grid, protocol, daemon, client, docs: keep a scrolled-back view on its lines as output arrives #169

Merged

natsukium merged 1 commit from daemon/viewport-anchor into main 2026-10-18 17:42:06 +09:00

Conversation 0 Commits 1 Files changed 35 +1151 -137

natsukium commented 2026-10-18 15:31:26 +09:00

Owner

Copy link

A scrolled-back window stays on the lines it shows while the program keeps printing, and the next scroll moves one line from them instead of jumping by the lines printed in between.

• felis-grid: Grid::viewport_anchor() / anchor_viewport(offset, since) grow a browsing offset by the rows pushed into scrollback, clamped to the retained history; 0 stays live. A resize, an erasing CSI 3 J, RIS or a screen switch moves the anchor's generation and returns the view to live. Embedders holding their own offset (GitHub mirror issue 4) call the same function.
• daemon: re-anchors each subscriber's offset every compose; browse rows are resent only when the top line or generation changes, so pure growth ships only a ViewportState.
• wire (minor 2, skippable): GridViewportState.anchor, echoed in InputViewport.anchor, so a step computed while a frame was in flight still lands one line away; SearchMatch.anchor lets the client keep highlights and n/N navigation on their lines. An unanchored request counts from the current bottom, as before.
• client: echoes the anchor, re-expresses search hits, keeps a selection across growth-only states (and clears it when a browse ends), and restores pipe/run returns with their saved anchor.

A step sent before the previous reply arrives is out of scope and tracked in #164.

Design and implementation each passed a sol review (pi-review); just check passes locally.

Closes #158

A scrolled-back window stays on the lines it shows while the program keeps printing, and the next scroll moves one line from them instead of jumping by the lines printed in between. - **felis-grid**: `Grid::viewport_anchor()` / `anchor_viewport(offset, since)` grow a browsing offset by the rows pushed into scrollback, clamped to the retained history; `0` stays live. A resize, an erasing `CSI 3 J`, RIS or a screen switch moves the anchor's generation and returns the view to live. Embedders holding their own offset (GitHub mirror issue 4) call the same function. - **daemon**: re-anchors each subscriber's offset every compose; browse rows are resent only when the top line or generation changes, so pure growth ships only a `ViewportState`. - **wire (minor 2, skippable)**: `GridViewportState.anchor`, echoed in `InputViewport.anchor`, so a step computed while a frame was in flight still lands one line away; `SearchMatch.anchor` lets the client keep highlights and n/N navigation on their lines. An unanchored request counts from the current bottom, as before. - **client**: echoes the anchor, re-expresses search hits, keeps a selection across growth-only states (and clears it when a browse ends), and restores pipe/run returns with their saved anchor. A step sent before the previous reply arrives is out of scope and tracked in #164. Design and implementation each passed a sol review (`pi-review`); `just check` passes locally. Closes #158

natsukium added 1 commit 2026-10-18 15:31:26 +09:00

grid, protocol, daemon, client, docs: keep a scrolled-back view on its lines as output arrives ... 074e356053

While a window was scrolled back and the program kept printing, the
daemon kept the subscriber's lines_from_bottom fixed. The rows on screen
stayed the ones composed at the old bottom, but the offset they were
composed at now named lines that many rows newer, so the next scroll
step, computed from that offset, landed as many lines away from what
the user was reading.

The offset now grows by the rows pushed into scrollback, clamped to the
retained history, as kitty grows scrolled_by and alacritty its display
offset; 0 stays the live bottom. A resize, an erasing CSI 3 J, RIS or a
screen switch returns a browsing view to live: each stops a push count
naming the same lines, and a generation counter records it even when one
burst erases history and refills it before the next compose, where a
clamp would land on unrelated rows. The rule lives in felis-grid
(Grid::viewport_anchor / anchor_viewport) so an embedder that holds its
own offset calls the same function. The daemon re-anchors each
subscriber's offset every compose and resends browse rows only when the
top line or the generation changed, so pure growth ships a
ViewportState and no rows.

Reporting the grown offset alone leaves a race: under pull pacing a
frame carrying it is usually in flight while the user scrolls, and on a
remote attachment the round trip exceeds a frame, so a step computed
from the previous offset would be read against the newer bottom.
ViewportState therefore carries the ViewportAnchor its offset is
expressed against (pushed rows plus that generation, present only
while browsing), and InputViewport echoes it; an unanchored request
counts from the current bottom as before, and 0 is live whatever its
anchor. Search matches carry the anchor they were found at, so the
client re-expresses highlights against the view it shows and navigates
to a hit in the hit's own frame. A selection survives a growth-only
state and is cleared when the view leaves a browse, whose visible-row
coordinates then name rows it never covered; a pipe/run return restores
the saved offset with its saved anchor. The fields are skippable
minor-2 additions; minor 2 is still unreleased.

A step sent before the reply to the previous one arrives still starts
from the acknowledged offset; that is independent of this change and
tracked in #164.

Closes #158

Assisted-by: Claude Code

natsukium force-pushed daemon/viewport-anchor from 074e356053 to 0805a6a1d3 2026-10-18 15:32:20 +09:00 Compare

natsukium scheduled this pull request to auto merge when all checks succeed 2026-10-18 15:34:32 +09:00

natsukium force-pushed daemon/viewport-anchor from 0805a6a1d3 to 7974260360 2026-10-18 17:23:09 +09:00 Compare

natsukium merged commit 4d783bb3cc into main 2026-10-18 17:42:06 +09:00

natsukium deleted branch daemon/viewport-anchor 2026-10-18 17:42:07 +09:00

natsukium referenced this pull request from a commit 2026-10-18 17:42:08 +09:00

Merge pull request 'grid, protocol, daemon, client, docs: keep a scrolled-back view on its lines as output arrives' (#169) from daemon/viewport-anchor into main

Sign in to join this conversation.

Reviewers

No reviewers

Labels

Clear labels   

Area/ci

CI workflows (.forgejo/workflows/)

  

Area/cli

felis-cli crate, the felis front-door binary

  

Area/client

felis-client crate, the winit GUI frontend

  

Area/client-core

felis-client-core crate, shadow screen, config, connect_or_spawn_daemon

  

Area/daemon

felis-daemon crate, session pool, IPC server

  

Area/deps

Dependency bumps

  

Area/docs

Documentation tree when no narrower area fits

  

Area/grid

felis-grid crate, cells, scrollback, image store

  

Area/manual

User-facing docs: tutorials, how-to, user-facing reference pages

  

Area/nix

Nix flake, home-manager module, package definitions

  

Area/protocol

felis-protocol crate, felis.proto, frame layout, version constants

  

Area/pty

felis-pty crate, PTY backends

  

Area/render

felis-render-wgpu crate, GPU pipeline, atlas

  

Area/shaping

felis-shaping crate, swash shaper, font fallback

  

Area/skills

Agent skills (skills/felis, .agents/skills/)

  

Area/transport

felis-transport crate, framing, socket/pipe, SSH carrier

  

Area/vt

felis-vt crate, VT parser, dispatch

  

Compat/Breaking

Breaking change that won't be backward compatible

  

Kind/Bug

Something is not working

  

Kind/Documentation

Documentation changes

  

Kind/Enhancement

Improve existing functionality

  

Kind/Feature

New functionality

  

Kind/Performance

Throughput, latency, or memory cost

  

Kind/Security

This is security issue

  

Kind/Testing

Issue or pull request related to testing

  

perf-regression-accepted

Passes the instruction-count bench gate for an intended cost; state why in a PR comment

  

Reviewed

Confirmed

Issue has been confirmed

  

Reviewed

Duplicate

This issue or pull request already exists

  

Reviewed

Invalid

Invalid issue

  

Reviewed

Won't Fix

This issue won't be fixed

  

Status

Blocked

Something is blocking this issue or pull request

  

Status

Need More Info

Feedback is required to reproduce issue or to continue work

  

Status

Upstream

Waiting on a change in an upstream project

No labels

Area/ci

Area/cli

Area/client

Area/client-core

Area/daemon

Area/deps

Area/docs

Area/grid

Area/manual

Area/nix

Area/protocol

Area/pty

Area/render

Area/shaping

Area/skills

Area/transport

Area/vt

Compat/Breaking

Kind/Bug

Kind/Documentation

Kind/Enhancement

Kind/Feature

Kind/Performance

Kind/Security

Kind/Testing

perf-regression-accepted

Reviewed

Confirmed

Reviewed

Duplicate

Reviewed

Invalid

Reviewed

Won't Fix

Status

Blocked

Status

Need More Info

Status

Upstream

Milestone

Clear milestone

No items

No milestone

Assignees

Clear assignees

No assignees

1 participant

Notifications

Subscribe

Due date

The due date is invalid or out of range. Please use the format "yyyy-mm-dd".

No due date set.

Dependencies

No dependencies set

Reference

felis-terminal/felis!169

No description provided.