Define 'Presentation Compositor' [TAG review]

[rhiaro]

Please forgive my ignorance as I get up to speed with this work.

The IMSC HRM spec contains the term 'Presentation Compositor' several times but does not link to or define what this is. Could you provide or point me to an explanation?

(cc w3ctag/design-reviews#788)

[palemieux]

The Presentation Compositor is one of the processing steps of the HRM -- see Figure 2.

[rhiaro]

Aha thanks, that explains why ctrl+f didn't find it.

[palemieux]

I suggest reopening this issue since this is something others are likely to run into.

[himorin]

Section 6 defines architectural components and their processing diagrams (Figure 2), but marked as non-normative. As above, some of defined components have normative SHALL texts for their behavior. (Also some part of diagrams seem to be only described in section 6, like switching between non-empty ISD and empty ISD?)
Are these (both components and diagrams) better to be normatively described at somewhere else than non-normative section 6??

(note, I lack enough experience on these normativeness, so comments should be wrong...)