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source dump of claude code forked from oppi.li/claude-code
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TypeScript
at main
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indentString from 'indent-string'import { applyTextStyles } from './colorize.js'import type { DOMElement } from './dom.js'import getMaxWidth from './get-max-width.js'import type { Rectangle } from './layout/geometry.js'import { LayoutDisplay, LayoutEdge, type LayoutNode } from './layout/node.js'import { nodeCache, pendingClears } from './node-cache.js'import type Output from './output.js'import renderBorder from './render-border.js'import type { Screen } from './screen.js'import { type StyledSegment, squashTextNodesToSegments,} from './squash-text-nodes.js'import type { Color } from './styles.js'import { isXtermJs } from './terminal.js'import { widestLine } from './widest-line.js'import wrapText from './wrap-text.js'
// Matches detectXtermJsWheel() in ScrollKeybindingHandler.tsx — the curve// and drain must agree on terminal detection. TERM_PROGRAM check is the sync// fallback; isXtermJs() is the authoritative XTVERSION-probe result.function isXtermJsHost(): boolean { return process.env.TERM_PROGRAM === 'vscode' || isXtermJs()}
// Per-frame scratch: set when any node's yoga position/size differs from// its cached value, or a child was removed. Read by ink.tsx to decide// whether the full-damage sledgehammer (PR #20120) is needed this frame.// Applies on both alt-screen and main-screen. Steady-state frames// (spinner tick, clock tick, text append into a fixed-height box) don't// shift layout → narrow damage bounds → O(changed cells) diff instead of// O(rows×cols).let layoutShifted = false
export function resetLayoutShifted(): void { layoutShifted = false}
export function didLayoutShift(): boolean { return layoutShifted}
// DECSTBM scroll optimization hint. When a ScrollBox's scrollTop changes// between frames (and nothing else moved), log-update.ts can emit a// hardware scroll (DECSTBM + SU/SD) instead of rewriting the whole// viewport. top/bottom are 0-indexed inclusive screen rows; delta > 0 =// content moved up (scrollTop increased, CSI n S).export type ScrollHint = { top: number; bottom: number; delta: number }let scrollHint: ScrollHint | null = null
// Rects of position:absolute nodes from the PREVIOUS frame, used by// ScrollBox's blit+shift third-pass repair (see usage site). Recorded at// three paths — full-render nodeCache.set, node-level blit early-return,// blitEscapingAbsoluteDescendants — so clean-overlay consecutive scrolls// still have the rect.let absoluteRectsPrev: Rectangle[] = []let absoluteRectsCur: Rectangle[] = []
export function resetScrollHint(): void { scrollHint = null absoluteRectsPrev = absoluteRectsCur absoluteRectsCur = []}
export function getScrollHint(): ScrollHint | null { return scrollHint}
// The ScrollBox DOM node (if any) with pendingScrollDelta left after this// frame's drain. renderer.ts calls markDirty(it) post-render so the NEXT// frame's root blit check fails and we descend to continue draining.// Without this, after the scrollbox's dirty flag is cleared (line ~721),// the next frame blits root and never reaches the scrollbox — drain stalls.let scrollDrainNode: DOMElement | null = null
export function resetScrollDrainNode(): void { scrollDrainNode = null}
export function getScrollDrainNode(): DOMElement | null { return scrollDrainNode}
// At-bottom follow scroll event this frame. When streaming content// triggers scrollTop = maxScroll, the ScrollBox records the delta +// viewport bounds here. ink.tsx consumes it post-render to translate any active// text selection by -delta so the highlight stays anchored to the TEXT// (native terminal behavior — the selection walks up the screen as content// scrolls, eventually clipping at the top). The frontFrame screen buffer// still holds the old content at that point — captureScrolledRows reads// from it before the front/back swap to preserve the text for copy.export type FollowScroll = { delta: number viewportTop: number viewportBottom: number}let followScroll: FollowScroll | null = null
export function consumeFollowScroll(): FollowScroll | null { const f = followScroll followScroll = null return f}
// ── Native terminal drain (iTerm2/Ghostty/etc. — proportional events) ──// Minimum rows applied per frame. Above this, drain is proportional (~3/4// of remaining) so big bursts catch up in log₄ frames while the tail// decelerates smoothly. Hard cap is innerHeight-1 so DECSTBM hint fires.const SCROLL_MIN_PER_FRAME = 4
// ── xterm.js (VS Code) smooth drain ──// Low pending (≤5) drains ALL in one frame — slow wheel clicks should be// instant (click → visible jump → done), not micro-stutter 1-row frames.// Higher pending drains at a small fixed step so fast-scroll animation// stays smooth (no big jumps). Pending >MAX snaps excess.const SCROLL_INSTANT_THRESHOLD = 5 // ≤ this: drain all at onceconst SCROLL_HIGH_PENDING = 12 // threshold for HIGH stepconst SCROLL_STEP_MED = 2 // pending (INSTANT, HIGH): catch-upconst SCROLL_STEP_HIGH = 3 // pending ≥ HIGH: fast flickconst SCROLL_MAX_PENDING = 30 // snap excess beyond this
// xterm.js adaptive drain. Returns rows applied; mutates pendingScrollDelta.function drainAdaptive( node: DOMElement, pending: number, innerHeight: number,): number { const sign = pending > 0 ? 1 : -1 let abs = Math.abs(pending) let applied = 0 // Snap excess beyond animation window so big flicks don't coast. if (abs > SCROLL_MAX_PENDING) { applied += sign * (abs - SCROLL_MAX_PENDING) abs = SCROLL_MAX_PENDING } // ≤5: drain all (slow click = instant). Above: small fixed step. const step = abs <= SCROLL_INSTANT_THRESHOLD ? abs : abs < SCROLL_HIGH_PENDING ? SCROLL_STEP_MED : SCROLL_STEP_HIGH applied += sign * step const rem = abs - step // Cap total at innerHeight-1 so DECSTBM blit+shift fast path fires // (matches drainProportional). Excess stays in pendingScrollDelta. const cap = Math.max(1, innerHeight - 1) const totalAbs = Math.abs(applied) if (totalAbs > cap) { const excess = totalAbs - cap node.pendingScrollDelta = sign * (rem + excess) return sign * cap } node.pendingScrollDelta = rem > 0 ? sign * rem : undefined return applied}
// Native proportional drain. step = max(MIN, floor(abs*3/4)), capped at// innerHeight-1 so DECSTBM + blit+shift fast path fire.function drainProportional( node: DOMElement, pending: number, innerHeight: number,): number { const abs = Math.abs(pending) const cap = Math.max(1, innerHeight - 1) const step = Math.min(cap, Math.max(SCROLL_MIN_PER_FRAME, (abs * 3) >> 2)) if (abs <= step) { node.pendingScrollDelta = undefined return pending } const applied = pending > 0 ? step : -step node.pendingScrollDelta = pending - applied return applied}
// OSC 8 hyperlink escape sequences. Empty params (;;) — ansi-tokenize only// recognizes this exact prefix. The id= param (for grouping wrapped lines)// is added at terminal-output time in termio/osc.ts link().const OSC = '\u001B]'const BEL = '\u0007'
function wrapWithOsc8Link(text: string, url: string): string { return `${OSC}8;;${url}${BEL}${text}${OSC}8;;${BEL}`}
/** * Build a mapping from each character position in the plain text to its segment index. * Returns an array where charToSegment[i] is the segment index for character i. */function buildCharToSegmentMap(segments: StyledSegment[]): number[] { const map: number[] = [] for (let i = 0; i < segments.length; i++) { const len = segments[i]!.text.length for (let j = 0; j < len; j++) { map.push(i) } } return map}
/** * Apply styles to wrapped text by mapping each character back to its original segment. * This preserves per-segment styles even when text wraps across lines. * * @param trimEnabled - Whether whitespace trimming is enabled (wrap-trim mode). * When true, we skip whitespace in the original that was trimmed from the output. * When false (wrap mode), all whitespace is preserved so no skipping is needed. */function applyStylesToWrappedText( wrappedPlain: string, segments: StyledSegment[], charToSegment: number[], originalPlain: string, trimEnabled: boolean = false,): string { const lines = wrappedPlain.split('\n') const resultLines: string[] = []
let charIndex = 0 for (let lineIdx = 0; lineIdx < lines.length; lineIdx++) { const line = lines[lineIdx]!
// In trim mode, skip leading whitespace that was trimmed from this line. // Only skip if the original has whitespace but the output line doesn't start // with whitespace (meaning it was trimmed). If both have whitespace, the // whitespace was preserved and we shouldn't skip. if (trimEnabled && line.length > 0) { const lineStartsWithWhitespace = /\s/.test(line[0]!) const originalHasWhitespace = charIndex < originalPlain.length && /\s/.test(originalPlain[charIndex]!)
// Only skip if original has whitespace but line doesn't if (originalHasWhitespace && !lineStartsWithWhitespace) { while ( charIndex < originalPlain.length && /\s/.test(originalPlain[charIndex]!) ) { charIndex++ } } }
let styledLine = '' let runStart = 0 let runSegmentIndex = charToSegment[charIndex] ?? 0
for (let i = 0; i < line.length; i++) { const currentSegmentIndex = charToSegment[charIndex] ?? runSegmentIndex
if (currentSegmentIndex !== runSegmentIndex) { // Flush the current run const runText = line.slice(runStart, i) const segment = segments[runSegmentIndex] if (segment) { let styled = applyTextStyles(runText, segment.styles) if (segment.hyperlink) { styled = wrapWithOsc8Link(styled, segment.hyperlink) } styledLine += styled } else { styledLine += runText } runStart = i runSegmentIndex = currentSegmentIndex }
charIndex++ }
// Flush the final run const runText = line.slice(runStart) const segment = segments[runSegmentIndex] if (segment) { let styled = applyTextStyles(runText, segment.styles) if (segment.hyperlink) { styled = wrapWithOsc8Link(styled, segment.hyperlink) } styledLine += styled } else { styledLine += runText }
resultLines.push(styledLine)
// Skip newline character in original that corresponds to this line break. // This is needed when the original text contains actual newlines (not just // wrapping-inserted newlines). Without this, charIndex gets out of sync // because the newline is in originalPlain/charToSegment but not in the // split lines. if (charIndex < originalPlain.length && originalPlain[charIndex] === '\n') { charIndex++ }
// In trim mode, skip whitespace that was replaced by newline when wrapping. // We skip whitespace in the original until we reach a character that matches // the first character of the next line. This handles cases like: // - "AB \tD" wrapped to "AB\n\tD" - skip spaces until we hit the tab // In non-trim mode, whitespace is preserved so no skipping is needed. if (trimEnabled && lineIdx < lines.length - 1) { const nextLine = lines[lineIdx + 1]! const nextLineFirstChar = nextLine.length > 0 ? nextLine[0] : null
// Skip whitespace until we hit a char that matches the next line's first char while ( charIndex < originalPlain.length && /\s/.test(originalPlain[charIndex]!) ) { // Stop if we found the character that starts the next line if ( nextLineFirstChar !== null && originalPlain[charIndex] === nextLineFirstChar ) { break } charIndex++ } } }
return resultLines.join('\n')}
/** * Wrap text and record which output lines are soft-wrap continuations * (i.e. the `\n` before them was inserted by word-wrap, not in the * source). wrapAnsi already processes each input line independently, so * wrapping per-input-line here gives identical output to a single * whole-string wrap while letting us mark per-piece provenance. * Truncate modes never add newlines (cli-truncate is whole-string) so * they fall through with softWrap undefined — no tracking, no behavior * change from the pre-softWrap path. */function wrapWithSoftWrap( plainText: string, maxWidth: number, textWrap: Parameters<typeof wrapText>[2],): { wrapped: string; softWrap: boolean[] | undefined } { if (textWrap !== 'wrap' && textWrap !== 'wrap-trim') { return { wrapped: wrapText(plainText, maxWidth, textWrap), softWrap: undefined, } } const origLines = plainText.split('\n') const outLines: string[] = [] const softWrap: boolean[] = [] for (const orig of origLines) { const pieces = wrapText(orig, maxWidth, textWrap).split('\n') for (let i = 0; i < pieces.length; i++) { outLines.push(pieces[i]!) softWrap.push(i > 0) } } return { wrapped: outLines.join('\n'), softWrap }}
// If parent container is `<Box>`, text nodes will be treated as separate nodes in// the tree and will have their own coordinates in the layout.// To ensure text nodes are aligned correctly, take X and Y of the first text node// and use it as offset for the rest of the nodes// Only first node is taken into account, because other text nodes can't have margin or padding,// so their coordinates will be relative to the first node anywayfunction applyPaddingToText( node: DOMElement, text: string, softWrap?: boolean[],): string { const yogaNode = node.childNodes[0]?.yogaNode
if (yogaNode) { const offsetX = yogaNode.getComputedLeft() const offsetY = yogaNode.getComputedTop() text = '\n'.repeat(offsetY) + indentString(text, offsetX) if (softWrap && offsetY > 0) { // Prepend `false` for each padding line so indices stay aligned // with text.split('\n'). Mutate in place — caller owns the array. softWrap.unshift(...Array<boolean>(offsetY).fill(false)) } }
return text}
// After nodes are laid out, render each to output object, which later gets rendered to terminalfunction renderNodeToOutput( node: DOMElement, output: Output, { offsetX = 0, offsetY = 0, prevScreen, skipSelfBlit = false, inheritedBackgroundColor, }: { offsetX?: number offsetY?: number prevScreen: Screen | undefined // Force this node to descend instead of blitting its own rect, while // still passing prevScreen to children. Used for non-opaque absolute // overlays over a dirty clipped region: the overlay's full rect has // transparent gaps (stale underlying content in prevScreen), but its // opaque descendants' narrower rects are safe to blit. skipSelfBlit?: boolean inheritedBackgroundColor?: Color },): void { const { yogaNode } = node
if (yogaNode) { if (yogaNode.getDisplay() === LayoutDisplay.None) { // Clear old position if node was visible before becoming hidden if (node.dirty) { const cached = nodeCache.get(node) if (cached) { output.clear({ x: Math.floor(cached.x), y: Math.floor(cached.y), width: Math.floor(cached.width), height: Math.floor(cached.height), }) // Drop descendants' cache too — hideInstance's markDirty walks UP // only, so descendants' .dirty stays false. Their nodeCache entries // survive with pre-hide rects. On unhide, if position didn't shift, // the blit check at line ~432 passes and copies EMPTY cells from // prevScreen (cleared here) → content vanishes. dropSubtreeCache(node) layoutShifted = true } } return }
// Left and top positions in Yoga are relative to their parent node const x = offsetX + yogaNode.getComputedLeft() const yogaTop = yogaNode.getComputedTop() let y = offsetY + yogaTop const width = yogaNode.getComputedWidth() const height = yogaNode.getComputedHeight()
// Absolute-positioned overlays (e.g. autocomplete menus with bottom='100%') // can compute negative screen y when they extend above the viewport. Without // clamping, setCellAt drops cells at y<0, clipping the TOP of the content // (best matches in an autocomplete). By clamping to 0, we shift the element // down so the top rows are visible and the bottom overflows below — the // opaque prop ensures it paints over whatever is underneath. if (y < 0 && node.style.position === 'absolute') { y = 0 }
// Check if we can skip this subtree (clean node with unchanged layout). // Blit cells from previous screen instead of re-rendering. const cached = nodeCache.get(node) if ( !node.dirty && !skipSelfBlit && node.pendingScrollDelta === undefined && cached && cached.x === x && cached.y === y && cached.width === width && cached.height === height && prevScreen ) { const fx = Math.floor(x) const fy = Math.floor(y) const fw = Math.floor(width) const fh = Math.floor(height) output.blit(prevScreen, fx, fy, fw, fh) if (node.style.position === 'absolute') { absoluteRectsCur.push(cached) } // Absolute descendants can paint outside this node's layout bounds // (e.g. a slash menu with position='absolute' bottom='100%' floats // above). If a dirty clipped sibling re-rendered and overwrote those // cells, the blit above only restored this node's own rect — the // absolute descendants' cells are lost. Re-blit them from prevScreen // so the overlays survive. blitEscapingAbsoluteDescendants(node, output, prevScreen, fx, fy, fw, fh) return }
// Clear stale content from the old position when re-rendering. // Dirty: content changed. Moved: position/size changed (e.g., sibling // above changed height), old cells still on the terminal. const positionChanged = cached !== undefined && (cached.x !== x || cached.y !== y || cached.width !== width || cached.height !== height) if (positionChanged) { layoutShifted = true } if (cached && (node.dirty || positionChanged)) { output.clear( { x: Math.floor(cached.x), y: Math.floor(cached.y), width: Math.floor(cached.width), height: Math.floor(cached.height), }, node.style.position === 'absolute', ) }
// Read before deleting — hasRemovedChild disables prevScreen blitting // for siblings to prevent stale overflow content from being restored. const clears = pendingClears.get(node) const hasRemovedChild = clears !== undefined if (hasRemovedChild) { layoutShifted = true for (const rect of clears) { output.clear({ x: Math.floor(rect.x), y: Math.floor(rect.y), width: Math.floor(rect.width), height: Math.floor(rect.height), }) } pendingClears.delete(node) }
// Yoga squeezed this node to zero height (overflow in a height-constrained // parent) AND a sibling lands at the same y. Skip rendering — both would // write to the same row; if the sibling's content is shorter, this node's // tail chars ghost (e.g. "false" + "true" = "truee"). The clear above // already handled the visible→squeezed transition. // // The sibling-overlap check is load-bearing: Yoga's pixel-grid rounding // can give a box h=0 while still leaving a row for it (next sibling at // y+1, not y). HelpV2's third shortcuts column hits this — skipping // unconditionally drops "ctrl + z to suspend" from /help output. if (height === 0 && siblingSharesY(node, yogaNode)) { nodeCache.set(node, { x, y, width, height, top: yogaTop }) node.dirty = false return }
if (node.nodeName === 'ink-raw-ansi') { // Pre-rendered ANSI content. The producer already wrapped to width and // emitted terminal-ready escape codes. Skip squash, measure, wrap, and // style re-application — output.write() parses ANSI directly into cells. const text = node.attributes['rawText'] as string if (text) { output.write(x, y, text) } } else if (node.nodeName === 'ink-text') { const segments = squashTextNodesToSegments( node, inheritedBackgroundColor ? { backgroundColor: inheritedBackgroundColor } : undefined, )
// First, get plain text to check if wrapping is needed const plainText = segments.map(s => s.text).join('')
if (plainText.length > 0) { // Upstream Ink uses getMaxWidth(yogaNode) unclamped here. That // width comes from Yoga's AtMost pass and can exceed the actual // screen space (see getMaxWidth docstring). Yoga's height for this // node already reflects the constrained Exactly pass, so clamping // the wrap width here keeps line count consistent with layout. // Without this, characters past the screen edge are dropped by // setCellAt's bounds check. const maxWidth = Math.min(getMaxWidth(yogaNode), output.width - x) const textWrap = node.style.textWrap ?? 'wrap'
// Check if wrapping is needed const needsWrapping = widestLine(plainText) > maxWidth
let text: string let softWrap: boolean[] | undefined if (needsWrapping && segments.length === 1) { // Single segment: wrap plain text first, then apply styles to each line const segment = segments[0]! const w = wrapWithSoftWrap(plainText, maxWidth, textWrap) softWrap = w.softWrap text = w.wrapped .split('\n') .map(line => { let styled = applyTextStyles(line, segment.styles) // Apply OSC 8 hyperlink per-line so each line is independently // clickable. output.ts splits on newlines and tokenizes each // line separately, so a single wrapper around the whole block // would only apply the hyperlink to the first line. if (segment.hyperlink) { styled = wrapWithOsc8Link(styled, segment.hyperlink) } return styled }) .join('\n') } else if (needsWrapping) { // Multiple segments with wrapping: wrap plain text first, then re-apply // each segment's styles based on character positions. This preserves // per-segment styles even when text wraps across lines. const w = wrapWithSoftWrap(plainText, maxWidth, textWrap) softWrap = w.softWrap const charToSegment = buildCharToSegmentMap(segments) text = applyStylesToWrappedText( w.wrapped, segments, charToSegment, plainText, textWrap === 'wrap-trim', ) // Hyperlinks are handled per-run in applyStylesToWrappedText via // wrapWithOsc8Link, similar to how styles are applied per-run. } else { // No wrapping needed: apply styles directly text = segments .map(segment => { let styledText = applyTextStyles(segment.text, segment.styles) if (segment.hyperlink) { styledText = wrapWithOsc8Link(styledText, segment.hyperlink) } return styledText }) .join('') }
text = applyPaddingToText(node, text, softWrap)
output.write(x, y, text, softWrap) } } else if (node.nodeName === 'ink-box') { const boxBackgroundColor = node.style.backgroundColor ?? inheritedBackgroundColor
// Mark this box's region as non-selectable (fullscreen text // selection). noSelect ops are applied AFTER blits/writes in // output.get(), so this wins regardless of what's rendered into // the region — including blits from prevScreen when the box is // clean (the op is emitted on both the dirty-render path here // AND on the blit fast-path at line ~235 since blitRegion copies // the noSelect bitmap alongside cells). // // 'from-left-edge' extends the exclusion from col 0 so any // upstream indentation (tool prefix, tree lines) is covered too // — a multi-row drag over a diff gutter shouldn't pick up the // ` ⎿ ` prefix on row 0 or the blank cells under it on row 1+. if (node.style.noSelect) { const boxX = Math.floor(x) const fromEdge = node.style.noSelect === 'from-left-edge' output.noSelect({ x: fromEdge ? 0 : boxX, y: Math.floor(y), width: fromEdge ? boxX + Math.floor(width) : Math.floor(width), height: Math.floor(height), }) }
const overflowX = node.style.overflowX ?? node.style.overflow const overflowY = node.style.overflowY ?? node.style.overflow const clipHorizontally = overflowX === 'hidden' || overflowX === 'scroll' const clipVertically = overflowY === 'hidden' || overflowY === 'scroll' const isScrollY = overflowY === 'scroll'
const needsClip = clipHorizontally || clipVertically let y1: number | undefined let y2: number | undefined if (needsClip) { const x1 = clipHorizontally ? x + yogaNode.getComputedBorder(LayoutEdge.Left) : undefined
const x2 = clipHorizontally ? x + yogaNode.getComputedWidth() - yogaNode.getComputedBorder(LayoutEdge.Right) : undefined
y1 = clipVertically ? y + yogaNode.getComputedBorder(LayoutEdge.Top) : undefined
y2 = clipVertically ? y + yogaNode.getComputedHeight() - yogaNode.getComputedBorder(LayoutEdge.Bottom) : undefined
output.clip({ x1, x2, y1, y2 }) }
if (isScrollY) { // Scroll containers follow the ScrollBox component structure: // a single content-wrapper child with flexShrink:0 (doesn't shrink // to fit), whose children are the scrollable items. scrollHeight // comes from the wrapper's intrinsic Yoga height. The wrapper is // rendered with its Y translated by -scrollTop; its children are // culled against the visible window. const padTop = yogaNode.getComputedPadding(LayoutEdge.Top) const innerHeight = Math.max( 0, (y2 ?? y + height) - (y1 ?? y) - padTop - yogaNode.getComputedPadding(LayoutEdge.Bottom), )
const content = node.childNodes.find(c => (c as DOMElement).yogaNode) as | DOMElement | undefined const contentYoga = content?.yogaNode // scrollHeight is the intrinsic height of the content wrapper. // Do NOT add getComputedTop() — that's the wrapper's offset // within the viewport (equal to the scroll container's // paddingTop), and innerHeight already subtracts padding, so // including it double-counts padding and inflates maxScroll. const scrollHeight = contentYoga?.getComputedHeight() ?? 0 // Capture previous scroll bounds BEFORE overwriting — the at-bottom // follow check compares against last frame's max. const prevScrollHeight = node.scrollHeight ?? scrollHeight const prevInnerHeight = node.scrollViewportHeight ?? innerHeight node.scrollHeight = scrollHeight node.scrollViewportHeight = innerHeight // Absolute screen-buffer row where the scrollable area (inside // padding) begins. Exposed via ScrollBoxHandle.getViewportTop() so // drag-to-scroll can detect when the drag leaves the scroll viewport. node.scrollViewportTop = (y1 ?? y) + padTop
const maxScroll = Math.max(0, scrollHeight - innerHeight) // scrollAnchor: scroll so the anchored element's top is at the // viewport top (plus offset). Yoga is FRESH — same calculateLayout // pass that just produced scrollHeight. Deterministic alternative // to scrollTo(N) which bakes a number that's stale by the throttled // render; the element ref defers the read to now. One-shot snap. // A prior eased-seek version (proportional drain over ~5 frames) // moved scrollTop without firing React's notify → parent's quantized // store snapshot never updated → StickyTracker got stale range props // → firstVisible wrong. Also: SCROLL_MIN_PER_FRAME=4 with snap-at-1 // ping-ponged forever at delta=2. Smooth needs drain-end notify // plumbing; shipping instant first. stickyScroll overrides. if (node.scrollAnchor) { const anchorTop = node.scrollAnchor.el.yogaNode?.getComputedTop() if (anchorTop != null) { node.scrollTop = anchorTop + node.scrollAnchor.offset node.pendingScrollDelta = undefined } node.scrollAnchor = undefined } // At-bottom follow. Positional: if scrollTop was at (or past) the // previous max, pin to the new max. Scroll away → stop following; // scroll back (or scrollToBottom/sticky attr) → resume. The sticky // flag is OR'd in for cold start (scrollTop=0 before first layout) // and scrollToBottom-from-far-away (flag set before scrollTop moves) // — the imperative field takes precedence over the attribute so // scrollTo/scrollBy can break stickiness. pendingDelta<0 guard: // don't cancel an in-flight scroll-up when content races in. // Capture scrollTop before follow so ink.tsx can translate any // active text selection by the same delta (native terminal behavior: // view keeps scrolling, highlight walks up with the text). const scrollTopBeforeFollow = node.scrollTop ?? 0 const sticky = node.stickyScroll ?? Boolean(node.attributes['stickyScroll']) const prevMaxScroll = Math.max(0, prevScrollHeight - prevInnerHeight) // Positional check only valid when content grew — virtualization can // transiently SHRINK scrollHeight (tail unmount + stale heightCache // spacer) making scrollTop >= prevMaxScroll true by artifact, not // because the user was at bottom. const grew = scrollHeight >= prevScrollHeight const atBottom = sticky || (grew && scrollTopBeforeFollow >= prevMaxScroll) if (atBottom && (node.pendingScrollDelta ?? 0) >= 0) { node.scrollTop = maxScroll node.pendingScrollDelta = undefined // Sync flag so useVirtualScroll's isSticky() agrees with positional // state — sticky-broken-but-at-bottom (wheel tremor, click-select // at max) otherwise leaves useVirtualScroll's clamp holding the // viewport short of new streaming content. scrollTo/scrollBy set // false; this restores true, same as scrollToBottom() would. // Only restore when (a) positionally at bottom and (b) the flag // was explicitly broken (===false) by scrollTo/scrollBy. When // undefined (never set by user action) leave it alone — setting it // would make the sticky flag sticky-by-default and lock out // direct scrollTop writes (e.g. the alt-screen-perf test). if ( node.stickyScroll === false && scrollTopBeforeFollow >= prevMaxScroll ) { node.stickyScroll = true } } const followDelta = (node.scrollTop ?? 0) - scrollTopBeforeFollow if (followDelta > 0) { const vpTop = node.scrollViewportTop ?? 0 followScroll = { delta: followDelta, viewportTop: vpTop, viewportBottom: vpTop + innerHeight - 1, } } // Drain pendingScrollDelta. Native terminals (proportional burst // events) use proportional drain; xterm.js (VS Code, sparse events + // app-side accel curve) uses adaptive small-step drain. isXtermJs() // depends on the async XTVERSION probe, but by the time this runs // (pendingScrollDelta is only set by wheel events, >>50ms after // startup) the probe has resolved — same timing guarantee the // wheel-accel curve relies on. let cur = node.scrollTop ?? 0 const pending = node.pendingScrollDelta const cMin = node.scrollClampMin const cMax = node.scrollClampMax const haveClamp = cMin !== undefined && cMax !== undefined if (pending !== undefined && pending !== 0) { // Drain continues even past the clamp — the render-clamp below // holds the VISUAL at the mounted edge regardless. Hard-stopping // here caused stop-start jutter: drain hits edge → pause → React // commits → clamp widens → drain resumes → edge again. Letting // scrollTop advance smoothly while the clamp lags gives continuous // visual scroll at React's commit rate (the clamp catches up each // commit). But THROTTLE the drain when already past the clamp so // scrollTop doesn't race 5000 rows ahead of the mounted range // (slide-cap would then take 200 commits to catch up = long // perceived stall at the edge). Past-clamp drain caps at ~4 rows/ // frame, roughly matching React's slide rate so the gap stays // bounded and catch-up is quick once input stops. const pastClamp = haveClamp && ((pending < 0 && cur < cMin) || (pending > 0 && cur > cMax)) const eff = pastClamp ? Math.min(4, innerHeight >> 3) : innerHeight cur += isXtermJsHost() ? drainAdaptive(node, pending, eff) : drainProportional(node, pending, eff) } else if (pending === 0) { // Opposite scrollBy calls cancelled to zero — clear so we don't // schedule an infinite loop of no-op drain frames. node.pendingScrollDelta = undefined } let scrollTop = Math.max(0, Math.min(cur, maxScroll)) // Virtual-scroll clamp: if scrollTop raced past the currently-mounted // range (burst PageUp before React re-renders), render at the EDGE of // the mounted children instead of blank spacer. Do NOT write back to // node.scrollTop — the clamped value is for this paint only; the real // scrollTop stays so React's next commit sees the target and mounts // the right range. Not scheduling scrollDrainNode here keeps the // clamp passive — React's commit → resetAfterCommit → onRender will // paint again with fresh bounds. const clamped = haveClamp ? Math.max(cMin, Math.min(scrollTop, cMax)) : scrollTop node.scrollTop = scrollTop // Clamp hitting top/bottom consumes any remainder. Set drainPending // only after clamp so a wasted no-op frame isn't scheduled. if (scrollTop !== cur) node.pendingScrollDelta = undefined if (node.pendingScrollDelta !== undefined) scrollDrainNode = node scrollTop = clamped
if (content && contentYoga) { // Compute content wrapper's absolute render position with scroll // offset applied, then render its children with culling. const contentX = x + contentYoga.getComputedLeft() const contentY = y + contentYoga.getComputedTop() - scrollTop // layoutShifted detection gap: when scrollTop moves by >= viewport // height (batched PageUps, fast wheel), every visible child gets // culled (cache dropped) and every newly-visible child has no // cache — so the children's positionChanged check can't fire. // The content wrapper's cached y (which encodes -scrollTop) is // the only node that survives to witness the scroll. const contentCached = nodeCache.get(content) let hint: ScrollHint | null = null if (contentCached && contentCached.y !== contentY) { // delta = newScrollTop - oldScrollTop (positive = scrolled down). // Capture a DECSTBM hint if the container itself didn't move // and the shift fits within the viewport — otherwise the full // rewrite is needed anyway, and layoutShifted stays the fallback. const delta = contentCached.y - contentY const regionTop = Math.floor(y + contentYoga.getComputedTop()) const regionBottom = regionTop + innerHeight - 1 if ( cached?.y === y && cached.height === height && innerHeight > 0 && Math.abs(delta) < innerHeight ) { hint = { top: regionTop, bottom: regionBottom, delta } scrollHint = hint } else { layoutShifted = true } } // Fast path: scroll (hint captured) with usable prevScreen. // Blit prevScreen's scroll region into next.screen, shift in-place // by delta (mirrors DECSTBM), then render ONLY the edge rows. The // nested clip keeps child writes out of stable rows — a tall child // that spans edge+stable still renders but stable cells are // clipped, preserving the blit. Avoids re-rendering every visible // child (expensive for long syntax-highlighted transcripts). // // When content.dirty (e.g. streaming text at the bottom of the // scroll), we still use the fast path — the dirty child is almost // always in the edge rows (the bottom, where new content appears). // After edge rendering, any dirty children in stable rows are // re-rendered in a second pass to avoid showing stale blitted // content. // // Guard: the fast path only handles pure scroll or bottom-append. // Child removal/insertion changes the content height in a way that // doesn't match the scroll delta — fall back to the full path so // removed children don't leave stale cells and shifted siblings // render at their new positions. const scrollHeight = contentYoga.getComputedHeight() const prevHeight = contentCached?.height ?? scrollHeight const heightDelta = scrollHeight - prevHeight const safeForFastPath = !hint || heightDelta === 0 || (hint.delta > 0 && heightDelta === hint.delta) // scrollHint is set above when hint is captured. If safeForFastPath // is false the full path renders a next.screen that doesn't match // the DECSTBM shift — emitting DECSTBM leaves stale rows (seen as // content bleeding through during scroll-up + streaming). Clear it. if (!safeForFastPath) scrollHint = null if (hint && prevScreen && safeForFastPath) { const { top, bottom, delta } = hint const w = Math.floor(width) output.blit(prevScreen, Math.floor(x), top, w, bottom - top + 1) output.shift(top, bottom, delta) // Edge rows: new content entering the viewport. const edgeTop = delta > 0 ? bottom - delta + 1 : top const edgeBottom = delta > 0 ? bottom : top - delta - 1 output.clear({ x: Math.floor(x), y: edgeTop, width: w, height: edgeBottom - edgeTop + 1, }) output.clip({ x1: undefined, x2: undefined, y1: edgeTop, y2: edgeBottom + 1, }) // Snapshot dirty children before the first pass — the first // pass clears dirty flags, and edge-spanning children would be // missed by the second pass without this snapshot. const dirtyChildren = content.dirty ? new Set(content.childNodes.filter(c => (c as DOMElement).dirty)) : null renderScrolledChildren( content, output, contentX, contentY, hasRemovedChild, undefined, // Cull to edge in child-local coords (inverse of contentY offset). edgeTop - contentY, edgeBottom + 1 - contentY, boxBackgroundColor, true, ) output.unclip()
// Second pass: re-render children in stable rows whose screen // position doesn't match where the shift put their old pixels. // Covers TWO cases: // 1. Dirty children — their content changed, blitted pixels are // stale regardless of position. // 2. Clean children BELOW a middle-growth point — when a dirty // sibling above them grows, their yogaTop increases but // scrollTop increases by the same amount (sticky), so their // screenY is CONSTANT. The shift moved their old pixels to // screenY-delta (wrong); they should stay at screenY. Without // this, the spinner/tmux-monitor ghost at shifted positions // during streaming (e.g. triple spinner, pill duplication). // For bottom-append (the common case), all clean children are // ABOVE the growth point; their screenY decreased by delta and // the shift put them at the right place — skipped here, fast // path preserved. if (dirtyChildren) { const edgeTopLocal = edgeTop - contentY const edgeBottomLocal = edgeBottom + 1 - contentY const spaces = ' '.repeat(w) // Track cumulative height change of children iterated so far. // A clean child's yogaTop is unchanged iff this is zero (no // sibling above it grew/shrank/mounted). When zero, the skip // check cached.y−delta === screenY reduces to delta === delta // (tautology) → skip without yoga reads. Restores O(dirty) // that #24536 traded away: for bottom-append the dirty child // is last (all clean children skip); for virtual-scroll range // shift the topSpacer shrink + new-item heights self-balance // to zero before reaching the clean block. Middle-growth // leaves shift non-zero → clean children after the growth // point fall through to yoga + the fine-grained check below, // preserving the ghost-box fix. let cumHeightShift = 0 for (const childNode of content.childNodes) { const childElem = childNode as DOMElement const isDirty = dirtyChildren.has(childNode) if (!isDirty && cumHeightShift === 0) { if (nodeCache.has(childElem)) continue // Uncached = culled last frame, now re-entering. blit // never painted it → fall through to yoga + render. // Height unchanged (clean), so cumHeightShift stays 0. } const cy = childElem.yogaNode if (!cy) continue const childTop = cy.getComputedTop() const childH = cy.getComputedHeight() const childBottom = childTop + childH if (isDirty) { const prev = nodeCache.get(childElem) cumHeightShift += childH - (prev ? prev.height : 0) } // Skip culled children (outside viewport) if ( childBottom <= scrollTop || childTop >= scrollTop + innerHeight ) continue // Skip children entirely within edge rows (already rendered) if (childTop >= edgeTopLocal && childBottom <= edgeBottomLocal) continue const screenY = Math.floor(contentY + childTop) // Clean children reaching here have cumHeightShift ≠ 0 OR // no cache. Re-check precisely: cached.y − delta is where // the shift left old pixels; if it equals new screenY the // blit is correct (shift re-balanced at this child, or // yogaTop happens to net out). No cache → blit never // painted it → render. if (!isDirty) { const childCached = nodeCache.get(childElem) if ( childCached && Math.floor(childCached.y) - delta === screenY ) { continue } } // Wipe this child's region with spaces to overwrite stale // blitted content — output.clear() only expands damage and // cannot zero cells that the blit already wrote. const screenBottom = Math.min( Math.floor(contentY + childBottom), Math.floor((y1 ?? y) + padTop + innerHeight), ) if (screenY < screenBottom) { const fill = Array(screenBottom - screenY) .fill(spaces) .join('\n') output.write(Math.floor(x), screenY, fill) output.clip({ x1: undefined, x2: undefined, y1: screenY, y2: screenBottom, }) renderNodeToOutput(childElem, output, { offsetX: contentX, offsetY: contentY, prevScreen: undefined, inheritedBackgroundColor: boxBackgroundColor, }) output.unclip() } } }
// Third pass: repair rows where shifted copies of absolute // overlays landed. The blit copied prevScreen cells INCLUDING // overlay pixels (overlays render AFTER this ScrollBox so they // painted into prevScreen's scroll region). After shift, those // pixels sit at (rect.y - delta) — neither edge render nor the // overlay's own re-render covers them. Wipe and re-render // ScrollBox content so the diff writes correct cells. const spaces = absoluteRectsPrev.length ? ' '.repeat(w) : '' for (const r of absoluteRectsPrev) { if (r.y >= bottom + 1 || r.y + r.height <= top) continue const shiftedTop = Math.max(top, Math.floor(r.y) - delta) const shiftedBottom = Math.min( bottom + 1, Math.floor(r.y + r.height) - delta, ) // Skip if entirely within edge rows (already rendered). if (shiftedTop >= edgeTop && shiftedBottom <= edgeBottom + 1) continue if (shiftedTop >= shiftedBottom) continue const fill = Array(shiftedBottom - shiftedTop) .fill(spaces) .join('\n') output.write(Math.floor(x), shiftedTop, fill) output.clip({ x1: undefined, x2: undefined, y1: shiftedTop, y2: shiftedBottom, }) renderScrolledChildren( content, output, contentX, contentY, hasRemovedChild, undefined, shiftedTop - contentY, shiftedBottom - contentY, boxBackgroundColor, true, ) output.unclip() } } else { // Full path. Two sub-cases: // // Scrolled without a usable hint (big jump, container moved): // child positions in prevScreen are stale. Clear the viewport // and disable blit so children don't restore shifted content. // // No scroll (spinner tick, content edit): child positions in // prevScreen are still valid. Skip the viewport clear and pass // prevScreen so unchanged children blit. Dirty children already // self-clear via their own cached-rect clear. Without this, a // spinner inside ScrollBox forces a full-content rewrite every // frame — on wide terminals over tmux (no BSU/ESU) the // bandwidth crosses the chunk boundary and the frame tears. const scrolled = contentCached && contentCached.y !== contentY if (scrolled && y1 !== undefined && y2 !== undefined) { output.clear({ x: Math.floor(x), y: Math.floor(y1), width: Math.floor(width), height: Math.floor(y2 - y1), }) } // positionChanged (ScrollBox height shrunk — pill mount) means a // child spanning the old bottom edge would blit its full cached // rect past the new clip. output.ts clips blits now, but also // disable prevScreen here so the partial-row child re-renders at // correct bounds instead of blitting a clipped (truncated) old // rect. renderScrolledChildren( content, output, contentX, contentY, hasRemovedChild, scrolled || positionChanged ? undefined : prevScreen, scrollTop, scrollTop + innerHeight, boxBackgroundColor, ) } nodeCache.set(content, { x: contentX, y: contentY, width: contentYoga.getComputedWidth(), height: contentYoga.getComputedHeight(), }) content.dirty = false } } else { // Fill interior with background color before rendering children. // This covers padding areas and empty space; child text inherits // the color via inheritedBackgroundColor so written cells also // get the background. // Disable prevScreen for children: the fill overwrites the entire // interior each render, so child blits from prevScreen would restore // stale cells (wrong bg if it changed) on top of the fresh fill. const ownBackgroundColor = node.style.backgroundColor if (ownBackgroundColor || node.style.opaque) { const borderLeft = yogaNode.getComputedBorder(LayoutEdge.Left) const borderRight = yogaNode.getComputedBorder(LayoutEdge.Right) const borderTop = yogaNode.getComputedBorder(LayoutEdge.Top) const borderBottom = yogaNode.getComputedBorder(LayoutEdge.Bottom) const innerWidth = Math.floor(width) - borderLeft - borderRight const innerHeight = Math.floor(height) - borderTop - borderBottom if (innerWidth > 0 && innerHeight > 0) { const spaces = ' '.repeat(innerWidth) const fillLine = ownBackgroundColor ? applyTextStyles(spaces, { backgroundColor: ownBackgroundColor }) : spaces const fill = Array(innerHeight).fill(fillLine).join('\n') output.write(x + borderLeft, y + borderTop, fill) } }
renderChildren( node, output, x, y, hasRemovedChild, // backgroundColor and opaque both disable child blit: the fill // overwrites the entire interior each render, so any child whose // layout position shifted would blit stale cells from prevScreen // on top of the fresh fill. Previously opaque kept blit enabled // on the assumption that plain-space fill + unchanged children = // valid composite, but children CAN reposition (ScrollBox remeasure // on re-render → /permissions body blanked on Down arrow, #25436). ownBackgroundColor || node.style.opaque ? undefined : prevScreen, boxBackgroundColor, ) }
if (needsClip) { output.unclip() }
// Render border AFTER children to ensure it's not overwritten by child // clearing operations. When a child shrinks, it clears its old area, // which may overlap with where the parent's border now is. renderBorder(x, y, node, output) } else if (node.nodeName === 'ink-root') { renderChildren( node, output, x, y, hasRemovedChild, prevScreen, inheritedBackgroundColor, ) }
// Cache layout bounds for dirty tracking const rect = { x, y, width, height, top: yogaTop } nodeCache.set(node, rect) if (node.style.position === 'absolute') { absoluteRectsCur.push(rect) } node.dirty = false }}
// Overflow contamination: content overflows right/down, so clean siblings// AFTER a dirty/removed sibling can contain stale overflow in prevScreen.// Disable blit for siblings after a dirty child — but still pass prevScreen// TO the dirty child itself so its clean descendants can blit. The dirty// child's own blit check already fails (node.dirty=true at line 216), so// passing prevScreen only benefits its subtree.// For removed children we don't know their original position, so// conservatively disable blit for all.//// Clipped children (overflow hidden/scroll on both axes) cannot overflow// onto later siblings — their content is confined to their layout bounds.// Skip the contamination guard for them so later siblings can still blit.// Without this, a spinner inside a ScrollBox dirties the wrapper on every// tick and the bottom prompt section never blits → 100% writes every frame.//// Exception: absolute-positioned clipped children may have layout bounds// that overlap arbitrary siblings, so the clipping does not help.//// Overlap contamination (seenDirtyClipped): a later ABSOLUTE sibling whose// rect sits inside a dirty clipped child's bounds would blit stale cells// from prevScreen — the clipped child just rewrote those cells this frame.// The clipsBothAxes skip only protects against OVERFLOW (clipped child// painting outside its bounds), not overlap (absolute sibling painting// inside them). For non-opaque absolute siblings, skipSelfBlit forces// descent (the full-width rect has transparent gaps → stale blit) while// still passing prevScreen so opaque descendants can blit their narrower// rects (NewMessagesPill's inner Text with backgroundColor). Opaque// absolute siblings fill their entire rect — direct blit is safe.function renderChildren( node: DOMElement, output: Output, offsetX: number, offsetY: number, hasRemovedChild: boolean, prevScreen: Screen | undefined, inheritedBackgroundColor: Color | undefined,): void { let seenDirtyChild = false let seenDirtyClipped = false for (const childNode of node.childNodes) { const childElem = childNode as DOMElement // Capture dirty before rendering — renderNodeToOutput clears the flag const wasDirty = childElem.dirty const isAbsolute = childElem.style.position === 'absolute' renderNodeToOutput(childElem, output, { offsetX, offsetY, prevScreen: hasRemovedChild || seenDirtyChild ? undefined : prevScreen, // Short-circuits on seenDirtyClipped (false in the common case) so // the opaque/bg reads don't happen per-child per-frame. skipSelfBlit: seenDirtyClipped && isAbsolute && !childElem.style.opaque && childElem.style.backgroundColor === undefined, inheritedBackgroundColor, }) if (wasDirty && !seenDirtyChild) { if (!clipsBothAxes(childElem) || isAbsolute) { seenDirtyChild = true } else { seenDirtyClipped = true } } }}
function clipsBothAxes(node: DOMElement): boolean { const ox = node.style.overflowX ?? node.style.overflow const oy = node.style.overflowY ?? node.style.overflow return ( (ox === 'hidden' || ox === 'scroll') && (oy === 'hidden' || oy === 'scroll') )}
// When Yoga squeezes a box to h=0, the ghost only happens if a sibling// lands at the same computed top — then both write to that row and the// shorter content leaves the longer's tail visible. Yoga's pixel-grid// rounding can give h=0 while still advancing the next sibling's top// (HelpV2's third shortcuts column), so h=0 alone isn't sufficient.function siblingSharesY(node: DOMElement, yogaNode: LayoutNode): boolean { const parent = node.parentNode if (!parent) return false const myTop = yogaNode.getComputedTop() const siblings = parent.childNodes const idx = siblings.indexOf(node) for (let i = idx + 1; i < siblings.length; i++) { const sib = (siblings[i] as DOMElement).yogaNode if (!sib) continue return sib.getComputedTop() === myTop } // No next sibling with a yoga node — check previous. A run of h=0 boxes // at the tail would all share y with each other. for (let i = idx - 1; i >= 0; i--) { const sib = (siblings[i] as DOMElement).yogaNode if (!sib) continue return sib.getComputedTop() === myTop } return false}
// When a node blits, its absolute-positioned descendants that paint outside// the node's layout bounds are NOT covered by the blit (which only copies// the node's own rect). If a dirty sibling re-rendered and overwrote those// cells, we must re-blit them from prevScreen so the overlays survive.// Example: PromptInputFooter's slash menu uses position='absolute' bottom='100%'// to float above the prompt; a spinner tick in the ScrollBox above re-renders// and overwrites those cells. Without this, the menu vanishes on the next frame.function blitEscapingAbsoluteDescendants( node: DOMElement, output: Output, prevScreen: Screen, px: number, py: number, pw: number, ph: number,): void { const pr = px + pw const pb = py + ph for (const child of node.childNodes) { if (child.nodeName === '#text') continue const elem = child as DOMElement if (elem.style.position === 'absolute') { const cached = nodeCache.get(elem) if (cached) { absoluteRectsCur.push(cached) const cx = Math.floor(cached.x) const cy = Math.floor(cached.y) const cw = Math.floor(cached.width) const ch = Math.floor(cached.height) // Only blit rects that extend outside the parent's layout bounds — // cells within the parent rect are already covered by the parent blit. if (cx < px || cy < py || cx + cw > pr || cy + ch > pb) { output.blit(prevScreen, cx, cy, cw, ch) } } } // Recurse — absolute descendants can be nested arbitrarily deep blitEscapingAbsoluteDescendants(elem, output, prevScreen, px, py, pw, ph) }}
// Render children of a scroll container with viewport culling.// scrollTopY..scrollBottomY are the visible window in CHILD-LOCAL Yoga coords// (i.e. what getComputedTop() returns). Children entirely outside this window// are skipped; their nodeCache entry is deleted so if they re-enter the// viewport later they don't emit a stale clear for a position now occupied// by a sibling.function renderScrolledChildren( node: DOMElement, output: Output, offsetX: number, offsetY: number, hasRemovedChild: boolean, prevScreen: Screen | undefined, scrollTopY: number, scrollBottomY: number, inheritedBackgroundColor: Color | undefined, // When true (DECSTBM fast path), culled children keep their cache — // the blit+shift put stable rows in next.screen so stale cache is // never read. Avoids walking O(total_children * subtree_depth) per frame. preserveCulledCache = false,): void { let seenDirtyChild = false // Track cumulative height shift of dirty children iterated so far. When // zero, a clean child's yogaTop is unchanged (no sibling above it grew), // so cached.top is fresh and the cull check skips yoga. Bottom-append // has the dirty child last → all prior clean children hit cache → // O(dirty) not O(mounted). Middle-growth leaves shift non-zero after // the dirty child → subsequent children yoga-read (needed for correct // culling since their yogaTop shifted). let cumHeightShift = 0 for (const childNode of node.childNodes) { const childElem = childNode as DOMElement const cy = childElem.yogaNode if (cy) { const cached = nodeCache.get(childElem) let top: number let height: number if ( cached?.top !== undefined && !childElem.dirty && cumHeightShift === 0 ) { top = cached.top height = cached.height } else { top = cy.getComputedTop() height = cy.getComputedHeight() if (childElem.dirty) { cumHeightShift += height - (cached ? cached.height : 0) } // Refresh cached top so next frame's cumShift===0 path stays // correct. For culled children with preserveCulledCache=true this // is the ONLY refresh point — without it, a middle-growth frame // leaves stale tops that misfire next frame. if (cached) cached.top = top } const bottom = top + height if (bottom <= scrollTopY || top >= scrollBottomY) { // Culled — outside visible window. Drop stale cache entries from // the subtree so when this child re-enters it doesn't fire clears // at positions now occupied by siblings. The viewport-clear on // scroll-change handles the visible-area repaint. if (!preserveCulledCache) dropSubtreeCache(childElem) continue } } const wasDirty = childElem.dirty renderNodeToOutput(childElem, output, { offsetX, offsetY, prevScreen: hasRemovedChild || seenDirtyChild ? undefined : prevScreen, inheritedBackgroundColor, }) if (wasDirty) { seenDirtyChild = true } }}
function dropSubtreeCache(node: DOMElement): void { nodeCache.delete(node) for (const child of node.childNodes) { if (child.nodeName !== '#text') { dropSubtreeCache(child as DOMElement) } }}
// Exported for testingexport { buildCharToSegmentMap, applyStylesToWrappedText }
export default renderNodeToOutput