Minimal control of views through SDK

[jleibs]

The long-term goal for controlling the UI is introduction of a blueprint store for most UI state: https://github.com/rerun-io/rerun/blob/main/design/blueprint_store.md

However, we can create immediate value for users (in particular in a notebook context) with just a subset of the functionality from the RFC.

In order of priority:

• Specify panel state (collapsed or expanded) for the 3 panels
• Specify selected timeline
• Specify whether to enable auto-view creation (this should be one of the first things logged; probably part of init?)
• Specify views to be created (view name, space root, and list of entity paths)
• Specify entity properties
  • Split out to: Blueprint APIs for component overrides #5519

Notably this does not try to tackle:

• View Layout
• Data queries / filters
• Data-overrides / defaults

Proposed API:

# Trivial
rr.view.Spatial2D(origin="world/camera")

# Implies
rr.view.Spatial2D(origin="world/camera", contents="$origin/**")

EntityPathExpressionLike: (str, Sequence[str], EntityPathExpression)
Spatial2D(origin: str, contents: EntityPathExpressoinLike = "$origin/**")

# Which is syntactic sugar for:
entities = rr.view.EntityPathExpression("$origin/**")
rr.view.Spatial2D(origin="world/camera", contents=entities)

# With extra data
rr.view.Spatial2D(origin="world/camera", contents="+$origin/** +/world/points")

# Or for python formatter clarity, allow lists:
rr.view.Spatial2D(
    origin="world/camera",
    contents=[
        "+$origin/**",
        "+/",
    ],
)

[emilk]

Let's get started on the design of this ASAP

• What is the "entity path" of the selection panel?
• What is the "entity path" of a view?
• What happens if the UI set blueprint conflicts with the one set by the recording?
• Needs SDK design too
• Can we map the whole blueprint store to a nice JSON-like structure?
• How do we override entity components via the blueprint store

Current design outline: https://github.com/rerun-io/rerun/blob/main/design/blueprint_store.md

[jleibs]

Done in:

• MVP Blueprint APIs for layout and contents #5408
• Control panel expanded state via blueprint APIs #5484
• Add the remaining space views and name them consistently #5498