From 9da295c11f90dcfbf254ccf23b9124c87ccd8ddf Mon Sep 17 00:00:00 2001
From: Alexander Orzechowski <alex@ozal.ski>
Date: Wed, 22 Nov 2023 15:11:12 -0500
Subject: [PATCH] scene_graph: Implement toplevel clipping

---
 include/sway/tree/view.h   |  2 +-
 sway/desktop/transaction.c |  2 +-
 sway/desktop/xdg_shell.c   |  4 ++--
 sway/desktop/xwayland.c    |  4 ++--
 sway/tree/view.c           | 27 +++++++++++++++++++++------
 5 files changed, 27 insertions(+), 12 deletions(-)

diff --git a/include/sway/tree/view.h b/include/sway/tree/view.h
index 80097dd3e..3e5a9bfe3 100644
--- a/include/sway/tree/view.h
+++ b/include/sway/tree/view.h
@@ -274,7 +274,7 @@ void view_map(struct sway_view *view, struct wlr_surface *wlr_surface,
 void view_unmap(struct sway_view *view);
 
 void view_update_size(struct sway_view *view);
-void view_center_surface(struct sway_view *view);
+void view_center_and_clip_surface(struct sway_view *view);
 
 struct sway_view *view_from_wlr_xdg_surface(
 	struct wlr_xdg_surface *xdg_surface);
diff --git a/sway/desktop/transaction.c b/sway/desktop/transaction.c
index 0755c8a00..980e839ee 100644
--- a/sway/desktop/transaction.c
+++ b/sway/desktop/transaction.c
@@ -248,7 +248,7 @@ static void apply_container_state(struct sway_container *container,
 		// the container. This is important for fullscreen views which
 		// refuse to resize to the size of the output.
 		if (view->surface) {
-			view_center_surface(view);
+			view_center_and_clip_surface(view);
 		}
 	}
 }
diff --git a/sway/desktop/xdg_shell.c b/sway/desktop/xdg_shell.c
index 48b7b4c7e..7cdd97c83 100644
--- a/sway/desktop/xdg_shell.c
+++ b/sway/desktop/xdg_shell.c
@@ -306,9 +306,9 @@ static void handle_commit(struct wl_listener *listener, void *data) {
 					view->geometry.height);
 			}
 			transaction_commit_dirty_client();
-		} else {
-			view_center_surface(view);
 		}
+
+		view_center_and_clip_surface(view);
 	}
 
 	if (view->container->node.instruction) {
diff --git a/sway/desktop/xwayland.c b/sway/desktop/xwayland.c
index e0c80c074..9f3f4d5f2 100644
--- a/sway/desktop/xwayland.c
+++ b/sway/desktop/xwayland.c
@@ -436,9 +436,9 @@ static void handle_commit(struct wl_listener *listener, void *data) {
 		if (container_is_floating(view->container)) {
 			view_update_size(view);
 			transaction_commit_dirty_client();
-		} else {
-			view_center_surface(view);
 		}
+
+		view_center_and_clip_surface(view);
 	}
 
 	if (view->container->node.instruction) {
diff --git a/sway/tree/view.c b/sway/tree/view.c
index 3bc0855bc..d69841783 100644
--- a/sway/tree/view.c
+++ b/sway/tree/view.c
@@ -893,14 +893,29 @@ void view_update_size(struct sway_view *view) {
 	container_set_geometry_from_content(con);
 }
 
-void view_center_surface(struct sway_view *view) {
+void view_center_and_clip_surface(struct sway_view *view) {
 	struct sway_container *con = view->container;
-	// We always center the current coordinates rather than the next, as the
-	// geometry immediately affects the currently active rendering.
-	int x = (int) fmax(0, (con->current.content_width - view->geometry.width) / 2);
-	int y = (int) fmax(0, (con->current.content_height - view->geometry.height) / 2);
 
-	wlr_scene_node_set_position(&view->content_tree->node, x, y);
+	if (container_is_floating(con)) {
+		// We always center the current coordinates rather than the next, as the
+		// geometry immediately affects the currently active rendering.
+		int x = (int) fmax(0, (con->current.content_width - view->geometry.width) / 2);
+		int y = (int) fmax(0, (con->current.content_height - view->geometry.height) / 2);
+
+		wlr_scene_node_set_position(&view->content_tree->node, x, y);
+	} else {
+		wlr_scene_node_set_position(&view->content_tree->node, 0, 0);
+	}
+
+	// only make sure to clip the content if there is content to clip
+	if (!wl_list_empty(&con->view->content_tree->children)) {
+		wlr_scene_subsurface_tree_set_clip(&con->view->content_tree->node, &(struct wlr_box){
+			.x = con->view->geometry.x,
+			.y = con->view->geometry.y,
+			.width = con->current.content_width,
+			.height = con->current.content_height,
+		});
+	}
 }
 
 struct sway_view *view_from_wlr_surface(struct wlr_surface *wlr_surface) {