Updated the examples

elements/box.go

@@ -54,9 +54,16 @@ func NewHBox (space Space, children ...tomo.Element) (element *Box) {
 }
 
 // NewHBox creates a new vertical box.
-func NewVBox (space Space) (element *Box) {
-	element = NewHBox(space)
-	element.vertical = true
+func NewVBox (space Space, children ...tomo.Element) (element *Box) {
+	element = &Box {
+		padding:  space.Includes(SpacePadding),
+		margin:   space.Includes(SpaceMargin),
+		vertical: true,
+	}
+	element.scratch = make(map[tomo.Element] scratchEntry)
+	element.theme.Case = tomo.C("tomo", "box")
+	element.entity = tomo.NewEntity(element).(tomo.ContainerEntity)
+	element.Adopt(children...)
 	return
 }
 

elements/containers/common.go

@@ -0,0 +1,104 @@
+package containers
+
+import "image"
+import "git.tebibyte.media/sashakoshka/tomo"
+import "git.tebibyte.media/sashakoshka/tomo/default/theme"
+import "git.tebibyte.media/sashakoshka/tomo/default/config"
+
+type childManager struct {
+	onChange func ()
+	children []tomo.LayoutEntry
+	parent   tomo.Parent
+	theme    theme.Wrapped
+	config   config.Wrapped
+}
+
+// Adopt adds a new child element to the container. If expand is set to true,
+// the element will expand (instead of contract to its minimum size), in
+// whatever way is defined by the container's layout.
+func (manager *childManager) Adopt (child tomo.Element, expand bool) {
+	if child0, ok := child.(tomo.Themeable); ok {
+		child0.SetTheme(manager.theme.Theme)
+	}
+	if child0, ok := child.(tomo.Configurable); ok {
+		child0.SetConfig(manager.config.Config)
+	}
+	child.SetParent(manager.parent)
+
+	manager.children = append (manager.children, tomo.LayoutEntry {
+		Element: child,
+		Expand:  expand,
+	})
+	
+	manager.onChange()
+}
+
+
+// Disown removes the given child from the container if it is contained within
+// it.
+func (manager *childManager) Disown (child tomo.Element) {
+	for index, entry := range manager.children {
+		if entry.Element == child {
+			manager.clearChildEventHandlers(entry.Element)
+			manager.children = append (
+				manager.children[:index],
+				manager.children[index + 1:]...)
+				break
+		}
+	}
+
+	manager.onChange()
+}
+
+// DisownAll removes all child elements from the container at once.
+func (manager *childManager) DisownAll () {
+	for _, entry := range manager.children {
+		manager.clearChildEventHandlers(entry.Element)
+	}
+	manager.children = nil
+
+	manager.onChange()
+}
+
+// Children returns a slice containing this element's children.
+func (manager *childManager) Children () (children []tomo.Element) {
+	children = make([]tomo.Element, len(manager.children))
+	for index, entry := range manager.children {
+		children[index] = entry.Element
+	}
+	return
+}
+
+// CountChildren returns the amount of children contained within this element.
+func (manager *childManager) CountChildren () (count int) {
+	return len(manager.children)
+}
+
+// Child returns the child at the specified index. If the index is out of
+// bounds, this method will return nil.
+func (manager *childManager) Child (index int) (child tomo.Element) {
+	if index < 0 || index > len(manager.children) { return }
+	return manager.children[index].Element
+}
+
+// ChildAt returns the child that contains the specified x and y coordinates. If
+// there are no children at the coordinates, this method will return nil.
+func (manager *childManager) ChildAt (point image.Point) (child tomo.Element) {
+	for _, entry := range manager.children {
+		if point.In(entry.Bounds) {
+			child = entry.Element
+		}
+	}
+	return
+}
+
+func (manager *childManager) clearChildEventHandlers (child tomo.Element) {
+	child.DrawTo(nil, image.Rectangle { }, nil)
+	child.SetParent(nil)
+	
+	if child, ok := child.(tomo.Focusable); ok {
+		if child.Focused() {
+			child.HandleUnfocus()
+		}
+	}
+}