FlowBox.java

/*******************************************************************************
 * Copyright (c) 2000, 2005 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;

/**
 * A Geometric object for representing a region on a line of Text. This class adds the
 * notion of a baseline to {@link org.eclipse.draw2d.geometry.Rectangle}. <i>Ascent</i> is
 * the distance above the baseline. <i>Descent</i> is the distance below the baseline.
 * <P>
 * This class should not be treated as a <code>Rectangle</code> by clients.  It is
 * important to use getters when available for lazy calculation of values.
 * 
 * @author hudsonr
 * @since 2.1
 */
public abstract class FlowBox {

int width;

/**
 * The x location
 */
private int x;

/**
 * This method must be called on a block that is completely positioned and committed.
 * @param x X
 * @param y Y
 * @return <code>true</code> if the FlowBox contains the point
 */
public abstract boolean containsPoint(int x, int y);

/**
 * Returns the amount of line content in pixels which is above the baseline.  Ascent and
 * descent are used to space consecutive lines apart. Certain types of line content, such
 * as borders, extend beyond the ascent and descent.
 * @return the <i>descent</i> in pixels below the baseline
 */
public abstract int getAscent();

/**
 * Returns y coordinate for the box's baseline.
 * @return the baseline location
 * @since 3.1
 */
public abstract int getBaseline();

/**
 * Returns the amount of line content in pixels which is below the baseline.  
 * @return the <i>descent</i> in pixels
 * @see #getAscent()
 */
public abstract int getDescent();

/**
 * Returns the root LineBox in which this box is placed.  The root line is interesting
 * when painting selection or hit testing.  All boxes in a line should render selection at
 * the same top and bottom location.
 * @return the line root.
 * @since 3.1
 */
abstract LineRoot getLineRoot();

/**
 * Returns the outer ascent of this box.  The outer ascent is the ascent above the
 * baseline including the border size and margin.  This is used when adding content into a
 * LineBox.  The linebox's own border must be drawn around the children.
 */
int getOuterAscent() {
	return getAscent();
}

/**
 * Returns the outer descent of this box. The outer descent is the space below the
 * baseline including the border size and margin. This is used when adding content into a
 * LineBox. The linebox's own border must be drawn around the children.
 */
int getOuterDescent() {
	return getDescent();
}

int getAscentWithBorder() {
	throw new RuntimeException("Not valid on this box type"); //$NON-NLS-1$
}

int getDescentWithBorder() {
	throw new RuntimeException("Not valid on this box type"); //$NON-NLS-1$
}

/**
 * Returns the width of the box.
 * @return the box's width
 */
public int getWidth() {
	return width;
}

/**
 * Returns the X coordinate of the box.
 * @return the x coordinate
 * @since 3.1
 */
public int getX() {
	return x;
}

/**
 * Returns <code>true</code> if any of the children are bi-directional.  Default
 * implementation returns false.
 * 
 * @return <code>true</code> if the box is bi-directional
 * @since 3.1
 */
public boolean requiresBidi() {
	return false;
}

/**
 * Sets the line root.
 * @param root the line root
 * @since 3.1
 */
void setLineRoot(LineRoot root) {
}

/**
 * Sets the width of the box.
 * @param width the new width
 * @since 3.1
 */
public void setWidth(int width) {
	this.width = width;
}

/**
 * Sets the x coordinate for this box.
 * @param x the x coordinate
 * @since 3.1
 */
public void setX(int x) {
	this.x = x;
}

}