CaretInfo.java

/*******************************************************************************
 * Copyright (c) 2004, 2010 IBM Corporation and others.
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * which accompanies this distribution, and is available at
 * http://www.eclipse.org/legal/epl-v10.html
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/

package org.eclipse.draw2d.text;

import org.eclipse.draw2d.geometry.Translatable;

/**
 * Stores positional information about where a caret should be placed. This
 * structure currently only offers integer precision. Scaling operations will
 * result in rounding.
 * 
 * @since 3.1
 */
public class CaretInfo implements Translatable {

	private int ascent, lineAscent, descent, lineDescent, baseline, x;

	/**
	 * Constructor for use by TextFlow. Constructs a new CaretInfo with the
	 * figure's ascent and descent and line information.
	 * <P>
	 * <EM>WARNING:</EM> This constructor should not be called by clients. It is
	 * for use by {@link TextFlow}, and may change in future releases.
	 * 
	 * @param x
	 *            the x location
	 * @param y
	 *            the y location of the top of the caret
	 * @param ascent
	 *            the ascent
	 * @param descent
	 *            the descent
	 * @param lineAscent
	 *            the ascent of the line on which the caret is placed
	 * @param lineDescent
	 *            the descent of the line on which the caret is placed
	 */
	protected CaretInfo(int x, int y, int ascent, int descent, int lineAscent,
			int lineDescent) {
		this.x = x;
		this.baseline = y + ascent;
		this.ascent = ascent;
		this.descent = descent;
		this.lineAscent = lineAscent;
		this.lineDescent = lineDescent;
	}

	/**
	 * Constructs a CaretInfo object by copying the values from another
	 * instance.
	 * 
	 * @param info
	 *            the reference
	 * @since 3.2
	 */
	protected CaretInfo(CaretInfo info) {
		this.ascent = info.ascent;
		this.baseline = info.baseline;
		this.descent = info.descent;
		this.lineAscent = info.lineAscent;
		this.lineDescent = info.lineDescent;
		this.x = info.x;
	}

	/**
	 * Returns the y location of the baseline.
	 * 
	 * @return the y coordinate of the baseline
	 */
	public int getBaseline() {
		return baseline;
	}

	/**
	 * Returns the total height of the caret. The height is the sum of the
	 * ascent and descent.
	 * 
	 * @return the height
	 */
	public int getHeight() {
		return ascent + descent;
	}

	/**
	 * @return the total height of the line on which the caret is placed
	 */
	public int getLineHeight() {
		return lineAscent + lineDescent;
	}

	/**
	 * @return the y location of the line on which the caret is placed
	 */
	public int getLineY() {
		return baseline - lineAscent;
	}

	/**
	 * Returns the x location of the caret.
	 * 
	 * @return the x coordinate
	 */
	public int getX() {
		return x;
	}

	/**
	 * Returns the y location of the caret.
	 * 
	 * @return the y coordinate
	 */
	public int getY() {
		return baseline - ascent;
	}

	/**
	 * @see Translatable#performScale(double)
	 */
	public void performScale(double factor) {
		x *= factor;
		baseline *= factor;
		descent *= factor;
		ascent *= factor;
		lineAscent *= factor;
		lineDescent *= factor;
	}

	/**
	 * @see Translatable#performTranslate(int, int)
	 */
	public void performTranslate(int dx, int dy) {
		x += dx;
		baseline += dy;
	}

}