Runtime widget layout diagnostics

widget.get_runtime can return a read-only layout snapshot for every runtime widget node while PIE is active. It complements the native Widget Reflector with structured output that an automated client can inspect and compare.

Opting in

The layout block is off by default. Pass includeLayout: true:

{
  "action": "get_runtime",
  "className": "WBP_HUD",
  "includeLayout": true
}

It is opt-in because the block is large. Every node gains geometry, render transform, clipping, viewport, parent and delta objects, and the slot object reflects every property on the slot class, so a deep hierarchy returns far more JSON than the default response. Without includeLayout, the response shape is unchanged: name, class, visibility, isVisible, text, brush, percent and the style values, walked to maxDepth.

What each node reports

With includeLayout, every node adds:

• desired, local, and absolute size;
• absolute position, layout bounds, and render bounds;
• render transform, pivot, accumulated layout scale, and effective opacity;
• complete reflected slot properties;
• structured Canvas anchors, offsets, alignment, auto-size, and Z-order;
• authored clipping mode and a derived effective clipping rectangle;
• parent bounds and whether the child extends beyond them;
• viewport rectangle and whether the node falls outside it;
• widgetPath, the stable identifier used to match nodes between captures;
• diagnostics, a list of (code, severity, message) for suspicious layout relationships.

Response shape

tree is the widget tree root, or the widget named by childName. That is the same node the default response returns, so maxDepth counts from the same place either way, and tree is the string "empty" when the widget has no root widget.

includeLayout adds three top-level keys:

• host: the hosting UUserWidget node with its own layout block and no children. The host is not a panel parent, so its geometry, clipping and opacity are otherwise unreachable from the tree root. Its clip state and opacity seed the tree walk.
• layoutCapture: capture sequence number, frame, time, node count, changed node count, diagnostic count, and the viewport rectangle.
• instanceId: the unique id of the located widget instance.

Comparing captures

The handler retains the previous capture for the same PIE widget instance and optional childName. Calling widget.get_runtime again with includeLayout after moving, resizing, toggling, or changing the viewport produces deltaSincePreviousCapture for each node. This detects position-dependent dimensions such as a vertically stretched Canvas slot whose Bottom offset was mistakenly treated as height, reported as the position_dependent_canvas_height diagnostic.

Calls without includeLayout neither read nor write the retained captures.

Recommended debugging sequence

1. Start client-mode PIE on the required test map.
2. Open the affected screen.
3. Capture the PIE window for visual evidence.
4. Call widget.get_runtime with includeLayout for the affected widget class or instance.
5. Reproduce one layout-affecting change.
6. Call widget.get_runtime with includeLayout again and inspect changed nodes and diagnostics.
7. Inspect designer properties and bindings before changing presentation.

Boundary with Widget Reflector

The reported clipping rectangle is derived from UMG clipping modes and cached render bounds. It is suitable for layout diagnosis, but it is not a serialized copy of Slate's paint-element clip stack. Use a native Widget Reflector .widgetsnapshot when exact paint clipping, hit-test grids, or Slate source addresses are required.