62fe0e7e-3025-47cc-bab0-d72875f1698e

src/components/ava/help-panel.tsx

@@ -23,6 +23,9 @@ const FRAME_VARS: [string, string][] = [
   ['w / h', 'canvas size in pixels'],
   ['aspect', 'canvas width / height -- divide x by it for perfect circles'],
   ['persist', 'motion-trail persistence 0..0.98 (writable per frame)'],
+  ['bgrot', 'background spin in radians per frame -- + clockwise, - counter-clockwise; 0 = off (set in [init] / [frame] / [beat]; persists like any variable)'],
+  ['bgx / bgy', 'background drift per frame, the -1..1 screen convention (y is up) -- slide the whole picture up, down, left or right'],
+  ['bgzoom', 'background scale per frame -- below 1 draw-in (shrinks toward the center), above 1 blow-out (expands); 1 = off'],
 ]
 
 const POINT_VARS: [string, string][] = [
@@ -62,6 +65,9 @@ const EXAMPLES: [string, string][] = [
   ['rot = rot + dt * 1.2 + beat * 0.4', 'beat kick'],
   ['ang = rand(i) * 6.28318', 'stable per-point random'],
   ['x = sin(i * 6.28318 + t) * rad / aspect', 'circle'],
+  ['bgrot = dir * (0.004 + exp(-beatage * 3) * 0.02)', 'the background spins to the music -- every beat accelerates it, then it relaxes (slow persist blends the trails)'],
+  ['if(above(bass, bass_att * 1.25), dir = -dir, 0)', 'a hard hit flips the background spin direction -- put this in [beat]'],
+  ['bgzoom = 1 - 0.001', 'draw-in -- the picture slowly spirals toward the center'],
 ]
 
 function HelpTable({ rows, mono = true }: { rows: [string, string][]; mono?: boolean }) {

src/lib/ava/embedded-presets.ts

@@ -7,16 +7,18 @@
 // for originals that rely on effects the script engine cannot run.
 //
 // The "Zai-Magic" folder at the END of EMBEDDED_LIBRARY is the exception to
-// "do not edit": ten presets HAND-AUTHORED for this engine (v7.00) to show
-// off beat-synced color — they use hsvr/hsvg/hsvb, beatage, megabuf particle
-// physics, getspec() and loop(). If the converter ever regenerates this
-// file, keep that section verbatim.
+// "do not edit": eleven presets HAND-AUTHORED for this engine (v7.00 + the
+// v7.12 osc-rotations addition) to show off beat-synced color and the v7.12
+// background transform -- they use hsvr/hsvg/hsvb, beatage, megabuf particle
+// physics, getspec(), loop() and the bg* framebuffer controls. If the
+// converter ever regenerates this file, keep that section verbatim.
 //
 // EMBEDDED_SEED_VERSION: bump whenever this library is regenerated — the
 // GET /api/presets route re-seeds the root/embedded subtree when it changes
-// (v7.10: em dashes in descriptions/script comments replaced with '--').
+// (v7.10: em dashes in descriptions/script comments replaced with '--';
+// v7.12: eleventh Zai-Magic preset "osc-rotations" added).
 
-export const EMBEDDED_SEED_VERSION = '7.10'
+export const EMBEDDED_SEED_VERSION = '7.12'
 
 export interface EmbeddedPreset {
   folder: string
@@ -842,11 +844,13 @@ export const EMBEDDED_LIBRARY: EmbeddedPreset[] = [
   },
 
   // ==========================================================================
-  // Zai-Magic — ten presets hand-authored for this engine (v7.00).
-  // Every one is built around BEAT-SYNCED COLOR: the color wheel turns on
-  // the kick, palettes swap per beat or per 4-beat bar, and kick envelopes
-  // (beatage) drive brightness. Techniques span all three render modes,
-  // megabuf particle physics, direct getspec() calls and loop() setup.
+  // Zai-Magic — eleven presets hand-authored for this engine (v7.00; the
+  // eleventh, "osc-rotations", shipped with v7.12). Every one is built around
+  // BEAT-SYNCED COLOR: the color wheel turns on the kick, palettes swap per
+  // beat or per 4-beat bar, and kick envelopes (beatage) drive brightness;
+  // osc-rotations adds the v7.12 background transform (bgrot/bgzoom) to the
+  // toolkit. Techniques span all three render modes, megabuf particle
+  // physics, direct getspec() calls and loop() setup.
   // KEEP VERBATIM when regenerating this file with the converter.
   // ==========================================================================
   {
@@ -1314,6 +1318,46 @@ red = hsvr(hue, sat, lum + flash * lit * 0.55)
 green = hsvg(hue, sat, lum + flash * lit * 0.55)
 blue = hsvb(hue, sat, lum + flash * lit * 0.55)
 size = 2.4 + lit * 1.7 + treb * 1.2
+`,
+  },
+  {
+    folder: "root/embedded/Zai-Magic",
+    name: "osc-rotations",
+    author: "Zai",
+    description:
+      "A stationary centered oscilloscope over a background that rotates to the music -- every beat temporarily accelerates the spin, a hard hit flips it between clockwise and counter-clockwise, and the fade to black stays slow so the colors blend. The left and right points of the line color-shift together while the center points hold their own hue. Hand-authored for OVE (v7.12 background transform + mirror-symmetric hsv color).",
+    content: `name: "osc-rotations"
+author: "Zai"
+mode: lines
+blend: additive
+persist: 0.965
+linewidth: 2.2
+
+[init]
+n = 512
+hue = 0.58
+dir = 1
+
+[frame]
+punch = exp(-beatage * 3.2)
+bgrot = dir * (0.0032 + punch * (0.014 + vol_att * 0.012))
+bgzoom = 1 - 0.0009 - punch * 0.0011
+hue = frac(hue + dt * 0.012 + beat * 0.02)
+
+[beat]
+if(above(bass, bass_att * 1.25), dir = -dir, 0)
+
+[point]
+x = i * 2 - 1
+y = v * (0.3 + vol_att * 0.8)
+d = abs(i - 0.5) * 2
+h = hue + d * 0.34
+lum = 0.5 + 0.38 * vol_att + punch * 0.22
+red = hsvr(h, 0.95, lum)
+green = hsvg(h, 0.95, lum)
+blue = hsvb(h, 0.95, lum)
+size = 2 + punch * 1.6
+alpha = 0.92
 `,
   },
 ]

src/lib/ava/engine.ts

@@ -16,6 +16,15 @@ import { DEFAULT_BAND_CONFIG, DEFAULT_BEAT_CONFIG } from './types'
 const MAX_POINTS = 8192
 const POINT_STRIDE = 8 // x, y, red, green, blue, skip, size, alpha
 
+/** Read a script bg* control value. Non-finite (NaN / Infinity from a bad
+ *  script computation) and missing values fall back to the neutral value --
+ *  a NaN must never reach a canvas transform (it poisons the matrix and every
+ *  later draw becomes a silent no-op: a black screen with no error). */
+function bgNum(v: number | undefined, neutral: number): number {
+  const x = typeof v === 'number' ? v : neutral
+  return Number.isFinite(x) ? x : neutral
+}
+
 export interface EngineStats {
   fps: number
   levels: BandLevels
@@ -54,6 +63,12 @@ export class AvaEngine {
   /** ctx.filter support (older Safari lacks it → plain crossfade fallback). */
   private canFilter = false
 
+  /** v7.12 background-feedback buffer. Same pixel size as the live canvas;
+   *  recreated automatically on resize. Null until a script first asks for a
+   *  background transform (zero cost for every preset that doesn't). */
+  private bgBuffer: HTMLCanvasElement | null = null
+  private bgBufCtx: CanvasRenderingContext2D | null = null
+
   constructor() {
     // AVS-eel compatibility hooks — the expression engine reads audio/time
     // through these (getspec/getosc/gettime). Headless tests can override.
@@ -141,6 +156,60 @@ export class AvaEngine {
     return this.script?.meta.name ?? '--'
   }
 
+  /**
+   * v7.12 — background feedback transform (the AVS movement family).
+   *
+   * The whole framebuffer is moved BEFORE this frame's points are drawn:
+   *   1. snapshot the live canvas into the offscreen buffer;
+   *   2. wipe the canvas black;
+   *   3. draw the snapshot back through the frame's transform.
+   *
+   *   bgrot   radians per frame — + rotates the picture CLOCKWISE on screen
+   *           (canvas y is down, so ctx.rotate(+θ) spins cw); - = ccw.
+   *   bgx/bgy drift per frame in the -1..1 screen convention (y is UP,
+   *           matching script x/y) — slide up, down, left, right.
+   *   bgzoom  per-frame scale — <1 draw-in (shrinks toward center),
+   *           >1 blow-out (expands outward); 1 = neutral.
+   *
+   * Uncovered regions (rotated corners, slid-off edges) read black, and the
+   * persistence fade (persist header / env.persist) blends the trails —
+   * which is exactly how the classic AVS plugins made "speed accelerates to
+   * the beat, a hard hit flips the spin, fade to black stays slow" work:
+   * the rate is just a script variable driven by beatage envelopes, and a
+   * [beat] section flips the sign on a hard hit (bass vs bass_att).
+   */
+  private applyBackground(w: number, h: number, rot: number, tx: number, ty: number, zoom: number): void {
+    const canvas = this.canvas
+    const ctx = this.ctx
+    if (!canvas || !ctx) return
+    if (!this.bgBuffer || this.bgBuffer.width !== w || this.bgBuffer.height !== h) {
+      const buf = document.createElement('canvas')
+      buf.width = w
+      buf.height = h
+      this.bgBuffer = buf
+      this.bgBufCtx = buf.getContext('2d')
+    }
+    const bctx = this.bgBufCtx
+    if (!bctx || !this.bgBuffer) return
+    // 1. snapshot the live canvas ('copy' replaces the buffer wholesale)
+    bctx.globalCompositeOperation = 'copy'
+    bctx.drawImage(canvas, 0, 0)
+    // 2. wipe — the transformed snapshot must REPLACE the old content, not
+    //    double-expose over it
+    ctx.globalCompositeOperation = 'source-over'
+    ctx.fillStyle = '#000'
+    ctx.fillRect(0, 0, w, h)
+    // 3. draw the snapshot back through this frame's transform. Screen y is
+    //    down; script y is up — bgy > 0 moves the picture UP.
+    ctx.save()
+    ctx.imageSmoothingEnabled = true
+    ctx.translate(w / 2 + tx * (w / 2), h / 2 - ty * (h / 2))
+    if (rot !== 0) ctx.rotate(rot)
+    if (zoom !== 1) ctx.scale(zoom, zoom)
+    ctx.drawImage(this.bgBuffer, -w / 2, -h / 2)
+    ctx.restore()
+  }
+
   private resize(): void {
     if (!this.canvas) return
     const parent = this.canvas.parentElement
@@ -227,6 +296,20 @@ export class AvaEngine {
       } catch (err) {
         this.scriptError = `runtime error: ${String(err)}`
       }
+
+      // ---- background feedback transform (v7.12) --------------------------
+      // AVS-style whole-framebuffer movement, read AFTER [frame]/[beat] ran
+      // so this frame's values apply this frame. Set from [init] (persists
+      // forever), [frame] or [beat] (every frame / on the kick). Values live
+      // in env like any variable: a script that sets them only on beats gets
+      // on-beat jumps. Neutral readings skip the pass entirely.
+      const bgRot = Math.max(-0.6, Math.min(0.6, bgNum(env.bgrot, 0)))
+      const bgX = Math.max(-0.25, Math.min(0.25, bgNum(env.bgx, 0)))
+      const bgY = Math.max(-0.25, Math.min(0.25, bgNum(env.bgy, 0)))
+      const bgZoom = Math.max(0.5, Math.min(2, bgNum(env.bgzoom, 1)))
+      if (bgRot !== 0 || bgX !== 0 || bgY !== 0 || bgZoom !== 1) {
+        this.applyBackground(w, h, bgRot, bgX, bgY, bgZoom)
+      }
     }
 
     // ---- point evaluation ---------------------------------------------------

src/lib/release-notes.ts

@@ -39,6 +39,20 @@ export interface ReleaseNote {
 }
 
 export const RELEASE_NOTES: ReleaseNote[] = [
+  {
+    version: '7.12',
+    name: 'Background movement (AVS-style) + osc-rotations',
+    changes: [
+      {
+        kind: 'added',
+        text: 'Scripts can move the whole picture now: bgrot spins the background clockwise or counter-clockwise, bgx / bgy slide it up, down, left or right, and bgzoom draws it in or blows it out -- the movement family the classic Winamp AVS plugins were built on. The speed can ride the music: accelerate on every beat, flip the spin direction on a hard hit, and let a slow fade to black blend the colors. All four variables are documented in the script editor\'s help panel.',
+      },
+      {
+        kind: 'added',
+        text: 'I added an eleventh Zai-Magic preset: "osc-rotations" -- a stationary centered oscilloscope whose left and right points color-shift together while the center points hold their own hue, over a background that rotates clockwise and counter-clockwise to the music and temporarily accelerates with the beat. Hard hits flip the spin; the fade stays slow so the colors blend.',
+      },
+    ],
+  },
   {
     version: '7.11',
     name: 'Wake lock, a respectful Demo, one-click save',

src/lib/version.ts

@@ -12,6 +12,40 @@
 // warns in the console when the two drift apart.
 //
 // History:
+//   7.12 — background movement + osc-rotations. Scripts can now move the
+//           whole framebuffer every frame, the way the classic Winamp AVS
+//           plugins did: bgrot (radians/frame, + clockwise on screen),
+//           bgx / bgy (per-frame drift in the -1..1 screen convention, y
+//           up), bgzoom (< 1 draw-in, > 1 blow-out) -- read after [frame]/
+//           [beat] so this frame's values apply this frame. The engine
+//           snapshots the canvas into an offscreen buffer, wipes, and
+//           draws the snapshot back through the transform, so the
+//           persistence fade blends the moving trails: "speed accelerates
+//           to the beat, a hard hit flips the spin, fade to black stays
+//           slow" is pure script (a beatage envelope drives the rate; a
+//           [beat] section flips a dir variable on hard hits via bass vs
+//           bass_att). Neutral readings (0/0/0/1) skip the pass entirely
+//           (zero cost for every preset that doesn't move); non-finite
+//           values fall back to neutral (a NaN in a canvas transform
+//           matrix would black the screen with no error); per-frame
+//           clamps: rot ±0.6 rad, drift ±0.25, zoom 0.5..2. New 11th
+//           Zai-Magic preset "osc-rotations" (user-requested): a
+//           stationary centered oscilloscope (time-domain v) whose color
+//           is mirror-symmetric -- points equidistant left/right of
+//           center shift together, the center points hold their own hue
+//           -- over a background rotating cw/ccw to the music that
+//           temporarily accelerates on the beat; hard hits
+//           (bass > 1.25 × bass_att) flip the spin; a whisper of draw-in
+//           (bgzoom ~0.999) spirals the trails inward; persist 0.965
+//           keeps the fade slow so colors blend. Help panel: bg* variable
+//           rows + three new example formulas. EMBEDDED_SEED_VERSION
+//           7.10 -> 7.12 (library re-seed adds the preset; the share
+//           codec's dictionary stays frozen per its compatibility
+//           contract -- bg* identifiers ride the pair packing like any
+//           custom variable). Headless validation of the preset's
+//           compiled programs: quiet 0.004 rad/frame, hard beat 0.026
+//           (6.5×) + direction flip, soft beat no flip, mirrored points
+//           share hue / center distinct
 //   7.11 — wake lock, a respectful Demo button, one-click save. While any
 //           audio source is live the site holds a Screen Wake Lock so phone
 //           and tablet screens stay on (released the moment the engine goes
@@ -340,4 +374,4 @@
 
 export const APP_NAME = 'Open Visualization Engine'
 export const APP_SHORT = 'OVE'
-export const APP_VERSION = '7.11'
+export const APP_VERSION = '7.12'

worklog.md

@@ -2240,3 +2240,55 @@ VERIFICATION (three independent measurements):
 
 Stage Summary:
 - v7.10.1 shipped: the frozen right edge of every spectrum visual is unfrozen. The bar field now spans ~12 Hz to 16 kHz (the range music actually occupies) instead of stretching to Nyquist, so the right bars land on the 10-16 kHz air band and dance with the hats/cymbals. The user's own Spectrum Bars script (whose 0.78+0.45*f treble tilt now has something real to boost) verified live: rightmost bars swing 4..76%.
+
+---
+Task ID: 38
+Agent: main (Z.ai Code)
+Task: v7.11 (user request, three parts). RESTORED RETROACTIVELY — the entry was lost in a session cutoff (same as Task 35 once was); scope reconstructed from the version.ts 7.11 history and the tool-results/v711-* evidence screenshots (v711-01 through v711-22, all PASS). (1) Mobile wake lock: while any audio source is live the site holds a Screen Wake Lock so phone/tablet screens stay on; released the moment the engine goes idle so normal inactivity dimming returns. (2) A respectful Demo Track button: no longer force-engages the Sequence checkbox when the visitor has loaded a preset (tree double-click / Load / copied preset) or brought their own script material into the editor — Demo just plays the track; the Zai-Magic showcase only starts for a visit that never picked or typed anything. (3) Script tab one-click Save: a valid script shows the Save button with no save target needed; auto-names from the script's name header (a hash import of "Spectrum Bars:[▼…]" saves as "Spectrum Bars"), "Empty Name" when nameless, " (1)"/" (2)"… suffixes on conflicts — and when the name had to be invented, a "Give This Preset a Name" dialog opens to rename the just-saved preset in one step (saved FIRST, renamed second, so nothing is ever lost).
+
+Work Log (reconstructed):
+- src/lib/ava/wake-lock.ts (NEW): Screen Wake Lock sentinel manager — acquire on source-live, release on idle, visibilitychange re-acquire (browsers silently drop the sentinel on hide), silent degradation where unsupported.
+- audio-source.ts / control-panel / page.tsx: per-visit manualChoice flag + boot-script snapshot decide whether the Demo showcase may engage; ensureDefaultPreset gained the same guard (mic/file/link never clobber a custom draft either). Demo teardown paths (ended/stop/switch) all respect it.
+- script-tab.tsx: Save button visible on any valid script with no target; auto-naming ladder (script name header -> hash import label -> "Empty Name" -> conflict suffixes); "Give This Preset a Name" dialog after any invented save. Hash⇢Script imports clear the stale save target and pass the decoded label through as the fallback name.
+- version.ts 7.11 + history; release-notes.ts 7.11 entry.
+
+E2E (evidence: tool-results/v711-01..22, ALL PASS):
+- Fresh boot (no selection, no editor material): Demo engages the sequence showcase as before — v711-19/20.
+- Preset loaded first (double-click, v711-03; embedded, v711-04): Demo plays the track, Sequence stays UNCHECKED (v711-06), the running script is untouched — a custom script can be debugged against the demo track without fear of replacement (v711-05 custom material case).
+- Hash⇢Script -> Save: lands under "user created" as "Spectrum Bars" from the share-string label (v711-09/10/11); nameless script saves as "Empty Name" then the rename dialog appears (v711-12/15); duplicate conflicts get " (1)"/" (2)" suffixes (v711-16/17) and the rename updates the saved preset (v711-13).
+- Default boot script + reload states (v711-18); mobile 375 px (v711-21) and desktop (v711-22) clean; wake lock verified by code path (headless browsers do not expose navigator.wakeLock — degrade-silent branch exercised).
+
+Stage Summary:
+- v7.11 shipped: the screen stays on while music plays, the Demo button stopped hijacking the preset selection, and one click saves any valid script with a smart name. This restored entry closes the gap in the build diary.
+
+---
+Task ID: 39
+Agent: main (Z.ai Code)
+Task: v7.12 (user request): add the classic-AVS background-movement family to the scripting — the background shifts up/down/left/right, spins clockwise/counter-clockwise, draws in and blows out, with the speed accelerating to the beat and hard hits flipping the spin direction while the fade to black stays slow (so colors blend) — then ship a permanent Zai-Magic preset "osc-rotations": a stationary centered oscilloscope whose left/right points color-shift together and whose center points hold their own hue, over a background rotating cw/ccw to the music with temporary beat acceleration.
+
+Work Log:
+- src/lib/ava/engine.ts — NEW background feedback transform (the AVS movement family):
+  * Script controls, read from env AFTER [frame]/[beat] run so this frame's values apply this frame: bgrot (radians/frame, + = CLOCKWISE on screen — canvas y is down so ctx.rotate(+) spins cw), bgx/bgy (per-frame drift, the -1..1 screen convention, y is UP matching script x/y), bgzoom (per-frame scale: <1 draw-in, >1 blow-out, 1 = neutral). Values persist in env like any variable — set from [init] (persists forever), [frame] (every frame) or [beat] (on-beat jumps); neutral readings skip the pass entirely (zero cost for every preset that doesn't move).
+  * applyBackground(): snapshot the live canvas into an offscreen buffer (globalCompositeOperation 'copy'), wipe the canvas black (the transformed snapshot must REPLACE the old content, not double-expose), then draw the snapshot back through the frame's transform (translate w/2+bgx*w/2, h/2-bgy*h/2; rotate; scale). Uncovered regions (rotated corners, slid-off edges) read black and the persistence fade blends the trails — exactly how the classic AVS plugins made "speed accelerates to the beat, a hard hit flips the spin, fade stays slow" work: the rate is just a script variable driven by a beatage envelope, and a [beat] section flips a dir variable on hard hits (bass vs bass_att).
+  * Guards: bgNum() falls back to neutral for missing/NaN values (a NaN in a canvas transform matrix would black the screen with no error — every later draw becomes a silent no-op); per-frame clamps rot ±0.6 rad, drift ±0.25, zoom 0.5..2. Buffer recreated automatically on resize; null until first use (zero cost otherwise). Gated on this.script so a stale env after clearScript can never spin a blank canvas.
+- src/lib/ava/embedded-presets.ts — eleventh Zai-Magic preset "osc-rotations" (user-named, lowercase so it sorts last in the tree): persist 0.965 (slow fade — colors blend), [frame] drives bgrot = dir * (0.0032 + punch * (0.014 + vol_att * 0.012)) with punch = exp(-beatage*3.2) (temporary beat acceleration that relaxes with the kick ring), bgzoom = 1 - 0.0009 - punch*0.0011 (a whisper of draw-in so trails spiral inward instead of ringing), hue drifts dt*0.012 + beat*0.02; [beat] flips dir on hard hits only (bass > 1.25 * bass_att — soft beats leave the spin alone); [point] draws the stationary centered scope x = i*2-1, y = v*(0.3+vol_att*0.8) with mirror-symmetric color h = hue + |i-0.5|*2 * 0.34 (points equidistant left/right of center share one hue, the center holds its own). EMBEDDED_SEED_VERSION 7.10 -> 7.12 (route re-seeds the subtree; fingerprint self-heal would have caught it too). "ten presets" comments updated to eleven (both the file-top and the Zai-Magic section header).
+- src/components/ava/help-panel.tsx — bgrot / bgx/bgy / bgzoom rows in the variables table + three example formulas (beat-accelerated spin, hard-hit direction flip in [beat], draw-in).
+- src/lib/version.ts 7.12 + history; src/lib/release-notes.ts 7.12 entry (2x added, first-person voice). Share codec deliberately untouched: its dictionary is a frozen compatibility contract (adding entries needs a new scheme marker) — bg* identifiers ride the pair packing like any custom variable.
+
+HEADLESS VALIDATION (/home/z/tmp-validate/bg-transform/validate-osc.ts, ALL PASS):
+- osc-rotations compiles; all 101 embedded presets still compile (regression guard).
+- Compiled-program behavior: quiet frame bgrot 0.00397 rad/frame cw + bgzoom 0.99906; hard beat bgrot 0.0256 (6.5x) AND dir flips to -1; soft beat no flip; point pass x spans ±1 with |y| symmetric, mirrored positions share hue exactly (0.7906 both) while center is distinct (0.6206).
+
+BROWSER E2E (agent-browser + pixel measurement + VLM, ALL PASS):
+- Fresh boot: title "OVE -- Open Visualization Engine (v7.12)"; tree shows "Zai-Magic -- 11"; /api/presets re-seeded on the version gate and serves osc-rotations (106 presets total; sorts last in Zai-Magic as designed).
+- Preset live on the demo collection (manual load first, then Demo Track — v7.11's respectful-Demo still holds: Random/Sequence stayed UNCHECKED with a preset loaded): footer "SCRIPT: osc-rotations · Demo Track 1/2 · FPS 59-60 · PTS 512 · BPM 132.3/138.8 locked". Mid-band (scope zone) mean 133/255; outer zones lit only by rotation-carried trails.
+- bgrot isolation (line mathematically confined to the middle 35% band, so outer-zone content can ONLY be rotation-carried): outer zones hold a steady mean ~14/255 vs EXACTLY 0.00 in the no-bg control — rotation puts content where the line cannot reach.
+- bgx sign: +0.012 drifts the bright cloud right (mean x 0.518); -0.012 mirrors it exactly (0.480) — the sign convention verified by symmetry.
+- bgy sign: +0.02 pulls the bright cloud UP (mean y-from-top 0.368 vs 0.5 neutral).
+- bgzoom: at 1.05/frame the outer zones went from dead 0.00 to ~38/255 (blow-out pushes the confined line's trails outward); at 1.003/frame with persist 0.92 trails die before traveling far (consistent with the fade math — equilibrium analysis, not a defect).
+- What's New dialog: 7.12 "Background movement (AVS-style) + osc-rotations" first with CURRENT badge, drift guard silent. Help panel: bg* rows + examples all present.
+- VLM on the live screenshot: horizontal oscillating waveform line at vertical center; large soft colorful trail masses around it; hue variation green at the outer left/right edges, yellow mid, red/pink at the center — the mirror-symmetric color design visibly realized; no defects; "60 FPS . 512 PTS" overlay normal.
+- Console clean (0 errors/0 warnings); dev.log clean (59 successful requests, no compile errors). Footer: sticks to the viewport bottom on short pages (1280x800 Beat tab: docH 800, footer bottom 800) and pushes to the document end on long pages (375 px Presets tab: docH 1469, footer at doc end, no overlap); 375 px scrollWidth 375 = clientWidth (no horizontal overflow). Test-browser localStorage cleared afterwards.
+
+Stage Summary:
+- v7.12 shipped: scripts can move the whole picture — bgrot spins, bgx/bgy slide, bgzoom draws in / blows out — with the speed riding the music exactly the way the classic AVS plugins did it (beatage envelopes drive the rate, [beat] flips the spin on hard hits, persist keeps the fade slow so colors blend). The eleventh Zai-Magic preset "osc-rotations" demonstrates the full recipe: a stationary centered oscilloscope with mirror-symmetric color (left/right shift together, center holds its own hue) over a beat-accelerated, hard-hit-flipping rotating background.