Andreas,
just to follow up and show that I have not forgotten your recent
email :)
Am 29.05.2008 um 19:01 schrieb Andreas Delmelle:
There is still an open issue: When the font is changed, the metrics
for the line are not. E.g. when i have something like
test SIGMA test
<fo:block>test ∑ test</fo:block>
the SIGMA character is set lower than it should be. At this time I
was
unable to find the cause of this behavior. Maybe someone has a hint
as
to why this happens?
To further investigate, compare the behavior with:
<fo:block>test <fo:inline font-family="Symbol">∑</fo:inline>
test</fo:block>
<fo:block>test <fo:character font-family="Symbol"
character="∑" /> test</fo:block>
The fo:inline or fo:character trigger the creation of a new
org.apache.fop.layoutmgr.inline.AlignmentContext, which is taken
into account by the LineLayoutManager associated to the fo:block.
That context is used to determine the alignment point for the
content of the fo:inline vis-à-vis the dominant-baseline of the
enclosing line.
The above would expand to:
<fo:block alignment-adjust="auto"
alignment-baseline="auto"
baseline-shift="baseline"
dominant-baseline="auto">
test <fo:inline font-family="Symbol"
alignment-adjust="auto"
alignment-baseline="auto"
baseline-shift="baseline"
dominant-baseline="auto">∑</fo:inline> test
</fo:block>
(analogously for the fo:character)
Strictly following the XSL-FO Rec, the behavior for the initial
sample should be identical to using a fo:character, so most likely,
something similar should happen when the font is switched in the
TextLayoutManager internally. TextLayoutManager.AreaInfo does not
carry a reference to any AlignmentContext like
LeafNodeLayoutManager.AreaInfo. Instead the used AlignmentContext is
always the one passed by the parent.
(see TextLayoutManager.getNextKnuthElements(), third line in the
method:
alignmentContext = context.getAlignmentContext()
This is definitely the right place, thanks for pointing this out!
-> that context is used in addElementsForAWordFragment() when
creating the corresponding KnuthInlineBox)
If we can simply make sure that each box gets the alignment context
appropriate for the font used for the word-fragment, that should
suffice.
This could be done either by passing the AlignmentContext via the
AreaInfo, as is done in the superclass, or by having the TextLM hold
a reference to a collection of AlignmentContexts (one for each
effectively used font), and use the appropriate one when creating
the boxes.
I tried this, and it failed. At this point, there are too many
variables called "aligmnmentContext". The superclass (LeafNodeManager)
has one, TextLayoutManager has one, and LNM has a function
"makeAlignmentContext" which is supposed to be overridden to supply a
new AlignmentContext. This is confusing and needs to be cleaned up.
I'll try investigating here.
I've tried modifying the alignmentContext by creating a child algnment
context, and even by creating a direct clone (copying of all
attributes) of the parent alignment context, and it always failed the
testsuite. So at this point I belive there are some calles to setters
which throw it off.
HTH!
Cheers
Andreas
Max
