From e22084f63967aa72cb56873aeb48b01fb8dc2c9b Mon Sep 17 00:00:00 2001
From: Isaac Freund <mail@isaacfreund.com>
Date: Mon, 30 Mar 2026 11:45:54 +0200
Subject: [PATCH] ext_image_capture_source_v1/scene: fix extents

Currently the width/height of the extents is too small if the first node
visited has position/dimensions 0,0,100,100 and the second node has
position/dimensions -20,-20,10,10.

In this case the current code calculates total extents as
-20,-20,100,100 but the correct extents are -20,-20,120,120.

References: https://codeberg.org/river/river-classic/issues/17
---
 types/ext_image_capture_source_v1/scene.c | 28 +++++++++++++----------
 1 file changed, 16 insertions(+), 12 deletions(-)

diff --git a/types/ext_image_capture_source_v1/scene.c b/types/ext_image_capture_source_v1/scene.c
index 99d34e012..7d4b8928a 100644
--- a/types/ext_image_capture_source_v1/scene.c
+++ b/types/ext_image_capture_source_v1/scene.c
@@ -34,13 +34,14 @@ struct scene_node_source_frame_event {
 
 static size_t last_output_num = 0;
 
-static void _get_scene_node_extents(struct wlr_scene_node *node, struct wlr_box *box, int lx, int ly) {
+static void _get_scene_node_extents(struct wlr_scene_node *node, int lx, int ly,
+		int *x_min, int *y_min, int *x_max, int *y_max) {
 	switch (node->type) {
 	case WLR_SCENE_NODE_TREE:;
 		struct wlr_scene_tree *scene_tree = wlr_scene_tree_from_node(node);
 		struct wlr_scene_node *child;
 		wl_list_for_each(child, &scene_tree->children, link) {
-			_get_scene_node_extents(child, box, lx + child->x, ly + child->y);
+			_get_scene_node_extents(child, lx + child->x, ly + child->y, x_min, y_min, x_max, y_max);
 		}
 		break;
 	case WLR_SCENE_NODE_RECT:
@@ -48,27 +49,30 @@ static void _get_scene_node_extents(struct wlr_scene_node *node, struct wlr_box
 		struct wlr_box node_box = { .x = lx, .y = ly };
 		scene_node_get_size(node, &node_box.width, &node_box.height);
 
-		if (node_box.x < box->x) {
-			box->x = node_box.x;
+		if (node_box.x < *x_min) {
+			*x_min = node_box.x;
 		}
-		if (node_box.y < box->y) {
-			box->y = node_box.y;
+		if (node_box.y < *y_min) {
+			*y_min = node_box.y;
 		}
-		if (node_box.x + node_box.width > box->x + box->width) {
-			box->width = node_box.x + node_box.width - box->x;
+		if (node_box.x + node_box.width > *x_max) {
+			*x_max = node_box.x + node_box.width;
 		}
-		if (node_box.y + node_box.height > box->y + box->height) {
-			box->height = node_box.y + node_box.height - box->y;
+		if (node_box.y + node_box.height > *y_max) {
+			*y_max = node_box.y + node_box.height;
 		}
 		break;
 	}
 }
 
 static void get_scene_node_extents(struct wlr_scene_node *node, struct wlr_box *box) {
-	*box = (struct wlr_box){ .x = INT_MAX, .y = INT_MAX };
 	int lx = 0, ly = 0;
 	wlr_scene_node_coords(node, &lx, &ly);
-	_get_scene_node_extents(node, box, lx, ly);
+	*box = (struct wlr_box){ .x = INT_MAX, .y = INT_MAX };
+	int x_max = INT_MIN, y_max = INT_MIN;
+	_get_scene_node_extents(node, lx, ly, &box->x, &box->y, &x_max, &y_max);
+	box->width = x_max - box->x;
+	box->height = y_max - box->y;
 }
 
 static void source_render(struct scene_node_source *source) {