001 /* BasicHTML.java -- Provides HTML support to ComponentUI implementations 002 Copyright (C) 2006 Free Software Foundation, Inc. 003 004 This file is part of GNU Classpath. 005 006 GNU Classpath is free software; you can redistribute it and/or modify 007 it under the terms of the GNU General Public License as published by 008 the Free Software Foundation; either version 2, or (at your option) 009 any later version. 010 011 GNU Classpath is distributed in the hope that it will be useful, but 012 WITHOUT ANY WARRANTY; without even the implied warranty of 013 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 014 General Public License for more details. 015 016 You should have received a copy of the GNU General Public License 017 along with GNU Classpath; see the file COPYING. If not, write to the 018 Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 019 02110-1301 USA. 020 021 Linking this library statically or dynamically with other modules is 022 making a combined work based on this library. Thus, the terms and 023 conditions of the GNU General Public License cover the whole 024 combination. 025 026 As a special exception, the copyright holders of this library give you 027 permission to link this library with independent modules to produce an 028 executable, regardless of the license terms of these independent 029 modules, and to copy and distribute the resulting executable under 030 terms of your choice, provided that you also meet, for each linked 031 independent module, the terms and conditions of the license of that 032 module. An independent module is a module which is not derived from 033 or based on this library. If you modify this library, you may extend 034 this exception to your version of the library, but you are not 035 obligated to do so. If you do not wish to do so, delete this 036 exception statement from your version. */ 037 038 039 package javax.swing.plaf.basic; 040 041 import java.awt.Container; 042 import java.awt.Graphics; 043 import java.awt.Rectangle; 044 import java.awt.Shape; 045 import java.io.IOException; 046 import java.io.StringReader; 047 048 import javax.swing.JComponent; 049 import javax.swing.SwingConstants; 050 import javax.swing.event.DocumentEvent; 051 import javax.swing.text.AttributeSet; 052 import javax.swing.text.BadLocationException; 053 import javax.swing.text.Document; 054 import javax.swing.text.EditorKit; 055 import javax.swing.text.Element; 056 import javax.swing.text.Position; 057 import javax.swing.text.View; 058 import javax.swing.text.ViewFactory; 059 import javax.swing.text.html.HTMLDocument; 060 import javax.swing.text.html.HTMLEditorKit; 061 062 /** 063 * Provides support for HTML rendering to {@link javax.swing.plaf.ComponentUI} 064 * implementations. 065 * 066 * @author Roman Kennke (kennke@aicas.com) 067 */ 068 public class BasicHTML 069 { 070 071 /** 072 * This class serves as the root view for HTML rendering components. 073 * Its purpose and implementation is similar to the BasicTextUI.RootView 074 * class, only that is implements some stuff differently due to the nature 075 * of not beeing inside a JTextComponent. 076 * 077 * @author Roman Kennke (kennke@aicas.com) 078 */ 079 private static class HTMLRootView extends View 080 { 081 /** 082 * The real root view. 083 */ 084 private View view; 085 086 /** 087 * The component on which to render the view. 088 */ 089 private JComponent component; 090 091 /** 092 * The EditorKit. 093 */ 094 private EditorKit editorKit; 095 096 /** 097 * The document to use. 098 */ 099 private Document document; 100 101 /** 102 * Creates a new RootView. 103 */ 104 public HTMLRootView(JComponent c, View view, EditorKit kit, Document doc) 105 { 106 super(null); 107 component = c; 108 editorKit = kit; 109 document = doc; 110 setView(view); 111 setSize(view.getPreferredSpan(X_AXIS), view.getPreferredSpan(Y_AXIS)); 112 } 113 114 /** 115 * Returns the ViewFactory for this RootView. If the current EditorKit 116 * provides a ViewFactory, this is used. Otherwise the TextUI itself 117 * is returned as a ViewFactory. 118 * 119 * @return the ViewFactory for this RootView 120 */ 121 public ViewFactory getViewFactory() 122 { 123 return editorKit.getViewFactory(); 124 } 125 126 /** 127 * Indicates that the preferences of one of the child view has changed. 128 * This calls revalidate on the text component. 129 * 130 * @param v the child view which's preference has changed 131 * @param width <code>true</code> if the width preference has changed 132 * @param height <code>true</code> if the height preference has changed 133 */ 134 public void preferenceChanged(View v, boolean width, boolean height) 135 { 136 component.revalidate(); 137 } 138 139 /** 140 * Sets the real root view. 141 * 142 * @param v the root view to set 143 */ 144 public void setView(View v) 145 { 146 if (view != null) 147 view.setParent(null); 148 149 if (v != null) 150 v.setParent(this); 151 152 view = v; 153 } 154 155 /** 156 * Overridden to forward to real view. 157 */ 158 public void setSize(float w, float h) 159 { 160 view.setSize(w, h); 161 } 162 163 /** 164 * Returns the real root view, regardless of the index. 165 * 166 * @param index not used here 167 * 168 * @return the real root view, regardless of the index. 169 */ 170 public View getView(int index) 171 { 172 return view; 173 } 174 175 /** 176 * Returns <code>1</code> since the RootView always contains one 177 * child, that is the real root of the View hierarchy. 178 * 179 * @return <code>1</code> since the RootView always contains one 180 * child, that is the real root of the View hierarchy 181 */ 182 public int getViewCount() 183 { 184 int count = 0; 185 if (view != null) 186 count = 1; 187 return count; 188 } 189 190 /** 191 * Returns the <code>Container</code> that contains this view. This 192 * normally will be the text component that is managed by this TextUI. 193 * 194 * @return the <code>Container</code> that contains this view 195 */ 196 public Container getContainer() 197 { 198 return component; 199 } 200 201 /** 202 * Returns the preferred span along the specified <code>axis</code>. 203 * This is delegated to the real root view. 204 * 205 * @param axis the axis for which the preferred span is queried 206 * 207 * @return the preferred span along the axis 208 */ 209 public float getPreferredSpan(int axis) 210 { 211 if (view != null) 212 return view.getPreferredSpan(axis); 213 214 return Integer.MAX_VALUE; 215 } 216 217 /** 218 * Paints the view. This is delegated to the real root view. 219 * 220 * @param g the <code>Graphics</code> context to paint to 221 * @param s the allocation for the View 222 */ 223 public void paint(Graphics g, Shape s) 224 { 225 if (view != null) 226 { 227 Rectangle b = s.getBounds(); 228 view.setSize(b.width, b.height); 229 view.paint(g, s); 230 } 231 } 232 233 234 /** 235 * Maps a position in the document into the coordinate space of the View. 236 * The output rectangle usually reflects the font height but has a width 237 * of zero. 238 * 239 * This is delegated to the real root view. 240 * 241 * @param position the position of the character in the model 242 * @param a the area that is occupied by the view 243 * @param bias either {@link Position.Bias#Forward} or 244 * {@link Position.Bias#Backward} depending on the preferred 245 * direction bias. If <code>null</code> this defaults to 246 * <code>Position.Bias.Forward</code> 247 * 248 * @return a rectangle that gives the location of the document position 249 * inside the view coordinate space 250 * 251 * @throws BadLocationException if <code>pos</code> is invalid 252 * @throws IllegalArgumentException if b is not one of the above listed 253 * valid values 254 */ 255 public Shape modelToView(int position, Shape a, Position.Bias bias) 256 throws BadLocationException 257 { 258 return view.modelToView(position, a, bias); 259 } 260 261 /** 262 * Maps coordinates from the <code>View</code>'s space into a position 263 * in the document model. 264 * 265 * @param x the x coordinate in the view space 266 * @param y the y coordinate in the view space 267 * @param a the allocation of this <code>View</code> 268 * @param b the bias to use 269 * 270 * @return the position in the document that corresponds to the screen 271 * coordinates <code>x, y</code> 272 */ 273 public int viewToModel(float x, float y, Shape a, Position.Bias[] b) 274 { 275 return view.viewToModel(x, y, a, b); 276 } 277 278 /** 279 * Notification about text insertions. These are forwarded to the 280 * real root view. 281 * 282 * @param ev the DocumentEvent describing the change 283 * @param shape the current allocation of the view's display 284 * @param vf the ViewFactory to use for creating new Views 285 */ 286 public void insertUpdate(DocumentEvent ev, Shape shape, ViewFactory vf) 287 { 288 view.insertUpdate(ev, shape, vf); 289 } 290 291 /** 292 * Notification about text removals. These are forwarded to the 293 * real root view. 294 * 295 * @param ev the DocumentEvent describing the change 296 * @param shape the current allocation of the view's display 297 * @param vf the ViewFactory to use for creating new Views 298 */ 299 public void removeUpdate(DocumentEvent ev, Shape shape, ViewFactory vf) 300 { 301 view.removeUpdate(ev, shape, vf); 302 } 303 304 /** 305 * Notification about text changes. These are forwarded to the 306 * real root view. 307 * 308 * @param ev the DocumentEvent describing the change 309 * @param shape the current allocation of the view's display 310 * @param vf the ViewFactory to use for creating new Views 311 */ 312 public void changedUpdate(DocumentEvent ev, Shape shape, ViewFactory vf) 313 { 314 view.changedUpdate(ev, shape, vf); 315 } 316 317 /** 318 * Returns the document position that is (visually) nearest to the given 319 * document position <code>pos</code> in the given direction <code>d</code>. 320 * 321 * @param pos the document position 322 * @param b the bias for <code>pos</code> 323 * @param a the allocation for the view 324 * @param d the direction, must be either {@link SwingConstants#NORTH}, 325 * {@link SwingConstants#SOUTH}, {@link SwingConstants#WEST} or 326 * {@link SwingConstants#EAST} 327 * @param biasRet an array of {@link Position.Bias} that can hold at least 328 * one element, which is filled with the bias of the return position 329 * on method exit 330 * 331 * @return the document position that is (visually) nearest to the given 332 * document position <code>pos</code> in the given direction 333 * <code>d</code> 334 * 335 * @throws BadLocationException if <code>pos</code> is not a valid offset in 336 * the document model 337 */ 338 public int getNextVisualPositionFrom(int pos, Position.Bias b, Shape a, 339 int d, Position.Bias[] biasRet) 340 throws BadLocationException 341 { 342 return view.getNextVisualPositionFrom(pos, b, a, d, biasRet); 343 } 344 345 public int getStartOffset() 346 { 347 return 0; 348 } 349 350 public int getEndOffset() 351 { 352 return getDocument().getLength(); 353 } 354 355 public Document getDocument() 356 { 357 return document; 358 } 359 360 /** 361 * Overridden to return null, as a RootView has no attributes on its own. 362 */ 363 public AttributeSet getAttributes() 364 { 365 return null; 366 } 367 368 /** 369 * Overridden to provide an element for the view. 370 */ 371 public Element getElement() 372 { 373 return view.getElement(); 374 } 375 } 376 377 /** 378 * The key that is used to store a HTML view in a JComponent's client 379 * properties. 380 */ 381 public static final String propertyKey = "html"; 382 383 /** 384 * The key that is used to store the document base in a JComponent's client 385 * properties. The document base is used to resolve relative references 386 * in HTML. 387 */ 388 public static final String documentBaseKey = "html.base"; 389 390 /** 391 * Creates a new instance of BasicHTML. This should not be necessary since 392 * all methods in this class are static. 393 */ 394 public BasicHTML() 395 { 396 // Nothing to do here. 397 } 398 399 /** 400 * Creates a {@link View} instance that can be used by the component 401 * <code>c</code> to render the HTML string <code>html</code>. 402 * 403 * @param c the component that needs to render the HTML string 404 * @param html the HTML string to be rendered 405 * 406 * @return a view that can render the HTML string 407 */ 408 public static View createHTMLView(JComponent c, String html) 409 { 410 // TODO: This might be wrong. Lets see if it turns out good when 411 // the javax.swing.text.html package is in a good shape. 412 HTMLDocument doc = new HTMLDocument(); 413 HTMLEditorKit kit = new HTMLEditorKit(); 414 StringReader reader = new StringReader(html); 415 try 416 { 417 kit.read(reader, doc, 0); 418 } 419 catch (IOException ex) 420 { 421 AssertionError err = new AssertionError("unexpected IOException"); 422 err.initCause(ex); 423 throw err; 424 } 425 catch (BadLocationException ex) 426 { 427 AssertionError err = 428 new AssertionError("unexpected BadLocationException"); 429 err.initCause(ex); 430 throw err; 431 } 432 ViewFactory vf = kit.getViewFactory(); 433 Element root = doc.getDefaultRootElement(); 434 View view = vf.create(root); 435 HTMLRootView rootView = new HTMLRootView(c, view, kit, doc); 436 return rootView; 437 } 438 439 /** 440 * Returns <code>true</code> if <code>s</code> is HTML, <code>false</code> 441 * otherwise. 442 * 443 * @param s the string to test 444 * 445 * @return <code>true</code> if <code>s</code> is HTML, <code>false</code> 446 * otherwise 447 */ 448 public static boolean isHTMLString(String s) 449 { 450 // We consider a string to be HTML if it contains both the '<' and '>' 451 // character at least once. 452 return (s != null) && s.contains("<") && s.contains(">"); 453 } 454 455 /** 456 * Stores a HTML renderer in <code>c</code>'s client property if 457 * <code>text</code> is HTML, otherwise it clears the corresponding client 458 * property. This is useful for {@link javax.swing.plaf.ComponentUI} 459 * implementations that are shared between it's components. 460 * 461 * @param c the component to update the renderer for 462 * @param text the string to be rendered 463 */ 464 public static void updateRenderer(JComponent c, String text) 465 { 466 if (isHTMLString(text)) 467 c.putClientProperty(propertyKey, createHTMLView(c, text)); 468 else 469 c.putClientProperty(propertyKey, null); 470 } 471 }