On 09/09/2011 01:38, John Haug wrote:
type= cite
>
If there are any specific problems with ECT, I'd love to have the details as both Doug and I noted early on that we think arbitrary order rejection is important to users.
I believe the issue can be illustrated in the example below.
Doc-v0:
<style:style style:name= Style1 style:family= paragraph >
<style:text-properties fo:font-weight= normal />
</style:style>
Doc-v1:
<style:style style:name= Style1 style:family= paragraph >
<style:text-properties fo:font-weight= normal
fo:font-style= italic />
</style:style>
Doc-v2:
<style:style style:name= Style1
style:family= paragraph >
<style:text-properties fo:font-weight= bold
fo:font-style= italic />
</style:style>
Change 1 (doc-v0 to doc-v1) adds fo:font-style= italic and so
caches
<style:style style:name= Style1 style:family= paragraph >
<style:text-properties fo:font-weight= normal />
</style:style>
and has:
<ct:format-change-start ct:id= 1 />
<style:style style:name= Style1 style:family= paragraph >
<style:text-properties fo:font-weight= normal
fo:font-style= italic />
</style:style>
<ct:format-change-end ct:id= 1 />
Change 2 (doc-v1 to doc-v2) changes fo:font-weight= normal to
fo:font-weight= bold and so caches
<style:style style:name= Style1 style:family= paragraph >
<style:text-properties fo:font-weight= normal
fo:font-style= italic />
</style:style>
and has:
<ct:format-change-start ct:id= 2 />
<style:style style:name= Style1
style:family= paragraph >
<style:text-properties fo:font-weight= bold
fo:font-style= italic />
</style:style>
<ct:format-change-end ct:id= 2 />
Then if you reject 2 then reject 1 it works OK, but reject 1 then
reject 2 would result in:
<style:style style:name= Style1 style:family= paragraph >
<style:text-properties fo:font-weight= normal
fo:font-style= italic />
</style:style>
which is incorrect because fo:font-style= italic remains there
although change 1 has been rejected.
I believe the situation is that for ECT any two changes that
affect one 'bucket' can only be rejected correctly in the reverse
order, i.e. if the last change is rejected first. Of course a user
does not know anything about buckets so this may lead to confusing
behaviour. This is one reason for my opinion that recording
changes to attributes is important.
Robin
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Robin La Fontaine, Director, DeltaXML Ltd
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