Dispatch virtual list scroll events

packages/core/events.cpp

@@ -50,6 +50,8 @@ const char *PointerEvent::typeName() const
 		return "keydown";
 	case PointerEventType::Rotary:
 		return "rotary";
+	case PointerEventType::Scroll:
+		return "scroll";
 	}
 	return "";
 }

packages/core/include/events.h

@@ -14,7 +14,8 @@ enum class PointerEventType {
 	Click,
 	Input,
 	KeyDown,
-	Rotary
+	Rotary,
+	Scroll
 };
 
 enum class EventPhase {

packages/core/index.d.ts

@@ -445,6 +445,7 @@ export interface GeaEventMap {
   input: InputEvent
   keydown: KeyEvent
   rotary: RotaryEvent
+  scroll: Event
 }
 
 export type TouchEventHandler = (event: TouchEvent) => void
@@ -1523,6 +1524,7 @@ export interface NativeButtonProps extends NativeEventAttributes {
 }
 
 export interface NativeVirtualListProps extends NativeEventAttributes {
+  onScroll?: (event: Event) => void
   id?: string
   class?: ClassValue
   style?: Style

packages/core/test/test_gea_engine_rare_data_main.cpp

@@ -115,6 +115,30 @@ int probe()
 		             kTestName, stopChildHits, stopParentHits);
 		return 33;
 	}
+	int nextChildHits = 0;
+	tree.setEventListener(stopChildId, "click", [&](gea::framework::events::PointerEvent &) { nextChildHits++; });
+	{
+		gea::framework::events::PointerEvent ev{};
+		ev.type = gea::framework::events::PointerEventType::Click;
+		ev.targetId = stopChildId;
+		tree.dispatchEvent(ev);
+	}
+	if (stopChildHits != 2 || nextChildHits != 1 || stopParentHits != 0) {
+		std::fprintf(stderr, "[%s] stopPropagation skipped a target listener or reached parent\n", kTestName);
+		return 39;
+	}
+	int parentScrollHits = 0;
+	tree.setEventListener(perParentId, "scroll", [&](gea::framework::events::PointerEvent &) { parentScrollHits++; });
+	{
+		gea::framework::events::PointerEvent ev{};
+		ev.type = gea::framework::events::PointerEventType::Scroll;
+		ev.targetId = perChildId;
+		ev.bubbles = false;
+		if (tree.dispatchEvent(ev) || parentScrollHits != 0) {
+			std::fprintf(stderr, "[%s] non-bubbling scroll reached parent without target listener\n", kTestName);
+			return 40;
+		}
+	}
 
 	// Removing a node must reclaim its rare-data block (no leak, no stale fire).
 	tree.removeNode(perChildId);

packages/elements/components/VirtualList.d.ts

@@ -1,4 +1,4 @@
-import type { ClassValue, TouchEventHandler } from '@geastack/core'
+import type { ClassValue, Event, TouchEventHandler } from '@geastack/core'
 
 export type VirtualListItemTemplate = (index: number, top: number) => any
 
@@ -15,6 +15,7 @@ export interface VirtualListProps {
   onTouchStart?: TouchEventHandler
   onTouchMove?: TouchEventHandler
   onTouchEnd?: TouchEventHandler
+  onScroll?: (event: Event) => void
 }
 
 export default function VirtualList(props: VirtualListProps): any

packages/elements/components/VirtualList.tsx

@@ -1,4 +1,4 @@
-import type { ClassValue, TouchEventHandler } from '@geastack/core'
+import type { ClassValue, Event, TouchEventHandler } from '@geastack/core'
 
 // A windowing list backed by the native <virtual-list> element. The element is
 // an ordinary overflow:scroll container that scrolls over a virtual content
@@ -25,6 +25,7 @@ export interface VirtualListProps {
   onTouchStart?: TouchEventHandler
   onTouchMove?: TouchEventHandler
   onTouchEnd?: TouchEventHandler
+  onScroll?: (event: Event) => void
 }
 
 const SLOT_COUNT = 16
@@ -94,7 +95,8 @@ export default function VirtualList({
   itemTemplate,
   onTouchStart,
   onTouchMove,
-  onTouchEnd
+  onTouchEnd,
+  onScroll
 }: VirtualListProps) {
   const rowOverscan = overscan === undefined ? 2 : overscan
   return (
@@ -105,6 +107,7 @@ export default function VirtualList({
       onTouchStart={onTouchStart}
       onTouchMove={onTouchMove}
       onTouchEnd={onTouchEnd}
+      onScroll={onScroll}
     >
       <VirtualListSlot slotIndex={0} scrollTop={scrollTop} itemHeight={itemHeight} overscan={rowOverscan} itemCount={itemCount} itemClass={itemClass} itemTemplate={itemTemplate} />
       <VirtualListSlot slotIndex={1} scrollTop={scrollTop} itemHeight={itemHeight} overscan={rowOverscan} itemCount={itemCount} itemClass={itemClass} itemTemplate={itemTemplate} />

packages/elements/ui/virtual_list.cpp

@@ -21,6 +21,18 @@ namespace gea::embedded::ui {
 
 namespace {
 
+void dispatchScrollEvent(int node)
+{
+	Tree &tree = Tree::instance();
+	if (!tree.hasListenersForType("scroll")) return;
+	gea::framework::events::PointerEvent event{};
+	event.type = gea::framework::events::PointerEventType::Scroll;
+	event.targetId = node;
+	event.bubbles = false;
+	event.cancelable = false;
+	tree.dispatchEvent(event);
+}
+
 int parseIntAttribute(const char *value, int fallback)
 {
 	if (!value || !value[0]) return fallback;
@@ -225,6 +237,7 @@ bool VirtualListRenderer::setScrollTop(int node, int scrollTop)
 	n.render.dirty = 1;
 	n.render.layout_dirty = 1;
 	Tree::instance().markScrollDirty(node);
+	dispatchScrollEvent(node);
 	return true;
 }
 
@@ -268,7 +281,11 @@ void Tree::setScrollTop(int node, int scrollTop)
 {
 	if (node < 0 || node >= nodeCount()) return;
 	Node &n = treeState().nodes[node];
-	if (!isViewLikeNodeType(n.type) || (n.type != NodeType::VirtualList && !scrollsOverflowY(n.style))) return;
+	if (n.type == NodeType::VirtualList) {
+		VirtualListRenderer::setScrollTop(node, scrollTop);
+		return;
+	}
+	if (!isViewLikeNodeType(n.type) || !scrollsOverflowY(n.style)) return;
 	const int maxY = ViewRenderer::scrollMaxY(n);
 	if (scrollTop < 0) scrollTop = 0;
 	if (scrollTop > maxY) scrollTop = maxY;

packages/engine/ui/tree_events.cpp

@@ -57,7 +57,7 @@ void applyAudioAttribute(Tree &tree, int node, const char *name, const char *val
 // Index order mirrors NodeEventListeners' slots and is kept in sync by
 // setEventListener (on the empty->set transition) and NodeEventListeners::clear()
 // (which every removal path calls).
-constexpr int kEventTypeCount = 6;
+constexpr int kEventTypeCount = 7;
 int g_listenerTypeCounts[kEventTypeCount] = {};
 EventListenerId g_nextEventListenerId = 1;
 
@@ -75,6 +75,7 @@ int eventTypeIndex(const char *type)
 	if (sameName(type, "touchend") || sameName(type, "pointerup")) return 3;
 	if (sameName(type, "input")) return 4;
 	if (sameName(type, "keydown")) return 5;
+	if (sameName(type, "scroll")) return 6;
 	return -1;
 }
 
@@ -276,6 +277,7 @@ void NodeEventListeners::clear()
 	release(touchend, 3);
 	release(input, 4);
 	release(keydown, 5);
+	release(scroll, 6);
 }
 
 NodeEventListenerList *NodeEventListeners::listenersFor(const char *type)
@@ -287,6 +289,7 @@ NodeEventListenerList *NodeEventListeners::listenersFor(const char *type)
 	if (sameName(type, "touchend") || sameName(type, "pointerup")) return &touchend;
 	if (sameName(type, "input")) return &input;
 	if (sameName(type, "keydown")) return &keydown;
+	if (sameName(type, "scroll")) return &scroll;
 	return nullptr;
 }
 
@@ -298,7 +301,7 @@ const NodeEventListenerList *NodeEventListeners::listenersFor(const char *type)
 bool NodeEventListeners::hasAny() const
 {
 	return !click.empty() || !touchstart.empty() || !touchmove.empty() ||
-	       !touchend.empty() || !input.empty() || !keydown.empty();
+	       !touchend.empty() || !input.empty() || !keydown.empty() || !scroll.empty();
 }
 
 EventListenerId Tree::setEventListener(int node, const char *type, gea::framework::events::EventListener listener)
@@ -367,6 +370,7 @@ bool Tree::dispatchEvent(gea::framework::events::PointerEvent &event)
 	event.target = gea::framework::events::EventTarget(event.targetId);
 	bool dispatched = false;
 	for (int node = event.targetId; node >= 0 && node < state.nodeCount; node = state.nodes[node].parent) {
+		if (!event.bubbles && node != event.targetId) break;
 		NodeRareData *rd = rareDataFor(node);
 		if (!rd) continue;
 		auto *initialList = rd->listeners.listenersFor(event.typeName());
@@ -408,7 +412,6 @@ bool Tree::dispatchEvent(gea::framework::events::PointerEvent &event)
 			cursor = nextId;
 			(*callback)(event);
 			dispatched = true;
-			if (event.propagationStopped || !event.bubbles) break;
 		}
 		if (event.propagationStopped || !event.bubbles) break;
 	}

packages/engine/ui/tree_events.h

@@ -55,6 +55,7 @@ struct NodeEventListeners {
 	NodeEventListenerList touchend;
 	NodeEventListenerList input;
 	NodeEventListenerList keydown;
+	NodeEventListenerList scroll;
 
 	void clear();
 	NodeEventListenerList *listenersFor(const char *type);

packages/geatsc-plugin-gea/src/host-shims.ts

@@ -34,6 +34,9 @@ const NODE_HANDLE_RECEIVER_TYPES = [
 // `NODE_HANDLE_RECEIVER_TYPES` above states.
 const EVENT_RECEIVER_TYPES = [
   "gea::framework::events::PointerEvent",
+  // The base interface every event extends, and the parameter `onScroll` and
+  // `EventTarget.addEventListener(type, listener)` declare.
+  "Event",
   "PointerEvent",
   "TouchEvent",
   "RotaryEvent",
@@ -318,6 +321,11 @@ export function createGeaHostShims(): HostShimDefinitions {
       PointerEvent: "gea::framework::events::PointerEvent",
       TouchEvent: "gea::framework::events::PointerEvent",
       RotaryEvent: "gea::framework::events::PointerEvent",
+      // The base interface, for `onScroll={e => ...}` and any listener typed by
+      // `EventTarget.addEventListener`. Without it `e` lowered to a synthesized
+      // record the listener adapter cannot build from `PointerEvent&`, so the
+      // app aborted on the first scroll.
+      Event: "gea::framework::events::PointerEvent",
       TouchPoint: "gea::framework::events::TouchPoint",
       // The text-input half of the same join. `onInput={e => ...}` /
       // `onKeyDown={e => ...}` declare `InputEvent` / `KeyEvent` (index.d.ts),
@@ -1613,6 +1621,15 @@ export function createGeaHostShims(): HostShimDefinitions {
       // member spellings, so emission refused `TouchEvent.clientX` by name --
       // the fail-closed guard reporting, correctly, that this table was the
       // thing missing.
+      // `Event.type`: the engine keeps the kind as an enum and names it with
+      // `typeName()` (events.cpp), the same string a listener was bound for.
+      type: [
+        {
+          emit: "std::string(({receiver}).typeName())",
+          returnType: "std::string",
+          receiverTypes: EVENT_RECEIVER_TYPES,
+        },
+      ],
       pointerId: [
         {
           emit: "static_cast<double>(({receiver}).pointerId)",

packages/geatsc-plugin-gea/test/host-shims-protocol.test.mjs

@@ -3,6 +3,26 @@ import test from 'node:test'
 
 import { createGeaHostShims } from '../dist/host-shims.js'
 
+// A listener parameter declared as any event interface index.d.ts publishes is
+// handed the engine's one event struct. `Event` is declared by `onScroll` and by
+// `EventTarget.addEventListener(type, listener: (event: Event) => void)`; without
+// a carrier it lowered to a synthesized record the runtime listener adapter
+// cannot build from a PointerEvent, and the app aborted on the first scroll.
+test('every declared event parameter type lowers to the engine event, including Event', () => {
+  const definitions = createGeaHostShims()
+  for (const name of ['Event', 'PointerEvent', 'TouchEvent', 'RotaryEvent', 'InputEvent', 'KeyEvent']) {
+    assert.equal(definitions.nativeTypes?.[name], 'gea::framework::events::PointerEvent', `${name} must lower to the engine event`)
+  }
+  for (const member of ['type', 'target', 'currentTarget']) {
+    const rows = definitions.nativeMemberPropertyGetters?.[member] ?? []
+    assert.ok(rows.some(row => row.receiverTypes?.includes('Event')), `Event.${member} must be a native member read`)
+  }
+  for (const method of ['preventDefault', 'stopPropagation']) {
+    const rows = definitions.nativeMemberMethods?.[method] ?? []
+    assert.ok(rows.some(row => row.receiverTypes?.includes('Event')), `Event.${method}() must be a native member call`)
+  }
+})
+
 test('geolocation snapshot operations publish their non-throwing physical contract', () => {
   const definitions = createGeaHostShims()
   for (const namespace of ['Geolocation', 'geolocation']) {