z-index system for wayland

fixes clicks penetrating to widgets behind one another and allows MwLLRaiseImpl to be implemented

include/Mw/LowLevel/Wayland.h

@@ -341,6 +341,9 @@ struct _MwLLWayland {
 
 	MwBool is_toplevel;
 
+	/* Stacking order among sibling sublevels. Higher values are drawn on top and get the pointer first. */
+	MwI32 z_index;
+
 	MwBool is_clipping;
 	MwRect clip;
 
@@ -505,6 +508,11 @@ void MwLLWaylandClipboardRead(wl_clipboard_device_context_t* ctx, int clipboard_
 /* Flush Wayland events */
 void MwLLWaylandFlush(MwLL handle);
 
+/* Get the sublevel children of a widget ordered from lowest to highest z-index (ties keep creation order). Free the result with arrfree. */
+MwLL* MwLLWaylandSublevelsByZIndex(MwLL handle);
+/* Set a sublevel's z-index and schedule a redraw so the new stacking order is shown. */
+void MwLLWaylandSetZIndex(MwLL handle, MwI32 z_index);
+
 /* recursively dispatch the key event to focused widgets.  */
 void MwLLRecursiveKeyDispatch(MwLL self, int* k, MwBool down);
 

src/backend/wayland/interfaces.c

@@ -721,33 +721,6 @@ static void pointer_motion(void* data, struct wl_pointer* wl_pointer, MwU32 time
 	}
 };
 
-static void recursive_dispatch_mouse_down(MwLL handle, MwMouse* p) {
-	MwWidget h = (MwWidget)handle->common.internal;
-	MwLLDispatch(handle, down, p);
-	if(h) {
-		int i;
-		for(i = 0; i < arrlen(h->children); i++) {
-			MwLLDispatch(h->children[i]->lowlevel, down, p);
-			if(arrlen(h->children[i]->children) > 0) {
-				recursive_dispatch_mouse_down(h->children[i]->lowlevel, p);
-			}
-		}
-	}
-};
-static void recursive_dispatch_mouse_up(MwLL handle, MwMouse* p) {
-	MwWidget h = (MwWidget)handle->common.internal;
-	MwLLDispatch(handle, up, p);
-	if(h) {
-		int i;
-		for(i = 0; i < arrlen(h->children); i++) {
-			MwLLDispatch(h->children[i]->lowlevel, up, p);
-			if(arrlen(h->children[i]->children) > 0) {
-				recursive_dispatch_mouse_up(h->children[i]->lowlevel, p);
-			}
-		}
-	}
-};
-
 static MwBool hit_detect(MwLL child, MwLL* _topmost_parent, MwPoint* _point, MwPoint* _relative_mouse_pos, MwPoint* _absolute_pos) {
 	MwLL	topmost_parent = child;
 	MwPoint point;
@@ -761,9 +734,7 @@ static MwBool hit_detect(MwLL child, MwLL* _topmost_parent, MwPoint* _point, MwP
 		if(topmost_parent) {
 			/* if the topmost parent is a popup/subwindow then its x/y is irrelevant to us. */
 			if(topmost_parent->wayland.type != MwLL_WAYLAND_POPUP && topmost_parent->wayland.type != MwLL_WAYLAND_TOPLEVEL) {
-				if(topmost_parent->wayland.x > 0)
 				absolute_pos.x += topmost_parent->wayland.x;
-				if(topmost_parent->wayland.y > 0)
 				absolute_pos.y += topmost_parent->wayland.y;
 			}
 		}
@@ -783,22 +754,42 @@ static MwBool hit_detect(MwLL child, MwLL* _topmost_parent, MwPoint* _point, MwP
 	       point.y >= absolute_pos.y && point.y <= absolute_pos.y + child->wayland.wh;
 }
 
-static void mouse_dispatch(MwLL self, MwMouse p, MwU32 state) {
-	switch(state) {
-	case WL_POINTER_BUTTON_STATE_PRESSED:
-		MwLLDispatch(self, down, &p);
-		break;
-	case WL_POINTER_BUTTON_STATE_RELEASED:
-		MwLLDispatch(self, up, &p);
+/* deepest, topmost-z sublevel under the pointer, or self if none */
+static MwLL find_target(MwLL self, MwPoint* local) {
+	MwLL* children = MwLLWaylandSublevelsByZIndex(self);
+	MwLL  target   = self;
+	int   i;
+	for(i = arrlen(children) - 1; i >= 0; i--) {
+		MwLL	tp;
+		MwPoint pt, rel, abs;
+		if(hit_detect(children[i], &tp, &pt, &rel, &abs)) {
+			*local = rel;
+			target = find_target(children[i], local);
 			break;
 		}
+	}
+	arrfree(children);
+	return target;
+}
 
-	if(self->common.internal) {
-		MwWidget w = self->common.internal;
+static void mouse_dispatch(MwLL self, MwMouse p, MwU32 state) {
+	MwLL target = find_target(self, &p.point);
+
+	switch(state) {
+	case WL_POINTER_BUTTON_STATE_PRESSED:
+		MwLLDispatch(target, down, &p);
+		break;
+	case WL_POINTER_BUTTON_STATE_RELEASED:
+		MwLLDispatch(target, up, &p);
+		return;
+	}
+
+	{
+		/* walk from the top of the stack down so that only the highest z-index sublevel under the pointer gets the click */
+		MwLL* children = MwLLWaylandSublevelsByZIndex(self);
 		int   i, n;
-		for(i = 0; i < arrlen(w->children); i++) {
-			if(w->children[i]->lowlevel->wayland.type == MwLL_WAYLAND_SUBLEVEL) {
-				MwLL	child	       = w->children[i]->lowlevel;
+		for(i = arrlen(children) - 1; i >= 0; i--) {
+			MwLL	child	       = children[i];
 			MwLL	topmost_parent = child;
 			MwPoint point;
 			MwPoint relative_mouse_pos;
@@ -827,9 +818,10 @@ static void mouse_dispatch(MwLL self, MwMouse p, MwU32 state) {
 				}
 
 				mouse_dispatch(child, p, state);
+				break;
 			}
 		}
-		}
+		arrfree(children);
 	}
 }
 

src/backend/wayland/wayland.c

@@ -13,17 +13,48 @@ MwBool MwWaylandVulkan = MwFALSE;
 
 MwBool MwWaylandCairoOnly = MwFALSE;
 
-void MwLLWaylandChildrenIterate(MwLL handle, void (*func)(MwLL handle, MwLL child)) {
+MwLL* MwLLWaylandSublevelsByZIndex(MwLL handle) {
+	MwLL* r = NULL;
 	if(handle->common.internal) {
 		MwWidget w = handle->common.internal;
-		int	 i;
+		int	 i, j;
 		for(i = 0; i < arrlen(w->children); i++) {
-			if(w->children[i]->lowlevel->wayland.type == MwLL_WAYLAND_SUBLEVEL) {
 			MwLL child = w->children[i]->lowlevel;
-				func(handle, child);
+			if(child->wayland.type != MwLL_WAYLAND_SUBLEVEL) continue;
+
+			/* insertion sort, stable so that equal z-indexes keep their creation order */
+			arrput(r, child);
+			for(j = arrlen(r) - 1; j > 0 && r[j - 1]->wayland.z_index > child->wayland.z_index; j--) {
+				r[j] = r[j - 1];
+			}
+			r[j] = child;
 		}
 	}
+	return r;
 }
+
+void MwLLWaylandSetZIndex(MwLL handle, MwI32 z_index) {
+	MwLL root = handle;
+
+	if(handle->wayland.z_index == z_index) return;
+	handle->wayland.z_index = z_index;
+
+	/* sublevels are composited by their root, so that's what needs to redraw */
+	while(root->wayland.type == MwLL_WAYLAND_SUBLEVEL && root->wayland.parent) {
+		root = root->wayland.parent;
+	}
+	root->wayland.do_cascading_draw = MwTRUE;
+	root->wayland.events_pending	= 1;
+}
+
+/* Iterate over the sublevel children of a widget, from the bottom of the stack to the top */
+void MwLLWaylandChildrenIterate(MwLL handle, void (*func)(MwLL handle, MwLL child)) {
+	MwLL* children = MwLLWaylandSublevelsByZIndex(handle);
+	int   i;
+	for(i = 0; i < arrlen(children); i++) {
+		func(handle, children[i]);
+	}
+	arrfree(children);
 }
 
 static int event_loop(MwLL handle);
@@ -813,35 +844,21 @@ static void clip(MwLL handle) {
 		cy = 0;
 		mx = toplevel->wayland.ww;
 		my = toplevel->wayland.wh;
-		// ws is traversed result
-		// ws[ws.length - 1] is ignored bc it's toplevel
+		/* ws is traversed result */
+		/* ws[arrlen(ws) - 1] is the toplevel, which is the origin */
 		for(i = arrlen(ws) - 2; i >= 0; i--) {
-			int j;
-			int l = 0;
-
 			x += ws[i]->wayland.x;
 			y += ws[i]->wayland.y;
 
-			for(j = i - 1; j >= 0; j--) {
-				if(ws[j]->wayland.x > cx) l = 1;
-				if(ws[j]->wayland.y > cy) l = 1;
-				if(l) break;
+			cx = MAX(cx, x);
+			cy = MAX(cy, y);
+			mx = MIN(mx, x + (int)ws[i]->wayland.ww);
+			my = MIN(my, y + (int)ws[i]->wayland.wh);
 		}
 
-			if(!l) {
-				cx = MAX(cx, ws[i]->wayland.x);
-				cy = MAX(cy, ws[i]->wayland.y);
-			}
-
-			mx = MIN(mx, x + ws[i]->wayland.ww);
-			my = MIN(my, y + ws[i]->wayland.wh);
-		}
-
-		if(mx < cx) mx = cx;
-		if(my < cy) my = cy;
-
 		arrfree(ws);
 
+		/* fully hidden, clip to an empty rectangle */
 		if(mx < cx) mx = cx;
 		if(my < cy) my = cy;
 
@@ -1937,21 +1954,20 @@ static MwBool MwLLDoModernImpl(MwLL handle) {
 }
 
 static void MwLLRaiseImpl(MwLL handle) {
-	(void)handle;
-	/*
+	MwLL* siblings;
+	int   n;
 
-	if(handle->wayland.type == MwLL_WAYLAND_SUBLEVEL) {
-		MwLL topmost_parent = handle;
-		int  children_num;
-		while(topmost_parent->wayland.parent) topmost_parent = topmost_parent->wayland.parent;
-		children_num = arrlen(((MwWidget)topmost_parent->common.internal)->children);
-
-		if(children_num > 1) {
-			printf("%d\n", children_num);
-			MwWidget last_child = ((MwWidget)topmost_parent->common.internal)->children[children_num - 1];
-			wl_subsurface_place_above(handle->wayland.sublevel->subsurface, last_child->lowlevel->wayland.framebuffer.surface);
+	if(handle->wayland.type != MwLL_WAYLAND_SUBLEVEL || !handle->wayland.parent) {
+		return;
 	}
-		}*/
+
+	/* put it one above whichever sibling is currently on top */
+	siblings = MwLLWaylandSublevelsByZIndex(handle->wayland.parent);
+	n	 = arrlen(siblings);
+	if(n > 0 && siblings[n - 1] != handle) {
+		MwLLWaylandSetZIndex(handle, siblings[n - 1]->wayland.z_index + 1);
+	}
+	arrfree(siblings);
 }
 
 static void MwLLClipImpl(MwLL handle, MwRect* rect) {