Is line of sight affected by scrying?

[SangoProduction]

Or similar such effects, like sharing vision with a familiar.

[sreservoir]

Generally no; in fact, if it were, then scrying wouldn't need the text letting you cast certain spells through it, they'd just work. Line of sight is defined in terms of "an imaginary line between your space and the target's space":

line of sight: Two creatures can see each other if they have line of sight to each other. To determine line of sight, draw an imaginary line between your space and the target's space. If any such line is clear (not blocked), then you have line of sight to the creature (and it has line of sight to you). The line is clear if it doesn't intersect or even touch squares that block line of sight. If you can't see the target (for instance, if you're blind or the target is invisible), you can't have line of sight to it even if you could draw an unblocked line between your space and the target's.

We can also infer from the definition of line of effect:

Line of Effect: A line of effect is a straight, unblocked path that indicates what a spell can affect. A line of effect is canceled by a solid barrier. It's like line of sight for ranged weapons, except that it's not blocked by fog, darkness, and other factors that limit normal sight.
that line of sight is, conversely, like line of sight except that it's blocked by factors that limit normal sight instead of (necessarily) solid barriers.

[Doctor Despair]

An interesting thought is a wizard using scry while flying high in the air to KNOW they have los/loe to enemies at the edge of their long range where their spot check is otherwise insufficient to make them out