001// License: GPL. For details, see LICENSE file. 002package org.openstreetmap.josm.gui.widgets; 003 004import java.awt.Dimension; 005import java.awt.Rectangle; 006 007import javax.swing.JLabel; 008import javax.swing.plaf.basic.BasicHTML; 009import javax.swing.text.View; 010 011/** 012 * Creates a normal label that will wrap its contents if there less width than 013 * required to print it in one line. Additionally the maximum width of the text 014 * can be set using <code>setMaxWidth</code>. 015 * 016 * Note that this won't work if JMultilineLabel is put into a JScrollBox or 017 * similar as the bounds will never change. Instead scrollbars will be displayed. 018 * 019 * @since 6340 020 */ 021public class JMultilineLabel extends JLabel { 022 private int maxWidth = Integer.MAX_VALUE; 023 private Rectangle oldbounds = null; 024 private Dimension oldPreferred = null; 025 026 /** 027 * Constructs a normal label but adds HTML tags if not already done so. 028 * Supports both newline characters (<code>\n</code>) as well as the HTML 029 * <code><br></code> to insert new lines. 030 * 031 * Use setMaxWidth to limit the width of the label. 032 * @param text The text to display 033 */ 034 public JMultilineLabel(String text) { 035 super(); 036 String html = text.trim().replaceAll("\n", "<br>"); 037 if (!html.startsWith("<html>")) { 038 html = "<html>" + html + "</html>"; 039 } 040 super.setText(html); 041 } 042 043 /** 044 * Set the maximum width. Use this method instead of setMaximumSize because 045 * this saves a little bit of overhead and is actually taken into account. 046 * 047 * @param width 048 */ 049 public void setMaxWidth(int width) { 050 this.maxWidth = width; 051 } 052 053 /** 054 * Tries to determine a suitable height for the given contents and return 055 * that dimension. 056 */ 057 @Override 058 public Dimension getPreferredSize() { 059 // Without this check it will result in an infinite loop calling 060 // getPreferredSize. Remember the old bounds and only recalculate if 061 // the size actually changed. 062 if (this.getBounds().equals(oldbounds) && oldPreferred != null) { 063 return oldPreferred; 064 } 065 oldbounds = this.getBounds(); 066 067 Dimension superPreferred = super.getPreferredSize(); 068 // Make it not larger than required 069 int width = Math.min(superPreferred.width, maxWidth); 070 071 // Calculate suitable width and height 072 final View v = (View) super.getClientProperty(BasicHTML.propertyKey); 073 074 if (v == null) { 075 return superPreferred; 076 } 077 078 v.setSize(width, 0); 079 int w = (int) Math.ceil(v.getPreferredSpan(View.X_AXIS)); 080 int h = (int) Math.ceil(v.getPreferredSpan(View.Y_AXIS)); 081 082 oldPreferred = new Dimension(w, h); 083 return oldPreferred; 084 } 085}