init

ink/node-cache.ts

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+import type { DOMElement } from './dom.js'
+import type { Rectangle } from './layout/geometry.js'
+
+/**
+ * Cached layout bounds for each rendered node (used for blit + clearing).
+ * `top` is the yoga-local getComputedTop() — stored so ScrollBox viewport
+ * culling can skip yoga reads for clean children whose position hasn't
+ * shifted (O(dirty) instead of O(mounted) first-pass).
+ */
+export type CachedLayout = {
+  x: number
+  y: number
+  width: number
+  height: number
+  top?: number
+}
+
+export const nodeCache = new WeakMap<DOMElement, CachedLayout>()
+
+/** Rects of removed children that need clearing on next render */
+export const pendingClears = new WeakMap<DOMElement, Rectangle[]>()
+
+/**
+ * Set when a pendingClear is added for an absolute-positioned node.
+ * Signals renderer to disable blit for the next frame: the removed node
+ * may have painted over non-siblings (e.g. an overlay over a ScrollBox
+ * earlier in tree order), so their blits from prevScreen would restore
+ * the overlay's pixels. Normal-flow removals are already handled by
+ * hasRemovedChild at the parent level; only absolute positioning paints
+ * cross-subtree. Reset at the start of each render.
+ */
+let absoluteNodeRemoved = false
+
+export function addPendingClear(
+  parent: DOMElement,
+  rect: Rectangle,
+  isAbsolute: boolean,
+): void {
+  const existing = pendingClears.get(parent)
+  if (existing) {
+    existing.push(rect)
+  } else {
+    pendingClears.set(parent, [rect])
+  }
+  if (isAbsolute) {
+    absoluteNodeRemoved = true
+  }
+}
+
+export function consumeAbsoluteRemovedFlag(): boolean {
+  const had = absoluteNodeRemoved
+  absoluteNodeRemoved = false
+  return had
+}