Child property change events make more sense now

backends/x/entity.go

@@ -79,7 +79,8 @@ func (entity *entity) SetMinimumSize (width, height int) {
 	if entity.parent == nil {
 		entity.window.setMinimumSize(width, height)
 	} else {
-		entity.parent.element.(tomo.Container).HandleChildMinimumSizeChange()
+		entity.parent.element.(tomo.Container).
+			HandleChildMinimumSizeChange(entity.element)
 	}
 }
 
@@ -172,10 +173,11 @@ func (entity *entity) FocusPrevious () {
 
 // ----------- FlexibleEntity ----------- //
 
-func (entity *entity) NotifyFlexibleHeightChange (child tomo.Flexible) {
+func (entity *entity) NotifyFlexibleHeightChange () {
 	if entity.parent == nil { return }
 	if parent, ok := entity.parent.element.(tomo.FlexibleContainer); ok {
-		parent.HandleChildFlexibleHeightChange()
+		parent.HandleChildFlexibleHeightChange (
+			entity.element.(tomo.Flexible))
 	}
 }
 
@@ -184,6 +186,7 @@ func (entity *entity) NotifyFlexibleHeightChange (child tomo.Flexible) {
 func (entity *entity) NotifyScrollBoundsChange () {
 	if entity.parent == nil { return }
 	if parent, ok := entity.parent.element.(tomo.ScrollableContainer); ok {
-		parent.HandleChildScrollBoundsChange()
+		parent.HandleChildScrollBoundsChange (
+			entity.element.(tomo.Scrollable))
 	}
 }

element.go

@@ -28,7 +28,7 @@ type Container interface {
 
 	// HandleChildMinimumSizeChange is called when a child's minimum size is
 	// changed.
-	HandleChildMinimumSizeChange ()
+	HandleChildMinimumSizeChange (child Element)
 }
 
 // Focusable represents an element that has keyboard navigation support.
@@ -115,7 +115,7 @@ type FlexibleContainer interface {
 
 	// HandleChildFlexibleHeightChange is called when the parameters
 	// affecting a child's flexible height are changed.
-	HandleChildFlexibleHeightChange ()
+	HandleChildFlexibleHeightChange (child Flexible)
 }
 
 // Scrollable represents an element that can be scrolled. It acts as a viewport
@@ -145,7 +145,7 @@ type ScrollableContainer interface {
 
 	// HandleChildScrollBoundsChange is called when the content bounds,
 	// viewport bounds, or scroll axes of a child are changed.
-	HandleChildScrollBoundsChange()
+	HandleChildScrollBoundsChange (child Scrollable)
 }
 
 // Collapsible represents an element who's minimum width and height can be

elements/label.go

@@ -153,8 +153,7 @@ func (element *Label) updateMinimumSize () {
 			em = element.theme.Padding(tomo.PatternBackground)[0]
 		}
 		width, height = em, element.drawer.LineHeight().Round()
-		// FIXME we shoudl not have to pass in the element here
+		element.entity.NotifyFlexibleHeightChange()
-		element.entity.NotifyFlexibleHeightChange(element)
 	} else {
 		bounds := element.drawer.LayoutBounds()
 		width, height = bounds.Dx(), bounds.Dy()

entity.go

@@ -91,20 +91,19 @@ type FlexibleEntity interface {
 	Entity
 
 	// NotifyFlexibleHeightChange notifies the system that the parameters
-	// affecting a child's flexible height have changed. This method is
+	// affecting the element's flexible height have changed. This method is
-	// expected to be called by flexible child element when their content
+	// expected to be called by flexible elements when their content changes.
-	// changes.
+	NotifyFlexibleHeightChange ()
-	NotifyFlexibleHeightChange (child Flexible)
 }
 
 // ScrollableEntity is given to elements that support the Scrollable interface.
 type ScrollableEntity interface {
 	Entity
 	
-	// NotifyScrollBoundsChange notifies the parent that a child's scroll
+	// NotifyScrollBoundsChange notifies the system that the element's
-	// content bounds or viewport bounds have changed. This is expected to
+	// scroll content bounds or viewport bounds have changed. This is
-	// be called by child elements when they change their supported scroll
+	// expected to be called by scrollable elements when they change their
-	// axes, their scroll position (either autonomously or as a result of a
+	// supported scroll axes, their scroll position (either autonomously or
-	// call to ScrollTo()), or their content size.
+	// as a result of a call to ScrollTo()), or their content size.
-	NotifyScrollBoundsChange (child Scrollable)
+	NotifyScrollBoundsChange ()
 }