chore: import upstream snapshot with attribution

apps/sim/lib/pptx-renderer/model/nodes/group-node.ts

@@ -0,0 +1,62 @@
+/**
+ * Group node parser — handles grouped shapes (p:grpSp).
+ */
+
+import { emuToPx } from '../../parser/units'
+import type { SafeXmlNode } from '../../parser/xml-parser'
+import { type BaseNodeData, type Position, parseBaseProps, type Size } from './base-node'
+
+export interface GroupNodeData extends BaseNodeData {
+  nodeType: 'group'
+  childOffset: Position
+  childExtent: Size
+  /** @internal Raw XML nodes — opaque to consumers. Use serializePresentation() for JSON-safe data. */
+  children: SafeXmlNode[]
+}
+
+/** Tag names of elements that can be children in a group's spTree. */
+const GROUP_CHILD_TAGS = new Set(['sp', 'pic', 'grpSp', 'graphicFrame', 'cxnSp'])
+
+/**
+ * Parse a group shape XML node (`p:grpSp`) into GroupNodeData.
+ */
+export function parseGroupNode(grpNode: SafeXmlNode): GroupNodeData {
+  const base = parseBaseProps(grpNode)
+
+  // --- Child coordinate space from grpSpPr > a:xfrm ---
+  // OOXML: when chOff/chExt omitted, child box equals group box (chOff=0,0, chExt=ext).
+  const grpSpPr = grpNode.child('grpSpPr')
+  const xfrm = grpSpPr.child('xfrm')
+  const chOff = xfrm.child('chOff')
+  const chExt = xfrm.child('chExt')
+
+  const childOffset: Position = chOff.exists()
+    ? { x: emuToPx(chOff.numAttr('x') ?? 0), y: emuToPx(chOff.numAttr('y') ?? 0) }
+    : { x: 0, y: 0 }
+
+  const childExtent: Size = (() => {
+    if (!chExt.exists()) return { w: base.size.w, h: base.size.h }
+    const cx = chExt.numAttr('cx')
+    const cy = chExt.numAttr('cy')
+    return {
+      w: cx !== undefined && cx > 0 ? emuToPx(cx) : base.size.w,
+      h: cy !== undefined && cy > 0 ? emuToPx(cy) : base.size.h,
+    }
+  })()
+
+  // --- Collect direct child shape nodes ---
+  const children: SafeXmlNode[] = []
+  for (const child of grpNode.allChildren()) {
+    if (GROUP_CHILD_TAGS.has(child.localName)) {
+      children.push(child)
+    }
+  }
+
+  return {
+    ...base,
+    nodeType: 'group',
+    childOffset,
+    childExtent,
+    children,
+  }
+}