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Graphics.UI.Gtk.Abstract.Container

Portability | portable (depends on GHC)
Stability | provisional
Maintainer | gtk2hs-users@lists.sourceforge.net

Contents

Detail
  Size Requisition
  Size Allocation
  Child attributes
Class Hierarchy
Types
Methods
Attributes
Signals
Deprecated

Description
Base class for widgets which contain other widgets
Synopsis

data Container
class WidgetClass o => ContainerClass o
castToContainer :: GObjectClass obj => obj -> Container
toContainer :: ContainerClass o => o -> Container
type ContainerForeachCB = Widget -> IO ()

data ResizeMode

= ResizeParent
| ResizeQueue
| ResizeImmediate

containerAdd :: (ContainerClass self, WidgetClass widget) => self -> widget -> IO ()
containerRemove :: (ContainerClass self, WidgetClass widget) => self -> widget -> IO ()
containerForeach :: ContainerClass self => self -> ContainerForeachCB -> IO ()
containerForall :: ContainerClass self => self -> ContainerForeachCB -> IO ()
containerGetChildren :: ContainerClass self => self -> IO [Widget]
containerSetFocusChild :: (ContainerClass self, WidgetClass child) => self -> child -> IO ()
containerSetFocusChain :: ContainerClass self => self -> [Widget] -> IO ()
containerGetFocusChain :: ContainerClass self => self -> IO (Maybe [Widget])
containerUnsetFocusChain :: ContainerClass self => self -> IO ()
containerSetFocusVAdjustment :: ContainerClass self => self -> Adjustment -> IO ()
containerGetFocusVAdjustment :: ContainerClass self => self -> IO (Maybe Adjustment)
containerSetFocusHAdjustment :: ContainerClass self => self -> Adjustment -> IO ()
containerGetFocusHAdjustment :: ContainerClass self => self -> IO (Maybe Adjustment)
containerResizeChildren :: ContainerClass self => self -> IO ()
containerSetBorderWidth :: ContainerClass self => self -> Int -> IO ()
containerGetBorderWidth :: ContainerClass self => self -> IO Int
containerGetResizeMode :: ContainerClass self => self -> IO ResizeMode
containerSetResizeMode :: ContainerClass self => self -> ResizeMode -> IO ()
containerResizeMode :: ContainerClass self => Attr self ResizeMode
containerBorderWidth :: ContainerClass self => Attr self Int
containerChild :: (ContainerClass self, WidgetClass widget) => WriteAttr self widget
containerFocusHAdjustment :: ContainerClass self => ReadWriteAttr self (Maybe Adjustment) Adjustment
containerFocusVAdjustment :: ContainerClass self => ReadWriteAttr self (Maybe Adjustment) Adjustment
add :: ContainerClass self => Signal self (Widget -> IO ())
checkResize :: ContainerClass self => Signal self (IO ())
remove :: ContainerClass self => Signal self (Widget -> IO ())
setFocusChild :: ContainerClass self => Signal self (Widget -> IO ())
onAdd :: ContainerClass self => self -> (Widget -> IO ()) -> IO (ConnectId self)
afterAdd :: ContainerClass self => self -> (Widget -> IO ()) -> IO (ConnectId self)
onCheckResize :: ContainerClass self => self -> IO () -> IO (ConnectId self)
afterCheckResize :: ContainerClass self => self -> IO () -> IO (ConnectId self)
onRemove :: ContainerClass self => self -> (Widget -> IO ()) -> IO (ConnectId self)
afterRemove :: ContainerClass self => self -> (Widget -> IO ()) -> IO (ConnectId self)
onSetFocusChild :: ContainerClass self => self -> (Widget -> IO ()) -> IO (ConnectId self)
afterSetFocusChild :: ContainerClass self => self -> (Widget -> IO ()) -> IO (ConnectId self)

Detail

A Gtk+ user interface is constructed by nesting widgets inside widgets. Container widgets are the inner nodes in the resulting tree of widgets: they contain other widgets. So, for example, you might have a `Window` containing a `Frame` containing a `Label`. If you wanted an image instead of a textual label inside the frame, you might replace the `Label` widget with a `Image` widget.

There are two major kinds of container widgets in Gtk+. Both are subclasses of the abstract `Container` base class.

The first type of container widget has a single child widget and derives from `Bin`. These containers are decorators, which add some kind of functionality to the child. For example, a `Button` makes its child into a clickable button; a `Frame` draws a frame around its child and a `Window` places its child widget inside a top-level window.

The second type of container can have more than one child; its purpose is to manage layout. This means that these containers assign sizes and positions to their children. For example, a `HBox` arranges its children in a horizontal row, and a `Table` arranges the widgets it contains in a two-dimensional grid.

To fulfill its task, a layout container must negotiate the size requirements with its parent and its children. This negotiation is carried out in two phases, size requisition and size allocation.

Size Requisition

The size requisition of a widget is it's desired width and height. This is represented by a Requisition.

How a widget determines its desired size depends on the widget. A `Label`, for example, requests enough space to display all its text. Container widgets generally base their size request on the requisitions of their children.

The size requisition phase of the widget layout process operates top-down. It starts at a top-level widget, typically a `Window`. The top-level widget asks its child for its size requisition by calling widgetSizeRequest. To determine its requisition, the child asks its own children for their requisitions and so on. Finally, the top-level widget will get a requisition back from its child.

Size Allocation

When the top-level widget has determined how much space its child would like to have, the second phase of the size negotiation, size allocation, begins. Depending on its configuration (see windowSetResizable), the top-level widget may be able to expand in order to satisfy the size request or it may have to ignore the size request and keep its fixed size. It then tells its child widget how much space it gets by calling widgetSizeAllocate. The child widget divides the space among its children and tells each child how much space it got, and so on. Under normal circumstances, a `Window` will always give its child the amount of space the child requested.

A child's size allocation is represented by an Allocation. This contains not only a width and height, but also a position (i.e. X and Y coordinates), so that containers can tell their children not only how much space they have gotten, but also where they are positioned inside the space available to the container.

Widgets are required to honor the size allocation they receive; a size request is only a request, and widgets must be able to cope with any size.

Child attributes

`Container` introduces child attributes - these are object attributes that are not specific to either the container or the contained widget, but rather to their relation. Typical examples of child attributes are the position or pack-type of a widget which is contained in a `Box`.

The `Container` class does not itself define any child attributes, they are defined (and documented) by the various `Container` subclasses.

Child attributes can be set or obtained in a similar way to ordinary attributes. So ordinary attributes are set like so:

     set object [ attr := value ]

Whereas child attributes take the child object as a parameter:

     set container [ attr child := value ]

And similarily for getting a child attribute's value:

     value <- get container (attr child)

Class Hierarchy

     |  GObject
     |   +----Object
     |         +----Widget
     |               +----Container
     |                     +----Bin
     |                     +----Box
     |                     +----CList
     |                     +----Fixed
     |                     +----Paned
     |                     +----IconView
     |                     +----Layout
     |                     +----List
     |                     +----MenuShell
     |                     +----Notebook
     |                     +----Socket
     |                     +----Table
     |                     +----TextView
     |                     +----Toolbar
     |                     +----TreeView

Types
data Container

Instances

GObjectClass Container
ContainerClass Container
WidgetClass Container
ObjectClass Container

class WidgetClass o => ContainerClass o

Instances

ContainerClass TreeView
ContainerClass Toolbar
ContainerClass TextView
ContainerClass Table
ContainerClass Socket
ContainerClass Notebook
ContainerClass MenuBar
ContainerClass Menu
ContainerClass MenuShell
ContainerClass List
ContainerClass Layout
ContainerClass IconView
ContainerClass VPaned
ContainerClass HPaned
ContainerClass Paned
ContainerClass Fixed
ContainerClass CTree
ContainerClass CList
ContainerClass Statusbar
ContainerClass FileChooserButton
ContainerClass Combo
ContainerClass HBox
ContainerClass FileChooserWidget
ContainerClass FontSelection
ContainerClass ColorSelection
ContainerClass VBox
ContainerClass VButtonBox
ContainerClass HButtonBox
ContainerClass ButtonBox
ContainerClass Box
ContainerClass SeparatorToolItem
ContainerClass RadioToolButton
ContainerClass ToggleToolButton
ContainerClass MenuToolButton
ContainerClass ToolButton
ContainerClass ToolItem
ContainerClass ComboBoxEntry
ContainerClass ComboBox
ContainerClass Expander
ContainerClass Viewport
ContainerClass ScrolledWindow
ContainerClass HandleBox
ContainerClass EventBox
ContainerClass Plug
ContainerClass MessageDialog
ContainerClass InputDialog
ContainerClass FontSelectionDialog
ContainerClass FileChooserDialog
ContainerClass FileSelection
ContainerClass ColorSelectionDialog
ContainerClass AboutDialog
ContainerClass Dialog
ContainerClass Window
ContainerClass ListItem
ContainerClass SeparatorMenuItem
ContainerClass ImageMenuItem
ContainerClass TearoffMenuItem
ContainerClass RadioMenuItem
ContainerClass CheckMenuItem
ContainerClass MenuItem
ContainerClass Item
ContainerClass OptionMenu
ContainerClass FontButton
ContainerClass ColorButton
ContainerClass RadioButton
ContainerClass CheckButton
ContainerClass ToggleButton
ContainerClass Button
ContainerClass AspectFrame
ContainerClass Frame
ContainerClass Alignment
ContainerClass Bin
ContainerClass Container
ContainerClass SourceView
ContainerClass MozEmbed

castToContainer :: GObjectClass obj => obj -> Container
toContainer :: ContainerClass o => o -> Container
type ContainerForeachCB = Widget -> IO ()
A function that is invoked for all widgets in a container.
data ResizeMode

Resize mode, for containers

- `ResizeParent` Pass resize request to the parent
- `ResizeQueue` Queue resizes on this widget
- `ResizeImmediate` Perform the resizes now

Constructors

ResizeParent |
ResizeQueue |
ResizeImmediate |

Instances

Enum ResizeMode
Eq ResizeMode
Show ResizeMode

Methods
containerAdd

:: (ContainerClass self, WidgetClass widget) |
=> self |
-> widget | `widget` - a widget to be placed inside `container`
-> IO () |

Adds `widget` to the container. Typically used for simple containers such as `Window`, `Frame`, or `Button`; for more complicated layout containers such as `Box` or `Table`, this function will pick default packing parameters that may not be correct. So consider functions such as boxPackStart and tableAttach as an alternative to `containerAdd` in those cases. A widget may be added to only one container at a time; you can't place the same widget inside two different containers.

containerRemove

:: (ContainerClass self, WidgetClass widget) |
=> self |
-> widget | `widget` - a current child of `container`
-> IO () |
Removes `widget` from `container`. `widget` must be inside `container`.

containerForeach :: ContainerClass self => self -> ContainerForeachCB -> IO ()
Maps `callback` over each non-internal child of `container`. See `containerForall` for details on what constitutes an "internal" child. Most applications should use `containerForeach`, rather than `containerForall`.
containerForall

:: ContainerClass self |
=> self |
-> ContainerForeachCB | `callback` - a callback
-> IO () |
Maps `callback` over each child of `container`, including children that are considered "internal" (implementation details of the container). "Internal" children generally weren't added by the user of the container, but were added by the container implementation itself. Most applications should use `containerForeach`, rather than `containerForall`.

containerGetChildren :: ContainerClass self => self -> IO [Widget]
Returns the container's non-internal children. See `containerForall` for details on what constitutes an "internal" child.
containerSetFocusChild

:: (ContainerClass self, WidgetClass child) |
=> self |

-> child

    child

-> IO () |
Give the focus to a specific child of the container.

containerSetFocusChain

:: ContainerClass self |
=> self |
-> [Widget] | `focusableWidgets` - the new focus chain.
-> IO () |
Sets a focus chain, overriding the one computed automatically by Gtk+. In principle each widget in the chain should be a descendant of the container, but this is not enforced by this method, since it's allowed to set the focus chain before you pack the widgets, or have a widget in the chain that isn't always packed. The necessary checks are done when the focus chain is actually traversed.

containerGetFocusChain :: ContainerClass self => self -> IO (Maybe [Widget])
Retrieves the focus chain of the container, if one has been set explicitly. If no focus chain has been explicitly set, Gtk+ computes the focus chain based on the positions of the children. In that case the function returns `Nothing`.
containerUnsetFocusChain :: ContainerClass self => self -> IO ()
Removes a focus chain explicitly set with `containerSetFocusChain`.
containerSetFocusVAdjustment

:: ContainerClass self |
=> self |
-> Adjustment | `adjustment` - an adjustment which should be adjusted when the focus is moved among the descendents of `container`
-> IO () |

Hooks up an adjustment to focus handling in a container, so when a child of the container is focused, the adjustment is scrolled to show that widget. This function sets the vertical alignment. See scrolledWindowGetVAdjustment for a typical way of obtaining the adjustment and `containerSetFocusHAdjustment` for setting the horizontal adjustment.

The adjustments have to be in pixel units and in the same coordinate system as the allocation for immediate children of the container.

containerGetFocusVAdjustment

:: ContainerClass self |
=> self |
-> IO (Maybe Adjustment) | returns the vertical focus adjustment, or `Nothing` if none has been set.
Retrieves the vertical focus adjustment for the container. See `containerSetFocusVAdjustment`.

containerSetFocusHAdjustment

:: ContainerClass self |
=> self |
-> Adjustment | `adjustment` - an adjustment which should be adjusted when the focus is moved among the descendents of `container`
-> IO () |

Hooks up an adjustment to focus handling in a container, so when a child of the container is focused, the adjustment is scrolled to show that widget. This function sets the horizontal alignment. See scrolledWindowGetHAdjustment for a typical way of obtaining the adjustment and `containerSetFocusVAdjustment` for setting the vertical adjustment.

The adjustments have to be in pixel units and in the same coordinate system as the allocation for immediate children of the container.

containerGetFocusHAdjustment

:: ContainerClass self |
=> self |
-> IO (Maybe Adjustment) | returns the horizontal focus adjustment, or `Nothing` if none has been set.
Retrieves the horizontal focus adjustment for the container. See `containerSetFocusHAdjustment`.

containerResizeChildren :: ContainerClass self => self -> IO ()
Make the container resize its children.
containerSetBorderWidth

:: ContainerClass self |
=> self |
-> Int | `borderWidth` - amount of blank space to leave outside the container. Valid values are in the range 0-65535 pixels.
-> IO () |

Sets the border width of the container.

The border width of a container is the amount of space to leave around the outside of the container. The only exception to this is `Window`; because toplevel windows can't leave space outside, they leave the space inside. The border is added on all sides of the container. To add space to only one side, one approach is to create a `Alignment` widget, call widgetSetUsize to give it a size, and place it on the side of the container as a spacer.

containerGetBorderWidth

:: ContainerClass self |
=> self |
-> IO Int | returns the current border width
Retrieves the border width of the container. See `containerSetBorderWidth`.

containerGetResizeMode

:: ContainerClass self |
=> self |
-> IO ResizeMode | returns the current resize mode
Returns the resize mode for the container. See `containerSetResizeMode`.

containerSetResizeMode

:: ContainerClass self |
=> self |
-> ResizeMode | `resizeMode` - the new resize mode.
-> IO () |
Sets the resize mode for the container. The resize mode of a container determines whether a resize request will be passed to the container's parent, queued for later execution or executed immediately.

Attributes
containerResizeMode :: ContainerClass self => Attr self ResizeMode
Specify how resize events are handled. Default value: `ResizeParent`
containerBorderWidth :: ContainerClass self => Attr self Int
The width of the empty border outside the containers children. Allowed values: <= `(`maxBound` :: Int)` Default value: 0
containerChild :: (ContainerClass self, WidgetClass widget) => WriteAttr self widget
Can be used to add a new child to the container.
containerFocusHAdjustment :: ContainerClass self => ReadWriteAttr self (Maybe Adjustment) Adjustment
'focusHadjustment' property. See `containerGetFocusHAdjustment` and `containerSetFocusHAdjustment`
containerFocusVAdjustment :: ContainerClass self => ReadWriteAttr self (Maybe Adjustment) Adjustment
'focusVadjustment' property. See `containerGetFocusVAdjustment` and `containerSetFocusVAdjustment`
Signals
add :: ContainerClass self => Signal self (Widget -> IO ())
checkResize :: ContainerClass self => Signal self (IO ())
remove :: ContainerClass self => Signal self (Widget -> IO ())
setFocusChild :: ContainerClass self => Signal self (Widget -> IO ())
Deprecated
onAdd :: ContainerClass self => self -> (Widget -> IO ()) -> IO (ConnectId self)
afterAdd :: ContainerClass self => self -> (Widget -> IO ()) -> IO (ConnectId self)
onCheckResize :: ContainerClass self => self -> IO () -> IO (ConnectId self)
afterCheckResize :: ContainerClass self => self -> IO () -> IO (ConnectId self)
onRemove :: ContainerClass self => self -> (Widget -> IO ()) -> IO (ConnectId self)
afterRemove :: ContainerClass self => self -> (Widget -> IO ()) -> IO (ConnectId self)
onSetFocusChild :: ContainerClass self => self -> (Widget -> IO ()) -> IO (ConnectId self)
afterSetFocusChild :: ContainerClass self => self -> (Widget -> IO ()) -> IO (ConnectId self)
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