases requiring the standard linebreaking to be
overwritten is to add a zero width breaking or non breaking (depending on what
you want to achieve) joiner character to the input stream. Typically as part of
the XSL transformation step if you have one.
>
> The simplest change would be to make the LineBreakUtils class public, change
> the PAIR_TABLE to non-final and then add a method setLineBreakPairProperty(int,
> int, byte). This would not break any existing unittests or functionality, but
> would allow me to write something like this when I create my FopFactory:
>
> LineBreakUtils.setLineBreakPairProperty(
> LineBreakUtils.LINE_BREAK_PROPERTY_AL,
> LineBreakUtils.LINE_BREAK_PROPERTY_PR,
> LineBreakUtils.PROHIBITED_BREAK);
>
While it is desirable to make line breaking behaviour more flexible your
approach of exposing setters on static variables making them modifiable at
runtime is non thread safe and also does not allow linebreaking customization
on a per fop invocation basis as obviously these tables are shared across all
fop instances.
A more generic approach possibly using interfaces, factories and configurable
line breaking providers may be more appropriate. However, as pointed out above
this may be an overkill in your case as, depending on your FOP production
pipeline, injecting non breaking word joiner (U+2060) into your currency
amounts could be a simple solution not requiring any FOP code changes.
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DO NOT REPLY [Bug 48733] Extend Line Break algorithm to support
non-standard configuration
Posted by bu...@apache.org.
https://issues.apache.org/bugzilla/show_bug.cgi?id=48733
Glenn Adams <gl...@skynav.com> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|RESOLVED |CLOSED
--- Comment #3 from Glenn Adams <gl...@skynav.com> 2012-04-01 13:55:06 UTC ---
batch transition to closed remaining pre-FOP1.0 resolved bugs
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