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Posted to fop-dev@xmlgraphics.apache.org by bu...@apache.org on 2009/07/16 15:07:08 UTC
DO NOT REPLY [Bug 47541] New: Wrong handling of "retained"
conditionality when space-before is inherited
https://issues.apache.org/bugzilla/show_bug.cgi?id=47541
Summary: Wrong handling of "retained" conditionality when
space-before is inherited
Product: Fop
Version: all
Platform: All
OS/Version: All
Status: NEW
Severity: normal
Priority: P2
Component: fo tree
AssignedTo: fop-dev@xmlgraphics.apache.org
ReportedBy: vhennebert@gmail.com
Created an attachment (id=23993)
--> (https://issues.apache.org/bugzilla/attachment.cgi?id=23993)
Sample FO file showing the problem
See attached file: block b4 inherits the space-before property from the parent
block and overrides the .conditionality component to "retain". This results
into a space before the first block, at the top of the first page. Normally
block 4 should start the second page with a space before it. The bug doesn't
occur if all the components of the space are specified on the block instead of
being inherited.
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DO NOT REPLY [Bug 47541] Wrong handling of "retained" conditionality
when space-before is inherited
Posted by bu...@apache.org.
https://issues.apache.org/bugzilla/show_bug.cgi?id=47541
--- Comment #5 from Andreas L. Delmelle <ad...@apache.org> 2009-07-17 08:04:24 PST ---
(In reply to comment #4)
Sorry, mixing things up with the inherited indent properties. Should have
looked at the sample, of course...
> That doesn't justify the space before the first block on the first page. It
> clearly looks like some object is directly passed to the child FO, instead of a
> copy of it. Setting the conditionality to "retain" on block 4 seems to have set
> it also to the surrounding block.
OK, now I see it. The SpaceProperty instance is re-used/shared between the
blocks, due to the value of inherit, but when the additional component is
specified on the fourth block, it also sets the component for all the other
blocks. Specifying a value other than inherit, or specifying it for the
individual components, generates a separate instance, so there are no
side-effects. SpaceProperty is one type that is not cached yet, so even
identical property specs will yield separate instances (unless inheritance of
the base property is used, obviously).
Not sure how easy it would be to fix this behavior, yet. Could be as simple as
modifying the behavior in PropertyList.findBaseProperty() to conditionally
duplicate the instance...
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DO NOT REPLY [Bug 47541] Wrong handling of "retained" conditionality
when space-before is inherited
Posted by bu...@apache.org.
https://issues.apache.org/bugzilla/show_bug.cgi?id=47541
Glenn Adams <gl...@skynav.com> changed:
What |Removed |Added
----------------------------------------------------------------------------
Priority|P2 |P3
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DO NOT REPLY [Bug 47541] Wrong handling of "retained" conditionality
when space-before is inherited
Posted by bu...@apache.org.
https://issues.apache.org/bugzilla/show_bug.cgi?id=47541
--- Comment #3 from Andreas L. Delmelle <ad...@apache.org> 2009-07-16 14:03:20 PST ---
Just some additional notes explaining the behavior, that even though it seems
unexpected, is actually OK.
For compound properties, specifying only one of the components is equivalent to
setting all the other components to their initial value. They are not
initialized with the inherited value, since the components are NOT(!) separate
properties. Implicit inheritance is always defined on the level of the complete
property. If one of the components appears as a specified value, the entire
property is no longer inherited. If we want to inherit some of the components
and override others, we need to use explicit values of 'inherit'. (Seems to be
precisely one of the prime use-cases for that keyword)
IOW:
<block space-before="2em">
<block space-before.conditionality="retain">
is semantically equivalent to
<block space-before.optimum="2em"
space-before.conditionality="discard"
space-before.precedence="0">
<block space-before.optimum="0pt"
space-before.conditionality="retain"
space-before.precedence="0">
To achieve the expected result, the correct spec would be:
<block space-before="2em">
<block space-before.optimum="inherit" space-before.conditionality="retain">
Technically, in FOP (see also the Wiki about property resolution) specified
values are always processed first and added to the PropertyList. Later, when
binding the PropertyList to the FObj, if there was no specified value for a
given applicable property, inheritance will always be tried before reverting to
the initial value.
When processing the specified properties, and encountering a specified
component, we first check if the compound property already exists on the
PropertyList. In this context, we don't try inheritance, as we're actually
looking for a base property that possibly resulted from other components that
were processed before (= appeared earlier in the Attributes).
If it does not exist, then we generate that base property, also bypassing
inheritance, since we're creating an instance for a specified value.
I think this is completely in line with the Recommendation (5.1.4), which hints
at the inherited value actually being a fallback for an absent specified value
(not a replacement for the initial value; note the order of the resolution
rules in 5.1.1).
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DO NOT REPLY [Bug 47541] Wrong handling of "retained" conditionality
when space-before is inherited
Posted by bu...@apache.org.
https://issues.apache.org/bugzilla/show_bug.cgi?id=47541
--- Comment #6 from Glenn Adams <gl...@skynav.com> 2012-04-07 01:44:10 UTC ---
resetting P2 open bugs to P3 pending further review
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DO NOT REPLY [Bug 47541] Wrong handling of "retained" conditionality
when space-before is inherited
Posted by bu...@apache.org.
https://issues.apache.org/bugzilla/show_bug.cgi?id=47541
Vincent Hennebert <vh...@gmail.com> changed:
What |Removed |Added
----------------------------------------------------------------------------
Attachment #23993|0 |1
is obsolete| |
--- Comment #1 from Vincent Hennebert <vh...@gmail.com> 2009-07-16 06:08:55 PST ---
Created an attachment (id=23994)
--> (https://issues.apache.org/bugzilla/attachment.cgi?id=23994)
The true sample file that shows the problem
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DO NOT REPLY [Bug 47541] Wrong handling of "retained" conditionality
when space-before is inherited
Posted by bu...@apache.org.
https://issues.apache.org/bugzilla/show_bug.cgi?id=47541
Vincent Hennebert <vh...@gmail.com> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|RESOLVED |REOPENED
Resolution|WORKSFORME |
--- Comment #4 from Vincent Hennebert <vh...@gmail.com> 2009-07-17 07:04:35 PST ---
That doesn't justify the space before the first block on the first page. It
clearly looks like some object is directly passed to the child FO, instead of a
copy of it. Setting the conditionality to "retain" on block 4 seems to have set
it also to the surrounding block.
Also:
(In reply to comment #3)
> Just some additional notes explaining the behavior, that even though it seems
> unexpected, is actually OK.
>
> For compound properties, specifying only one of the components is equivalent to
> setting all the other components to their initial value. They are not
> initialized with the inherited value, since the components are NOT(!) separate
> properties. Implicit inheritance is always defined on the level of the complete
> property.
This is not what the following sentence from section 5.11 says: "Compound
values of properties are inherited as a unit and not as individual components.
After inheritance any complete form specification for a component is used to
set its value." So non-specified components take the inherited value.
Anyway, that doesn't apply to space-before since it's not an inheritable
property.
> If one of the components appears as a specified value, the entire
> property is no longer inherited. If we want to inherit some of the components
> and override others, we need to use explicit values of 'inherit'. (Seems to be
> precisely one of the prime use-cases for that keyword)
Which is what is done in the sample FO file. According to the following
sentence in section 5.11: "Short forms may be used together with complete
forms; the complete forms have precedence over the expansion of a short form."
the result for block b4 should be the following one:
space-before.minimum=10pt
space-before.optimum=12pt
space-before.maximum=50pt
space-before.precedence=0
space-before.conditionality=retain
<snip/>
> I think this is completely in line with the Recommendation (5.1.4), which hints
> at the inherited value actually being a fallback for an absent specified value
> (not a replacement for the initial value; note the order of the resolution
> rules in 5.1.1).
Like above, since space-before is not an inheritable property, section 5.1.4
doesn't apply here.
Vincent
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DO NOT REPLY [Bug 47541] Wrong handling of "retained" conditionality
when space-before is inherited
Posted by bu...@apache.org.
https://issues.apache.org/bugzilla/show_bug.cgi?id=47541
Andreas L. Delmelle <ad...@apache.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|NEW |RESOLVED
Resolution| |WORKSFORME
--- Comment #2 from Andreas L. Delmelle <ad...@apache.org> 2009-07-16 12:36:44 PST ---
Not a 100% sure, but I think this behavior has been discussed (way back when),
and this is actually not a bug.
By specifying the .conditionality component, you implicitly set the other
property components to their initial value. Either all the components are
inherited, or none.
To achieve the desired result, it is wrong to rely on implicit inheritance.
Instead, specify a value of 'inherit' for the .length component to avoid using
the initial value (0pt).
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