Fix Gallery preview_close event not firing on ESC key (#12577)

* Fix Gallery preview_close event not firing on ESC key (#12553)

The on_keydown handler was setting selected_index to null when ESC
was pressed, but it wasn't dispatching the preview_close event.
The close button (X) correctly dispatches this event, so ESC key
should have the same behavior.

Changes:
- Add dispatch("preview_close") in on_keydown when Escape is pressed
- Add test case for ESC key triggering preview_close event

* add changeset

---------

Co-authored-by: gradio-pr-bot <[email protected]>

Author: majiayu000

.changeset/every-groups-say.md

@@ -0,0 +1,6 @@
+---
+"@gradio/gallery": patch
+"gradio": patch
+---
+
+fix:Fix Gallery preview_close event not firing on ESC key

js/gallery/Gallery.test.ts

@@ -104,4 +104,41 @@ describe("Gallery", () => {
 		});
 		assert.equal(change_event.callCount, 0);
 	});
+
+	test("triggers preview_close event when pressing Escape key", async () => {
+		const { listen, getByTestId } = await render(Gallery, {
+			show_label: true,
+			label: "Gallery",
+			loading_status: loading_status,
+			preview: true,
+			buttons: ["share", "download", "fullscreen"],
+			value: [
+				{
+					image: {
+						path: "https://raw.githubusercontent.com/gradio-app/gradio/main/gradio/demo/gallery_component/files/cheetah.jpg",
+						url: "https://raw.githubusercontent.com/gradio-app/gradio/main/gradio/demo/gallery_component/files/cheetah.jpg"
+					},
+					caption: null
+				}
+			]
+		});
+
+		const preview_close_event = listen("preview_close");
+
+		// Find the preview container and dispatch Escape key event
+		const preview = document.querySelector(".preview");
+		if (preview) {
+			const escapeEvent = new KeyboardEvent("keydown", {
+				code: "Escape",
+				key: "Escape",
+				bubbles: true
+			});
+			preview.dispatchEvent(escapeEvent);
+		}
+
+		assert.isTrue(
+			preview_close_event.callCount >= 1,
+			"preview_close event should be triggered when pressing Escape"
+		);
+	});
 });

js/gallery/shared/Gallery.svelte

@@ -164,6 +164,7 @@
 			case "Escape":
 				e.preventDefault();
 				selected_index = null;
+				dispatch("preview_close");
 				break;
 			case "ArrowLeft":
 				e.preventDefault();