an opinionated terminal multiplexer in C with programmable pane chrome https://git.sl0p.foo/slosh.git/atom/src/app_draw.c?h=master 2026-10-09T10:31:53Z 2026-10-09T10:31:53Z user user@clank 2026-10-09T10:24:23Z urn:sha1:3a0825c6890eff566307c0eaad809cdbcf854efd `tab_bar_width` was a reservation: the configured columns came off the screen whatever the screen was, and the only fallback was all the way back to the top row. On a narrow terminal that is chrome displacing the thing it is chrome for, and the jump to the top moves every target you were aiming at. It is a ceiling now. app_tab_bar_cols takes the app, because the answer depends on the terminal and not only on the config: held to the columns left after a pane's collapse width, and to a third of the screen, and narrowed rather than dropped. TAB_BAR_FIT (14) is the narrowest width this code will invent on its own -- a config that asks for less is taken at its word -- and 0 means there is no room for a sidebar at all, which is the one case that still falls back on top. Height counts too, which it did not before: a sidebar spends a row per tab, so a wide but short terminal runs out of list before it runs out of screen, and a tab with no row is not clipped, it is unreachable. tab_bar_min_rows is that floor. Not when the top strip could not seat them either -- moving them would gain nothing, so the side you configured stands. All of it is re-derived per frame, like the layout, so a resize moves the bar and nothing remembers that it did. test_tab_bar also stops depending on where the suite is run from. An unnamed tab borrows the basename of its focused pane's cwd, so eight checks read `tests` under `make test` (which cds there) and `slosh` from the repository root, where they failed. They are about padding, alignment and the index, not about that derivation, so they name the tab first -- by id, since `set-name` takes 0 for the focused *pane* only. 147 checks, green from either directory. 2026-09-22T13:38:08Z user user@clank 2026-09-22T13:38:08Z urn:sha1:1cbfb4474ca31c61254be8d5f3ec046967bd1ff3 It was drawn in tab_status_busy, the colour of the words it sits beside, which made one decision out of two. The words have to stay readable at a glance and a mark does not: a theme may well want the glyph loud and the text calm -- or the text in the accent and the mark a quiet dot -- and with one entry neither is available without moving both. Unset it follows tab_status_busy, derived after it and from whatever that resolved to, named or derived, so nothing changes for anyone who does not ask and no theme in contrib needs a line. `--dump-theme` writes both, like every other colour the compositor draws. 2026-09-22T13:24:16Z user user@clank 2026-09-22T13:24:16Z urn:sha1:ecdc8d0c335c35a74b46ddb22773e8ef4b222891 `│⠋bash: cd` -- the mark landed in the one column of left padding there was, so it ended up welded to the first letter of the status. The rule was "the mark takes a column the padding was already holding blank", which is right about not reflowing and wrong about there being enough of it. So the mark takes the *first* column of the indent and whatever is left over is the air after it, and the default indent is two columns instead of one. One column is still available -- `tab_bar_padding 0 1` -- and now means the squashed look on purpose rather than by default; three gives two spaces; zero still puts everything against the frame. Nothing reflows when a program starts or stops working, which was the point of taking a column that was already blank. The labels and the tab numbers move with it, because the indent is the strip's and not the status's -- a status still starts in the column its tab's name starts in, which is the rule the leading space existed for in the first place. 2026-09-22T13:12:02Z user user@clank 2026-09-22T13:12:02Z urn:sha1:720aa48e249c0c962e8f73372ceded6092414a6e A status is a line of text, and a line of text cannot say whether it is still true. "building 3/7" reads exactly the same while it builds and ten minutes after it stopped, which is the one thing somebody reading it from another tab wants to know -- and the only workaround available to a program was to write the answer into the words and keep rewriting them. So `busy`: printf '\033]5577;1;status;make test\033\\' printf '\033]5577;1;busy;1\033\\' ... printf '\033]5577;1;busy;0\033\\' A flag of its own rather than a field of `status`, because a status is the *whole* payload after the verb -- `status;a;b;c` has always been the text "a;b;c" -- so anything added to that line would change what every existing sender means, including the five pi extensions D1 promises byte compatibility to. Orthogonal, so a program can leave one line up and toggle the other; anything but 0/false/no/off is on; `clear` takes both; and a pane whose program has gone is never busy, whatever it last claimed, because a spinner turning under a dead tab is a lie you keep looking at. In a sidebar the row turns `tab_status_busy` -- the theme's accent, derived like the other status colours, so no theme needs a line -- and takes a spinner in the column `tab_bar_padding` was already holding blank, so nothing reflows when a program starts or stops working. `busy_mark` is the frames, separated by spaces: one frame is a static mark and costs nothing, several make it turn, and only then does the session keep a frame clock -- via the same `animating` flag an animated shader uses, so the cost lands only while such a row is actually composed, and `""` drops the mark entirely and leaves the colour to say it. The frame is a pure function of the clock, like every other pulse here, so two clients attached to one session show the same one. `panes` now reports `status` and `busy`, which is the scriptable half of the same fact: what a pane says about itself, without reading its screen. 2026-09-22T13:01:07Z user user@clank 2026-09-22T13:01:07Z urn:sha1:43ab0d0c0dc0c79f04c7e70f5ab3b22b3e36e09a `padding` is a pane's: the ring between a frame and the text it holds, in rows times gap_aspect so a `1` looks square around a block of prose. Handing the same knob to the sidebar looked tempting and is wrong twice over. The sidebar is chrome, not a pane, and its width is fixed by tab_bar_width -- so `padding 1` would quietly eat four of a sixteen-column strip (two cells a side, aspect included) and shorten every tab name, because somebody wanted their terminal text to breathe. And its two axes are not one idea: the columns are an indent for labels, the rows are air above a list. So tab_bar_padding, its own knob in the family the rest of the sidebar's air already lives in (tab_bar_pad, tab_gap, newtab_pad), taking the same 1/2/4 CSS-order values as `padding` -- one reader for both, so they cannot drift into meaning different things -- but counted in cells. The default `0 1` is what the sidebar already drew: that one column is where every label's leading space has been hard-coded since the sidebar existed, and moving it into a setting is what makes `tab_bar_padding 0` possible at all -- names flush against the frame, which was not previously a thing anyone could ask for. The statuses, the `+ new tab` row and the pane count follow the same indent, since they were each carrying their own copy of that space. It is air *inside* the plate: a tab's fill still spans the whole row and the whole row is still the hit, because the row is what you click and a highlight that stopped short of the frame would read as a highlighted word rather than a chosen row. The bottom rows are given up when the strip is short of them, like every other piece of air in here. tab_bar_pad is the older name for the top component alone. It still works, still means exactly that, and wins where a config writes both -- it is the more specific of the two. The dump writes tab_bar_padding and mentions it. 2026-09-22T11:14:24Z user user@clank 2026-09-22T11:14:24Z urn:sha1:24bfcc26df376621ccfe1e695bb4f5e6f1807e56 `1:api` puts a number at the start of every row, and in a sidebar that is a column of digits in front of the thing you are actually reading -- the names start one, two or three cells in depending on how many tabs you have, and the numbers are only wanted at the moment you reach for C-a 2. tab_bar_index "right" moves them: │ tests 1 │ │ 1:tests │ │ verylongproj 2 │ vs │ 2:verylongproje│ │ api 3 │ │ 3:api │ Every name starts in the same column and the numbers line up in one of their own, which costs a column of sidebar and buys the list a shape. "prefix" stays the default, because it is what the strip has always drawn and the strip is where most people meet it. Sidebars only, and not by omission: a tab in the top strip is exactly as wide as its label, so there is no far end to align against and a number floating after a name it does not belong to would be worse than the prefix it replaced. The setting is ignored there rather than half-honoured. A row too narrow to spare the columns (under the number plus five) also keeps the prefix, since the name is the part you came for, and the rename editor keeps the whole cell as it always did. A name long enough to reach the number stops one cell short of it, because `verylongproje2` is a tab called verylongproje2 as far as any reader can tell. The cell comes back as padding, so the plate is unbroken and the hit is still the whole row -- clicking the number is clicking the tab, and the number brightens with the label under the pointer rather than leaving half a row lit. The bell mark keeps its place between them, budgeted first as before, so a long name cannot eat either of the two things that are not the name. 2026-09-22T09:59:10Z user user@clank 2026-09-22T09:59:10Z urn:sha1:cb0d993fa284005d5679b628bb08d51f12812b8c The active tab has been filled with the accent since the strip existed; every other tab was words on the background. That leaves the strip with one shape on it and nothing to compare it against -- where a tab ends, how far the row you are about to click reaches, and in the sidebar which rows are tabs rather than statuses, all had to be read off the text. tab_idle_bg fills them. Barely off the background and in the label's own grey, because this is not a second highlight: it gives a tab edges, and it gives the accent something to be brighter than, which on a strip of short labels is most of how the eye finds the tab it is in. Hover keeps it for the same reason the active tab keeps its fill -- losing the plate under the pointer would read as the tab going away -- so hovering still lands on the text, and the bell mark sits on the plate rather than punching a hole in it. Derived a third of the way from default_bg to tab_idle when nobody names it, the same bargain tab_status_fg and tab_status_stripe already make: both ends are colours every theme in contrib defines, so each gets a plate in its own family -- paper lightens, phosphor greens, mono stays grey -- without a line added to any of them. Naming it wins, and naming your own background is how you ask for the bare tabs back. The `+ new tab` button and the gaps between tabs stay unpainted: the button is the one row in the list that does not mean "go here", and tab_gap is air between plates, which is what makes them read as separate tabs at all. 2026-09-20T18:23:23Z Peter Geissler peter@haxx.in 2026-09-20T18:23:23Z urn:sha1:07e1adf1124657aaea4fa32874282812281e4889 A tab carrying three rows of wrapped status and the tab under it carrying three more read as one column of text: the labels are in there, but the list has stopped looking like a list. tab_gap is the blank rows between them, 0 by default, which is exactly what the sidebar has always drawn. It is the space *between* tabs and nothing else. Above the first tab is tab_bar_pad's and before the button is newtab_pad's, so the gap is applied before each label except the first and none of the three is ever paid twice. Given up a row at a time when the list is short of room, ahead of every label and the button, which is the same order the pad and the statuses already follow: a gap that pushed a tab off the bottom would be spacing costing you the thing it spaces. Paint rather than layout, so tuning it repaints without reflowing any pane. Sidebars only -- the top strip is one row, and the space between tabs there is the label's own padding. 2026-09-20T17:55:03Z Peter Geissler peter@haxx.in 2026-09-20T17:55:03Z urn:sha1:65a694b194bd68f8c6ba4b961e2cc906b8738a6c Sixteen cells is not enough for a sentence, and a sentence is what a pane has to say: "add a summary…" is most of a status and none of its meaning. tab_bar_status_lines 3 word-wraps instead of cutting, and the same column carries forty-eight cells rather than sixteen. Wrapped, the rows under a tab stop being a list of panes and become a paragraph each, so the shape no longer says where one pane's status ends and the next begins -- both are italic text down one column. Alternate panes are drawn on alternate bands to say it instead: tab_status_stripe, derived from the theme like tab_status_fg, so a theme that has never heard of any of this still gets a band in its own family. Nothing is painted at one line, where there is no ambiguity to resolve and a band would take a translucent terminal's background away for nothing. 1 is the default and is the old behaviour exactly, down to cutting at the column rather than the last word before it: with no next row to move the word to, breaking early would spend cells on nothing. The reason to prefer a word boundary only exists once there is somewhere for the word to go. Rows count against tab_bar_status as before, so wrapping trades panes for words within the same allowance, and the allowance itself still gives way to the tabs. A status that will not fit whole is dropped whole and reported with the ellipsis, rather than shown as a fragment that reads like the whole thing. Every row of a status is the same `find:` door. tabstatus's buffer goes to 256 to match pane_status's own slot: at one line the drawing cut it anyway, but wrapped it is the whole string that has to survive the trip. 2026-09-20T17:49:09Z Peter Geissler peter@haxx.in 2026-09-20T17:49:09Z urn:sha1:1b70e64fdb82344edb9b56a7374263539ce3fa0d Rows were spent in tab order until they ran out, so statuses from early tabs simply consumed the rows later tabs needed for their labels. Four tabs of three announcing panes in a sixteen-row terminal left the fourth tab with no row and no hit anywhere on the sidebar -- not clipped, unreachable -- and the new-tab button went with it. The list is the navigation and a status is an annotation on it, so the annotation is what gives way. Before drawing a tab's statuses, reserve a row for each tab still to come and one for the button, and allow the statuses only what is left over. The "and more" ellipsis is measured against that allowance rather than the cap, so a list cut short by the height still says it was cut, the same as one cut short by the setting. The pad is deliberately not reserved: it already gives itself up a cell at a time, which is the same order of surrender -- spacing, then extra statuses, then statuses, never the thing they are about.