/*******************************************************************************
* 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.ui;
import com.badlogic.gdx.graphics.g2d.SpriteBatch;
import com.badlogic.gdx.scenes.scene2d.Actor;
import com.badlogic.gdx.scenes.scene2d.Group;
import com.badlogic.gdx.scenes.scene2d.Stage;
import com.badlogic.gdx.scenes.scene2d.utils.Layout;
/** An {@link Actor} that participates in layout and provides a minimum, preferred, and maximum size.
* <p>
* The default preferred size of a widget is 0 and this is almost always overridden by a subclass. The default minimum size
* returns the preferred size, so a subclass may choose to return 0 if it wants to allow itself to be sized smaller. The default
* maximum size is 0, which means no maximum size.
* <p>
* See {@link Layout} for details on how a widget should participate in layout. A widget's mutator methods should call
* {@link #invalidate()} or {@link #invalidateHierarchy()} as needed.
* @author mzechner
* @author Nathan Sweet */
public class Widget extends Actor implements Layout {
private boolean needsLayout = true;
private boolean fillParent;
private boolean layoutEnabled = true;
public float getMinWidth () {
return getPrefWidth();
}
public float getMinHeight () {
return getPrefHeight();
}
public float getPrefWidth () {
return 0;
}
public float getPrefHeight () {
return 0;
}
public float getMaxWidth () {
return 0;
}
public float getMaxHeight () {
return 0;
}
public void setLayoutEnabled (boolean enabled) {
layoutEnabled = enabled;
if (enabled) invalidateHierarchy();
}
public void validate () {
if (!layoutEnabled) return;
Group parent = getParent();
if (fillParent && parent != null) {
float parentWidth, parentHeight;
Stage stage = getStage();
if (stage != null && parent == stage.getRoot()) {
parentWidth = stage.getWidth();
parentHeight = stage.getHeight();
} else {
parentWidth = parent.getWidth();
parentHeight = parent.getHeight();
}
setSize(parentWidth, parentHeight);
}
if (!needsLayout) return;
needsLayout = false;
layout();
}
/** Returns true if the widget's layout has been {@link #invalidate() invalidated}. */
public boolean needsLayout () {
return needsLayout;
}
public void invalidate () {
needsLayout = true;
}
public void invalidateHierarchy () {
if (!layoutEnabled) return;
invalidate();
Group parent = getParent();
if (parent instanceof Layout) ((Layout)parent).invalidateHierarchy();
}
protected void sizeChanged () {
invalidate();
}
public void pack () {
setSize(getPrefWidth(), getPrefHeight());
validate();
}
public void setFillParent (boolean fillParent) {
this.fillParent = fillParent;
}
/** If this method is overridden, the super method or {@link #validate()} should be called to ensure the widget is laid out. */
public void draw (SpriteBatch batch, float parentAlpha) {
validate();
}
public void layout () {
}
}