An empty layout item that expands into empty space based on its size configuration. More...

Inherits BLayoutItem.

Public Member Functions
	BSpaceLayoutItem (BMessage *archive)
	Constructs a BSpaceLayoutItem from an archive message.

	BSpaceLayoutItem (BSize minSize, BSize maxSize, BSize preferredSize, BAlignment alignment)
	Create a space layout item with specific properties.

virtual	~BSpaceLayoutItem ()
	Destructor.

virtual BAlignment	Alignment ()

virtual status_t	Archive (BMessage *into, bool deep=true) const
	Archive the object into a BMessage.

virtual BRect	Frame ()

virtual bool	IsVisible ()
	Return the current local visibility of this item.

virtual BSize	MaxSize ()

virtual BSize	MinSize ()

virtual BSize	PreferredSize ()

virtual void	SetExplicitAlignment (BAlignment alignment)

virtual void	SetExplicitMaxSize (BSize size)

virtual void	SetExplicitMinSize (BSize size)

virtual void	SetExplicitPreferredSize (BSize size)

virtual void	SetFrame (BRect frame)

virtual void	SetVisible (bool visible)
	Set the visibility of this space layout item.

Public Member Functions inherited from BLayoutItem
	BLayoutItem (BMessage *from)
	Archive constructor.

virtual status_t	Archive (BMessage *into, bool deep=true) const
	Archive the object into a BMessage.

BLayout *	Layout () const
	Returns the BLayout this BLayoutItem resides in.

virtual status_t	Perform (perform_code d, void *arg)
	Perform some action (Internal method defined for binary compatibility purposes).

bool	RemoveSelf ()
	Remove this layout item from the BLayout it is a part of.

virtual BView *	View ()
	Return the BView this item is representing, or `NULL` if it does not represent any view.

virtual bool	HasHeightForWidth ()
	Returns whether or not this BLayoutItem's height constraints are dependent on its width.

virtual void	GetHeightForWidth (float width, float min, float max, float *preferred)
	Get this BLayoutItem's height constraints for a given width.

void	SetExplicitSize (BSize size)
	Set the explicity size to size.

void	AlignInFrame (BRect frame)
	Position this BLayoutItem within frame, given the value returned by Alignment(), and the size constraints for this item.

virtual void	InvalidateLayout (bool children=false)
	Invalidate the layout of this item, or the object it represents.

virtual void	Relayout (bool immediate=false)
	Relayout any children or onscreen data this item contains. Often this request is forwarded to another object.

void *	LayoutData () const
	Retrieve arbitrary data attached to this BLayoutItem.

void	SetLayoutData (void *data)
	Attach arbitrary data to this BLayoutItem.

Public Member Functions inherited from BArchivable
	BArchivable ()
	Constructor. Does nothing.

	BArchivable (BMessage *from)
	Constructor. Does important behind-the-scenes work in the unarchiving process.

virtual	~BArchivable ()
	Destructor. Does nothing.

virtual status_t	AllArchived (BMessage *archive) const
	Method relating to the use of `BArchiver`.

virtual status_t	AllUnarchived (const BMessage *archive)
	Method relating to the use of `BUnarchiver`.

virtual status_t	Archive (BMessage *into, bool deep=true) const
	Archive the object into a BMessage.

virtual status_t	Perform (perform_code d, void *arg)
	Perform some action (Internal method defined for binary compatibility purposes).

Static Public Member Functions
static BSpaceLayoutItem *	CreateGlue ()
	Create a layout item that acts like glue.

static BSpaceLayoutItem *	CreateHorizontalStrut (float width)
	Create a layout item that horizontally expands to a maximum width.

static BSpaceLayoutItem *	CreateVerticalStrut (float height)
	Create a layout item that vertically expands to a maximum height.

static BArchivable *	Instantiate (BMessage *from)
	Instantiate the item from the message from.

Static Public Member Functions inherited from BArchivable
static BArchivable *	Instantiate (BMessage *archive)
	Static member to restore objects from messages.

Additional Inherited Members
Protected Member Functions inherited from BLayoutItem
virtual status_t	AllArchived (BMessage *into) const
	Method relating to the use of `BArchiver`.

virtual status_t	AllUnarchived (const BMessage *from)
	Method relating to the use of `BUnarchiver`.

virtual void	LayoutInvalidated (bool children)
	Hook called from InvalidateLayout().

virtual void	AttachedToLayout ()
	Hook called when this object is attached to a BLayout (via BLayout::AddItem())

virtual void	DetachedFromLayout (BLayout *layout)
	Hook called when this object is attached to a BLayout (via BLayout::RemoveItem())

virtual void	AncestorVisibilityChanged (bool shown)
	Hook called when this BLayoutItem's ancestors change visibility, effectively hiding or showing this item.

Detailed Description

An empty layout item that expands into empty space based on its size configuration.

This class is a specialized layout item, that is used to distribute space within one of the layouts. The layout item can be manually configured, but there are also two default varieties.

The first variety is the glue variety. Glue is an element that expands to the maximum space that is available. Let's say, you have a horizontal BGroupLayout. You want a button on the left, and a button on the right, with empty space in the middle. The middle element can be a glue element. The glue will push the right button all the way to the end of the available space. If the host view gets larger, the glue will expand. You can use the static method BSpaceLayoutItem::CreateGlue() to easily create a glue element.

Another variety is the strut. A is a layout item with no minimum size, and a maximum size. This means that the item might be smaller than the maximum size, but it will never be larger than the maximum size. You can use the static methods BSpaceLayoutItem::CreateVerticalStrut() and BSpaceLayoutItem::CreateHorizontalStrut() to create a strut item.

The default constructor allows you to create a layout item with custom minimum sizes, maximum sizes, preferred sizes and alignments.

See also: Where applicable, the Layout API builder classes have convenience methods to add glue or struts. See BLayoutBuilder::Group<ParentBuilder>::AddGlue() or BLayoutBuilder::Group<ParentBuilder>::AddStrut().

Since: Haiku R1

Constructor & Destructor Documentation

◆ BSpaceLayoutItem() [1/2]

BSpaceLayoutItem::BSpaceLayoutItem	(	BSize	minSize,
		BSize	maxSize,
		BSize	preferredSize,
		BAlignment	alignment
	)

Create a space layout item with specific properties.

See the CreateGlue(), CreateVerticalStrut() and CreateHorizontalStruct static methods to create common space items.

Parameters

minSize	The minimum size for this item.
maxSize	The maximum size for this item.
preferredSize	The preferred size for this item.
alignment	The alignment of this item.

Since: Haiku R1

◆ BSpaceLayoutItem() [2/2]

BSpaceLayoutItem::BSpaceLayoutItem ( BMessage * archive )

Constructs a BSpaceLayoutItem from an archive message.

This method is usually not called directly, if you want to build a space layout item from an archived message you should call Instantiate() instead because it can handle errors properly.

Parameters

archive The BMessage that contains the space layout item.

Since: Haiku R1

◆ ~BSpaceLayoutItem()

BSpaceLayoutItem::~BSpaceLayoutItem ( )

virtual

Destructor.

Since: Haiku R1

Member Function Documentation

◆ Alignment()

BAlignment BSpaceLayoutItem::Alignment ( )

virtual

Returns the requested alignment for this item.

The value returned from this method is used in BLayoutItem::AlignInFrame(), which BLayouts use to position and resize items. In a vertical BGroupLayout, for example, although each item recieves the same horizontal area, each item can use that area differently, aligning to the left, right or center for example.

Since: Haiku R1

Implements BLayoutItem.

◆ Archive()

virtual status_t BSpaceLayoutItem::Archive	(	BMessage *	into,
		bool	deep = `true`
	)		const

virtual

Archive the object into a BMessage.

You should call this method from your derived implementation as it adds the data needed to instantiate your object to the message.

Parameters

into	The message you store your object in.
deep	If `true`, all children of this object should be archived as well.

Return values

B_OK	The archive operation was successful.
B_BAD_VALUE	`NULL` archive message.
B_ERROR	The archive operation failed.

Since: BeOS R3

Reimplemented from BLayoutItem.

◆ CreateGlue()

static BSpaceLayoutItem * BSpaceLayoutItem::CreateGlue ( )

static

Create a layout item that acts like glue.

This type of space layout item has no minimum size, and expands to the maximum available space in all directions.

Returns: Creates a new BSpaceLayoutItem and returns ownership to the caller.

Since: Haiku R1

Referenced by BLayoutBuilder::Group< ParentBuilder >::AddGlue(), and BLayoutBuilder::Grid< ParentBuilder >::AddGlue().

◆ CreateHorizontalStrut()

static BSpaceLayoutItem * BSpaceLayoutItem::CreateHorizontalStrut ( float width )

static

Create a layout item that horizontally expands to a maximum width.

The item has no minimum size, meaning that if the total available width is smaller than the maximum width, the strut will use the available space.

Parameters

width The maximum width.

Returns: Creates a new BSpaceLayoutItem and returns ownership to the caller.

Since: Haiku R1

Referenced by BLayoutBuilder::Group< ParentBuilder >::AddStrut().

◆ CreateVerticalStrut()

static static BSpaceLayoutItem * BSpaceLayoutItem::CreateVerticalStrut ( float height )

static

Create a layout item that vertically expands to a maximum height.

The item has no minimum size, meaning that if the total available height is smaller than the maximum width, the strut will use the available space.

Parameters

height The maximum height.

Returns: Creates a new BSpaceLayoutItem and returns ownership to the caller.

Since: Haiku R1

Referenced by BLayoutBuilder::Group< ParentBuilder >::AddStrut().

◆ Frame()

BRect BSpaceLayoutItem::Frame ( )

virtual

Return the bounding frame of this item.

The returned BRect is in the coordinate system of the target view of the BLayout this item belongs to.

Since: Haiku R1

Implements BLayoutItem.

◆ Instantiate()

static BArchivable * BSpaceLayoutItem::Instantiate ( BMessage * from )

static

Instantiate the item from the message from.

Since: Haiku R1

◆ IsVisible()

bool BSpaceLayoutItem::IsVisible ( )

virtual

Return the current local visibility of this item.

The visibility is set explicitly through SetVisible(). By default, the layout item is visible.

Since: Haiku R1

Implements BLayoutItem.

◆ MaxSize()

BSize BSpaceLayoutItem::MaxSize ( )

virtual

Returns the maximum desirable size for this item.

Since: Haiku R1

Implements BLayoutItem.

◆ MinSize()

BSize BSpaceLayoutItem::MinSize ( )

virtual

Returns the minimum desirable size for this item.

Since: Haiku R1

Implements BLayoutItem.

◆ PreferredSize()

BSize BSpaceLayoutItem::PreferredSize ( )

virtual

Returns the preferred size for this item.

Since: Haiku R1

Implements BLayoutItem.

◆ SetExplicitAlignment()

void BSpaceLayoutItem::SetExplicitAlignment ( BAlignment alignment )

virtual

Set this item's explicit alignment, to be used in Alignment().

Since: Haiku R1

Implements BLayoutItem.

◆ SetExplicitMaxSize()

void BSpaceLayoutItem::SetExplicitMaxSize ( BSize size )

virtual

Set this item's explicit max size, to be used in MaxSize().

Since: Haiku R1

Implements BLayoutItem.

◆ SetExplicitMinSize()

void BSpaceLayoutItem::SetExplicitMinSize ( BSize size )

virtual

Set this item's explicit min size, to be used in MinSize().

This forces the minimal size for the item and overrides any constraints that would normally be used to compute it. Most importantly, the minimal size of children is ignored, so setting this can lead to the children not fitting the view.

Since: Haiku R1

Implements BLayoutItem.

◆ SetExplicitPreferredSize()

void BSpaceLayoutItem::SetExplicitPreferredSize ( BSize size )

virtual

Set this item's explicit preferred size, to be used in PreferredSize().

Since: Haiku R1

Implements BLayoutItem.

◆ SetFrame()

void BSpaceLayoutItem::SetFrame ( BRect frame )

virtual

Set the bounding frame of this item.

frame is in the coordinate system of the target view of the BLayout that this item belongs to.

Since: Haiku R1

Implements BLayoutItem.

◆ SetVisible()

void BSpaceLayoutItem::SetVisible ( bool visible )

virtual

Set the visibility of this space layout item.

Parameters

visible The desired visibility of the layout item.

Since: Haiku R1

Implements BLayoutItem.

Public Member Functions

Static Public Member Functions

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ BSpaceLayoutItem() [1/2]

◆ BSpaceLayoutItem() [2/2]

◆ ~BSpaceLayoutItem()

Member Function Documentation

◆ Alignment()

◆ Archive()

◆ CreateGlue()

◆ CreateHorizontalStrut()

◆ CreateVerticalStrut()

◆ Frame()

◆ Instantiate()

◆ IsVisible()

◆ MaxSize()

◆ MinSize()

◆ PreferredSize()

◆ SetExplicitAlignment()

◆ SetExplicitMaxSize()

◆ SetExplicitMinSize()

◆ SetExplicitPreferredSize()

◆ SetFrame()

◆ SetVisible()