yx.zhang
5720917ea7
Drop the width handle's double-click reset and tooltip — the handle is now drag-only and a stored preference is only replaced by another drag — and add a tertiary description line under the Settings font-size title stating the size only affects conversation content. Update both Agent Notes and the settings dialog goldens.
5.3 KiB
Agent Note: Settings-backed conversation content font size
Status: implemented
English | 中文
Problem
The conversation's body text size was fixed (14px after the 0.875 markdown-ladder rescale). Users asked for a Settings control: a "字号大小" row under General → Appearance with a stepper, range 12–17, default 14, that resizes the transcript body text and the composer input text together.
Decision
The theme plugin owns the setting. ThemeSettingsSchema gains fontSize (z.number().step(1).min(12).max(17).default(14)) beside preference in the existing ui-theme namespace — one durable section, one settings scope, one adoption path. ThemeRuntime carries fontSize in ThemeSnapshot, exposes setFontSize(px) (integer-and-range validated, throws a teaching error), and republishes on theme/change. The same plugin registers the FontSizeRow into settings.general.item at order 11, directly under the Appearance cubes (order 10).
Presentation rides the existing snapshot pipeline. The service never touches the DOM: ui-layout's ThemePresenter writes --dsh-content-font-size on body from each snapshot (and retracts it on dispose), and the Host boot script embeds the durable value in the index response so first paint uses the chosen size — the same pre-plugin path the dark-mode attribute takes, avoiding a font-size flash.
One CSS delta variable moves the ladder. gradient-shadow-text.css derives --dsh-content-font-delta: calc(var(--dsh-content-font-size, 14px) - 14px) and shifts the markdown h1–h4 and base variants (size and line height) by that same px increment, preserving the heading hierarchy and each variant's leading. Table, small, and code variants stay fixed — as does the interrupted-turn .stopped tag (11px): they are dense secondary text whose defaults would fall below legibility when stepped down. Consumers outside the token ladder read var(--dsh-content-font-size, 14px) (or calc(<own default> + var(--dsh-content-font-delta, 0px)) for smaller steps) and calc(<default line-height> + var(--dsh-content-font-delta, 0px)) directly: the assistant narration root, the user bubble (reference summaries and their inline glyphs included), the composer card (whose textarea/mirror/backdrop stack inherits font metrics from the card by design), and the flow chrome around them — the shared DisclosureRow header (tool calls, think, commands; row height, title, and leading box all move) with its expanded bodies' 22px + delta indent keeping content aligned under the shifted title start, ToolRow/bash-row summaries and file links, think text (12px keeping its 2px step under the body), compaction/context/retry/error rows, StatsLine, the chat hint and open-error strips, the workflow-run panel (run/phase headers and expanded member rows), the message clock and icon actions (slot-injected message-feedback actions match through the same variables), and the turn status line. Flow icons scale through each leading box's CSS edge (svg width/height overriding the glyph attributes); StateDot is exempt via its data-state attribute — a status mark, not text furniture. The 14px fallbacks keep every surface pixel-identical when the variable is absent (tests, storybook-like mounts, remote compositions before adoption).
The stepper is a pill, not a menu. The row reuses the selector-pill geometry (h36 r18 module fill) with the value centered in the pill, the up/down arrow column revealed on hover/focus-within and absolutely anchored to the pill's right edge (so revealing never moves the value), and a px unit label after the pill. A tertiary description line under the title states the scope — the size only affects conversation content, not the application chrome. Arrows disable at the bounds; the display follows the store mirror, never the click echo — the same store/face pattern as the Appearance row.
Alternatives considered
A separate settings namespace or plugin. Rejected: the font size is an appearance preference with the same persistence, adoption, and remote-browser semantics as the theme preference; a second namespace duplicates the scope machinery for one integer.
Scaling via a multiplier (em/percentage) instead of a px delta. Rejected: multiplying spreads the 12–17px range disproportionately across the ladder (21px h1 would swing ~18–25.5px) and produces fractional line heights; the fixed px shift keeps every step integer and the hierarchy's px gaps intact.
Scaling every font token (tables, code, small). Rejected: those variants are secondary/dense by design; at −2 the small ladder would hit 10px and code 9px, below legibility.
Consequences
The 0.875 markdown-ladder rescale (body 16 → 14) ships with this change as the new default rendering; at delta 0 every axis consumer is pixel-identical to that rescaled baseline, and surfaces without the variable fall back to the same 14px. A changed size persists in $DSH_HOME/settings.yaml, survives reloads without flashing (the boot script writes the durable value pre-hydration and ThemeRuntime seeds its initial snapshot from it), applies live across transcript and composer, and remote browsers keep the process-local-selection rule the theme preference already has. setFontSize joins the model-visible cordis client API catalog beside setTheme.