UE3:UIScrollbar (UDK)

Object >> UIRoot >> UIScreenObject >> UIObject >> UIScrollbar

Package: 

Engine

Known classes within UIScrollbar:

UIScrollbarButton, UIScrollbarMarkerButton

This class in other games:

UT3

This component when integrated into a widget allows for scrolling the contents of the widget, i.e. UIList. UIScrollbar has built-in functionality to autoposition itself within the owner widget depending on its orientation

Properties

Property group 'Appearance'

bAddCornerPadding

Type: bool

Specifies wheather to leave extra space between the bottom/right corner of the scrollbar and its owner widget. Extra space prevents ovelapping if both horizontal and vertical scrollbars exist within one widget

Default value: True

BarWidth

Type: UIRoot.UIScreenValue_Extent

Determines scrollbar's thickness

Default value:

Member	Value
Value	16.0

ButtonsExtent

Type: UIRoot.UIScreenValue_Extent

Determines the length of the Increment/Decrement buttons

Default value:

Member	Value
Orientation	UIORIENT_Vertical
Value	16.0

MinimumMarkerSize

Type: UIRoot.UIScreenValue_Extent

Specifies the minimum size for the scrollbar marker. Useful to prevent the marker from becoming too small if there are lots of items in the list.

Default value:

Member	Value
Orientation	UIORIENT_Vertical
Value	12.0

ScrollbarOrientation

Type: UIRoot.EUIOrientation

Controls whether this scrollbar is vertical or horizontal

Default value: UIORIENT_Vertical

Property group 'Components'

BackgroundImageComponent

Type: UIComp_DrawImage

Modifiers: editinline, const, noclear

Component for rendering the background image

Default value: UIComp_DrawImage'ScrollBarBackgroundImageTemplate'

Property group 'Interaction'

NudgeMultiplier

Type: float

The NudgeMultiplier value indicates by how many NudgeValues will the marker move when the increment or decrement button is pressed, NudgeValue is multiplied by NudgeMultiplier to obtain final pixel amount

Default value: 1.0

Internal variables

bInitializeMarker

Type: bool

Modifiers: private, transient

A private flag indicating that the marker needs to be repositioned and resized to the bounds of the uiscrollbar

DecrementButton

Type: UIScrollbarButton

Modifiers: private, const

DecrementStyle

Type: UIRoot.UIStyleReference

Modifiers: private

Default value:

Member	Value
DefaultStyleTag	'DefaultScrollbarDecrement'
RequiredStyleClass	Class'Engine.UIStyle_Image'

IncrementButton

Type: UIScrollbarButton

Modifiers: private, const

Buttons that can be used to increment and decrement the marker of the scrollbar.

IncrementStyle

Type: UIRoot.UIStyleReference

Modifiers: private

The styles used for the increment, decrement and marker buttons

Default value:

Member	Value
DefaultStyleTag	'DefaultScrollbarIncrement'
RequiredStyleClass	Class'Engine.UIStyle_Image'

MarkerButton

Type: UIScrollbarMarkerButton

Modifiers: private, const

The marker which can be manipulated to change the value of the scrollbar

MarkerPosPercent

Type: float

Modifiers: private, transient

MarkerSizePercent

Type: float

Modifiers: private, transient

MarkerStyle

Type: UIRoot.UIStyleReference

Modifiers: private

Default value:

Member	Value
DefaultStyleTag	'DefaultScrollBarStyle'
RequiredStyleClass	Class'Engine.UIStyle_Image'

MousePosition

Type: UIRoot.UIScreenValue_Position

Modifiers: transient

The current position of the mouse cursor, used in dragging handling

MousePositionDelta

Type: float

Modifiers: private, transient

The accumulated mouse position delta during dragging. The change in mouse position is accumulated until it is greater than the nudge value, at which point it will then call the OnScrollActivity delegate to move the content.

NudgePercent

Type: float

Modifiers: private, transient

Values which store current state of the scrollbar's marker

NudgeValue

Type: float

Modifiers: private, transient

The nudge value indicates how much marker movement will cause one position update "tick", value is stored in pixels. It can be set to 1 as is the case with the UIScrollframe, or it can be evaluated based on some percentage of the total available size as is the case with the UIList

Default values

Property	Value
bSupportsPrimaryStyle	False
DefaultStates[2]	Class'Engine.UIState_Focused'
DefaultStates[3]	Class'Engine.UIState_Pressed'
DefaultStates[4]	Class'Engine.UIState_Active'
PrimaryStyle	Member Value DefaultStyleTag 'DefaultScrollZoneStyle' RequiredStyleClass Class'Engine.UIStyle_Image'
PrivateFlags	1044

Subobjects

ScrollBarBackgroundImageTemplate

Class: Engine.UIComp_DrawImage

Property	Value
ImageStyle	Member Value DefaultStyleTag 'DefaultScrollZoneStyle'
StyleResolverTag	'Background Image Style'

WidgetEventComponent

Class: Engine.UIComp_Event

Inherits from: UIObject.WidgetEventComponent

No new values.

Delegates

OnClickedScrollZone

delegate OnClickedScrollZone (UIScrollbar Sender, float PositionPerc, int PlayerIndex)

Called when the user clicks anywhere in the scrollbar other than on one of the buttons.

Parameters:

• Sender - the scrollbar that was clicked.
• PositionPerc - a value from 0.0 - 1.0, representing the location of the click within the region between the increment and decrement buttons. Values closer to 0.0 means that the user clicked near the decrement button; values closer to 1.0 are nearer the increment button.
• PlayerIndex - Player that performed the action that issued the event.

OnScrollActivity

delegate bool OnScrollActivity (UIScrollbar Sender, float PositionChange, optional bool bPositionMaxed)

Delegate invoked on scrolling activity

Parameters:

• Sender - the scrollbar that generated the event.
• PositionChange - the number of nudge values by which the marker was moved
• bPositionMaxed - indicates that the scrollbar's marker has reached its farthest available position, used to obtain pixel exact scrolling

Returns:

currently unused.

Functions

Native functions

DragScroll

native final function DragScroll (UIScrollbarMarkerButton Sender, int PlayerIndex)

Called during the dragging process

Parameters:

• EventObject - Object that issued the event.
• PlayerIndex - Player that performed the action that issued the event.

DragScrollBegin

native final function DragScrollBegin (UIScreenObject Sender, int PlayerIndex)

Initiates mouse drag scrolling. The scroll bar marker will slide on its axis with the mouse cursor until DragScrollEnd is called.

Parameters:

• EventObject - Object that issued the event.
• PlayerIndex - Player that performed the action that issued the event.

DragScrollEnd

native final function DragScrollEnd (UIScreenObject Sender, int PlayerIndex)

Terminates mouse drag scrolling.

Parameters:

• EventObject - Object that issued the event.
• PlayerIndex - Player that performed the action that issued the event.

Returns:

return TRUE to prevent the kismet OnClick event from firing.

EnableCornerPadding

native final function EnableCornerPadding (bool FlagValue)

Sets the value of the bAddCornerPadding flag

GetMarkerButtonPosition

native final function float GetMarkerButtonPosition () const

Returns the position of this scrollbar's top face (if orientation is vertical) or left face (for horizontal), in pixels.

GetScrollZoneExtent

native final noexport function float GetScrollZoneExtent (optional out float ScrollZoneStart) const

Returns the size of the scroll-zone (the region between the decrement and increment buttons), along the same orientation as the scrollbar.

Parameters:

• ScrollZoneStart - receives the value of the location of the beginning of the scroll zone, in pixels relative to the scrollbar.

Returns:

the height (if the scrollbar's orientation is vertical) or width (if horizontal) of the region between the increment and decrement buttons, in pixels.

Note: noexport so that the native implementation can declare the optional out as a * will default value of NULL.

GetScrollZoneWidth

native final function float GetScrollZoneWidth () const

Returns the size of the scroll-zone (the region between the decrement and increment buttons), for the orientation opposite that of the scrollbar.

Returns:

the height (if the scrollbar's orientation is vertical) or width (if horizontal) of the region between the increment and decrement buttons, in pixels.

ScrollDecrement

native final function ScrollDecrement (UIScreenObject Sender, int PlayerIndex)

Decrements marker position by the amount of nudges specified in the NudgeMultiplier. Decrement direction is either up or left, depending on marker's orientation

Parameters:

• EventObject - Object that issued the event.
• PlayerIndex - Player that performed the action that issued the event.

ScrollIncrement

native final function ScrollIncrement (UIScreenObject Sender, int PlayerIndex)

Increments marker position by the amount of nudges specified in the NudgeMultiplier. Increment direction is either down or right, depending on scrollbar's orientation.

Parameters:

• EventObject - Object that issued the event.
• PlayerIndex - Player that performed the action that issued the event.

SetMarkerPosition

native final function SetMarkerPosition (float PositionPercentage)

Sets marker's top or left face position to start at some percentage of total scrollbar extent

Parameters:

• PositionPercentage - determines where the marker should start, value needs to be in the range [ 0 , 1 ] and should correspond to the position of the topmost or leftmost item in the viewing area

SetMarkerSize

native final function SetMarkerSize (float SizePercentage)

Sets marker's extent to a percentage of scrollbar size, the direction will be vertical or horizontal depending scrollbar's orientation

Parameters:

• SizePercentage - determines the size of the marker, value needs to be in the range [ 0 , 1 ] and should be equal to the ratio of viewing area to total widget scroll area

SetNudgeSizePercent

native final function SetNudgeSizePercent (float NudgePercentage)

Sets the amount by which the marker will move to cause one position tick

Parameters:

• NudgePercentage - percentage of total scrollbar area which will amount to one tick value needs to be in the range [ 0 , 1 ]

SetNudgeSizePixels

native final function SetNudgeSizePixels (float NudgePixels)

Sets the amount by which the marker will move to cause one position tick

Parameters:

• NudgePixels - Number of pixels by which the marker will need to be moved to cause one tick

Events

Initialized

event Initialized ()

Overrides: UIScreenObject.Initialized

Initializes the clicked delegates in the increment, decrement and marker buttons.

PostInitialize

event PostInitialize ()

Overrides: UIScreenObject.PostInitialize

Propagate the enabled state of this widget.

Other instance functions

GetMarkerPosPercent

final function float GetMarkerPosPercent ()

GetMarkerSizePercent

final function float GetMarkerSizePercent ()

GetNudgePercent

final function float GetNudgePercent ()

GetNudgeValue

final function float GetNudgeValue ()

Simple accessors