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/* FencedAtom.java
* =========================================================================
* This file is part of the JMathTeX Library - http://jmathtex.sourceforge.net
*
* Copyright (C) 2004-2007 Universiteit Gent
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or (at
* your option) any later version.
*
* This program is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* A copy of the GNU General Public License can be found in the file
* LICENSE.txt provided with the source distribution of this program (see
* the META-INF directory in the source jar). This license can also be
* found on the GNU website at http://www.gnu.org/licenses/gpl.html.
*
* If you did not receive a copy of the GNU General Public License along
* with this program, contact the lead developer, or write to the Free
* Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
* 02110-1301, USA.
*
*/
package be.ugent.caagt.jmathtex;
/**
* An atom representing a base atom surrounded with delimiters that change their size
* according to the height of the base.
*/
class FencedAtom extends Atom {
// parameters used in the TeX algorithm
private static final int DELIMITER_FACTOR = 901;
private static final float DELIMITER_SHORTFALL = 0.5f;
// base atom
private final Atom base;
// delimiters
private final SymbolAtom left;
private final SymbolAtom right;
/**
* Creates a new FencedAtom from the given base and delimiters
*
* @param base the base to be surrounded with delimiters
* @param l the left delimiter
* @param r the right delimiter
*/
public FencedAtom(Atom base, SymbolAtom l, SymbolAtom r) {
if (base == null)
this.base = new RowAtom(); // empty base
else
this.base = base;
left = l;
right = r;
}
public int getLeftType() {
return TeXConstants.TYPE_OPENING;
}
public int getRightType() {
return TeXConstants.TYPE_CLOSING;
}
/**
* Centers the given box with resprect to the given axis, by setting an appropriate
* shift value.
*
* @param box
* box to be vertically centered with respect to the axis
*/
private static void center(Box box, float axis) {
float h = box.getHeight(), total = h + box.getDepth();
box.setShift(-(total / 2 - h) - axis);
}
public Box createBox(TeXEnvironment env) {
TeXFont tf = env.getTeXFont();
Box content = base.createBox(env);
float axis = axis = tf.getAxisHeight(env.getStyle()), delta = Math.max(
content.getHeight() - axis, content.getDepth() + axis), minHeight = Math
.max((delta / 500) * DELIMITER_FACTOR, 2 * delta
- DELIMITER_SHORTFALL);
// construct box
HorizontalBox hBox = new HorizontalBox();
// left delimiter
if (left != null) {
Box b = DelimiterFactory.create(left.getName(), env, minHeight);
center(b, axis);
hBox.add(b);
}
// glue between left delimiter and content (if not whitespace)
if (!(base instanceof SpaceAtom))
hBox.add(Glue.get(TeXConstants.TYPE_OPENING, base.getLeftType(), env));
// add content
hBox.add(content);
// glue between right delimiter and content (if not whitespace)
if (!(base instanceof SpaceAtom))
hBox
.add(Glue.get(base.getRightType(), TeXConstants.TYPE_CLOSING,
env));
// right delimiter
if (right != null) {
Box b = DelimiterFactory.create(right.getName(), env, minHeight);
center(b, axis);
hBox.add(b);
}
return hBox;
}
}
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