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* graphics: a frame the client never got must be said againuser2026-08-29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | A pane image is re-emitted to the client as decoded RGBA, which for one screenshot is ~4MB of base64 in a single indivisible message -- and conn_send silently dropped anything that would overflow the 4MB outbox, while push_graphics ignored the refusal and the model advanced anyway. Everything stateful in that dropped frame was lost for good: the image was marked sent (so its placements drew nothing, forever), and the deletions rode out with it (so a placement the client had was never revoked). Reported as screenshots in a recovered pi transcript parked at a fixed spot on the screen, immune to scrolling and pane swaps -- those were placements whose deletion left with a dropped frame. The 1000x800 one could never be delivered at all: its transmission alone was bigger than the cap. So the frame is now transactional. Deletions queue and are repeated every flush until gfx_commit() confirms the client heard them; transmissions recorded in a frame are unwound by an undelivered commit so they are sent again. A flush nobody commits counts as undelivered at the next gfx_begin(), which is what the `graphics` control command is: bytes rendered for a CLI, not the client. The server reports the verdict and keeps the paint pending until it lands. The outbox cap now bounds the backlog rather than backlog-plus-message, so one big transmission on a drained queue always fits -- and that surfaced a second way to lose: a queued image legitimately holds the backlog over the cap until the client swallows it, and push_frame read that as a dead client and closed the connection. The session auto-detached every time a screenshot crossed the wire. A full outbox is a client that is *behind*, not gone: push_frame now marks the screen for a full repaint (the dropped diff means the client's cells are unknown) and retries as POLLOUT drains the queue; a client that truly left still shows up as a write error there. The headless suite pins the owed-until-committed contract; the new tests/live_graphics.py drives the real socket with a bigger-than-the-cap image and a reader that stalls, and would have caught both bugs: the flood must not detach, the transmission must arrive whole, and a placement scrolled away must be deleted -- then come back on scroll without a second copy of the pixels.
* sl0ppty: clang-format the treeuser2026-08-17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The bumpy one. `make fmt` over every `.c` and `.h` outside `vendor/`: 32 files, 1,843 lines rewritten, no behaviour changed. Nothing here is worth reading -- the next commit adds it to `.git-blame-ignore-revs` so `git blame` walks past it. Two thirds of it is alignment the formatter now owns: trailing comments in a struct, continuation lines under a signature. The rest is the hand-packed tables opening up to one entry per line -- `ACTIONS`, `NAMED_KEYS`, `ACTION_HELP`. That is a real loss of density and a real gain in diffs: adding an action was a reflow of the block and is now one line. Anything worth keeping packed can be fenced with `// clang-format off`; nothing was, on the grounds that a table is the thing a formatter is for. **One change is not formatting.** `src/config.h` had three trailing comments glued onto one field: uint16_t hover_delay_ms; /* how long the pointer must rest to arm a guide */ /* how long an announcement stays up */ /* rows per wheel notch */ -- `toast_ms`'s and `scroll_lines`' comments, landed on their neighbour by an earlier edit, documenting the wrong things ever since. It is in this commit because it is what caught it: clang-format could not settle on that line, wrapping it one way and then re-indenting the wrap on a second pass, so `make fmt` was not idempotent. The comments are back where they belong and it is. Verified after the reformat, not before: `make clean && make all` is warning-free, `make retest` is 1801 checks green, and `make fmt` twice in a row changes nothing the second time. A formatter that alters behaviour would be worse than none, so the gate was the whole suite rather than a reading of the diff.
* sl0ppty: answer the terminal when it is asked how big it isuser2026-08-15
| | | | | | | | | | | | | | | | | | | | | | | | | | | XTWINOPS (CSI 14/16/18 t) went unanswered. A program that draws images needs the cell size to keep an aspect ratio; the pty's pixel fields are the first way to get it (D17) and this query is the second, which is what a program reaches for when those come back zeroed -- as they do on the far side of an ssh hop. Unanswered, the query times out and the program falls back to a guess: ida-tui guesses 10x20, and against a real 9x22 cell that is every image stretched by a fifth, which looks like a bug in the program rather than in us. Found alongside the png bug and from the same program, which asks `CSI 16 t` in the same round trip as its graphics query -- so once the png decoded, the picture would have appeared at the wrong shape. lib-vt encodes and writes the reply once the callback says what the numbers are; they come from the pane's own geometry, so a program is told about the pane it is in rather than the window. Mode 2048 (the in-band report on resize) already worked, because that one is answered from the size passed to ghostty_terminal_resize. Also notes in graphics.c what re-emission actually costs: we send decoded pixels because that is the only form lib-vt keeps, so an 819KB png reaches the client as 3.3MB of base64, once per image and again after a reattach clears `sent`. Fine for a splash, and written down so the next person to wonder does not have to measure it again.
* sl0ppty: the graphics stream gives the cursor backuser2026-08-14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Reported as "the cursor is not rendered in zsh" in a newly spawned pane. It was not about zsh, or about that pane: it was about the pane next to it, which was animating an image. Placing an image means parking the cursor on its target cell first, and the graphics bytes go out *after* the cell diff -- deliberately, so a repainted cell cannot land on top of a placement. That is also after the frame has put the real cursor where the focused pane wants it. So with any image on screen, the last instruction the terminal received every frame was "go to wherever that image is", and the cursor sat there: in another pane, moving about with the picture. With a bouncing DVD logo next door it is quite a sight. gfx_begin() now opens the stream with DECSC and gfx_flush() closes it with DECRC, so the whole thing is cursor-neutral no matter what it contains. The save has to be written at the start of the frame rather than at flush time, because transmissions are emitted as images are recorded and are already in the buffer by then. A frame with nothing to say drops both and still emits not one byte, which the test asserts, because a save/restore pair on every idle frame is exactly the sort of cost that creeps in unnoticed. Two tests: that the stream is bracketed (and that it really does move the cursor, or the assertion proves nothing), and that an idle frame is empty. One C trap worth the comment it now has: "\x1b7" is a *single* hex escape, 0x1b7, not ESC followed by 7. The compiler catches that one because it is out of range -- and would not catch "\x1b1", which compiles quietly into one wrong byte. Escape then digit is always two strings.
* sl0ppty: re-emit what the program meant, not what it coversuser2026-08-14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Images rendered after the last commit, and were still wrong twice. Both mistakes are invisible in a still picture, which is what every test was looking at, and obvious the moment anything moves. **The sub-cell offset was dropped.** A placement says where the image starts *inside* its first cell (`X=`/`Y=`); that is what makes motion smooth rather than a slideshow. We tracked the placement and re-emitted it without those, so a bouncing logo moved in steps of a whole cell -- eight pixels across, sixteen down. **`c=`/`r=` were passed on unconditionally.** They mean *scale the image into this many cells*, and the count a natural-size image happens to cover goes up by one whenever it straddles one more boundary -- so the picture changed size as it slid along. They are now sent only when the program asked for them, which lib-vt reports as 0 when it did not. Cropping splits the same way, and getting it wrong took a test failure to notice: at natural size a lost cell costs the screen pixels the pane has left (measured from the offset, not the cell edge, or an offset image hangs up to a cell over the border); when the program asked to scale, a lost cell is worth source/cells pixels and the crop is proportional. Cropping a 4-pixel image scaled across 40 cells by screen pixels removes all of it. gfx_place() took twenty positional arguments, half of them uint32_t pixel quantities where a transposed pair compiles perfectly and lands the picture slightly wrong -- the exact bug class this file exists for. It takes a struct now. `{"cmd":"graphics","format":"bytes"}` answers with the escape sequences the client is actually sent. The model being right is not the same as the bytes being right, and this whole episode was a lesson in asserting on the first while the second was wrong. The new tests assert on the bytes.
* sl0ptty: kitty graphics passthroughsl0p2026-08-14
A program in a pane transmits an image and it appears. libghostty-vt parses the protocol and tracks images and placements; what a multiplexer has to add is re-emitting them to the client, which is exactly what tmux and zellij do not do — and the reason tools fall back to sixel under them. Per frame: walk the visible tab's panes, transmit each image once (a=t), place every visible placement (a=p,C=1) after the cell diff so a repainted cell cannot land on top of one, and delete placements that vanished. Image ids are remapped into a high range, so two panes both using image 7 stay two images and neither collides with what the client's terminal already had. A reattaching client is told everything again, because it has seen nothing. The cropping rule is the part worth remembering: a placement is N pixels drawn across M cells, so the placement itself tells you the pixels per cell — the client's font metrics never come into it. Clipping at a pane edge, or at the top of the viewport when a tall image is partly scrolled off, moves the source rectangle; asking for fewer columns or rows alone scales the image into them instead of cropping it. The first version did exactly that, and dropped partially-visible placements entirely rather than cropping them. Tests cover the multiplexer-specific case first: two panes, both using image id 7, must get different client ids. Then placement position in screen cells, following the layout, cropping at edges and when taller than the pane, nothing from collapsed panes, and removal when a pane closes or the image scrolls away. A live check confirms the wire: transmitted once, re-placed per frame, not re-transmitted. 416 checks green (389 headless + 27 live).