gtk3-0.14.2: Binding to the Gtk+ 3 graphical user interface library

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Stabilityprovisional
Portabilityportable (depends on GHC)
Safe HaskellNone
LanguageHaskell98

Graphics.UI.Gtk.Abstract.Box

Contents

Description

Base class for box containers

Synopsis

Detail

Box is an abstract widget which encapsulates functionality for a particular kind of container, one that organizes a variable number of widgets into a rectangular area. Box currently has two derived classes, HBox and VBox.

The rectangular area of a Box is organized into either a single row or a single column of child widgets depending upon whether the box is of type HBox or VBox, respectively. Thus, all children of a Box are allocated one dimension in common, which is the height of a row, or the width of a column.

Box uses a notion of packing. Packing refers to adding widgets with reference to a particular position in a Container. For a Box, there are two reference positions: the start and the end of the box. For a VBox, the start is defined as the top of the box and the end is defined as the bottom. For a HBox the start is defined as the left side and the end is defined as the right side.

Use repeated calls to boxPackStart to pack widgets into a Box from start to end. Use boxPackEnd to add widgets from end to start. You may intersperse these calls and add widgets from both ends of the same Box. Besides adding widgets at the start or the end of a box, you can also specify the padding around each widget (in pixels) and a Packing parameter that denotes how to fill up unused space.

While the right amount of padding around each widget is a matter of appearance, the Packing paramter specifies the way the widgets in the container behave when the window is resized and thereby affect the usability. Hence, once you have created a window, you should resize it and see if the widgets behave as expected. The Packing parameter of each child widget determines how excess space is used by that particular widget. See the description of Packing for a detailed explanaition.

Because Box is a Container, you may also use containerAdd to insert widgets into the box, and they will be packed as if with boxPackStart with PackRepel and 0 padding. Use containerRemove to remove widgets from the Box.

Use boxSetHomogeneous to specify whether or not all children of the Box are forced to get the same amount of space. Note that the Packing options PackNatural and PackRepel coincide if space is allotted homogeneously.

Use boxSetSpacing to determine how much space will be minimally placed between all children in the Box.

Use boxReorderChild to move a Box child to a different place in the box.

Use boxSetChildPacking to reset the expand, fill, and padding attributes of any Box child. Use boxQueryChildPacking to query these fields.

Class Hierarchy

| GObject
| +----Object
| +----Widget
| +----Container
| +----Box
| +----ButtonBox
| +----VBox
| +----HBox

Types

data Box

Instances

class ContainerClass o => BoxClass o

Instances

castToBox :: GObjectClass obj => obj -> Box

gTypeBox :: GType

toBox :: BoxClass o => o -> Box

data Packing

Packing parameters of a widget

  • The Packing parameter determines how the child behaves in the horizontal or vertical way in an HBox or VBox, respectively. PackNatural means the child is as big as it requests. It will stay at the start or end of a Box if there is more space available. All children packed with PackRepel will be padded on both sides with additional space. PackGrow will increase the size of a widget so that it covers the available space. A menu bar, for instance, should always stay at the top of a window and should only occupy as little space as possible. Hence it should be packed at the start of a VBox with the packing option PackNatural. The working area of a window (e.g. the text area in an editor) should expand when the window is resized. Here the packing option PackGrow is the right choice and it is irrelevant whether the main area is inserted at the start or the end of a box. Finally PackRepel is most useful in a window where no widget can make use of excess space. Examples include a dialog box without list boxes or text fields.

Constructors

PackRepel 
PackGrow 
PackNatural 

Instances

Methods

boxPackStart

Arguments

:: (BoxClass self, WidgetClass child) 
=> self 
-> child

child - the Widget to be added to the box.

-> Packing 
-> Int

padding - extra space in pixels to put between this child and its neighbors, over and above the global amount specified by spacing boxSetSpacing. If child is a widget at one of the reference ends of box, then padding pixels are also put between child and the reference edge of box.

-> IO () 

Adds the child widget to the box, packed with reference to the start of the box. The child is packed after any other child packed with reference to the start of the box.

boxPackEnd

Arguments

:: (BoxClass self, WidgetClass child) 
=> self 
-> child

child - the Widget to be added to the box.

-> Packing 
-> Int

padding - extra space in pixels to put between this child and its neighbors, over and above the global amount specified by spacing boxSetSpacing. If child is a widget at one of the reference ends of box, then padding pixels are also put between child and the reference edge of box.

-> IO () 

Adds the child widget to the box, packed with reference to the end of the box. The child is packed after (away from end of) any other child packed with reference to the end of the box.

Note that for boxPackEnd the PackNatural option will move a child to the right in an HBox or to the bottom in an VBox if there is more space availble.

boxGetHomogeneous

Arguments

:: BoxClass self 
=> self 
-> IO Bool

returns True if the box is homogeneous.

Returns whether the box is homogeneous (all children are the same size). See boxSetHomogeneous.

boxSetHomogeneous

Arguments

:: BoxClass self 
=> self 
-> Bool

homogeneous - a boolean value, True to create equal allotments, False for variable allotments.

-> IO () 

Sets the homogeneous property, controlling whether or not all children of the box are given equal space

boxGetSpacing

Arguments

:: BoxClass self 
=> self 
-> IO Int

returns spacing between children

Retrieves the standard spacing between widgets.

boxSetSpacing

Arguments

:: BoxClass self 
=> self 
-> Int

spacing - the number of pixels to put between children.

-> IO () 

Set the standard spacing between two children.

This space is in addition to the padding parameter that is given for each child.

boxReorderChild

Arguments

:: (BoxClass self, WidgetClass child) 
=> self 
-> child

child - the Widget to move.

-> Int

position - the new position for child in the children list starting from 0. If negative, indicates the end of the list.

-> IO () 

Moves child to a new position in the list of box children. The list contains both widgets packed PackStart as well as widgets packed PackEnd, in the order that these widgets were added to the box.

A widget's position in the box children list determines where the widget is packed into the box. A child widget at some position in the list will be packed just after all other widgets of the same packing type that appear earlier in the list.

boxQueryChildPacking

Arguments

:: (BoxClass self, WidgetClass child) 
=> self 
-> child

child - the Widget of the child to query.

-> IO (Packing, Int, PackType)
(packing, padding, packType)

Returns information about how child is packed into the box.

Returns information on the behaviour if free space is available (in Packing), the additional padding for this widget and if the widget was inserted at the start or end of the container (PackType).

boxSetChildPacking

Arguments

:: (BoxClass self, WidgetClass child) 
=> self 
-> child

child - the Widget of the child to set.

-> Packing 
-> Int
padding
-> PackType
packType
-> IO () 

Sets the way child is packed into the box.

boxGetBaselinePosition :: BoxClass self => self -> IO BaselinePosition

Gets the value set by boxSetBaselinePostion

boxSetBaselinePosition :: BoxClass self => self -> BaselinePosition -> IO ()

Sets the baseline position of a box. This affects only horizontal boxes with at least one baseline aligned child. If there is more vertical space available than requested, and the baseline is not allocated by the parent then position is used to allocate the baseline wrt the extra space available.

boxGetCenterWidget :: BoxClass self => self -> IO Widget

Retrieves the center widget of the box.

boxSetCenterWidget :: (BoxClass self, WidgetClass widget) => self -> widget -> IO ()

Sets a center widget; that is a child widget that will be centered with respect to the full width of the box, even if the children at either side take up different amounts of space.

Attributes

boxSpacing :: BoxClass self => Attr self Int

The amount of space between children.

Allowed values: >= 0

Default value: 0

boxHomogeneous :: BoxClass self => Attr self Bool

Whether the children should all be the same size.

Default value: False

boxBaselinePosition :: BoxClass self => Attr self BaselinePosition

The position of the baseline aligned widgets if extra space is available.

boxCenterWidget :: (BoxClass self, WidgetClass widget) => ReadWriteAttr self Widget widget

A child widget that will be centered with respect to the full width of the box, even if the children at either side take up different amounts of space.

Child Attributes

boxChildPacking :: (BoxClass self, WidgetClass child) => child -> Attr self Packing

The packing style of the child.

Default value: PackGrow

boxChildPadding :: (BoxClass self, WidgetClass child) => child -> Attr self Int

Extra space to put between the child and its neighbors, in pixels.

Allowed values: <= (maxBound :: Int)

Default value: 0

boxChildPackType :: (BoxClass self, WidgetClass child) => child -> Attr self PackType

A PackType indicating whether the child is packed with reference to the start or end of the parent.

Default value: PackStart

boxChildPosition :: (BoxClass self, WidgetClass child) => child -> Attr self Int

The index of the child in the parent.

Allowed values: >= -1

Default value: 0