The mysteries of the XSL-FO specification are dazzling us gain. In 5.1.4 it
says:
"In most cases, elements inherit computed values. However, there are some
properties whose specified value may be inherited (e.g., some values for the
"line-height" property). In the cases where child elements do not inherit
the computed value, this is described in the property definition."
Under 7.15.4 "line-height" the above mentioned exception to the rule of
computed values being inherited is specified for <number> where it says:
"However, the number, not the computed value, is inherited."
But this inheritance exception does not apply to <percentage> or <length>
specifications. However, it does apply to 'normal' as it says the value has
the same meaning as <number>.
So my understanding of this is that
<fo:block font-size="12pt" line-height="1.2">
<fo:block font-size="8pt">
is identical to
<fo:block font-size="12pt" line-height="1.2">
<fo:block font-size="8pt" line-height="1.2">
But
<fo:block font-size="12pt" line-height="120%">
<fo:block font-size="8pt">
means
<fo:block font-size="12pt" line-height="120%">
<fo:block font-size="8pt" line-height="14.4pt">
I believe the exceptional inheritance behaviour of 'normal' and <number> is
simply done so that the initial value which is 'normal' behaves
appropriately otherwise in the absence of any line-height specifications all
lines would have a fixed line-height based on the initial font-size.
BTW, all of this is unchanged in XSL-FO 1.1.
Manuel
> -----Original Message-----
> From: Pascal Sancho [mailto:[EMAIL PROTECTED]
> Sent: Wednesday, 9 April 2008 3:03 PM
> To: [email protected]
> Subject: RE: Line-height inheritance
>
> Hi Andrea,
>
> > -----Message d'origine-----
> > De : Andreas Delmelle [mailto:[EMAIL PROTECTED]
> > Envoyé : mardi 8 avril 2008 23:36
> >
> > On Apr 8, 2008, at 15:20, Pascal Sancho wrote:
> >
> >
> > Hi Pascal,
> >
> > > Reading the spec 7.16.4, line-height property is inherited
> > and accepts
> > > percentages values.
> > > FOP behaves as follow:
> > > If the line-height value is a percentage, the inherited value is the
> > > computed trait: font-size*line-height(in %)
> > > I'm not sure if FOP behaviour is correct. I was expecting the
> > > percentage
> > > value for the inheried line-height.
> > > Am I wrong?
> >
> > FOP's behavior is correct, I think.
> >
> > 5.1.4 Inheritance
> >
> > ... For a given inheritable property, if that property is present on
> > a child, ... otherwise, the specified value of that property on the
> > child is the /computed/ value of that property on the parent
> > formatting object.
> >
> >
> > In other words, if you have:
> >
> > <fo:block font-size="12pt" line-height="120%">
> > <fo:block font-size="8pt">
> >
> > Then the specified line-height for the inner block would be "12pt x
> > 120%", and not, if I interpret your question correctly, "8pt x 120%".
> >
> > Cheers
> > Andreas
>
> IIUC, the following snippet should be interpreted as you said above about
> percentage.
> The 2nd fo:block line-height should be 12*1.2
>
> <fo:block font-size="12pt" line-height="1.2">
> <fo:block font-size="8pt">
>
> IMHO, behaviour should be the same for either percentage or numeric value.
> IIUC your point of view, in both cases, according to the spec, inherited
> line-height should be computed value.
>
> What I expect, is that inherited line-height should remain relative when
> possible.
> (What about line-height expressed in 'em'?)
>
> WDYT?
>
> Pascal
>
>
>
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