com.badlogic.gdx.scenes.scene2d.utils.Layout Maven / Gradle / Ivy
/*******************************************************************************
* Copyright 2011 See AUTHORS file.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
******************************************************************************/
package com.badlogic.gdx.scenes.scene2d.utils;
import com.badlogic.gdx.graphics.g2d.Batch;
import com.badlogic.gdx.scenes.scene2d.Actor;
/** Provides methods for an actor to participate in layout and to provide a minimum, preferred, and maximum size.
* @author Nathan Sweet */
public interface Layout {
/** Computes and caches any information needed for drawing and, if this actor has children, positions and sizes each child,
* calls {@link #invalidate()} on any each child whose width or height has changed, and calls {@link #validate()} on each
* child. This method should almost never be called directly, instead {@link #validate()} should be used. */
public void layout ();
/** Invalidates this actor's layout, causing {@link #layout()} to happen the next time {@link #validate()} is called. This
* method should be called when state changes in the actor that requires a layout but does not change the minimum, preferred,
* maximum, or actual size of the actor (meaning it does not affect the parent actor's layout). */
public void invalidate ();
/** Invalidates this actor and its ascendants, calling {@link #invalidate()} on each. This method should be called when state
* changes in the actor that affects the minimum, preferred, maximum, or actual size of the actor (meaning it potentially
* affects the parent actor's layout). */
public void invalidateHierarchy ();
/** Ensures the actor has been laid out. Calls {@link #layout()} if {@link #invalidate()} has been called since the last time
* {@link #validate()} was called, or if the actor otherwise needs to be laid out. This method is usually called in
* {@link Actor#draw(Batch, float)} by the actor itself before drawing is performed. */
public void validate ();
/** Sizes this actor to its preferred width and height, then calls {@link #validate()}.
*
* Generally this method should not be called in an actor's constructor because it calls {@link #layout()}, which means a
* subclass would have layout() called before the subclass' constructor. Instead, in constructors simply set the actor's size
* to {@link #getPrefWidth()} and {@link #getPrefHeight()}. This allows the actor to have a size at construction time for more
* convenient use with groups that do not layout their children. */
public void pack ();
/** If true, this actor will be sized to the parent in {@link #validate()}. If the parent is the stage, the actor will be sized
* to the stage. This method is for convenience only when the widget's parent does not set the size of its children (such as
* the stage). */
public void setFillParent (boolean fillParent);
/** Enables or disables the layout for this actor and all child actors, recursively. When false, {@link #validate()} will not
* cause a layout to occur. This can be useful when an actor will be manipulated externally, such as with actions. Default is
* true. */
public void setLayoutEnabled (boolean enabled);
public float getMinWidth ();
public float getMinHeight ();
public float getPrefWidth ();
public float getPrefHeight ();
/** Zero indicates no max width. */
public float getMaxWidth ();
/** Zero indicates no max height. */
public float getMaxHeight ();
}