Nix: fix hidpi patch

flake.nix

@@ -47,6 +47,17 @@
                 sha256 = "sha256-/q79o13Zvu7x02SBGu0W5yQznQ+p7ltZ9L6cMW5t/o4=";
               };
             });
+
+            libliftoff = prev.libliftoff.overrideAttrs (old: {
+              version = "0.5.0-dev";
+              src = prev.fetchFromGitLab {
+                domain = "gitlab.freedesktop.org";
+                owner = "emersion";
+                repo = old.pname;
+                rev = "d98ae243280074b0ba44bff92215ae8d785658c0";
+                sha256 = "sha256-DjwlS8rXE7srs7A8+tHqXyUsFGtucYSeq6X0T/pVOc8=";
+              };
+            });
           })
         ];
       });

nix/wlroots-hidpi.patch

@@ -0,0 +1,164 @@
+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);

nix/wlroots.nix

@@ -9,7 +9,7 @@
   hwdata,
   libliftoff,
   libdisplay-info,
-  hidpiXWayland ? false,
+  hidpiXWayland ? true,
   enableXWayland ? true,
   nvidiaPatches ? false,
 }:
@@ -35,10 +35,8 @@ assert (lib.assertMsg (hidpiXWayland -> enableXWayland) ''
       patches =
         (old.patches or [])
         ++ (lib.optionals (enableXWayland && hidpiXWayland) [
-          (fetchpatch {
+          # adapted from https://gitlab.freedesktop.org/lilydjwg/wlroots/-/commit/6c5ffcd1fee9e44780a6a8792f74ecfbe24a1ca7
-            url = "https://gitlab.freedesktop.org/lilydjwg/wlroots/-/commit/6c5ffcd1fee9e44780a6a8792f74ecfbe24a1ca7.diff";
+          ./wlroots-hidpi.patch
-            sha256 = "sha256-Eo1pTa/PIiJsRZwIUnHGTIFFIedzODVf0ZeuXb0a3TQ=";
-          })
           (fetchpatch {
             url = "https://gitlab.freedesktop.org/wlroots/wlroots/-/commit/18595000f3a21502fd60bf213122859cc348f9af.diff";
             sha256 = "sha256-jvfkAMh3gzkfuoRhB4E9T5X1Hu62wgUjj4tZkJm0mrI=";