source: josm/trunk/src/org/openstreetmap/josm/gui/JMultilineLabel.java@ 935

// License: GPL. For details, see LICENSE file.

// This class was taken from 
// http://forum.java.sun.com/thread.jspa?threadID=459705&messageID=2104021
// - Removed hardcoded margin
// -  Added constructor

package org.openstreetmap.josm.gui;

import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Insets;
import java.awt.font.FontRenderContext;
import java.awt.font.LineBreakMeasurer;
import java.awt.font.TextAttribute;
import java.text.AttributedCharacterIterator;
import java.text.AttributedString;
import java.awt.font.TextLayout;

import javax.swing.JComponent;

public class JMultilineLabel extends JComponent {
        private String text;
        private int maxWidth = Integer.MAX_VALUE;
        private boolean justify;
        private final FontRenderContext frc = new FontRenderContext(null, false, false);

        public JMultilineLabel(String description) {
                super();
                setText(description);
        }

        private void morph() {
                revalidate();
                repaint();
        }

        public String getText() {
                return text;
        }

        public void setText(String text) {
                String old = this.text;
                this.text = text;
                firePropertyChange("text", old, this.text);
                if ((old == null) ? text!=null : !old.equals(text))
                        morph();
        }

        public int getMaxWidth() {
                return maxWidth;
        }

        public void setMaxWidth(int maxWidth) {
                if (maxWidth <= 0)
                        throw new IllegalArgumentException();
                int old = this.maxWidth;
                this.maxWidth = maxWidth;
                firePropertyChange("maxWidth", old, this.maxWidth);
                if (old !=      this.maxWidth)
                        morph();
        }

        public boolean isJustified() {
                return justify;
        }

        public void setJustified(boolean justify) {
                boolean old = this.justify;
                this.justify = justify;
                firePropertyChange("justified", old, this.justify);
                if (old != this.justify)
                        repaint();
        }

        public Dimension getPreferredSize() {
                return paintOrGetSize(null, getMaxWidth());
        }

        public Dimension getMinimumSize() {
                return getPreferredSize();
        }

        protected void paintComponent(Graphics g) {
                super.paintComponent(g);
                paintOrGetSize((Graphics2D)g, getWidth());
        }

        private Dimension paintOrGetSize(Graphics2D g, int width) {
                Insets insets = getInsets();
                width -= insets.left + insets.right;
                float w = insets.left + insets.right;
                float x = insets.left, y=insets.top;
                if (width > 0 && text != null && text.length() > 0) {
                        AttributedString as = new AttributedString(getText());
                        as.addAttribute(TextAttribute.FONT, getFont());
                        AttributedCharacterIterator aci = as.getIterator();
                        LineBreakMeasurer lbm = new LineBreakMeasurer(aci, frc);
                        float max = 0;
                        while (lbm.getPosition() < aci.getEndIndex()) {
                                TextLayout textLayout = lbm.nextLayout(width);
                                if (g != null && isJustified() && textLayout.getVisibleAdvance() > 0.80 * width)
                                        textLayout = textLayout.getJustifiedLayout(width);
                                if (g != null)
                                        textLayout.draw(g, x, y + textLayout.getAscent());
                                y += textLayout.getDescent() + textLayout.getLeading() + textLayout.getAscent();
                                max = Math.max(max, textLayout.getVisibleAdvance());
                        }
                        w += max;
                }
                return new Dimension((int)Math.ceil(w), (int)Math.ceil(y) + insets.bottom);
        }
}