Graphics.UI.Gtk.Misc.Adjustment

A Object representing an adjustable bounded value

Detail

The Adjustment object represents a value which has an associated lower and upper bound, together with step and page increments, and a page size. It is used within several Gtk+ widgets, including SpinButton, Viewport, and Range (which is a base class for HScrollbar, VScrollbar, HScale, and VScale).

The Adjustment object does not update the value itself. Instead it is left up to the owner of the Adjustment to control the value.

The owner of the Adjustment typically calls the adjustmentValueChanged and adjustmentChanged functions after changing the value and its bounds. This results in the emission of the "value_changed" or "changed" signal respectively.

Class Hierarchy

| GObject
| +----Object
| +----Adjustment

Types

data Adjustment

Instances

Eq Adjustment

Ord Adjustment

GObjectClass Adjustment

AdjustmentClass Adjustment

class GObjectClass o => AdjustmentClass o

Instances

AdjustmentClass Adjustment

castToAdjustment :: GObjectClass obj => obj -> Adjustment

gTypeAdjustment :: GType

toAdjustment :: AdjustmentClass o => o -> Adjustment

Constructors

adjustmentNew

Arguments

:: Double

value - the initial value.

-> Double

lower - the minimum value.

-> Double

upper - the maximum value.

-> Double

stepIncrement - the step increment.

-> Double

pageIncrement - the page increment.

-> Double

pageSize - the page size.

-> IO Adjustment

Creates a new Adjustment.

The creation function take every value that is contained in the object: value is the initial value and should be between the upper and lower bounds of the slider. Clicking on the arrows increases this value by stepIncrement. Clicking in the slider advances by pageIncrement. The pageSize is needed to determine if the end of the slider is still in the range.

Methods

adjustmentSetLower :: Adjustment -> Double -> IO ()

Set the lower value.

adjustmentGetLower :: Adjustment -> IO Double

Retrieve the lower value.

adjustmentSetPageIncrement :: Adjustment -> Double -> IO ()

Set the page increment value.

adjustmentGetPageIncrement :: Adjustment -> IO Double

Retrieve the pageincrement value.

adjustmentSetPageSize :: Adjustment -> Double -> IO ()

Set the page size value.

adjustmentGetPageSize :: Adjustment -> IO Double

Retrieve the page size value.

adjustmentSetStepIncrement :: Adjustment -> Double -> IO ()

Set the step-increment value.

adjustmentGetStepIncrement :: Adjustment -> IO Double

Retrieve the step-increment value.

adjustmentSetUpper :: Adjustment -> Double -> IO ()

Set the upper value.

adjustmentGetUpper :: Adjustment -> IO Double

Retrieve the upper value.

adjustmentSetValue :: Adjustment -> Double -> IO ()

Sets the current value of the Adjustment object. The value is clamped to lie between the adjustment's lower and upper values. See adjustmentNew for details of these properties.

Note that for adjustments which are used in a Scrollbar, the effective range of allowed values goes from lower to upper - page_size.

adjustmentGetValue :: Adjustment -> IO Double

Gets the current value of the adjustment. See adjustmentSetValue.

adjustmentClampPage

Arguments

:: Adjustment

-> Double

lower - the lower value.

-> Double

upper - the upper value.

-> IO ()

Updates the Adjustment value to ensure that the range between lower and upper is in the current page (i.e. between value and value + pageSize). If the range is larger than the page size, then only the start of it will be in the current page. A "changed" signal will be emitted if the value is changed.

adjustmentAdjChanged :: Adjustment -> IO ()

Emit the onAdjChanged signal.

adjustmentValueChanged :: Adjustment -> IO ()

Emit the onValueChanged signal.

• When adjusting the or bounds, this function can be called to enforce a visual update of the containing widget.

Attributes

adjustmentValue :: Attr Adjustment Double

The value of the adjustment.

Default value: 0

adjustmentLower :: Attr Adjustment Double

The minimum value of the adjustment.

Default value: 0

adjustmentUpper :: Attr Adjustment Double

The maximum value of the adjustment. Note that values will be restricted by upper - page-size if the page-size property is nonzero.

Default value: 0

adjustmentStepIncrement :: Attr Adjustment Double

The step increment of the adjustment.

Default value: 0

adjustmentPageIncrement :: Attr Adjustment Double

The page increment of the adjustment.

Default value: 0

adjustmentPageSize :: Attr Adjustment Double

The page size of the adjustment. Note that the page-size is irrelevant and should be set to zero if the adjustment is used for a simple scalar value, e.g. in a SpinButton.

Default value: 0

Signals

onAdjChanged :: Adjustment -> IO () -> IO (ConnectId Adjustment)

Emitted when one or more of the Adjustment fields have been changed, other than the value field.

afterAdjChanged :: Adjustment -> IO () -> IO (ConnectId Adjustment)

Emitted when one or more of the Adjustment fields have been changed, other than the value field.

onValueChanged :: Adjustment -> IO () -> IO (ConnectId Adjustment)

Emitted when the Adjustment value field has been changed.

afterValueChanged :: Adjustment -> IO () -> IO (ConnectId Adjustment)

Emitted when the Adjustment value field has been changed.