From b46fa5e00657c9750bce5edbba272b1d611cf4a1 Mon Sep 17 00:00:00 2001
From: Johan Malm <jgm323@gmail.com>
Date: Thu, 17 Sep 2020 21:11:54 +0100
Subject: [PATCH] xwayland: constrain view to top/left edge

---
 include/labwc.h |  3 ++-
 src/deco.c      | 18 +++++++++++++-----
 src/xdg.c       |  2 +-
 src/xwayland.c  | 23 +++++++++++++++--------
 4 files changed, 31 insertions(+), 15 deletions(-)

diff --git a/include/labwc.h b/include/labwc.h
index c76a6684..c210ae7f 100644
--- a/include/labwc.h
+++ b/include/labwc.h
@@ -234,7 +234,8 @@ void keyboard_new(struct server *server, struct wlr_input_device *device);
 void output_frame(struct wl_listener *listener, void *data);
 void output_new(struct wl_listener *listener, void *data);
 
-struct border deco_max_extents(struct view *view);
+struct border deco_thickness(struct view *view);
+struct wlr_box deco_max_extents(struct view *view);
 struct wlr_box deco_box(struct view *view, enum deco_part deco_part);
 enum deco_part deco_at(struct view *view, double lx, double ly);
 
diff --git a/src/deco.c b/src/deco.c
index 4b365c16..6974003b 100644
--- a/src/deco.c
+++ b/src/deco.c
@@ -12,7 +12,7 @@
 
 #define BORDER_WIDTH (2)
 
-struct border deco_max_extents(struct view *view)
+struct border deco_thickness(struct view *view)
 {
 	struct border border = {
 		.top = rc.title_height + BORDER_WIDTH,
@@ -23,16 +23,24 @@ struct border deco_max_extents(struct view *view)
 	return border;
 }
 
+struct wlr_box deco_max_extents(struct view *view)
+{
+	struct border border = deco_thickness(view);
+	struct wlr_box box = {
+		.x = view->x - border.left,
+		.y = view->y - border.top,
+		.width = view->w + border.left + border.right,
+		.height = view->h + border.top + border.bottom,
+	};
+	return box;
+}
+
 struct wlr_box deco_box(struct view *view, enum deco_part deco_part)
 {
 	int margin;
 
 	struct wlr_box box = { .x = 0, .y = 0, .width = 0, .height = 0 };
 	BUG_ON(!view);
-	if ((view->w < 1) || (view->h < 1)) {
-		warn("view (%p) has no width/height", view);
-		return box;
-	}
 	switch (deco_part) {
 	case LAB_DECO_BUTTON_CLOSE:
 		wlr_texture_get_size(theme.xbm_close_active_unpressed,
diff --git a/src/xdg.c b/src/xdg.c
index 48117dfb..c5c761b2 100644
--- a/src/xdg.c
+++ b/src/xdg.c
@@ -149,7 +149,7 @@ static void xdg_toplevel_view_map(struct view *view)
 	if (!view->been_mapped) {
 		view->server_side_deco = has_ssd(view);
 		if (view->server_side_deco) {
-			view->margin = deco_max_extents(view);
+			view->margin = deco_thickness(view);
 		} else {
 			view->margin = xdg_shell_border(view);
 			view->xdg_grab_offset = -view->margin.left;
diff --git a/src/xwayland.c b/src/xwayland.c
index cdb842e4..006d1375 100644
--- a/src/xwayland.c
+++ b/src/xwayland.c
@@ -61,6 +61,19 @@ static bool want_deco(struct view *view)
 	       WLR_XWAYLAND_SURFACE_DECORATIONS_ALL;
 }
 
+static void top_left_edge_boundary_check(struct view *view)
+{
+	struct wlr_box deco = deco_max_extents(view);
+	if (deco.x < 0)
+		view->x -= deco.x;
+	if (deco.y < 0)
+		view->y -= deco.y;
+	struct wlr_box box = {
+		.x = view->x, .y = view->y, .width = view->w, .height = view->h
+	};
+	view->impl->configure(view, box);
+}
+
 static void map(struct view *view)
 {
 	view->mapped = true;
@@ -71,15 +84,9 @@ static void map(struct view *view)
 	view->surface = view->xwayland_surface->surface;
 	view->server_side_deco = want_deco(view);
 
-	view->margin = deco_max_extents(view);
+	view->margin = deco_thickness(view);
 
-	/* ensure we're inside screen */
-	view->x += view->margin.left;
-	view->y += view->margin.top;
-	struct wlr_box box = {
-		.x = view->x, .y = view->y, .width = view->w, .height = view->h
-	};
-	view->impl->configure(view, box);
+	top_left_edge_boundary_check(view);
 
 	/* Add commit here, as xwayland map/unmap can change the wlr_surface */
 	wl_signal_add(&view->xwayland_surface->surface->events.commit,