Scaling.java

/*******************************************************************************
 * 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.utils;

import com.badlogic.gdx.math.Vector2;

/**
 * Various scaling types for fitting one rectangle into another.
 * 
 * @author Nathan Sweet
 */
public enum Scaling {
	/**
	 * Scales the source to fit the target while keeping the same aspect ratio. This may cause the source to be smaller
	 * than the target in one direction.
	 */
	fit,
	/**
	 * Scales the source to fill the target while keeping the same aspect ratio. This may cause the source to be larger
	 * than the target in one direction.
	 */
	fill,
	/**
	 * Scales the source to fill the target in the x direction while keeping the same aspect ratio. This may cause the
	 * source to be smaller or larger than the target in the y direction.
	 */
	fillX,
	/**
	 * Scales the source to fill the target in the y direction while keeping the same aspect ratio. This may cause the
	 * source to be smaller or larger than the target in the x direction.
	 */
	fillY,
	/** Scales the source to fill the target. This may cause the source to not keep the same aspect ratio. */
	stretch,
	/**
	 * Scales the source to fill the target in the x direction, without changing the y direction. This may cause the
	 * source to not keep the same aspect ratio.
	 */
	stretchX,
	/**
	 * Scales the source to fill the target in the y direction, without changing the x direction. This may cause the
	 * source to not keep the same aspect ratio.
	 */
	stretchY,
	/** The source is not scaled. */
	none;

	static private Vector2 temp = new Vector2();

	/**
	 * Returns the size of the source scaled to the target. Note the same Vector2 instance is always returned and should
	 * never be cached.
	 */
	public Vector2 apply(float sourceWidth, float sourceHeight, float targetWidth, float targetHeight) {
		switch (this) {
		case fit: {
			float targetRatio = targetHeight / targetWidth;
			float sourceRatio = sourceHeight / sourceWidth;
			float scale = targetRatio > sourceRatio ? targetWidth / sourceWidth : targetHeight / sourceHeight;
			temp.x = sourceWidth * scale;
			temp.y = sourceHeight * scale;
			break;
		}
		case fill: {
			float targetRatio = targetHeight / targetWidth;
			float sourceRatio = sourceHeight / sourceWidth;
			float scale = targetRatio < sourceRatio ? targetWidth / sourceWidth : targetHeight / sourceHeight;
			temp.x = sourceWidth * scale;
			temp.y = sourceHeight * scale;
			break;
		}
		case fillX: {
			float targetRatio = targetHeight / targetWidth;
			float sourceRatio = sourceHeight / sourceWidth;
			float scale = targetWidth / sourceWidth;
			temp.x = sourceWidth * scale;
			temp.y = sourceHeight * scale;
			break;
		}
		case fillY: {
			float targetRatio = targetHeight / targetWidth;
			float sourceRatio = sourceHeight / sourceWidth;
			float scale = targetHeight / sourceHeight;
			temp.x = sourceWidth * scale;
			temp.y = sourceHeight * scale;
			break;
		}
		case stretch:
			temp.x = targetWidth;
			temp.y = targetHeight;
			break;
		case stretchX:
			temp.x = targetWidth;
			temp.y = sourceHeight;
			break;
		case stretchY:
			temp.x = sourceWidth;
			temp.y = targetHeight;
			break;
		case none:
			temp.x = sourceWidth;
			temp.y = sourceHeight;
			break;
		}
		return temp;
	}
}