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Comparison · Analytics
silx vs vellum
A side-by-side editorial comparison of silx and vellum — release velocity, themes, recent moves, and the top alternatives to consider.
silx vs vellum: at a glance
What is silx?
silx settles into maintenance a release after its PySide6 migration
silx is in the quiet phase after a generational release. 3.1.1 is a single fix to FitWidget loading a fit function from file. The release before it, 3.1.0, was the first real feature work since the migration - asinh axis scaling, twilight colormaps, and dark-theme icons - and 3.0.1 was similarly small. The 3.0.0 cut that reset the Qt binding and Python floor still defines what the line is doing.
What is vellum?
vellum's bugs are now found by using it, not testing it — the downstream grammar is doing the QA.
The rendering engine shipped nine releases in the two weeks around the end of July, six of them on a single day. Almost every entry is a correctness fix in a capability that worked when drawn and failed when measured, or worked in isolation and failed in composition. The release notes are unusually forensic: each one states the mechanism, the observable symptom, and why the fix mirrors the draw path rather than reimplementing it.
silx vs vellum: editorial side-by-side
silx
5.0ANALYTICS
silx settles into maintenance a release after its PySide6 migration
◆ Current state
silx is in the quiet phase after a generational release. 3.1.1 is a single fix to FitWidget loading a fit function from file. The release before it, 3.1.0, was the first real feature work since the migration - asinh axis scaling, twilight colormaps, and dark-theme icons - and 3.0.1 was similarly small. The 3.0.0 cut that reset the Qt binding and Python floor still defines what the line is doing.
◆ Where it's heading
The cadence has slowed markedly since April, and the content has shifted from structural change to plotting and colormap refinement. That is the expected shape after a binding migration: downstream beamline code needs a stable target, so the project trades feature velocity for a quiet surface. The gap between 3.0.1 in May and 3.1.0 in August is the clearest signal of the deliberate slowdown.
◆ Prediction
Expect further point releases servicing the plotting and fitting widgets rather than another structural change, with feature work continuing to arrive in the 3.1.x minors rather than patches.
vellum
5.0ANALYTICS
vellum's bugs are now found by using it, not testing it — the downstream grammar is doing the QA.
◆ Current state
The rendering engine shipped nine releases in the two weeks around the end of July, six of them on a single day. Almost every entry is a correctness fix in a capability that worked when drawn and failed when measured, or worked in isolation and failed in composition. The release notes are unusually forensic: each one states the mechanism, the observable symptom, and why the fix mirrors the draw path rather than reimplementing it.
◆ Where it's heading
The pivotal detail is stated outright in 0.6.3 — the first bug in the series found by using the engine from vellumplot rather than testing it in isolation. Every release since names the downstream as the source: the contrast rule's false positives, the lint rules that fired on all five sample plots, the keyed roundrect batch. A rendering engine with a real grammar built on top of it is now getting the integration coverage that unit tests structurally cannot provide, and the fixes are converging on one theme: the measurement path and the draw path must not drift.
◆ Prediction
Expect the release rate to fall as the vellumplot integration surface is exhausted, with remaining work concentrated in the lint rule set now that it is meant to gate builds rather than just inform.
Alternatives to silx and vellum
Other Analytics products tracked by Sparkpulse, ranked by recent ship velocity. Each card links to a full editorial trajectory and lets you pivot into a head-to-head comparison with either silx or vellum.
Plotly
Plotly is turning its cloud into a metered compute platform with an enterprise on-ramp.
aniread
aniread stops asking you to know which tracker wrote the file
Rho
Rho's release machinery finally produced a stable build — and it shipped no new product.
Usermaven
Usermaven closed the loop: data comes in from anywhere, and now it goes back out.
OpenCTI
OpenCTI spends a release unblocking queues and hardening upserts
Recent activity from silx and vellum
Latest ship moves from both products, interleaved chronologically. ⚡ = editorial spark.
- 4h agosilxFitWidget fix for loading a fit function from file
- 9d agosilx3.1.0: asinh axis scaling, twilight colormaps, dark-theme icons
- 15d agovellumLinter grows to 20 rules and stops firing on every plot
- 16d agovellumAnimated SVGs no longer blink once and vanish or play in reverse
- 17d agovellumPick table now reports device pixels instead of two coordinate systems
- 18d agovellumContrast rule stops flagging every plot; gridlines become PDF artifacts
- 18d agovellumgrobwidth and grobheight now measure wrapped text, not the unwrapped line
- 18d agovellumKeyed roundrect becomes a real batch after downstream integration exposes it
- 3mo agosilx3.0.1: silx view fails to disable HDF5 file locking
- 3mo agosilx3.0.0: PySide6 becomes the default Qt binding, Python 3.10 required ⚡
- 3mo agosilx3.0.0rc1: release candidate for the PySide6 migration
- 1y agosilx2.2.2: plot axes limits, OpenGL axes and libhdf5 1.14 fixes
Frequently asked questions
What is the difference between silx and vellum?
They serve adjacent needs but don't currently overlap on shipped themes. silx and vellum are shipping at a similar cadence (velocity 5.0 vs 5.0, both within Sparkpulse's "active" band). See the at-a-glance table above for a side-by-side breakdown of velocity, recent sparks, and editorial themes.
Is silx better than vellum?
Sparkpulse doesn't pick a winner — we score release velocity, not feature parity. silx and vellum are shipping at a similar cadence (velocity 5.0 vs 5.0, both within Sparkpulse's "active" band). For your specific use case, the alternatives sections above list other Analytics products to evaluate alongside.
What are the best alternatives to silx?
Top silx alternatives in Analytics are ranked by recent ship velocity. Browse the "silx alternatives" section above for the current picks, or visit /alternatives/silx for the full list with editorial commentary on each.
What are the best alternatives to vellum?
Top vellum alternatives in Analytics are ranked by recent ship velocity. Browse the "vellum alternatives" section above for the current picks, or visit /alternatives/vellum-r for the full list with editorial commentary on each.