fix mishandling of struts

1 files changed, 132 insertions, 22 deletions

diff --git a/src/sxwm.c b/src/sxwm.c
index a91f072..23a5544 100644
--- a/src/sxwm.c
+++ b/src/sxwm.c
@@ -3193,17 +3193,25 @@ void update_struts(void)
 {
 	/* reset all reserves */
 	for (int i = 0; i < n_mons; i++) {
-		mons[i].reserve_left = mons[i].reserve_right = mons[i].reserve_top = mons[i].reserve_bottom = 0;
+		mons[i].reserve_left   = 0;
+		mons[i].reserve_right  = 0;
+		mons[i].reserve_top    = 0;
+		mons[i].reserve_bottom = 0;
 	}
 
-	Window root_ret, parent_ret, *children;
-	unsigned int nchildren;
+	Window root_ret;
+	Window parent_ret;
+	Window *children = NULL;
+	unsigned int n_children = 0;
 
-	if (!XQueryTree(dpy, root, &root_ret, &parent_ret, &children, &nchildren)) {
+	if (!XQueryTree(dpy, root, &root_ret, &parent_ret, &children, &n_children)) {
 		return;
 	}
 
-	for (unsigned int i = 0; i < nchildren; i++) {
+	int screen_w = scr_width;
+	int screen_h = scr_height;
+
+	for (unsigned int i = 0; i < n_children; i++) {
 		Window w = children[i];
 
 		Atom actual_type;
@@ -3211,8 +3219,9 @@ void update_struts(void)
 		unsigned long n_items, bytes_after;
 		Atom *types = NULL;
 
-		if (XGetWindowProperty(dpy, w, _NET_WM_WINDOW_TYPE, 0, 4, False, XA_ATOM, &actual_type, &actual_format,
-		                       &n_items, &bytes_after, (unsigned char **)&types) != Success || !types) {
+		if (XGetWindowProperty(dpy, w, _NET_WM_WINDOW_TYPE, 0, 4, False, XA_ATOM,
+			&actual_type, &actual_format, &n_items, &bytes_after,
+			(unsigned char **)&types) != Success || !types) {
 			continue;
 		}
 
@@ -3231,27 +3240,128 @@ void update_struts(void)
 		long *str = NULL;
 		Atom actual;
 		int sfmt;
-		unsigned long len, rem;
+		unsigned long len;
+		unsigned long rem;
+
+		if (XGetWindowProperty(dpy, w, _NET_WM_STRUT_PARTIAL, 0, 12, False, XA_CARDINAL,
+					&actual, &sfmt, &len, &rem,
+					(unsigned char **)&str) == Success && str && len >= 12) {
+
+			/*
+			 ewmh:
+			 [0] left, [1] right, [2] top, [3] bottom
+			 
+			 [4] left_start_y,   [5] left_end_y
+			 [6] right_start_y,  [7] right_end_y
+			 [8] top_start_x,    [9] top_end_x
+			 [10] bottom_start_x,[11] bottom_end_x
+			 
+			 all coords are in root space.
+			 */
+			long left = str[0];
+			long right = str[1];
+			long top = str[2];
+			long bottom = str[3];
+			long left_start_y = str[4];
+			long left_end_y = str[5];
+			long right_start_y = str[6];
+			long right_end_y = str[7];
+			long top_start_x = str[8];
+			long top_end_x = str[9];
+			long bot_start_x = str[10];
+			long bot_end_x = str[11];
 
-		if (XGetWindowProperty(dpy, w, _NET_WM_STRUT_PARTIAL, 0, 12, False, XA_CARDINAL, &actual, &sfmt, &len, &rem,
-		                       (unsigned char **)&str) == Success && str && len >= 4) {
-			XWindowAttributes wa;
-			if (XGetWindowAttributes(dpy, w, &wa)) {
-				/* find the monitor this dock belongs to */
-				for (int m = 0; m < n_mons; m++) {
-					if (wa.x >= mons[m].x && wa.x < mons[m].x + mons[m].w && wa.y >= mons[m].y &&
-					    wa.y < mons[m].y + mons[m].h) {
-						mons[m].reserve_left = MAX(mons[m].reserve_left, str[0]);
-						mons[m].reserve_right = MAX(mons[m].reserve_right, str[1]);
-						mons[m].reserve_top = MAX(mons[m].reserve_top, str[2]);
-						mons[m].reserve_bottom = MAX(mons[m].reserve_bottom, str[3]);
+			XFree(str);
+
+			/* skip empty struts */
+			if (!left && !right && !top && !bottom) {
+				continue;
+			}
+
+			for (int m = 0; m < n_mons; m++) {
+				int mx = mons[m].x;
+				int my = mons[m].y;
+				int mw = mons[m].w;
+				int mh = mons[m].h;
+
+				/* strip monitors whose vertical span dostn intersect */
+				if (left > 0) {
+					long span_start = left_start_y;
+					long span_end   = left_end_y;
+					if (span_end >= my && span_start <= my + mh - 1) {
+						/*
+						 left is distance from root left edge to reserved area
+						 to map to mon, the portion is:
+						     reserve_left = MAX(0, left - mx)
+						 */
+						int reserve = (int)MAX(0, left - mx);
+						if (reserve > 0) {
+							mons[m].reserve_left = MAX(mons[m].reserve_left, reserve);
+						}
+					}
+				}
+
+				if (right > 0) {
+					long span_start = right_start_y;
+					long span_end   = right_end_y;
+					if (span_end >= my && span_start <= my + mh - 1) {
+						/*
+						 right is distance from root right edge to reserved area:
+						     right edge = screen_w
+							 mons right edge = mx + mw
+							 amount that cuts into monitor = MAX(0, (screen_w - right) - mx)
+						 */
+						int global_reserved_left = screen_w - (int)right;
+						int overlap = (mx + mw) - global_reserved_left;
+						int reserve = MAX(0, overlap);
+						if (reserve > 0) {
+							mons[m].reserve_right = MAX(mons[m].reserve_right, reserve);
+						}
+					}
+				}
+
+				if (top > 0) {
+					long span_start = top_start_x;
+					long span_end   = top_end_x;
+					if (span_end >= mx && span_start <= mx + mw - 1) {
+						/*
+						 top is distance from root top to reserved area
+							 mons top is at my, amount eaten:
+							 reserve_top = MAX(0, top - my)
+						 */
+						int reserve = (int)MAX(0, top - my);
+						if (reserve > 0) {
+							mons[m].reserve_top = MAX(mons[m].reserve_top, reserve);
+						}
+					}
+				}
+
+				if (bottom > 0) {
+					long span_start = bot_start_x;
+					long span_end   = bot_end_x;
+					if (span_end >= mx && span_start <= mx + mw - 1) {
+						/*
+						 bottom is distance from root bottom to reserved area
+						 global_reserved_top = screen_h - bottom;
+						 overlap to mon:
+						   overlap = (my + mh) - global_reserved_top;
+						   reserve_bottom = MAX(0, overlap)
+						 */
+						int global_reserved_top = screen_h - (int)bottom;
+						int overlap = (my + mh) - global_reserved_top;
+						int reserve = MAX(0, overlap);
+						if (reserve > 0) {
+							mons[m].reserve_bottom = MAX(mons[m].reserve_bottom, reserve);
+						}
 					}
 				}
 			}
-			XFree(str);
 		}
 	}
-	XFree(children);
+
+	if (children) {
+		XFree(children);
+	}
 	update_workarea();
 }