Pptxgenjs: Does anybody know why this number is used here - "4294967295"? Why not a simple value like "1"?
All 4 comments
My guess would be, that this is the last possible index.
Why the last?
It seems the index here is an unsigned 32bit number, starting at 0 and 4294967295 (= 2鲁虏-1) is the highest (last) representable number here.
Probably this is used to ensure, that no previous index is re-used or overwritten.
Just my 2 cents.
koddistortion
on 31 Aug 2020
Thanks, @koddistortion, I know about the upper bound of unsigned int type, but I've checked it on real pptx files and behavior a bit different with idx='4294967295' than, for example with idx='1' etc, and I'm trying to understand how does it work...
Kirill71
on 31 Aug 2020
I鈥檓 unable to recall where the value is derived from off-hand. I may have simply mimicked what PowerPoint produced.
gitbrent
on 1 Sep 2020
@gitbrent I've understood how to get this value in PP. For example, you have an inheritance chain: master slide placeholder with idx='1', slide layout placeholder with idx='1', and slide placeholder with idx='1'. if you remove the slide layout's placeholder the inheritance chain between the slide and the slide layout will be broken, but PP still has to inherit properties from parent entities in this case from the master slide, and it marks slide placeholder with idx='4294967295'. It's like a mark. If PP reads this value it inherits properties directly from the master slide, excludes the slide layout and it understands that placeholder which belongs to the slide layout has been removed.
How does it find the required placeholder if the slide placeholder changes from idx='1' to idx='4294967295'? I think MS PP does it by placeholder type, but I am not sure.
it's not a just upper bound value for unsigned int. It's part of MS PowerPoint behavior, but unfortunately this part under the hood and doesn't describe in OXML Standard. I've found a related article
Maybe it will be useful to someone.
Kirill71
on 1 Sep 2020
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Most helpful comment
@gitbrent I've understood how to get this value in PP. For example, you have an inheritance chain: master slide placeholder with
idx='1', slide layout placeholder withidx='1', and slide placeholder withidx='1'. if you remove the slide layout's placeholder the inheritance chain between the slide and the slide layout will be broken, but PP still has to inherit properties from parent entities in this case from the master slide, and it marks slide placeholder withidx='4294967295'. It's like a mark. If PP reads this value it inherits properties directly from the master slide, excludes the slide layout and it understands that placeholder which belongs to the slide layout has been removed.How does it find the required placeholder if the slide placeholder changes from
idx='1'toidx='4294967295'? I think MS PP does it by placeholder type, but I am not sure.it's not a just upper bound value for unsigned int. It's part of MS PowerPoint behavior, but unfortunately this part under the hood and doesn't describe in OXML Standard. I've found a related article
Maybe it will be useful to someone.