jscene: add a stronger focus function

include/justui/jscene.h

@@ -87,6 +87,14 @@ void *jscene_focused_widget(jscene *scene);
    The selected widget, obviously, must be a descendant of the scene. */
 void jscene_set_focused_widget(jscene *scene, void *widget);
 
+/* jscene_show_and_focus(): Make a widget visible and focus it
+   This function does three things:
+   1. Set the visibility of the target widget to [true]
+   2. Configure any parent with a stacked layout to show the child that
+      contains the target widget
+   3. Focus the target widget */
+void jscene_show_and_focus(jscene *scene, void *widget);
+
 /* jscene_process_key_event(): Send a key event to the focused widget
    Returns true if the event was accepted, false if it was ignored. */
 bool jscene_process_key_event(jscene *scene, key_event_t event);

include/justui/jwidget.h

@@ -204,6 +204,9 @@ void jwidget_insert_child(void *w, void *child, int position);
    (w) must be the parent of (child). The child is left without a parent. */
 void jwidget_remove_child(void *w, void *child);
 
+/* jwidget_child_position(): Find the position of a widget in the child list */
+int jwidget_child_position(void *w, void *child);
+
 //---
 // Sizing and stretching
 //---

src/jscene.c

@@ -138,6 +138,35 @@ void jscene_set_focused_widget(jscene *s, void *w0)
 		(jevent){ .type = JWIDGET_FOCUS_IN, .source = w });
 }
 
+void jscene_show_and_focus(jscene *scene, void *w0)
+{
+	J_CAST(w)
+
+	/* Ensure the widget is visible */
+	jwidget_set_visible(w, true);
+
+	/* Force stacked layouts all the wat up to [scene] to show [w] */
+	jwidget *current = w;
+	jwidget *parent = w->parent;
+
+	while(parent != (jwidget *)scene) {
+		jlayout_stack *stack = jlayout_get_stack(parent);
+		if(stack) {
+			int pos = jwidget_child_position(parent, current);
+			if(stack->active != pos) {
+				stack->active = pos;
+				parent->update = true;
+			}
+		}
+
+		current = parent;
+		parent = current->parent;
+	}
+
+	/* Give the widget focus */
+	jscene_set_focused_widget(scene, w);
+}
+
 bool jscene_process_key_event(jscene *scene, key_event_t event)
 {
 	jwidget *candidate = scene->focus;

src/jwidget.c

@@ -249,6 +249,18 @@ void jwidget_remove_child(void *w0, void *child0)
 	w->dirty = 1;
 }
 
+int jwidget_child_position(void *w0, void *child0)
+{
+	J_CAST(w, child)
+
+	for(int i = 0; i < w->child_count; i++) {
+		if(w->children[i] == child)
+			return i;
+	}
+
+	return -1;
+}
+
 //---
 // Sizing and stretching
 //---