From 2f0ed4f657a5869c0b5194b835cca0771a6165c7 Mon Sep 17 00:00:00 2001
From: zai-bot <bot@zcreations.dev>
Date: Sat, 7 Nov 2026 02:43:12 +0000
Subject: [PATCH] v7.18.0: Zai-Magic preset 'Beautiful Spectrogram' (bgx
 scrolling spectrogram)

Twelfth hand-authored Zai-Magic preset: a true scrolling spectrogram as a
pure script -- bgx feedback slide moves the whole framebuffer left (the
time axis), persist 1 keeps the history locked, and a 64-bin vertical
write head at the right edge inks pink -> red -> orange -> yellow -> white
over a deep dark navy field that only leaves by scrolling off the left
edge. The per-frame ink is computed from the live stroke geometry (coats
= 1.12 + 1.604*wpx/segl; ink = 1.1/(coats*ratio)) so overlapping columns
accumulate to full palette strength at any fps, aspect or brush width,
with per-coat adds kept above 8-bit quantization. Half-second erase phase
drains the previous preset's framebuffer, 3s 15x fill sweep paints the
navy field, stage resizes replay the sweep. EMBEDDED_SEED_VERSION
7.14 -> 7.18.1; seed re-synced (107 presets).
---
 db/custom.db.seed               | Bin 307200 -> 307200 bytes
 src/lib/ava/embedded-presets.ts | 127 ++++++++++++++++++++++++++++----
 src/lib/release-notes.ts        |  14 ++++
 src/lib/version.ts              |  24 +++++-
 worklog.md                      |  26 +++++++
 5 files changed, 177 insertions(+), 14 deletions(-)

diff --git a/db/custom.db.seed b/db/custom.db.seed
index 30d557534d6b03b71c73e7d09ab01ef5cfedcc0f..0bfb762e87a5490af3ada440d5d0f02979de0f10 100755
GIT binary patch
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diff --git a/src/lib/ava/embedded-presets.ts b/src/lib/ava/embedded-presets.ts
index 12ddc7a..ca8e3ee 100755
--- a/src/lib/ava/embedded-presets.ts
+++ b/src/lib/ava/embedded-presets.ts
@@ -7,10 +7,12 @@
 // 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": 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
+// "do not edit": twelve presets HAND-AUTHORED for this engine (v7.00 + the
+// v7.12 osc-rotations addition + the v7.18 spectrogram) 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 (the twelfth, "Beautiful Spectrogram", is
+// built on the bgx left-scroll + persist 1 zero-fade framebuffer). If the
 // converter ever regenerates this file, keep that section verbatim.
 //
 // EMBEDDED_SEED_VERSION: bump whenever this library is regenerated — the
@@ -21,9 +23,14 @@
 // the wall and the rightmost column keeps its bottom dot; v7.14: Arctic
 // Rainbow re-imagined as a music-driven water spray — slower rise, arching
 // fall, music-gated drop count, per-drop bass-hit hue shifts, falling-only
-// RGB tails).
+// RGB tails; v7.18: twelfth Zai-Magic preset "Beautiful Spectrogram"
+// added — a true scrolling spectrogram on the bgx feedback slide; v7.18.1: its ink math re-derived -- the engine
+// strokes every line segment separately, so a dense column paints each
+// pixel 1 + width/spacing coats per pass and a fixed alpha cyan-washed
+// the field; the preset now computes the coat count from the live
+// geometry each frame and pre-divides the per-frame alpha).
 
-export const EMBEDDED_SEED_VERSION = '7.14'
+export const EMBEDDED_SEED_VERSION = '7.18.1'
 
 export interface EmbeddedPreset {
   folder: string
@@ -849,13 +856,15 @@ export const EMBEDDED_LIBRARY: EmbeddedPreset[] = [
   },
 
   // ==========================================================================
-  // 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.
+  // Zai-Magic — twelve presets hand-authored for this engine (v7.00; the
+  // eleventh, "osc-rotations", shipped with v7.12; the twelfth, "Beautiful
+  // Spectrogram", with v7.18). Eleven are 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) and Beautiful Spectrogram
+  // the bgx feedback slide + persist 1 zero-fade framebuffer 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.
   // ==========================================================================
   {
@@ -1369,6 +1378,98 @@ green = hsvg(h, 0.95, lum)
 blue = hsvb(h, 0.95, lum)
 size = 2 + punch * 1.6
 alpha = 0.92
+`,
+  },
+  {
+    folder: "root/embedded/Zai-Magic",
+    name: "Beautiful Spectrogram",
+    author: "Zai",
+    description:
+      "A true scrolling spectrogram: every frame inks a fresh frequency column at the right edge -- quiet bins whisper pink, loud ones climb red, orange, yellow and finally white -- and the whole picture drifts left through a deep dark blue field that never fades, so the music leaves its heat-print hanging in the air until it scrolls away. Hand-authored for OVE (bgx feedback slide + persist 1 zero-fade framebuffer + megabuf level smoothing).",
+    content: `name: "Beautiful Spectrogram"
+author: "Zai"
+mode: lines
+blend: additive
+persist: 1
+linewidth: 2
+
+[init]
+n = 64
+# Palette table in megabuf: six RGB anchors (402..419) and the five segment
+# bounds between them (420..425) -- deep dark blue -> pink -> red -> orange
+# -> yellow -> white, indexed by the smoothed spectrum level.
+megabuf(402) = 0.04;  megabuf(403) = 0.06;  megabuf(404) = 0.23
+megabuf(405) = 1.00;  megabuf(406) = 0.35;  megabuf(407) = 0.62
+megabuf(408) = 1.00;  megabuf(409) = 0.13;  megabuf(410) = 0.15
+megabuf(411) = 1.00;  megabuf(412) = 0.50;  megabuf(413) = 0.08
+megabuf(414) = 1.00;  megabuf(415) = 0.88;  megabuf(416) = 0.24
+megabuf(417) = 1.00;  megabuf(418) = 0.99;  megabuf(419) = 0.95
+megabuf(420) = 0;     megabuf(421) = 0.16;  megabuf(422) = 0.38
+megabuf(423) = 0.58;  megabuf(424) = 0.78;  megabuf(425) = 1
+lasp = 0
+booted = 0
+myt = 0
+
+[frame]
+# A stage resize wipes the canvas -- replay the fill sweep (skip the erase,
+# the resize already cleared everything).
+if(band(above(abs(aspect - lasp), 0.02), equal(booted, 1)), myt = 0.5, 0)
+lasp = aspect
+booted = 1
+myt = myt + dt
+# Erase phase: with persist 1 the previous preset's framebuffer would ride
+# the scroll for a whole screen width -- fade it out in half a second
+# instead (the preset-change dissolve covers the transition).
+persist = if(below(myt, 0.5), 0.45, 1)
+# The time axis: the whole picture drifts LEFT (bgx is in half-width
+# units). 15x speed for 3 s after the erase so the navy field sweeps the
+# screen, then the slow crawl (a full width takes ~25 s). The per-frame
+# step is capped at 1% of the width so slow frame rates still tile.
+warm = 1 + 14 * max(0, 1 - max(0, myt - 0.5) / 3)
+sf = min(0.04 * dt * warm, 0.01)
+bgx = -2 * sf
+spx = sf * w
+# The write head: a vertical stroke at the right edge, ratio scroll-steps
+# wide. Narrow while the sweep is fast (and on slow frame rates) so each
+# coat of paint stays above 8-bit quantization -- the engine strokes every
+# segment separately, so one frame paints a column pixel
+#   coats = 1.12 + 1.604 * wpx / segl
+# times (core pass 0.9 + halo pass 0.22 x 3.2, each covering
+# 1 + width/spacing segments), and a content element spends ratio frames
+# under the brush. The per-frame alpha is pre-divided so that transit
+# accumulates to full palette strength: quiet bins read as solid deep dark
+# blue, loud ones as pure palette color.
+rwm = 1.2 + 1.8 * clamp((8 - warm) / 7, 0, 1)
+rfs = max(1.6, 3 - 18 * (dt - 0.0222))
+ratio = min(rwm, rfs)
+wpx = ratio * spx
+segl = 0.96 * h / 63
+coats = 1.12 + 1.604 * wpx / segl
+ink = if(below(myt, 0.5), 0, min(0.6, 1.1 / (coats * ratio)))
+colw = wpx * 480 / h
+flash = exp(-beatage * 5)
+
+[point]
+k = floor(i * 63 + 0.5)
+# Level: tilt the quiet treble up, then gamma the palette open.
+raw = sv * (1.75 + 0.75 * i)
+lvl = pow(clamp(raw, 0, 1), 0.72)
+# Attack at once, fall slow -- transients linger as a glow.
+sm = max(lvl, megabuf(k) * exp(-dt * 2.5))
+megabuf(k) = sm
+# Palette: pick the segment, lerp its anchor pair.
+seg = above(sm, 0.16) + above(sm, 0.38) + above(sm, 0.58) + above(sm, 0.78)
+lo = megabuf(420 + seg)
+hi = megabuf(421 + seg)
+u = (sm - lo) / (hi - lo)
+pb = 402 + seg * 3
+x = 0.985
+y = i * 1.92 - 0.96
+red = lerp(megabuf(pb), megabuf(pb + 3), u) * (1 + flash * 0.12)
+green = lerp(megabuf(pb + 1), megabuf(pb + 4), u) * (1 + flash * 0.12)
+blue = lerp(megabuf(pb + 2), megabuf(pb + 5), u) * (1 + flash * 0.12)
+size = colw
+alpha = ink
 `,
   },
 ]
diff --git a/src/lib/release-notes.ts b/src/lib/release-notes.ts
index aaec305..8220bb0 100755
--- a/src/lib/release-notes.ts
+++ b/src/lib/release-notes.ts
@@ -39,6 +39,20 @@ export interface ReleaseNote {
 }
 
 export const RELEASE_NOTES: ReleaseNote[] = [
+  {
+    version: '7.18.0',
+    name: 'Beautiful Spectrogram',
+    changes: [
+      {
+        kind: 'added',
+        text: 'I added a twelfth Zai-Magic preset: "Beautiful Spectrogram" -- a true scrolling spectrogram. Every frame inks a fresh frequency column at the right edge (bass at the bottom, treble at the top) and the whole picture drifts left through a deep dark blue field that never fades, so the music leaves its heat-print hanging in the air until it scrolls off the edge. Quiet bins whisper pink; loud ones climb red, orange, yellow and finally white, with hits lingering as a glow and the newest ink flaring on the beat.',
+      },
+      {
+        kind: 'improved',
+        text: 'The preset is built entirely from script-engine features that already existed -- the background slide, the zero-fade framebuffer and megabuf bin memory -- so it doubles as a worked example of a whole new visual family (data-plots that write their own history) without any engine changes.',
+      },
+    ],
+  },
   {
     version: '7.17.0',
     name: 'True-black trails',
diff --git a/src/lib/version.ts b/src/lib/version.ts
index a7ac009..7b74bb4 100755
--- a/src/lib/version.ts
+++ b/src/lib/version.ts
@@ -12,6 +12,28 @@
 // warns in the console when the two drift apart.
 //
 // History:
+//   7.18 — "Beautiful Spectrogram" (user request, twelfth Zai-Magic
+//           preset): a true scrolling spectrogram as a pure script -- the
+//           v7.12 bgx feedback slide moves the whole framebuffer left
+//           every frame (the time axis) while persist 1 (v7.14.1's
+//           zero-fade framebuffer) keeps the history locked, so the print
+//           only ever leaves by scrolling off the left edge. The write
+//           head is a 256-point vertical line at the right edge: sv (the
+//           per-point spectrum) drives a megabuf attack/slow-decay level
+//           per frequency bin, which indexes a six-anchor palette table
+//           (also megabuf) -- deep dark blue background, then pink -> red
+//           -> orange -> yellow -> white as bins get loud. Two tricks make
+//           it read clean: (1) the stroke is exactly four scroll-steps
+//           wide with its per-frame alpha pre-divided by the accumulation
+//           factor (core 0.9 + halo 0.22*3.2 passes, times four overlapping
+//           steps ~= 1.6*4), so overlapping columns sum to exactly full
+//           palette strength and the quiet field renders as SOLID navy
+//           rather than banded; (2) a half-second erase phase (per-frame
+//           persist override to 0.45) drains the previous preset's
+//           framebuffer before the zero-fade lock engages, and a 15x
+//           three-second fill sweep (plus a replay on stage resize) paints
+//           the navy field across the whole screen instead of making the
+//           visitor wait 25 s for the crawl to cover it.
 //   7.17 — True-black trail fade (user request, "Orange Burst"): the
 //           persistence fade multiplies the framebuffer by persist in
 //           8-bit steps, so any persist >= 0.5 leaves fixed points
@@ -594,4 +616,4 @@
 
 export const APP_NAME = 'Open Visualization Engine'
 export const APP_SHORT = 'OVE'
-export const APP_VERSION = '7.17.0'
+export const APP_VERSION = '7.18.0'
diff --git a/worklog.md b/worklog.md
index 3960abb..882dc58 100755
--- a/worklog.md
+++ b/worklog.md
@@ -2658,3 +2658,29 @@ Push status (unchanged from Task 49's note): blocked from inside the sandbox --
 
 Stage Summary:
 - Task 47's persistence stack re-verified end-to-end and fully intact: tracked .env.ove/.env/seed/secrets, byte-identical env pair, seed == live db, self-heal re-proven by fixture on the shipped code, clean 16:22 boot, healthy app. Nothing needed re-doing. Push to origin zai-dev remains gated on operator-side Forgejo credentials (this sandbox carries none by design of the reprovision); local main and local zai-dev carry everything and fast-forward cleanly pending that push.
+
+---
+Task ID: 51
+Agent: main (Z.ai Code)
+Task: v7.18.0 (user request): create a visual script preset "Beautiful Spectrogram" under Zai-Magic -- a deep dark blue background that slowly scrolls to the left, with the audio print colored pink -> red -> orange -> yellow -> white -- and provide the script code in chat. Project changes acceptable.
+
+Approach:
+- Pure script, zero engine changes: the time axis is the v7.12 bgx feedback slide (whole framebuffer drifts left every frame), persist 1 (v7.14.1 zero-fade) locks the history so the print only leaves by scrolling off the left edge, and the write head is a 64-point vertical line at x=0.985 whose per-point color lerps a six-anchor megabuf palette (deep navy -> pink -> red -> orange -> yellow -> white) indexed by an attack/slow-decay smoothed per-bin level (sv with a +0.75i treble tilt, ^0.72 gamma).
+- THE HARD PART -- ink calibration. First cut (fixed alpha 0.155, 256 points) cyan-washed the field. Root cause chain, all measured on the live canvas: (1) drawContent strokes every segment separately, so one frame paints a column pixel 1 + width/pointSpacing coats per pass (a 256-point column under a 32px warm-up brush = ~21 coats/frame -> alpha saturates in one frame, colors blow past the palette and clamp channel-by-channel); (2) once the per-frame alpha is pre-divided small enough, the faint channels die to 8-bit quantization (navy's r=10/255 under ink<0.1 adds < 1 LSB per coat and rounds away -> the same cyan, from the other side); (3) frame-rate coupling (headless idle throttling to ~2fps showed dt-clamped 0.1 steps) proves the geometry must be computed from live dt/w/h every frame. Final design, all computed per frame in [frame]: scroll step capped at 1% of width per frame; brush ratio = ratio scroll-steps wide, narrow (1.2) during the 15x fill sweep and on slow frame rates (1.6 floor), 3 at steady state; coats = 1.12 + 1.604*wpx/segl (core 0.9 + halo 0.22x3.2 passes, each covering 1 + width/spacing segments); ink = 1.1/(coats*ratio) clamped 0.6 -- so the ratio-frame transit accumulates to ~full palette strength at every fps, aspect and brush width, with per-coat adds kept >= ~2 LSB.
+- Lifecycle: a 0.5s erase phase (per-frame persist override 0.45, ink 0) drains the previous preset's framebuffer before the zero-fade lock engages (otherwise old art rides the scroll for a full screen width); then a 3s 15x fill sweep paints the navy field across the screen (96% coverage) so the visitor does not wait 25s for the crawl to cover it; a stage resize (canvas wipe) replays the sweep (aspect-change detector with a 0.02 deadband, booted flag so the first frame does not trigger); beat flare: newest ink brightens 12% on exp(-beatage*5).
+
+Work Log:
+- src/lib/ava/embedded-presets.ts: twelfth Zai-Magic preset "Beautiful Spectrogram" appended (KEEP VERBATIM section); EMBEDDED_SEED_VERSION 7.14 -> 7.18.1 (bumped twice: 7.18 added the preset, 7.18.1 replaced the first cut's flawed ink math -- the fingerprint gate only re-seeds on version change since folder+name were unchanged); file header + Zai-Magic section comments updated (eleven -> twelve).
+- src/lib/version.ts: APP_VERSION 7.18.0 + history entry (the full ink-math derivation). src/lib/release-notes.ts: 7.18.0 "Beautiful Spectrogram" (added + improved, first person, no em dashes).
+- db/custom.db.seed re-synced after the library re-seed (107 presets incl. the new row, verified by direct SQLite read).
+
+BROWSER E2E (agent-browser, ALL PASS):
+- Parse/compile: validateScript clean (lines/additive/persist 1); 64 points, megabuf palette + bins; offline simulation of [init]/[frame]/[point] across 10 scenarios (erase, wash t=1/2/3, steady 60/120/10fps, portrait, ultrawide, wash-at-10fps) -- every case ink 0.21-0.37, per-coat red add 1.9-3.4 LSB, accumulation 1.1x palette.
+- Library: /api/presets re-seeded on both version bumps; Zai-Magic serves 12 presets with Beautiful Spectrogram sorted between Aurora Veil and Bass Bloom; tree double-click loads it (footer SCRIPT: Beautiful Spectrogram, PTS: 64).
+- Canvas pixels (quiet passage): background rgb(5,13,54) = deep dark navy (palette anchor 10,15,59); palette census pink 5.2% / red 9.8% / orange 5.0% / yellow 3.5% / white 2.0% / green 0.00% / cyan 0.01% -- the first cut's cyan plague measured 23.5% white + green fields, now gone.
+- Scroll: engine bgx verified independently with a burst probe (bgx -0.01 -> 216px/s measured vs 209 predicted); the spectrogram measured per-frame via high-pass Pearson cross-correlation -- steady state 0.483px/frame vs 0.526 design (8%, beat-stripe noise), warm-up ramp 1.82px/frame at warm~5.5 as designed; direction LEFT (r up to 0.997).
+- VLM screenshot review (desktop, loud passage): "coherent scrolling spectrogram, sensible frequency-vs-time structure", ramp deep red -> orange -> golden yellow -> near-white, "no green or cyan anywhere"; portrait 420x800 renders at 60fps with the resize re-warm firing (harmonic stripe structure is real 64-bin resolution, not an artifact).
+- App: title "OVE -- Open Visualization Engine (v7.18.0)"; What's New dialog leads with 7.18.0 "Beautiful Spectrogram"; console 0 errors / 0 warnings; bun run lint clean; dev.log 200s only.
+
+Stage Summary:
+- v7.18.0 shipped: "Beautiful Spectrogram", the twelfth hand-authored Zai-Magic preset -- a true scrolling spectrogram as a pure script (bgx slide + persist 1 zero-fade + megabuf bin memory + palette table), with the per-frame ink computed from live stroke geometry so the accumulation lands on the palette at any fps/aspect/brush width. Browser-verified end to end: navy field, pink-to-white print, leftward crawl at design rate, no channel contamination, clean console.