Interface VFXScrollPaneSkin.LayoutHandler

All Known Implementing Classes:

VFXScrollPaneSkin.BottomLeftHandler, VFXScrollPaneSkin.BottomRightHandler, VFXScrollPaneSkin.TopLeftHandler, VFXScrollPaneSkin.TopRightHandler

Enclosing class:

VFXScrollPaneSkin

protected static interface VFXScrollPaneSkin.LayoutHandler

Simplifies the layout strategy by dividing it into four base cases which depend on the combination between the VFXScrollPane.vBarPosProperty() and the VFXScrollPane.hBarPosProperty(); and so this has four concrete implementations for the following positions: TOP_LEFT, TOP_RIGHT, BOTTOM_RIGHT, BOTTOM_LEFT.

It also defines common computations that depend on other properties and simpler conditions.

In general the scroll pane's layout is quite complex. For the sake of simplicity, and in some cases as design choices some properties may be ignored under specific conditions. See the methods docs.

Field Summary

Fields

Modifier and Type	Field	Description
static final Map<VFXScrollPaneSkin.PosPair,VFXScrollPaneSkin.LayoutHandler>	HANDLERS

Method Summary

Modifier and Type	Method	Description
default VFXScrollPaneSkin.LayoutInfo	computeViewportLayout(VFXScrollPane pane, VFXScrollBar vBar, VFXScrollBar hBar, double startXOffset, double endXOffset, double startYOffset, double endYOffset)	Determines the viewport's size and position.
default double	getBarsGap(VFXScrollPane pane, VFXScrollBar vBar, VFXScrollBar hBar)
default javafx.geometry.Insets	getBarsPadding(VFXScrollPane pane)	If the VFXScrollPane.layoutModeProperty() is set to ScrollPaneEnums.LayoutMode.COMPACT basically returns Region.insetsProperty(), otherwise returns Insets.EMPTY.
static VFXScrollPaneSkin.LayoutHandler	getHandler(VFXScrollPane pane)
void	layout(VFXScrollPane pane, javafx.scene.layout.Pane viewport, VFXScrollBar vBar, VFXScrollBar hBar)

Field Details

HANDLERS

static final Map<VFXScrollPaneSkin.PosPair,VFXScrollPaneSkin.LayoutHandler> HANDLERS

Method Details

getHandler

static VFXScrollPaneSkin.LayoutHandler getHandler(VFXScrollPane pane)

Returns:

the appropriate LayoutHandler implementation for the given scroll pane considering its VFXScrollPane.vBarPosProperty() and VFXScrollPane.hBarPosProperty()

layout

void layout(VFXScrollPane pane,
 javafx.scene.layout.Pane viewport,
 VFXScrollBar vBar,
 VFXScrollBar hBar)

getBarsGap

default double getBarsGap(VFXScrollPane pane,
 VFXScrollBar vBar,
 VFXScrollBar hBar)

Returns:

the values specified by the VFXScrollPane.scrollBarsGapProperty() or 0.0 if either the vBar or hBar are hidden.

See Also:

• VFXScrollPaneSkin.BarsVisibilityProperty

getBarsPadding

default javafx.geometry.Insets getBarsPadding(VFXScrollPane pane)

If the VFXScrollPane.layoutModeProperty() is set to ScrollPaneEnums.LayoutMode.COMPACT basically returns Region.insetsProperty(), otherwise returns Insets.EMPTY.

In other words: in compact mode the padding is used to space the scroll bars from the edges; in standard mode the bars cannot go on top of the viewport but instead the padding is used as the distance between the two.

Which values of the Insets object are used depend on the handler's implementation!!

computeViewportLayout

default VFXScrollPaneSkin.LayoutInfo computeViewportLayout(VFXScrollPane pane,
 VFXScrollBar vBar,
 VFXScrollBar hBar,
 double startXOffset,
 double endXOffset,
 double startYOffset,
 double endYOffset)

Determines the viewport's size and position.

When the VFXScrollPane.layoutModeProperty() is set to ScrollPaneEnums.LayoutMode.COMPACT the viewport always takes all the available space and is positioned at [0, 0].

In standard mode things are much more complicated. In simple terms, the offset parameters determine the distance from the origin ([0, 0]) and the end (which would be the scroll pane's [maxX, maxY]).

The reason for that is quite simple. This basically ensures that the viewport never covers the scroll bars and that there is the right distance between the three.

The offsets highly depend on the scroll bars positions as specified by the VFXScrollPane.vBarPosProperty() and VFXScrollPane.hBarPosProperty().

Last but not least, note that the x and y offsets are ignored if either the vertical or horizontal scroll bar are hidden!!

For example, if the vertical bar is not visible, then we don't want to take it into account when laying out the viewport. We want the latter to take all the horizontal space. When the bar is on the right side, then we simply stretch the viewport's width to the end of the scroll pane. When the bar is on the left side, things are a bit more complex, because we want the width to be the same as the scroll pane, but we also need to position the viewport at x = 0