An ItemLayout describes the constraints which are imposed on items in the layout. More...

Inheritance diagram for Dali::Toolkit::ItemLayout:

Public Member Functions
virtual	~ItemLayout ()
	Forward declare future extension interface.
void	SetOrientation (ControlOrientation::Type orientation)
	Set the orientation of the layout.
ControlOrientation::Type	GetOrientation () const
	Query the orientation of the layout.
void	SetLayoutProperties (const Property::Map &properties)
	Apply the layout Properties.
Property::Map	GetLayoutProperties ()
	Get the layout Properties.
void	GetItemSize (unsigned int itemId, const Vector3 &layoutSize, Vector3 &itemSize) const
	Retrieve the target size of an item in the layout.
void	SetItemSize (const Vector3 &itemSize)
	Overrides the default size for the layout.
virtual float	GetMinimumLayoutPosition (unsigned int numberOfItems, Vector3 layoutSize) const =0
	Query the minimum valid layout position; this is a negative value.
virtual float	GetClosestAnchorPosition (float layoutPosition) const =0
	Query the closest anchor position for the given layout position.
virtual float	GetItemScrollToPosition (unsigned int itemId) const =0
	Query the layout position for the first item in the layout to move to when the layout needs to scroll to a particular item.
virtual ItemRange	GetItemsWithinArea (float firstItemPosition, Vector3 layoutSize) const =0
	Query the items within a given layout-area.
virtual float	GetClosestOnScreenLayoutPosition (int itemID, float currentLayoutPosition, const Vector3 &layoutSize)
	Get the closest layout position to bring an item onto the screen.
virtual unsigned int	GetReserveItemCount (Vector3 layoutSize) const =0
	Query the number of items that should be reserved, for scrolling purposes.
virtual void	GetDefaultItemSize (unsigned int itemId, const Vector3 &layoutSize, Vector3 &itemSize) const =0
	Retrieve the default size of an item in the layout.
virtual Degree	GetScrollDirection () const =0
	Query the scroll direction of the layout.
virtual float	GetScrollSpeedFactor () const =0
	Query the scroll speed factor of the layout while dragging.
virtual float	GetMaximumSwipeSpeed () const =0
	Query the maximum swipe speed in pixels per second.
virtual float	GetItemFlickAnimationDuration () const =0
	Get the duration of the flick animation in second.
virtual int	GetNextFocusItemID (int itemID, int maxItems, Dali::Toolkit::Control::KeyboardFocus::Direction direction, bool loopEnabled)
	Gets the id of the next item for KeyboardFocusManager to focus on depending on the inputted item ID.
virtual float	GetFlickSpeedFactor () const
	Query the flick speed factor of the layout while swipping.
virtual void	ApplyConstraints (Actor &actor, const int itemId, const Vector3 &layoutSize, const Actor &itemViewActor)=0
	Applies constraints defined by the layout to an actor.
virtual Vector3	GetItemPosition (int itemID, float currentLayoutPosition, const Vector3 &layoutSize) const =0
	Gets the position of a given item.
virtual Extension *	GetExtension ()
	Retrieve the extension for this layout.
Protected Member Functions
	ItemLayout ()
	Create a new ItemLayout; Only derived versions are instantiatable.

Detailed Description

An ItemLayout describes the constraints which are imposed on items in the layout.

Potentially visible items are represented by Actors, created for ItemView by the ItemFactory.
Constraints are applied after ItemView activates a layout.

An ItemLayout also describes the direction of input gestures, used to scroll through the layout. Whilst scrolling, the layout provides a range of items that are within a layout-area (3D bounding volume).

Since:: 3.0, DALi version 1.0.0

Constructor & Destructor Documentation

virtual Dali::Toolkit::ItemLayout::~ItemLayout ( ) [virtual]

Forward declare future extension interface.

Virtual destructor.

Since:: 3.0, DALi version 1.0.0

Dali::Toolkit::ItemLayout::ItemLayout ( ) [protected]

Create a new ItemLayout; Only derived versions are instantiatable.

Since:: 3.0, DALi version 1.0.0

Member Function Documentation

virtual void Dali::Toolkit::ItemLayout::ApplyConstraints	(	Actor &	actor,
		const int	itemId,
		const Vector3 &	layoutSize,
		const Actor &	itemViewActor
	)		`[pure virtual]`

Applies constraints defined by the layout to an actor.

Parameters:

[in]	actor	The actor to constrain.
[in]	itemId	The ID of the item represented by the actor.
[in]	layoutSize	The current size of the item view instance.
[in]	itemViewActor	The item view instance which requests the application of constraints.

virtual float Dali::Toolkit::ItemLayout::GetClosestAnchorPosition ( float layoutPosition ) const [pure virtual]

Query the closest anchor position for the given layout position.

This anchor position is the position where all the items in the layout are aligned to their rounded layout positions in integer.

Since:: 3.0, DALi version 1.0.0

Parameters:

[in] layoutPosition The layout position.

Returns:: The closest anchor position for the given layout position.

virtual float Dali::Toolkit::ItemLayout::GetClosestOnScreenLayoutPosition	(	int	itemID,
		float	currentLayoutPosition,
		const Vector3 &	layoutSize
	)		`[virtual]`

Get the closest layout position to bring an item onto the screen.

If the item is already fully on the screen this function will return the current layout position.

This function is used by systems such as KeyboardFocusManager to bring the next focusable item into view and all layout implementations should provide their own version of this function to ensure proper functionality of internal toolkit systems.

Since:: 3.0, DALi version 1.0.0

Parameters:

[in]	itemID	id of the item to bring within the viewable screen area
[in]	currentLayoutPosition	the current layout position of the item view instance
[in]	layoutSize	the current size of the item view instance

Returns:: The layout position

virtual void Dali::Toolkit::ItemLayout::GetDefaultItemSize	(	unsigned int	itemId,
		const Vector3 &	layoutSize,
		Vector3 &	itemSize
	)		const `[pure virtual]`

Retrieve the default size of an item in the layout.

Since:: 3.0, DALi version 1.0.0

Parameters:

[in]	itemId	The ID of an item in the layout.
[in]	layoutSize	The layout size
[out]	itemSize	The target size of an item.

Note:: layout-position is not provided as a parameter, since applying size constraints is not recommended. Animating to target-sizes is preferable, since this allows controls to perform layouting without constraints.

virtual Extension* Dali::Toolkit::ItemLayout::GetExtension ( ) [virtual]

Retrieve the extension for this layout.

Since:: 3.0, DALi version 1.0.0

Returns:: The extension if available, NULL otherwise

virtual float Dali::Toolkit::ItemLayout::GetFlickSpeedFactor ( ) const [virtual]

Query the flick speed factor of the layout while swipping.

This factor is used by the layout to customise its scroll speed while swiping. The factor will be multiplied with the scroll distance of how many pixels in actor coordinate, and the layout position of the actors in ItemView will be moved by this result. For example, when the speed factor is 0.01, if the scroll distance is 100 pixels, the layout position of actors will be moved by 1. Therefore, the bigger the factor is, the faster the flick speed will be.

Since:: 3.0, DALi version 1.0.0

Returns:: The scroll speed factor of the layout.

virtual float Dali::Toolkit::ItemLayout::GetItemFlickAnimationDuration ( ) const [pure virtual]

Get the duration of the flick animation in second.

This is the time taken to animate each item to its next layout position (e.g. from 1.0 to 2.0) when a flick animation is triggered by a swipe gesture.

Since:: 3.0, DALi version 1.0.0

Returns:: The duration of the flick animation.

virtual Vector3 Dali::Toolkit::ItemLayout::GetItemPosition	(	int	itemID,
		float	currentLayoutPosition,
		const Vector3 &	layoutSize
	)		const `[pure virtual]`

Gets the position of a given item.

Since:: 3.0, DALi version 1.0.0

Parameters:

[in]	itemID	The id of the item we want to get its position
[in]	currentLayoutPosition	The current layout position of the item view instance
[in]	layoutSize	The current size of the item view instance

Returns:: The item position (x,y,z)

virtual float Dali::Toolkit::ItemLayout::GetItemScrollToPosition ( unsigned int itemId ) const [pure virtual]

Query the layout position for the first item in the layout to move to when the layout needs to scroll to a particular item.

Since:: 3.0, DALi version 1.0.0

Parameters:

[in] itemId The ID of an item in the layout.

Returns:: The layout position for the first item in the layout to move to.

void Dali::Toolkit::ItemLayout::GetItemSize	(	unsigned int	itemId,
		const Vector3 &	layoutSize,
		Vector3 &	itemSize
	)		const

Retrieve the target size of an item in the layout.

This will return the default size for the layout unless overridden by calling SetItemSize().

Since:: 3.0, DALi version 1.0.0

Parameters:

[in]	itemId	The ID of an item in the layout.
[in]	layoutSize	The layout size
[out]	itemSize	The target size of an item.

Note:: layout-position is not provided as a parameter, since applying size constraints is not recommended. Animating to target-sizes is preferable, since this allows controls to perform layouting without constraints.

virtual ItemRange Dali::Toolkit::ItemLayout::GetItemsWithinArea	(	float	firstItemPosition,
		Vector3	layoutSize
	)		const `[pure virtual]`

Query the items within a given layout-area.

Since:: 3.0, DALi version 1.0.0

Parameters:

[in]	firstItemPosition	The layout-position of the first item in the layout.
[in]	layoutSize	The size of the layout area.

Returns:: The ID of the first & last visible item.

Property::Map Dali::Toolkit::ItemLayout::GetLayoutProperties ( )

Get the layout Properties.

Since:: 4.0, DALi version 1.2.20

Returns:: the property of the layout.

virtual float Dali::Toolkit::ItemLayout::GetMaximumSwipeSpeed ( ) const [pure virtual]

Query the maximum swipe speed in pixels per second.

Swipe gestures will be clamped when exceeding this speed limit.

Since:: 3.0, DALi version 1.0.0

Returns:: speed The maximum swipe speed.

virtual float Dali::Toolkit::ItemLayout::GetMinimumLayoutPosition	(	unsigned int	numberOfItems,
		Vector3	layoutSize
	)		const `[pure virtual]`

Query the minimum valid layout position; this is a negative value.

When scrolling, the first item will move within the range 0 to GetMinimumLayoutPosition().

Since:: 3.0, DALi version 1.0.0

Parameters:

[in]	numberOfItems	The current number of items in the layout.
[in]	layoutSize	The size of the layout area.

Returns:: The minimum layout position.

virtual int Dali::Toolkit::ItemLayout::GetNextFocusItemID	(	int	itemID,
		int	maxItems,
		Dali::Toolkit::Control::KeyboardFocus::Direction	direction,
		bool	loopEnabled
	)		`[virtual]`

Gets the id of the next item for KeyboardFocusManager to focus on depending on the inputted item ID.

Since:: 3.0, DALi version 1.0.0

Parameters:

[in]	itemID	The current focused item
[in]	maxItems	The maximum number of items in the list
[in]	direction	The directional key pressed on the keyboard
[in]	loopEnabled	Whether the KeyboardFocusManager is set to wrap around between first and last item

Returns:: The next item ID.

ControlOrientation::Type Dali::Toolkit::ItemLayout::GetOrientation ( ) const

Query the orientation of the layout.

Since:: 3.0, DALi version 1.0.0

Returns:: the orientation of the layout.

virtual unsigned int Dali::Toolkit::ItemLayout::GetReserveItemCount ( Vector3 layoutSize ) const [pure virtual]

Query the number of items that should be reserved, for scrolling purposes.

Since:: 3.0, DALi version 1.0.0

Parameters:

[in] layoutSize The size of the layout area.

Returns:: The number of extra items. ItemView will populate itself with actors within the layout-area (see GetItemsWithinArea), plus this number of additional items on either-side.

virtual Degree Dali::Toolkit::ItemLayout::GetScrollDirection ( ) const [pure virtual]

Query the scroll direction of the layout.

When an input gesture follows this direction, the layout-position of items will be increased. If the input gesture points in the opposite direction, then the layout-positions will decrease.

Since:: 3.0, DALi version 1.0.0

Returns:: The scroll direction in degrees.

virtual float Dali::Toolkit::ItemLayout::GetScrollSpeedFactor ( ) const [pure virtual]

Query the scroll speed factor of the layout while dragging.

This factor is used by the layout to customise its scroll speed while dragging. The factor will be multiplied with the scroll distance of how many pixels in actor coordinate, and the layout position of the actors in ItemView will be moved by this result. For example, when the speed factor is 0.01, if the scroll distance is 100 pixels, the layout position of actors will be moved by 1. Therefore, the bigger the factor is, the faster the scroll speed will be.

Since:: 3.0, DALi version 1.0.0

Returns:: The scroll speed factor of the layout.

void Dali::Toolkit::ItemLayout::SetItemSize ( const Vector3 & itemSize )

Overrides the default size for the layout.

Since:: 3.0, DALi version 1.0.0

Parameters:

[in] itemSize The size of each item.

void Dali::Toolkit::ItemLayout::SetLayoutProperties ( const Property::Map & properties )

Apply the layout Properties.

Since:: 4.0, DALi version 1.2.20

Parameters:

[in] properties The properties the layout.

void Dali::Toolkit::ItemLayout::SetOrientation ( ControlOrientation::Type orientation )

Set the orientation of the layout.

Since:: 3.0, DALi version 1.0.0

Parameters:

[in] orientation The orientation of the layout.

Public Member Functions

Protected Member Functions

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation