element.go

@@ -6,54 +6,33 @@ import "git.tebibyte.media/sashakoshka/tomo/canvas"
 
 // Element represents a basic on-screen object.
 type Element interface {
-	// Bounds reports the element's bounding box. This must reflect the
+	// Bind assigns an Entity to this element.
-	// bounding last given to the element by DrawTo.
+	Bind (Entity)
-	Bounds () image.Rectangle
 	
-	// MinimumSize specifies the minimum amount of pixels this element's
+	// Draw causes the element to draw to the specified canvas. The bounds
-	// width and height may be set to. If the element is given a resize
+	// of this canvas specify the area that is actually drawn to, while the
-	// event with dimensions smaller than this, it will use its minimum
+	// Entity bounds specify the actual area of the element.
-	// instead of the offending dimension(s).
+	Draw (canvas.Canvas)
-	MinimumSize () (width, height int)
-
-	// SetParent sets the parent container of the element. This should only
-	// be called by the parent when the element is adopted. If parent is set
-	// to nil, it will mark itself as not having a parent. If this method is
-	// passed a non-nil value and the element already has a parent, it will
-	// panic.
-	SetParent (Parent)
-
-	// DrawTo gives the element a canvas to draw on, along with a bounding
-	// box to be used for laying out the element. This should only be called
-	// by the parent element. This is typically a region of the parent
-	// element's canvas.
-	DrawTo (canvas canvas.Canvas, bounds image.Rectangle, onDamage func (region image.Rectangle))
 }
 
-// Focusable represents an element that has keyboard navigation support. This
+// Container is an element capable of containing child elements.
-// includes inputs, buttons, sliders, etc. as well as any elements that have
+type Container interface {
-// children (so keyboard navigation events can be propagated downward).
+	Element
+
+	// Layout causes this element to arrange its children.
+	Layout ()
+
+	// DrawBackground draws this element's background pattern at the
+	// specified bounds to any canvas.
+	DrawBackground (destination canvas.Canvas, bounds image.Rectangle)
+}
+
+// Focusable represents an element that has keyboard navigation support.
 type Focusable interface {
 	Element
 
-	// Focused returns whether or not this element or any of its children
+	// HandleFocusChange is called when the element is focused or unfocused.
-	// are currently focused.
+	HandleFocusChange ()
-	Focused () bool
-
-	// Focus focuses this element, if its parent element grants the
-	// request.
-	Focus ()
-
-	// HandleFocus causes this element to mark itself as focused. If the
-	// element does not have children, it is disabled, or there are no more
-	// selectable children in the given direction, it should return false
-	// and do nothing. Otherwise, it should select itself and any children
-	// (if applicable) and return true.
-	HandleFocus (direction input.KeynavDirection) (accepted bool)
-
-	// HandleDeselection causes this element to mark itself and all of its
-	// children as unfocused.
-	HandleUnfocus ()
 }
 
 // KeyboardTarget represents an element that can receive keyboard input.

entity.go

@@ -0,0 +1,104 @@
+package tomo
+
+import "image"
+
+// Entity is a handle given to elements by the backend. Different types of
+// entities may be assigned to elements that support different capabilities.
+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
+	// themselves.
+	Invalidate ()
+
+	// Bounds returns the bounds of the element to be used for drawing and
+	// layout.
+	Bounds () image.Rectangle
+
+	// Window returns the window that the element is in.
+	Window () Window
+
+	// SetMinimumSize reports to the system what the element's minimum size
+	// can be. The minimum size of child elements should be taken into
+	// account when calculating this.
+	SetMinimumSize (width, height int)
+
+	// DrawBackground asks the parent element to draw its background pattern
+	// within the specified rectangle. This should be used for transparent
+	// elements like text labels.
+	DrawBackground (bounds image.Rectangle)
+}
+
+// ContainerEntity is given to elements that support the Container interface.
+type ContainerEntity interface {
+	Entity
+
+	// 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)
+
+	// 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 ()
+}
+
+// FlexibleEntity is given to elements that support the Flexible interface.
+type FlexibleEntity interface {
+	Entity
+
+	// NotifyFlexibleHeightChange notifies the system that the parameters
+	// affecting a child's flexible height have changed. This method is
+	// expected to be called by flexible child element when their content
+	// changes.
+	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
+	// content bounds or viewport bounds have changed. This is expected to
+	// be called by child 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 (child Scrollable)
+}

layout.go

@@ -1,37 +0,0 @@
-package tomo
-
-import "image"
-import "git.tebibyte.media/sashakoshka/tomo/artist"
-
-// LayoutEntry associates an element with layout and positioning information so
-// it can be arranged by a Layout.
-type LayoutEntry struct {
-	Element
-	Bounds image.Rectangle
-	Expand bool
-}
-
-// Layout is capable of arranging elements within a container. It is also able
-// to determine the minimum amount of room it needs to do so.
-type Layout interface {
-	// Arrange takes in a slice of entries and a bounding width and height,
-	// and changes the position of the entiries in the slice so that they
-	// are properly laid out. The given width and height should not be less
-	// than what is returned by MinimumSize.
-	Arrange (
-		entries []LayoutEntry,
-		margin  image.Point,
-		padding artist.Inset,
-		bounds image.Rectangle,
-	)
-
-	// MinimumSize returns the minimum width and height that the layout
-	// needs to properly arrange the given slice of layout entries.
-	MinimumSize (
-		entries []LayoutEntry,
-		margin  image.Point,
-		padding artist.Inset,
-	) (
-		width, height int,
-	)
-}

parent.go

@@ -1,71 +0,0 @@
-package tomo
-
-import "image"
-
-// Parent represents a type capable of containing child elements.
-type Parent interface {
-	// NotifyMinimumSizeChange notifies the container that a child element's
-	// minimum size has changed. This method is expected to be called by
-	// child elements when their minimum size changes.
-	NotifyMinimumSizeChange (child Element)
-
-	// Window returns the window containing the parent.
-	Window () Window
-}
-
-// FocusableParent represents a parent with keyboard navigation support.
-type FocusableParent interface {
-	Parent
-	
-	// RequestFocus notifies the parent that a child element is requesting
-	// keyboard focus. If the parent grants the request, the method will
-	// return true and the child element should behave as if a HandleFocus
-	// call was made.
-	RequestFocus (child Focusable) (granted bool)
-
-	// RequestFocusMotion notifies the parent that a child element wants the
-	// focus to be moved to the next focusable element.
-	RequestFocusNext (child Focusable)
-	
-	// RequestFocusMotion notifies the parent that a child element wants the
-	// focus to be moved to the previous focusable element.
-	RequestFocusPrevious (child Focusable)
-}
-
-// FlexibleParent represents a parent that accounts for elements with
-// flexible height.
-type FlexibleParent interface {
-	Parent
-
-	// NotifyFlexibleHeightChange notifies the parent that the parameters
-	// affecting a child's flexible height have changed. This method is
-	// expected to be called by flexible child element when their content
-	// changes.
-	NotifyFlexibleHeightChange (child Flexible)
-}
-
-// ScrollableParent represents a parent that can change the scroll
-// position of its child element(s).
-type ScrollableParent interface {
-	Parent
-	
-	// NotifyScrollBoundsChange notifies the parent that a child's scroll
-	// content bounds or viewport bounds have changed. This is expected to
-	// be called by child 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 (child Scrollable)
-}
-
-// BackgroundParent represents a parent that is able to re-draw a portion of its
-// background upon request. This is intended to be used by transparent elements
-// that want to adopt their parent's background pattern. If a parent implements
-// this interface, it should call a child's DrawTo method when its area of the
-// background is affected.
-type BackgroundParent interface {
-	Parent
-
-	// DrawBackground draws a portion of the parent's background pattern
-	// within the specified bounds. The parent will not push these changes.
-	DrawBackground (bounds image.Rectangle)
-}