Package arc.scene

Class Group

java.lang.Object

arc.scene.Element

arc.scene.Group

All Implemented Interfaces:

Cullable

Direct Known Subclasses:

ResearchDialog.View, WidgetGroup

public abstract class Group
extends Element
implements Cullable

2D scene graph node that may contain other actors.

Actors have a z-order equal to the order they were inserted into the group. Actors inserted later will be drawn on top of actors added earlier. Touch events that hit more than one actor are distributed to topmost actors first.

Field Summary

Fields

Modifier and Type	Field	Description
protected final SnapshotSeq<Element>	children
protected Rect	cullingArea
protected boolean	transform

Fields inherited from class arc.scene.Element

color, cullable, fillParent, height, name, originX, originY, parent, parentAlpha, rotation, scaleX, scaleY, touchable, touchablility, translation, userObject, visibility, visible, width, x, y

Constructor Summary

Constructors

Constructor	Description
Group()

Method Summary

Modifier and Type	Method	Description
void	act(float delta)	Updates the actor based on time.
void	addChild(Element actor)	Adds an actor as a child of this group, removing it from its previous parent.
void	addChildAfter(Element actorAfter, Element actor)	Adds an actor as a child of this group immediately after another child actor, removing it from its previous parent.
void	addChildAt(int index, Element actor)	Adds an actor as a child of this group at a specific index, removing it from its previous parent.
void	addChildBefore(Element actorBefore, Element actor)	Adds an actor as a child of this group immediately before another child actor, removing it from its previous parent.
protected void	applyTransform(Mat transform)	Set the batch's transformation matrix, often with the result of computeTransform().
protected void	childrenChanged()	Called when actors are added to or removed from the group.
void	clear()	Removes all children, actions, and listeners from this group.
void	clearChildren()	Removes all actors from this group.
protected Mat	computeTransform()	Returns the transform for this group's coordinate system.
void	draw()	Draws the element.
protected void	drawChildren()
void	fill(Cons<Table> cons)	Adds and returns a table.
void	fill(Drawable background, Cons<Table> cons)	Adds and returns a table.
Element	fill(Table.DrawRect rect)
<T extends Element> T	find(Boolf<Element> pred)	Find element by a predicate.
<T extends Element> T	find(String name)	Returns the first actor found with the specified name.
<T extends Element> T	findVisible(String name)	Finds only visible elements.
void	forEach(Cons<Element> cons)	Recursively iterates through every child of this group.
SnapshotSeq<Element>	getChildren()	Returns an ordered list of child actors in this group.
Rect	getCullingArea()
boolean	hasChildren()
Element	hit(float x, float y, boolean touchable)	Returns the deepest actor that contains the specified point and is touchable and visible, or null if no actor was hit.
boolean	isTransform()
Vec2	localToDescendantCoordinates(Element descendant, Vec2 localCoords)	Converts coordinates for this group to those of a descendant actor.
boolean	removeChild(Element actor)	Removes an actor from this group and unfocuses it.
boolean	removeChild(Element actor, boolean unfocus)	Removes an actor from this group.
protected void	resetTransform()	Restores the batch transform to what it was before applyTransform(Mat).
void	setCullingArea(Rect cullingArea)	Children completely outside of this rectangle will not be drawn.
protected void	setScene(Scene stage)	Called by the framework when this actor or any parent is added to a group that is in the stage.
void	setTransform(boolean transform)	When true (the default), the Batch is transformed so children are drawn in their parent's coordinate system.
boolean	swapActor(int first, int second)	Swaps two actors by index.
boolean	swapActor(Element first, Element second)	Swaps two actors.
String	toString()	Returns a description of the actor hierarchy, recursively.

Methods inherited from class arc.scene.Element

actions, addAction, addCaptureListener, addListener, change, changed, clearActions, clearListeners, clicked, clicked, clicked, clicked, clipBegin, clipBegin, clipEnd, dragged, exited, fire, fireClick, getActions, getCaptureListeners, getHeight, getListeners, getMaxHeight, getMaxWidth, getMinHeight, getMinWidth, getPrefHeight, getPrefWidth, getRight, getRotation, getScene, getTop, getWidth, getX, getY, getZIndex, hasActions, hasKeyboard, hasMouse, hasParent, hasScroll, hovered, invalidate, invalidateHierarchy, isAscendantOf, isDescendantOf, isDescendantOf, isTouchable, keepInStage, keyDown, keyDown, layout, localToAscendantCoordinates, localToParentCoordinates, localToStageCoordinates, moveBy, needsLayout, notify, pack, parentToLocalCoordinates, released, remove, removeAction, removeCaptureListener, removeListener, requestKeyboard, requestScroll, rotateBy, rotationChanged, scaleBy, scaleBy, screenToLocalCoordinates, scrolled, setBounds, setColor, setColor, setFillParent, setHeight, setLayoutEnabled, setOrigin, setOrigin, setPosition, setPosition, setRotation, setRotationOrigin, setScale, setScale, setSize, setSize, setTranslation, setWidth, setZIndex, sizeBy, sizeBy, sizeChanged, stageToLocalCoordinates, tapped, toBack, toFront, touchable, update, updateVisibility, validate, visible

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Details

children

protected final SnapshotSeq<Element> children

transform

protected boolean transform

cullingArea

protected Rect cullingArea

Constructor Details

Group

public Group()

Method Details

act

public void act(float delta)

Description copied from class: Element

Updates the actor based on time. Typically this is called each frame by Scene.act(float).

The default implementation calls Action.act(float) on each action and removes actions that are complete.

Overrides:

act in class Element

Parameters:

delta - Time in seconds since the last frame.

draw

public void draw()

Description copied from class: Element

Draws the element. Does nothing by default.

Overrides:

draw in class Element

drawChildren

protected void drawChildren()

computeTransform

protected Mat computeTransform()

Returns the transform for this group's coordinate system.

applyTransform

protected void applyTransform(Mat transform)

Set the batch's transformation matrix, often with the result of computeTransform(). Note this causes the batch to be flushed. resetTransform() will restore the transform to what it was before this call.

resetTransform

protected void resetTransform()

Restores the batch transform to what it was before applyTransform(Mat). Note this causes the batch to be flushed.

getCullingArea

public Rect getCullingArea()

Returns:

May be null.

See Also:

• setCullingArea(Rect)

setCullingArea

public void setCullingArea(Rect cullingArea)

Children completely outside of this rectangle will not be drawn. This is only valid for use with unrotated and unscaled actors.

Specified by:

setCullingArea in interface Cullable

Parameters:

cullingArea - May be null.

hit

public Element hit(float x,
 float y,
 boolean touchable)

Description copied from class: Element

Returns the deepest actor that contains the specified point and is touchable and visible, or null if no actor was hit. The point is specified in the actor's local coordinate system (0,0 is the bottom left of the actor and width,height is the upper right).

This method is used to delegate touchDown, mouse, and enter/exit events. If this method returns null, those events will not occur on this Actor.

The default implementation returns this actor if the point is within this actor's bounds.

Overrides:

hit in class Element

touchable - If true, the hit detection will respect the touchability.

See Also:

• Touchable

childrenChanged

protected void childrenChanged()

Called when actors are added to or removed from the group.

forEach

public void forEach(Cons<Element> cons)

Recursively iterates through every child of this group.

fill

public Element fill(Table.DrawRect rect)

fill

public void fill(Cons<Table> cons)

Adds and returns a table. This table will fill the whole scene.

fill

public void fill(Drawable background,
 Cons<Table> cons)

Adds and returns a table. This table will fill the whole scene.

addChild

public void addChild(Element actor)

Adds an actor as a child of this group, removing it from its previous parent. If the actor is already a child of this group, no changes are made.

addChildAt

public void addChildAt(int index,
 Element actor)

Adds an actor as a child of this group at a specific index, removing it from its previous parent. If the actor is already a child of this group, no changes are made.

Parameters:

index - May be greater than the number of children.

addChildBefore

public void addChildBefore(Element actorBefore,
 Element actor)

Adds an actor as a child of this group immediately before another child actor, removing it from its previous parent. If the actor is already a child of this group, no changes are made.

addChildAfter

public void addChildAfter(Element actorAfter,
 Element actor)

Adds an actor as a child of this group immediately after another child actor, removing it from its previous parent. If the actor is already a child of this group, no changes are made.

removeChild

public boolean removeChild(Element actor)

Removes an actor from this group and unfocuses it. Calls removeChild(Element, boolean) with true.

removeChild

public boolean removeChild(Element actor,
 boolean unfocus)

Removes an actor from this group. If the actor will not be used again and has actions, they should be cleared so the actions will be returned to their pool, if any. This is not done automatically.

Parameters:

unfocus - If true, Scene.unfocus(Element) is called.

Returns:

true if the actor was removed from this group.

clearChildren

public void clearChildren()

Removes all actors from this group.

clear

public void clear()

Removes all children, actions, and listeners from this group.

Overrides:

clear in class Element

find

public <T extends Element> T find(String name)

Returns the first actor found with the specified name. Note this recursively compares the name of every actor in the group.

findVisible

public <T extends Element> T findVisible(String name)

Finds only visible elements.

find

public <T extends Element> T find(Boolf<Element> pred)

Find element by a predicate.

setScene

protected void setScene(Scene stage)

Description copied from class: Element

Called by the framework when this actor or any parent is added to a group that is in the stage.

Overrides:

setScene in class Element

Parameters:

stage - May be null if the actor or any parent is no longer in a stage.

swapActor

public boolean swapActor(int first,
 int second)

Swaps two actors by index. Returns false if the swap did not occur because the indexes were out of bounds.

swapActor

public boolean swapActor(Element first,
 Element second)

Swaps two actors. Returns false if the swap did not occur because the actors are not children of this group.

getChildren

public SnapshotSeq<Element> getChildren()

Returns an ordered list of child actors in this group.

hasChildren

public boolean hasChildren()

isTransform

public boolean isTransform()

setTransform

public void setTransform(boolean transform)

When true (the default), the Batch is transformed so children are drawn in their parent's coordinate system. This has a performance impact because Batch.flush() must be done before and after the transform. If the actors in a group are not rotated or scaled, then the transform for the group can be set to false. In this case, each child's position will be offset by the group's position for drawing, causing the children to appear in the correct location even though the Batch has not been transformed.

localToDescendantCoordinates

public Vec2 localToDescendantCoordinates(Element descendant,
 Vec2 localCoords)

Converts coordinates for this group to those of a descendant actor. The descendant does not need to be a direct child.

toString

public String toString()

Returns a description of the actor hierarchy, recursively.

Overrides:

toString in class Element