frames/skills/frames-animation/transitions/TRANSITION-REGISTRY.md

Transition Registry — machine source of truth

Single source of truth for PLV scene-to-scene transitions. The deterministic injector (product-launch-video/scripts/inject-transitions.mjs) reads the JSON block below and stamps the matching gsap_template onto the master timeline. The planner (product-launch-video/agents/visual-design.md) names a transition by its name; everything else is harness.

This file is not the catalog of all transitions — that is catalog.md + css-*.md (≈40 CSS + shader). This registry is the curated subset that is Tier-B-ready: pure transform / opacity / filter on the two scene clip wrappers (#el-<sid>), no injected overlay DOM, no per-scene cooperation. Overlay families (staggered blocks, blinds, light leak, grid dissolve, page burn) and shader transitions are deferred to later phases.

How the injector applies a transition

At a break boundary between scene i (from) and scene i+1 (to), the injector:

1. Extends #el-<from> wrapper data-duration by duration_s (holds its final frame — verified: core/src/runtime/init.ts:1393-1410 external-slot branch).
2. Pulls #el-<to> wrapper data-start earlier by duration_s (creates the overlap window).
3. Reassigns all clip data-track-index as a 0/1 ping-pong so the two overlapping wrappers never share a track (same-track overlap is illegal — core/src/lint/rules/composition.ts). Higher track composites on top.
4. Stamps the gsap_template into window.__timelines["main"] at T = overlap-start.

Verified by prototype render (2026-05-31): the master-timeline wrapper tween is seeked and rendered (no double-seek with the sub-comp's own paused timeline — the runtime drives them independently), the extended wrapper holds scene i's final frame, and the higher-track incoming wrapper composites over + blends with the outgoing one.

Template placeholders

The injector substitutes these tokens in each gsap_template line:

Token	Meaning
__OLD__	"#el-<from>" — outgoing clip wrapper selector (quoted)
__NEW__	"#el-<to>" — incoming clip wrapper selector (quoted)
__T__	overlap-start time in seconds (master clock)
__DUR__	duration_s for this boundary
__DX__	horizontal travel for directional types: -1920 (LEFT) / 1920 (RIGHT)
__DY__	vertical travel: -1080 (UP) / 1080 (DOWN)
__ORIGIN_OUT__ / __ORIGIN_IN__	transformOrigin pair for squeeze

filter / scaleX / transformOrigin are lint-clean on the master timeline (verified: core/src/lint/rules/gsap.ts has no per-property whitelist and scopes its checks to data-composition-id ranges; the x/y/scale/rotation/opacity whitelist is a scene-worker prompt rule only — it does not bind index.html).

Registry

{
  "transitions": [
    {
      "name": "crossfade",
      "tier": "b",
      "overlay": false,
      "energy": "any",
      "default_duration_s": 0.5,
      "directions": [],
      "source": "css-dissolve.md",
      "gsap_template": [
        "tl.to(__OLD__, { opacity: 0, duration: __DUR__, ease: \"power2.inOut\" }, __T__);",
        "tl.fromTo(__NEW__, { opacity: 0 }, { opacity: 1, duration: __DUR__, ease: \"power2.inOut\" }, __T__);"
      ]
    },
    {
      "name": "blur-crossfade",
      "tier": "b",
      "overlay": false,
      "energy": "calm",
      "default_duration_s": 0.6,
      "directions": [],
      "source": "css-dissolve.md",
      "note": "Default when the two scenes' #root backgrounds differ a lot — the blur masks the background-color clash a plain crossfade would expose.",
      "gsap_template": [
        "tl.to(__OLD__, { filter: \"blur(10px)\", scale: 1.03, opacity: 0, duration: __DUR__, ease: \"power2.inOut\" }, __T__);",
        "tl.fromTo(__NEW__, { filter: \"blur(10px)\", scale: 0.97, opacity: 0 }, { filter: \"blur(0px)\", scale: 1, opacity: 1, duration: __DUR__, ease: \"power2.inOut\" }, __T__);"
      ]
    },
    {
      "name": "push-slide",
      "tier": "b",
      "overlay": false,
      "energy": "medium",
      "default_duration_s": 0.5,
      "directions": ["LEFT", "RIGHT", "UP", "DOWN"],
      "default_direction": "LEFT",
      "source": "css-push.md",
      "note": "Directional. The injector picks __DX__/__DY__ from the direction and emits the horizontal OR vertical pair (not both).",
      "gsap_template_horizontal": [
        "tl.to(__OLD__, { x: __DX__, duration: __DUR__, ease: \"power3.inOut\" }, __T__);",
        "tl.fromTo(__NEW__, { x: __DXIN__, opacity: 1 }, { x: 0, duration: __DUR__, ease: \"power3.inOut\" }, __T__);"
      ],
      "gsap_template_vertical": [
        "tl.to(__OLD__, { y: __DY__, duration: __DUR__, ease: \"power3.inOut\" }, __T__);",
        "tl.fromTo(__NEW__, { y: __DYIN__, opacity: 1 }, { y: 0, duration: __DUR__, ease: \"power3.inOut\" }, __T__);"
      ]
    },
    {
      "name": "zoom-through",
      "tier": "b",
      "overlay": false,
      "energy": "high",
      "default_duration_s": 0.4,
      "directions": [],
      "source": "css-scale.md",
      "gsap_template": [
        "tl.to(__OLD__, { scale: 2.5, opacity: 0, filter: \"blur(8px)\", duration: __DUR__, ease: \"power3.in\" }, __T__);",
        "tl.fromTo(__NEW__, { scale: 0.5, opacity: 0, filter: \"blur(8px)\" }, { scale: 1, opacity: 1, filter: \"blur(0px)\", duration: __DUR__, ease: \"power3.out\" }, __T__);"
      ]
    },
    {
      "name": "squeeze",
      "tier": "b",
      "overlay": false,
      "energy": "medium",
      "default_duration_s": 0.4,
      "directions": [],
      "source": "css-push.md",
      "note": "Old compresses to a vertical line on the left edge; new expands from the right edge. Incoming starts off (scaleX 0) so its higher-track stacking is harmless.",
      "gsap_template": [
        "tl.to(__OLD__, { scaleX: 0, transformOrigin: \"left center\", duration: __DUR__, ease: \"power3.inOut\" }, __T__);",
        "tl.fromTo(__NEW__, { scaleX: 0, transformOrigin: \"right center\", opacity: 1 }, { scaleX: 1, transformOrigin: \"right center\", duration: __DUR__, ease: \"power3.inOut\" }, __T__);"
      ]
    }
  ],
  "tier_a_types": ["morph", "shared-element"],
  "default_high_energy": "zoom-through",
  "default_calm": "blur-crossfade",
  "max_duration_s": 2.0
}

Default-derivation (used by prep.mjs when the planner omits **Transition:**)

A break boundary with no named transition gets a default:

1. If the incoming scene's creative brief reads HIGH energy (explosive / kinetic / frenetic keywords), use default_high_energy (zoom-through).
2. Otherwise use default_calm (blur-crossfade) — the universal default. The blur masks any background shift and reads intentional, which keeps the whole video to ~2 transition types (the "repeat 2-3" principle).

Choosing as a planner (the only agent touchpoint)

Pick 2-3 types for the whole video and repeat them — repetition is what reads as professional (see overview.md). This budget counts the Tier-B between-scene types only (the 5 in the registry above); the Tier-A shared-element morph is a worker-authored bridge driven by narrative intent: morph — it is exempt and does not count toward the 2-3. Name the entering transition on each scene:

**Transition:** blur-crossfade
**Transition:** push-slide LEFT
**Transition:** zoom-through 0.3s

Omit the anchor to accept the default above. Do NOT write GSAP, touch timing, or edit index.html — the harness stamps the code, computes the overlap, and assigns tracks.