The two drawn tab glyphs were judged not understandable enough; the
switcher goes to the wide policy with titles only, and the glyphs,
their gresource entries and the icon-naming code are removed.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
The bold pass had turned the trigger into half a period — a signal rising above its level — and that
lost the thing the glyph is for: the crossings. A crest and a trough read as a wave; a hump reads as a
hill, and a trigger that shows no crossing names the "above the level" half of an event. The full-period
sine with the dashed level through it is restored, exactly as it was, and the Signals pill carries the
same wave again so the pill and the toolbar button stay one picture.
The Measure glyph keeps the bold redesign, which is the part that was better: two cursors (a cap over two
4px dashes) beside a ruler of two bands with three 2x4 marks and no end caps. The Signals pill also keeps
its two bold channel rows.
Verified: `toolbar icons: trigger=udpscope-trigger-symbolic(ok)`;
`page icons: measure=udpscope-tab-measure-symbolic(ok) signals=udpscope-tab-signals-symbolic(ok)`;
`switcher: policy=narrow pills=2 labels=0 names=2 icon=32x32 size=308x36`; `[side-tab-probe] … advanced=4`;
the Preferences dialog opened in the same run with no "not present"; `make test-ui` 14 files; zero
`Gtk-CRITICAL`. The icons' blob is 12352 bytes, still over the C99 limit, so the clean-build warning count
stays four.
The previous pair were detailed miniatures — 1px ticks, 2px dashes, a 13-column wave — and at 32x16 that
reads as *texture* rather than as a shape, which is what "not clear" looks like. All three glyphs are
redrawn bold: one thick band, two thick dashes, few features.
- **Measure** is two cursors beside the ruler they read against. Each cursor is a cap over two bold
dashes (4px), where three 2px dashes read as a dotted column; the ruler is two bands with three 2x4
marks between them and **no end caps**, because a closed frame reads as a rectangle and costs a fifth
of the ink on two lines that say nothing. This is the layout whose first attempt looked like two icons
in a box — the difference is entirely the weight and the open ends.
- **Signals** is a signal rising above its level beside two bold channel rows. Half a period instead of
a full one: at this size a full period is a zigzag and a hump is unmistakably a wave, and the level's
marks survive on both sides of it instead of being swallowed by the crest.
- **The trigger's own icon** is now the same picture as the Signals pill, so the pill and the button that
turns the trigger on are recognisably about the same thing.
Each was rendered and read back as an ink map at 1:1 and at 2x before it was installed, and three
candidates were compared for the Measure glyph (markers *on* a scale, cursors *over* a ruler, and this):
the first two turned the marks and the shafts into blobs at the crossings. Ink is 18%, 30% and 29%,
inside the range the icons above them set, and everything stays inset two pixels.
Verified: `toolbar icons: trigger=udpscope-trigger-symbolic(ok)`;
`page icons: measure=udpscope-tab-measure-symbolic(ok) signals=udpscope-tab-signals-symbolic(ok)`;
`switcher: policy=narrow pills=2 labels=0 names=2 icon=32x32 size=308x36`; `[side-tab-probe] … advanced=4`;
the Preferences dialog opened in the same run with no "not present"; `make test-ui` 14 files; zero
`Gtk-CRITICAL`. The icons' blob is 11774 bytes, still over the C99 limit, so the clean-build warning
count stays four.
The previous Measure glyph was two icons sharing a box: a heavy closed ruler frame on the right and
two light caps on the left, with nothing relating them. It is now one instrument — two cursors
*standing on* the scale they read against, each marker centred on one of the scale's marks, so the
pair reads the way the pane works: bracket a window, read it against the axis.
Three things the render said, each fixed:
- **The closed frame was most of the ink.** Two lines and two end caps cost about a fifth of the
glyph's ink and say nothing a ruler's marks do not, so the scale is now one band with alternating
marks — long, short, long — hanging above it.
- **The caps were dashes, not grips.** 5x2 at 32px read as a horizontal stroke; they are 5x3, like the
caps on the toolbar's cursors icon.
- **The ticks were finer than everything else.** At 1px they were thinner than the 2px weight every
icon here uses, so they are 2px, and every mark alternates in height the way a ruler's do.
The Markers' shafts are dashed and meet the band rather than hovering over it, and the whole glyph is
inset two pixels like the others, so nothing is flush with an edge that a button's padding or a crop
takes a pixel off. Ink: 27%, inside the range the icons above it set.
Verified: `page icons: measure=udpscope-tab-measure-symbolic(ok) signals=udpscope-tab-signals-symbolic(ok)`;
`switcher: policy=narrow pills=2 labels=0 names=2 icon=32x32 size=308x36`; `[side-tab-probe] … advanced=4`;
the Preferences dialog opened in the same run with no "not present" (the plain ruler it uses is untouched);
`make test-ui` 14 files; zero `Gtk-CRITICAL`. The icons' blob is 12624 bytes, still over the C99 limit, so
the clean-build warning count stays four.
The trigger's toolbar icon was a rising edge, which names only one of the four shape triggers the panel
offers. It is now a sine with a dashed level through it — the trigger's actual job, find the signal where
it crosses this — and the Signals tab's pill carries the *same* picture beside the channel list, so the
pill and the button that turns the trigger on read as the same idea. Both are one period of one-pixel
stairs, the way the plot rasterises its own traces.
Everything is inset two pixels now. The previous drafts ran their level and their bars flush to the cell
edge, which is what makes art look shaved wherever a button's padding or a crop takes a pixel: nothing in
either tab glyph, or in the trigger's, touches an edge.
Each shape was drawn and then read back as an ink map rather than trusted — the first sine came out as a
thin antialiased diagonal (a polygon through whole-pixel vertices has diagonal *edges*), which is why the
band is now per-column stairs; the level-through-the-centre arrangement was chosen over level-above-the-
centre after rendering both, since at these sizes a level nearer the crest merges with it into a blob. The
four glyphs measure 18%, 22%, 25% and 25% ink, inside the range the icons above them set.
Verified: `toolbar icons: trigger=udpscope-trigger-symbolic(ok)` and
`page icons: measure=udpscope-tab-measure-symbolic(ok) signals=udpscope-tab-signals-symbolic(ok)`;
`switcher: policy=narrow pills=2 labels=0 names=2 icon=32x32 size=308x36`;
`[side-tab-probe] … advanced=4`; `make test-ui` 14 files; zero `Gtk-CRITICAL` and no missing icon. The
icons' GResource blob is 12408 bytes — the SVG sources are embedded, comments included — still over the
C99 limit, so the clean-build warning count stays four.
Each tab's icon is now two motifs side by side instead of one in a 16px square: the Measure pill is the
two cursors beside the ruler, the Signals pill the trigger beside three channel rows. A 16px cell carries
one motif — squeezing a pair into it is what turned both into a smear — and the pill has the width for a
pair in a 300px column with two pills in it.
Two measurements decided the size, both of which I had wrong from the outside:
- **GDK paints an icon into a square box whatever the document's aspect.** `gtk_icon_theme_lookup_icon()`
at 32 reports a `32x32` paintable for a 32x16 document, and librsvg fits it: rendered with aspect kept,
the artwork comes out `32x16` inside a 32 request. So the pair is letterboxed, not stretched, and
`pixel_size` 32 draws it at exactly the size it is written — 1:1, so the 2px bars stay crisp. A
fractional scale (24 or 48) is what would blur them, which is why nothing here is drawn at one.
- **The bar does not get taller for it.** `switcher: … icon=32x32 size=308x36`: 36px is what the switcher
measured with 16px icons too, because the pill's fixed height takes a 32px box without growing.
Both glyphs were drawn and then read back as ink maps rather than trusted: the first drafts came out at
39% and 44% ink (a blot beside the house 25–36%), and the tab bar is the last place a shape can be
checked, since no screenshot works under this X setup. The finished two measure 23% and 33%.
Verified: `switcher: policy=narrow pills=2 labels=0 names=2 icon=32x32 size=308x36`;
`page icons: measure=udpscope-tab-measure-symbolic(ok) signals=udpscope-tab-signals-symbolic(ok)`;
`[side-tab-probe] … advanced=4`; the Preferences dialog opened in the same run with no "not present";
`make test-ui` 14 files; zero `Gtk-CRITICAL`. The icons' GResource blob is 11661 bytes, still over the
C99 limit, so the clean-build warning count stays four.
The Measure tab is now `udpscope-tab-measure-symbolic` — the two cursors standing across a ruler — and
the Signals tab is `udpscope-tab-signals-symbolic` — the trigger's rising edge over the channel list it
acts on. Each is a 16px composite rather than one of the icons the toolbar carries: a glyph the toolbar
already uses for one thing means two things the moment a tab shows it too, which is why the ruler alone
and the trigger alone were both wrong here.
The plain ruler stays exactly where it was. `udpscope-measure-symbolic` is the Preferences window's Plot
page icon and is untouched; the tab's pair is a new file beside it, so nothing that already meant "the
measurement ruler" changed meaning. Seven action icons bundled, nine with the two app icons.
Both composites are at the limit of what 16px holds — four features each — so each was drawn and then
*measured*: rasterized and read back as an ink map, since the shapes have to be checked as pixels and the
house range is 25-36% ink (trigger 25, cursors 27, ruler 36). The Signals list is two rows and not three,
so the edge and the list get half the cell each; its bars are all one length, because unequal ones read as
a bar chart and a chart is not a list. The Measure ruler's ends are open on purpose: a closed frame puts
four more pixels of ink at the left and right edges, which is what turns a ruler into a rectangle at this
size. First drafts came out at 39% and 44% ink and were rebalanced to 32% and 36%.
Verified: `page icons: measure=udpscope-tab-measure-symbolic(ok) signals=udpscope-tab-signals-symbolic(ok)`;
`switcher: policy=narrow pills=2 labels=0 names=2`; `[side-tab-probe] … advanced=4` (switching by page
name still works); the Preferences dialog opened in the same run with no "not present"; `make test-ui` 14
files; zero `Gtk-CRITICAL`. The icons' GResource blob is now 11309 bytes, still over C99's 4095-byte
string-literal limit, so the clean-build warning count is still four.
Each sidebar page gets its own glyph and no visible text. The Measure tab reuses the ruler
(`udpscope-measure-symbolic`, the icon its deleted toolbar toggle used and the Plot preferences page
still carries); the Signals tab gets a new `udpscope-signals-symbolic` — three rows of a colour chip
and a name, which is what that tab mostly is — rather than a second copy of the trigger glyph, since
one shape meaning two things in one window is worse than a new one. Its bars are all one length: a
set of unequal ones reads as a bar chart, and a chart is not a list.
`AdwViewSwitcherPolicy.narrow` alone does **not** give an icon-only bar. Measured on libadwaita 1.10
by walking the switcher's tree: with `narrow` and a title, each pill holds a `GtkImage` *and* a
`GtkLabel` — 48px of "Measure" inside a 54px pill. So the pages' `title` is **empty** (their `name` is
what identifies them to `select_side_tab()` and to the session file, and both are unchanged) and the
words are re-attached in code: `name_side_tabs()` runs on the first tick — the pills are
`AdwViewSwitcher`'s own and exist only once it is mapped — and gives each pill a **tooltip and an
accessible name** from the page's name, then hides the empty label that would otherwise leave the
icon off-centre. An icon-only pill is still a named control for a screen reader, and the page icon
that does not resolve leaves a *blank* pill, which is why it is read like the toolbar's icons are.
Two readings, because the claim is two claims:
switcher: policy=narrow pills=2 labels=0 names=2
page icons: measure=udpscope-measure-symbolic(ok) signals=udpscope-signals-symbolic(ok)
`labels` counts *mapped labels with text* — a plain mapped count reads 2 either way, because the
narrow pill keeps an empty label in its layout — and `pills=2` is the guard that makes it mean
something: with nothing mapped the rest of the line is void rather than a pass.
Docs: the icon census (six action icons, eight bundled, and what each of the two new users is), the
switcher bullet in `invariants-gtk-and-chrome.md` with the measurement above, the two new dump lines
in `probe-readings.md`, the re-measured GResource figures in `verification.md` (icons 8613 -> 9842
bytes, help 514660 after this session's help rewrite; the count stays four), and the README recording
that the design spec had the switcher showing titles and neither page an icon.
Verified: `make test-ui` 14 files; `[side-tab-probe] … advanced=4` (tab switching by name still
works with empty titles); `signals panel: … divider=1`; `[math-probe] 3 math channels`; zero
`Gtk-CRITICAL` and no missing icon.
`udpscope-math-symbolic` was the toolbar's math-pane toggle, and that toggle is gone. Nothing
else names it: the census after the change is **five** action icons
(`udpscope-{trigger,cursors,measure,events,resize-rows}-symbolic.svg`) plus the two application
icons, seven bundled.
`udpscope-measure-symbolic` **stays**, and the plan's premise ("both lost their last user") is
wrong for it: `src/ui/preferences.ui` carries it as the Plot preferences page's icon -- a live
user, unrelated to the toggle that introduced it. Deleting it would have shipped a page whose
icon silently fails to resolve (GTK substitutes a placeholder and says nothing), so it stays and
the doc's census names it as the Preferences icon rather than as a toolbar one.
The warning baseline is unchanged: **four**, because the icons' generated GResource blob is
**8613 bytes** against C99's 4095-byte string-literal limit with the five action icons and the
two app icons -- removing one file did not put it back under, and neither figure moved on a
clean build. Measured by touching the two `*.gresource.xml` files and rebuilding, which
regenerates both blobs without one.
Verified: `make test-ui` 14 files; a run with the Preferences dialog opened resolves every icon
(`toolbar icons:` all `(ok)`, zero `Gtk-CRITICAL`, no "not present").
GTK4 and libadwaita. It receives one UDP stream through the vendored
udpsclient, buffers it in a large ring, and draws it with the vendored
plotter: a trigger with a pre/post event window, a pause that freezes the
window, cursors, measurements, math channels in a node editor, an event cache,
named configurations, preferences, and an export of the visible window to
.npy/.csv. Waveform files can be opened and analysed in place.
The interface is two threads -- a producer that owns the socket and the GTK
main thread that owns every widget and the GL context -- sharing one model
under one mutex, with samples crossing through lock-free rings.
deps/plotter is a submodule pinned to the commit this tree builds against;
deps/udpsclient is vendored in place. docs/claude/ documents the rules that
cost a defect to learn, and SPECS.md is the requirement document.
The flicker ("no data" at no constant frequency, worse with the measurements
and cursors panes up) was a torn read of the window's first stamp: acquire()
pins the window to the ring's oldest slot, and reading it at paint time races
the producer lapping it, returning a stamp one ring span too new. x0() is the
origin every trace point is reconstructed from, so one torn read produced a
refused neighbours(), a filter that dropped three quarters of the points, and
a polyline shifted off its axis. It is cached by acquire() under the lock now.
EventSeries::neighbours() answered from the (x - x0)/dx grid, whose drift from
the real arrival stamps arrives as a constant offset in seconds -- a doubling
share of the screen per zoom step, which is the "zooming into a held event
clips it more from the left" report. Both series binary-search the stamps now.
The measurements pane went through the LOD pyramid rather than reading its
window raw (19.7 ms per recompute to 1.2 ms, 0.1% of a 2 M-sample window) and
recomputes on a cadence; the math engine lost a per-slot heap allocation, a
per-sample source lookup by name and a fetch_add that cost more than the
arithmetic it counted.
The cursors pane's mix mode drew a line per *named* slot, so a slot holding a
signal that can never produce a channel -- the stream's timestamp -- got a row
that could only read "--", and such names were re-saved every session. It
counts bound traces now and apply_layout() refuses them.
Four toolbar icons are drawn for this app and compiled in as a GResource: the
stock ones were a record dot for the trigger and three magnifiers for cursors,
measurements and math.
New probes and dump lines for all of it (trace ink, measure cost, math cost,
event zoom, toolbar icons); README and CLAUDE.md record what they cure.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
