perf: improve large-sequence rendering

[AssociatedPrimeIdeal]

Summary

Fixes large-sequence loading and interaction bottlenecks.

Performance Issues Fixed

1. Quadratic minimap block-position construction (seqEditorProvider.ts)

   • Replaced the per-block prefix rescan with one running cumulative duration.
   • Changes block-position preparation from O(n^2) to O(n).
   • Preserves block indexes, start times, durations, and ordering.

2. Short estimated TR rounded to zero (trdetect.ts)

   • Replaced 10 ms rounding with 1 us quantization.

3. Full block scan and per-event Canvas state changes (drawing.js)

   • Uses binary search to select the visible block range.
   • Expands the candidate range by one block on both sides so ADC and other
     events extending beyond nominal block bounds are still considered.
   • Computes channel rows and colors once per frame.
   • Batches RF, phase, gradient, ADC, and trigger paths by channel.
   • Clips once per channel instead of calling save, clip, stroke, and
     restore for each event.
   • Changes visible-range lookup from O(n) to O(log n + v), where v is
     the number of visible blocks.

4. Full waveform redraw on every pointer event (interaction.js,
   drawing.js, state.js, template.html, styles.css)

   • Adds a dedicated Canvas overlay for the waveform cursor.
   • Coalesces pointer events with requestAnimationFrame.
   • Keeps only the latest pointer state in each display frame.
   • Updates cursor and tooltip state without redrawing static waveforms.
   • Ignores unrelated global pointer movement when no viewer drag is active.

5. Unnecessary WebGL trajectory redraw during waveform hover (kspace.js)

   • Separates the WebGL trajectory from the 2D axes/cursor overlay.
   • Waveform hover updates only the lightweight k-space overlay.
   • Redraws the WebGL trajectory only when the time window, camera,
     projection, point size, unit, or trajectory data changes.
   • Avoids repeated Canvas resize work during hover and camera animation.

Files Changed

• src/editor/seqEditorProvider.ts
• src/editor/webview/assets/drawing.js
• src/editor/webview/assets/interaction.js
• src/editor/webview/assets/kspace.js
• src/editor/webview/assets/state.js
• src/editor/webview/assets/styles.css
• src/editor/webview/assets/template.html
• src/pulseq/trdetect.ts
• web/index.html
• web/pulseq-bundle.js

[AssociatedPrimeIdeal]

ute_3d_rf-sinc_rw_s0.9791666666666666_N96_FOV0.4_TR0.00242_TE0.00024000000000000003_C=1.zip
Here is a sequence containing 40,000 blocks that you can use for testing.

[Copilot]

Pull request overview

This PR targets performance bottlenecks when rendering and interacting with large Pulseq sequences, primarily by reducing algorithmic complexity in minimap/block selection and by decoupling “cursor hover” updates from full waveform / WebGL redraws.

Changes:

• Optimizes minimap block-position construction to linear time in SeqEditorProvider.
• Improves rendering performance by selecting visible blocks via binary search and batching waveform drawing by channel.
• Adds a dedicated cursor overlay canvas and coalesces pointer updates to avoid full redraws on hover; splits k-space WebGL trajectory redraws from lightweight overlay redraws.

Reviewed changes

Copilot reviewed 10 out of 10 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
src/editor/seqEditorProvider.ts	Builds minimap block positions using a running cumulative sum (O(n) instead of O(n²)).
src/editor/webview/assets/drawing.js	Refactors waveform rendering to draw only visible blocks and adds cursor overlay rendering.
src/editor/webview/assets/interaction.js	Coalesces pointer events via requestAnimationFrame and updates overlays without full redraw.
src/editor/webview/assets/kspace.js	Separates fast 2D overlay redraws from WebGL trajectory redraws; adds debug counters.
src/editor/webview/assets/state.js	Introduces overlay canvas state and updates the draw scheduling to include k-space redraws.
src/editor/webview/assets/styles.css	Styles the new cursor overlay canvas (#moc).
src/editor/webview/assets/template.html	Adds the new overlay canvas element (<canvas id="moc">).
src/pulseq/trdetect.ts	Changes TR estimation rounding to microsecond quantization to avoid rounding short TR to zero.
web/index.html	Mirrors webview performance changes in the standalone web build (overlay canvas, coalesced pointer updates, batching).
web/pulseq-bundle.js	Updates bundled Pulseq version and mirrors TR rounding behavior change.

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