Feature idea: tmux-style layout preset cycling

[XinhhD]

Hi, I'm a long-time tmux user who recently switched to herdr for the agent-aware sidebar and session persistence. One thing I miss every day is prefix + Space — tmux's built-in layout cycling.

What I miss from tmux

In tmux, pressing prefix + Space rotates through predefined pane layouts:

• even-horizontal
• even-vertical
• main-horizontal
• main-vertical
• tiled

This is huge when you have 3–4 panes and want to reorganize them instantly. No mouse, no manual resizing, no closing and re-splitting — just one keypress.

What I'd like in herdr

I'd love the same ability in herdr. The underlying BSP tree already supports arbitrary splits, so the feature is really about exposing a few "preset" arrangements that rebuild the current tab's tree while keeping all existing pane IDs and terminals intact.

Proposed defaults:

• prefix + space → next layout preset
• prefix + shift + space → previous layout preset

The five presets would match tmux semantics:

Preset	Arrangement
even-horizontal	Panes stacked top-to-bottom, equal height
even-vertical	Panes side-by-side, equal width
main-horizontal	Focused pane on top (larger), rest below
main-vertical	Focused pane on the left (larger), rest to the right
tiled	Roughly square grid via alternating splits

Why this fits herdr

herdr already supports mouse-driven layout changes and manual splits. A keyboard-driven preset cycle would complement that without removing any existing behavior. It also aligns with herdr's "terminal-native" philosophy — it's a multiplexer feature, not a GUI abstraction.

For users coming from tmux (like me), it's one less piece of muscle memory to relearn.

Implementation note

I have a branch that adds this on top of the current master:

• New LayoutPreset enum and TileLayout::apply_layout_preset() in src/layout.rs
• New layout.apply_preset JSON-RPC/socket API method
• New next_layout / previous_layout keybinds
• Updated keyboard docs

The BSP tree is rebuilt in place, so pane IDs, terminals, and focus are preserved. The last-applied preset is remembered per tab so cycling advances correctly.

Open questions

1. Is prefix + shift + space OK as a default for previous? Some terminals don't distinguish Shift+Space, so I'm happy to leave it unbound by default if that's preferred.
2. Should this also be exposed as a top-level CLI command, or is the socket API enough for now?

If this direction sounds good, I'd love to open a PR. Thanks!

[danielo515]

Yes please! Sometimes I open a layout horizontally and then after a while I realize it would have been better to have it vertically. Really miss this feature from tmux

[ogulcancelik]

this should be an easy plugin ! let me know if plugin api missing any endpoint.

[danielo515]

Any reason you don't want this to be a built-in feature?

[ogulcancelik]

because i don't want to add every feature to herdr. i want plugin system robust enough. implementing anything materially has no cost now, thanks to agents.

everyone has their own needs, rather then supporting all different options, i want to emphasize plugins so everyone can build their own, while herdr stays lean.

because every feature i add, every config i append creates maintenance churn and tech debt.