com.badlogic.gdx.scenes.scene2d.ui.Value.java Source code

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Here is the source code for com.badlogic.gdx.scenes.scene2d.ui.Value.java

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/*******************************************************************************
 * 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.scenes.scene2d.Actor;
import com.badlogic.gdx.scenes.scene2d.utils.Layout;

/** Value placeholder, allowing the value to be computed on request. Values are provided an actor for context which reduces the
 * number of value instances that need to be created and reduces verbosity in code that specifies values.
 * @author Nathan Sweet */
abstract public class Value {
    /** @param context May be null. */
    abstract public float get(Actor context);

    /** A value that is always zero. */
    static public final Fixed zero = new Fixed(0);

    /** A fixed value that is not computed each time it is used.
     * @author Nathan Sweet */
    static public class Fixed extends Value {
        private final float value;

        public Fixed(float value) {
            this.value = value;
        }

        public float get(Actor context) {
            return value;
        }
    }

    /** Value that is the minWidth of the actor in the cell. */
    static public Value minWidth = new Value() {
        public float get(Actor context) {
            if (context instanceof Layout)
                return ((Layout) context).getMinWidth();
            return context == null ? 0 : context.getWidth();
        }
    };

    /** Value that is the minHeight of the actor in the cell. */
    static public Value minHeight = new Value() {
        public float get(Actor context) {
            if (context instanceof Layout)
                return ((Layout) context).getMinHeight();
            return context == null ? 0 : context.getHeight();
        }
    };

    /** Value that is the prefWidth of the actor in the cell. */
    static public Value prefWidth = new Value() {
        public float get(Actor context) {
            if (context instanceof Layout)
                return ((Layout) context).getPrefWidth();
            return context == null ? 0 : context.getWidth();

        }
    };

    /** Value that is the prefHeight of the actor in the cell. */
    static public Value prefHeight = new Value() {
        public float get(Actor context) {
            if (context instanceof Layout)
                return ((Layout) context).getPrefHeight();
            return context == null ? 0 : context.getHeight();
        }
    };

    /** Value that is the maxWidth of the actor in the cell. */
    static public Value maxWidth = new Value() {
        public float get(Actor context) {
            if (context instanceof Layout)
                return ((Layout) context).getMaxWidth();
            return context == null ? 0 : context.getWidth();
        }
    };

    /** Value that is the maxHeight of the actor in the cell. */
    static public Value maxHeight = new Value() {
        public float get(Actor context) {
            if (context instanceof Layout)
                return ((Layout) context).getMaxHeight();
            return context == null ? 0 : context.getHeight();
        }
    };

    /** Returns a value that is a percentage of the actor's width. */
    static public Value percentWidth(final float percent) {
        return new Value() {
            public float get(Actor actor) {
                return actor.getWidth() * percent;
            }
        };
    }

    /** Returns a value that is a percentage of the actor's height. */
    static public Value percentHeight(final float percent) {
        return new Value() {
            public float get(Actor actor) {
                return actor.getHeight() * percent;
            }
        };
    }

    /** Returns a value that is a percentage of the specified actor's width. The context actor is ignored. */
    static public Value percentWidth(final float percent, final Actor actor) {
        if (actor == null)
            throw new IllegalArgumentException("actor cannot be null.");
        return new Value() {
            public float get(Actor context) {
                return actor.getWidth() * percent;
            }
        };
    }

    /** Returns a value that is a percentage of the specified actor's height. The context actor is ignored. */
    static public Value percentHeight(final float percent, final Actor actor) {
        if (actor == null)
            throw new IllegalArgumentException("actor cannot be null.");
        return new Value() {
            public float get(Actor context) {
                return actor.getHeight() * percent;
            }
        };
    }
}