Moved a lot of interfaces out of the base tomo module and into an

abilities module

entity.go

@@ -3,8 +3,8 @@ package tomo
 import "image"
 import "git.tebibyte.media/sashakoshka/tomo/canvas"
 
-// Entity is a handle given to elements by the backend. Different types of
-// entities may be assigned to elements that support different capabilities.
+// Entity is a handle given to elements by the backend. Extended entity
+// interfaces are defined in the ability module.
 type Entity interface {
 	// Invalidate marks the element's current visual as invalid. At the end
 	// of every event, the backend will ask all invalid entities to redraw
@@ -30,100 +30,3 @@ type Entity interface {
 	// background pattern.
 	DrawBackground (canvas.Canvas)
 }
-
-// LayoutEntity is given to elements that support the Layoutable interface.
-type LayoutEntity interface {
-	Entity
-	
-	// InvalidateLayout marks the element's layout as invalid. At the end of
-	// every event, the backend will ask all invalid elements to recalculate
-	// their layouts.
-	InvalidateLayout ()
-}
-
-// ContainerEntity is given to elements that support the Container interface.
-type ContainerEntity interface {
-	Entity
-	LayoutEntity
-
-	// Adopt adds an element as a child.
-	Adopt (child Element)
-
-	// Insert inserts an element in the child list at the specified
-	// location.
-	Insert (index int, child Element)
-
-	// Disown removes the child at the specified index.
-	Disown (index int)
-
-	// IndexOf returns the index of the specified child.
-	IndexOf (child Element) int
-
-	// Child returns the child at the specified index.
-	Child (index int) Element
-
-	// CountChildren returns the amount of children the element has.
-	CountChildren () int
-
-	// PlaceChild sets the size and position of the child at the specified
-	// index to a bounding rectangle.
-	PlaceChild (index int, bounds image.Rectangle)
-
-	// SelectChild marks a child as selected or unselected, if it is
-	// selectable.
-	SelectChild (index int, selected bool)
-
-	// ChildMinimumSize returns the minimum size of the child at the
-	// specified index.
-	ChildMinimumSize (index int) (width, height int)
-}
-
-// FocusableEntity is given to elements that support the Focusable interface.
-type FocusableEntity interface {
-	Entity
-
-	// Focused returns whether the element currently has input focus.
-	Focused () bool
-
-	// Focus sets this element as focused. If this succeeds, the element will
-	// recieve a HandleFocus call.
-	Focus ()
-
-	// FocusNext causes the focus to move to the next element. If this
-	// succeeds, the element will recieve a HandleUnfocus call.
-	FocusNext ()
-
-	// FocusPrevious causes the focus to move to the next element. If this
-	// succeeds, the element will recieve a HandleUnfocus call.	
-	FocusPrevious ()
-}
-
-// SelectableEntity is given to elements that support the Selectable interface.
-type SelectableEntity interface {
-	Entity
-
-	// Selected returns whether this element is currently selected.
-	Selected () bool
-}
-
-// FlexibleEntity is given to elements that support the Flexible interface.
-type FlexibleEntity interface {
-	Entity
-
-	// NotifyFlexibleHeightChange notifies the system that the parameters
-	// affecting the element's flexible height have changed. This method is
-	// expected to be called by flexible elements when their content changes.
-	NotifyFlexibleHeightChange ()
-}
-
-// ScrollableEntity is given to elements that support the Scrollable interface.
-type ScrollableEntity interface {
-	Entity
-	
-	// NotifyScrollBoundsChange notifies the system that the element's
-	// scroll content bounds or viewport bounds have changed. This is
-	// expected to be called by scrollable elements when they change their
-	// supported scroll axes, their scroll position (either autonomously or
-	// as a result of a call to ScrollTo()), or their content size.
-	NotifyScrollBoundsChange ()
-}