Hyprland/nix/wlroots-hidpi.patch

diff --git a/include/xwayland/xwm.h b/include/xwayland/xwm.h
index c69504e8..40d8de8c 100644
--- a/include/xwayland/xwm.h
+++ b/include/xwayland/xwm.h
@@ -88,6 +88,7 @@ enum atom_name {
 	DND_ACTION_PRIVATE,
 	NET_CLIENT_LIST,
 	NET_CLIENT_LIST_STACKING,
+  XWAYLAND_GLOBAL_OUTPUT_SCALE,
 	ATOM_LAST // keep last
 };
 
@@ -98,6 +99,7 @@ struct wlr_xwm {
 	struct wl_event_source *event_source;
 	struct wlr_seat *seat;
 	uint32_t ping_timeout;
+  uint32_t scale;
 
 	xcb_atom_t atoms[ATOM_LAST];
 	xcb_connection_t *xcb_conn;
diff --git a/xwayland/xwm.c b/xwayland/xwm.c
index 5a36dc21..83981a87 100644
--- a/xwayland/xwm.c
+++ b/xwayland/xwm.c
@@ -19,6 +19,14 @@
 #include <xcb/xfixes.h>
 #include "xwayland/xwm.h"
 
+static int32_t scale(struct wlr_xwm *xwm, uint32_t val) {
+	return val * xwm->scale;
+}
+
+static int32_t unscale(struct wlr_xwm *xwm, uint32_t val) {
+	return (val + xwm->scale/2) / xwm->scale;
+}
+
 const char *const atom_map[ATOM_LAST] = {
 	[WL_SURFACE_ID] = "WL_SURFACE_ID",
 	[WL_SURFACE_SERIAL] = "WL_SURFACE_SERIAL",
@@ -90,6 +98,7 @@ const char *const atom_map[ATOM_LAST] = {
 	[DND_ACTION_PRIVATE] = "XdndActionPrivate",
 	[NET_CLIENT_LIST] = "_NET_CLIENT_LIST",
 	[NET_CLIENT_LIST_STACKING] = "_NET_CLIENT_LIST_STACKING",
+	[XWAYLAND_GLOBAL_OUTPUT_SCALE] = "_XWAYLAND_GLOBAL_OUTPUT_SCALE",
 };
 
 #define STARTUP_INFO_REMOVE_PREFIX "remove: ID="
@@ -968,8 +977,8 @@ static void xwm_handle_create_notify(struct wlr_xwm *xwm,
 		return;
 	}
 
-	xwayland_surface_create(xwm, ev->window, ev->x, ev->y,
-		ev->width, ev->height, ev->override_redirect);
+	xwayland_surface_create(xwm, ev->window, unscale(xwm, ev->x), unscale(xwm, ev->y),
+		unscale(xwm, ev->width), unscale(xwm, ev->height), ev->override_redirect);
 }
 
 static void xwm_handle_destroy_notify(struct wlr_xwm *xwm,
@@ -1000,10 +1009,10 @@ static void xwm_handle_configure_request(struct wlr_xwm *xwm,
 
 	struct wlr_xwayland_surface_configure_event wlr_event = {
 		.surface = surface,
-		.x = mask & XCB_CONFIG_WINDOW_X ? ev->x : surface->x,
-		.y = mask & XCB_CONFIG_WINDOW_Y ? ev->y : surface->y,
-		.width = mask & XCB_CONFIG_WINDOW_WIDTH ? ev->width : surface->width,
-		.height = mask & XCB_CONFIG_WINDOW_HEIGHT ? ev->height : surface->height,
+		.x = mask & XCB_CONFIG_WINDOW_X ? unscale(xwm, ev->x) : surface->x,
+		.y = mask & XCB_CONFIG_WINDOW_Y ? unscale(xwm, ev->y) : surface->y,
+		.width = mask & XCB_CONFIG_WINDOW_WIDTH ? unscale(xwm, ev->width) : surface->width,
+		.height = mask & XCB_CONFIG_WINDOW_HEIGHT ? unscale(xwm, ev->height) : surface->height,
 		.mask = mask,
 	};
 
@@ -1018,14 +1027,14 @@ static void xwm_handle_configure_notify(struct wlr_xwm *xwm,
 	}
 
 	bool geometry_changed =
-		(xsurface->x != ev->x || xsurface->y != ev->y ||
-		 xsurface->width != ev->width || xsurface->height != ev->height);
+		(xsurface->x != unscale(xwm, ev->x) || xsurface->y != unscale(xwm, ev->y) ||
+		 xsurface->width != unscale(xwm, ev->width) || xsurface->height != unscale(xwm, ev->height));
 
 	if (geometry_changed) {
-		xsurface->x = ev->x;
-		xsurface->y = ev->y;
-		xsurface->width = ev->width;
-		xsurface->height = ev->height;
+		xsurface->x = unscale(xwm, ev->x);
+		xsurface->y = unscale(xwm, ev->y);
+		xsurface->width = unscale(xwm, ev->width);
+		xsurface->height = unscale(xwm, ev->height);
 	}
 
 	if (xsurface->override_redirect != ev->override_redirect) {
@@ -1136,6 +1145,20 @@ static void xwm_handle_property_notify(struct wlr_xwm *xwm,
 		xcb_property_notify_event_t *ev) {
 	struct wlr_xwayland_surface *xsurface = lookup_surface(xwm, ev->window);
 	if (xsurface == NULL) {
+		if (ev->atom == xwm->atoms[XWAYLAND_GLOBAL_OUTPUT_SCALE]) {
+			xcb_get_property_cookie_t cookie = xcb_get_property(xwm->xcb_conn, 0,
+					ev->window, ev->atom, XCB_ATOM_ANY, 0, 2048);
+			xcb_get_property_reply_t *reply = xcb_get_property_reply(xwm->xcb_conn,
+					cookie, NULL);
+			if (reply == NULL) {
+				return;
+			}
+			if (reply->type == XCB_ATOM_CARDINAL) {
+				xwm->scale = *(uint32_t*)xcb_get_property_value(reply);
+			}
+			free(reply);
+		}
+
 		return;
 	}
 
@@ -1763,16 +1786,17 @@ void wlr_xwayland_surface_configure(struct wlr_xwayland_surface *xsurface,
 	int old_w = xsurface->width;
 	int old_h = xsurface->height;
 
+	struct wlr_xwm *xwm = xsurface->xwm;
+
 	xsurface->x = x;
 	xsurface->y = y;
 	xsurface->width = width;
 	xsurface->height = height;
 
-	struct wlr_xwm *xwm = xsurface->xwm;
 	uint32_t mask = XCB_CONFIG_WINDOW_X | XCB_CONFIG_WINDOW_Y |
 		XCB_CONFIG_WINDOW_WIDTH | XCB_CONFIG_WINDOW_HEIGHT |
 		XCB_CONFIG_WINDOW_BORDER_WIDTH;
-	uint32_t values[] = {x, y, width, height, 0};
+	uint32_t values[] = {scale(xwm, x), scale(xwm, y), scale(xwm, width), scale(xwm, height), 0};
 	xcb_configure_window(xwm->xcb_conn, xsurface->window_id, mask, values);
 
 	// If the window size did not change, then we cannot rely on
@@ -1780,15 +1804,15 @@ void wlr_xwayland_surface_configure(struct wlr_xwayland_surface *xsurface,
 	// we are supposed to send a synthetic event. See ICCCM part
 	// 4.1.5. But we ignore override-redirect windows as ICCCM does
 	// not apply to them.
-	if (width == old_w && height == old_h && !xsurface->override_redirect) {
+	if (scale(xwm, width) == scale(xwm, old_w) && scale(xwm, height) == scale(xwm, old_h) && !xsurface->override_redirect) {
 		xcb_configure_notify_event_t configure_notify = {
 			.response_type = XCB_CONFIGURE_NOTIFY,
 			.event = xsurface->window_id,
 			.window = xsurface->window_id,
-			.x = x,
-			.y = y,
-			.width = width,
-			.height = height,
+			.x = scale(xwm, x),
+			.y = scale(xwm, y),
+			.width = scale(xwm, width),
+			.height = scale(xwm, height),
 		};
 
 		xcb_send_event(xwm->xcb_conn, 0, xsurface->window_id,
@@ -2125,6 +2149,7 @@ struct wlr_xwm *xwm_create(struct wlr_xwayland *xwayland, int wm_fd) {
 	wl_list_init(&xwm->pending_startup_ids);
 	xwm->ping_timeout = 10000;
 
+	xwm->scale = 1;
 	xwm->xcb_conn = xcb_connect_to_fd(wm_fd, NULL);
 
 	int rc = xcb_connection_has_error(xwm->xcb_conn);