1 /*
   2  * Copyright (c) 2007, 2013, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.  Oracle designates this
   8  * particular file as subject to the "Classpath" exception as provided
   9  * by Oracle in the LICENSE file that accompanied this code.
  10  *
  11  * This code is distributed in the hope that it will be useful, but WITHOUT
  12  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  13  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  14  * version 2 for more details (a copy is included in the LICENSE file that
  15  * accompanied this code).
  16  *
  17  * You should have received a copy of the GNU General Public License version
  18  * 2 along with this work; if not, write to the Free Software Foundation,
  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 
  26 package sun.java2d.pipe;
  27 
  28 import java.awt.Shape;
  29 import java.awt.BasicStroke;
  30 import java.awt.geom.PathIterator;
  31 import java.awt.geom.AffineTransform;
  32 
  33 import java.security.PrivilegedAction;
  34 import java.security.AccessController;
  35 import java.util.ServiceLoader;
  36 import sun.security.action.GetPropertyAction;
  37 
  38 import sun.awt.geom.PathConsumer2D;
  39 
  40 /**
  41  * This class abstracts a number of features for which the Java 2D
  42  * implementation relies on proprietary licensed software libraries.
  43  * Access to those features is now achieved by retrieving the singleton
  44  * instance of this class and calling the appropriate methods on it.
  45  * The 3 primary features abstracted here include:
  46  * <dl>
  47  * <dt>Shape createStrokedShape(Shape, [BasicStroke attributes]);
  48  * <dd>This method implements the functionality of the method of the
  49  * same name on the {@link BasicStroke} class.
  50  * <dt>void strokeTo(Shape, [rendering parameters], PathConsumer2D);
  51  * <dd>This method performs widening of the source path on the fly
  52  * and sends the results to the given {@link PathConsumer2D} object.
  53  * This procedure avoids having to create an intermediate Shape
  54  * object to hold the results of the {@code createStrokedShape} method.
  55  * The main user of this method is the Java 2D non-antialiasing renderer.
  56  * <dt>AATileGenerator getAATileGenerator(Shape, [rendering parameters]);
  57  * <dd>This method returns an object which can iterate over the
  58  * specified bounding box and produce tiles of coverage values for
  59  * antialiased rendering.  The details of the operation of the
  60  * {@link AATileGenerator} object are explained in its class comments.
  61  * </dl>
  62  * Additionally, the following informational method supplies important
  63  * data about the implementation.
  64  * <dl>
  65  * <dt>float getMinimumAAPenSize()
  66  * <dd>This method provides information on how small the BasicStroke
  67  * line width can get before dropouts occur.  Rendering with a BasicStroke
  68  * is defined to never allow the line to have breaks, gaps, or dropouts
  69  * even if the width is set to 0.0f, so this information allows the
  70  * {@link SunGraphics2D} class to detect the "thin line" case and set
  71  * the rendering attributes accordingly.
  72  * </dl>
  73  * At startup the runtime will load a single instance of this class.
  74  * It searches the classpath for a registered provider of this API
  75  * and returns either the last one it finds, or the instance whose
  76  * class name matches the value supplied in the System property
  77  * {@code sun.java2d.renderer}.
  78  * Additionally, a runtime System property flag can be set to trace
  79  * all calls to methods on the {@code RenderingEngine} in use by
  80  * setting the sun.java2d.renderer.trace property to any non-null value.
  81  * <p>
  82  * Parts of the system that need to use any of the above features should
  83  * call {@code RenderingEngine.getInstance()} to obtain the properly
  84  * registered (and possibly trace-enabled) version of the RenderingEngine.
  85  */
  86 public abstract class RenderingEngine {
  87     private static RenderingEngine reImpl;
  88 
  89     /**
  90      * Returns an instance of {@code RenderingEngine} as determined
  91      * by the installation environment and runtime flags.
  92      * <p>
  93      * A specific instance of the {@code RenderingEngine} can be
  94      * chosen by specifying the runtime flag:
  95      * <pre>
  96      *     java -Dsun.java2d.renderer=&lt;classname&gt;
  97      * </pre>
  98      *
  99      * If no specific {@code RenderingEngine} is specified on the command
 100      * or Ductus renderer is specified, it will attempt loading the
 101      * sun.dc.DuctusRenderingEngine class using Class.forName as a fastpath;
 102      * if not found, use the ServiceLoader.
 103      * If no specific {@code RenderingEngine} is specified on the command
 104      * line then the last one returned by enumerating all subclasses of
 105      * {@code RenderingEngine} known to the ServiceLoader is used.
 106      * <p>
 107      * Runtime tracing of the actions of the {@code RenderingEngine}
 108      * can be enabled by specifying the runtime flag:
 109      * <pre>
 110      *     java -Dsun.java2d.renderer.trace=&lt;any string&gt;
 111      * </pre>
 112      * @return an instance of {@code RenderingEngine}
 113      * @since 1.7
 114      */
 115     public static synchronized RenderingEngine getInstance() {
 116         if (reImpl != null) {
 117             return reImpl;
 118         }
 119 
 120         reImpl =
 121             AccessController.doPrivileged(new PrivilegedAction<RenderingEngine>() {
 122                 public RenderingEngine run() {
 123                     final String ductusREClass = "sun.dc.DuctusRenderingEngine";
 124                     String reClass =
 125                         System.getProperty("sun.java2d.renderer", ductusREClass);
 126                     if (reClass.equals(ductusREClass)) {

 127                         try {
 128                             Class<?> cls = Class.forName(ductusREClass);
 129                             return (RenderingEngine) cls.newInstance();
 130                         } catch (ReflectiveOperationException ignored) {
 131                             // not found
 132                         }
 133                     }
 134 
 135                     ServiceLoader<RenderingEngine> reLoader =
 136                         ServiceLoader.loadInstalled(RenderingEngine.class);
 137 
 138                     RenderingEngine service = null;
 139 
 140                     for (RenderingEngine re : reLoader) {
 141                         service = re;
 142                         if (re.getClass().getName().equals(reClass)) {
 143                             break;
 144                         }
 145                     }
 146                     return service;
 147                 }
 148             });
 149 
 150         if (reImpl == null) {
 151             throw new InternalError("No RenderingEngine module found");
 152         }
 153 
 154         GetPropertyAction gpa =
 155             new GetPropertyAction("sun.java2d.renderer.trace");
 156         String reTrace = AccessController.doPrivileged(gpa);
 157         if (reTrace != null) {
 158             reImpl = new Tracer(reImpl);
 159         }
 160 
 161         return reImpl;
 162     }
 163 
 164     /**
 165      * Create a widened path as specified by the parameters.
 166      * <p>
 167      * The specified {@code src} {@link Shape} is widened according
 168      * to the specified attribute parameters as per the
 169      * {@link BasicStroke} specification.
 170      *
 171      * @param src the source path to be widened
 172      * @param width the width of the widened path as per {@code BasicStroke}
 173      * @param caps the end cap decorations as per {@code BasicStroke}
 174      * @param join the segment join decorations as per {@code BasicStroke}
 175      * @param miterlimit the miter limit as per {@code BasicStroke}
 176      * @param dashes the dash length array as per {@code BasicStroke}
 177      * @param dashphase the initial dash phase as per {@code BasicStroke}
 178      * @return the widened path stored in a new {@code Shape} object
 179      * @since 1.7
 180      */
 181     public abstract Shape createStrokedShape(Shape src,
 182                                              float width,
 183                                              int caps,
 184                                              int join,
 185                                              float miterlimit,
 186                                              float dashes[],
 187                                              float dashphase);
 188 
 189     /**
 190      * Sends the geometry for a widened path as specified by the parameters
 191      * to the specified consumer.
 192      * <p>
 193      * The specified {@code src} {@link Shape} is widened according
 194      * to the parameters specified by the {@link BasicStroke} object.
 195      * Adjustments are made to the path as appropriate for the
 196      * {@link VALUE_STROKE_NORMALIZE} hint if the {@code normalize}
 197      * boolean parameter is true.
 198      * Adjustments are made to the path as appropriate for the
 199      * {@link VALUE_ANTIALIAS_ON} hint if the {@code antialias}
 200      * boolean parameter is true.
 201      * <p>
 202      * The geometry of the widened path is forwarded to the indicated
 203      * {@link PathConsumer2D} object as it is calculated.
 204      *
 205      * @param src the source path to be widened
 206      * @param bs the {@code BasicSroke} object specifying the
 207      *           decorations to be applied to the widened path
 208      * @param normalize indicates whether stroke normalization should
 209      *                  be applied
 210      * @param antialias indicates whether or not adjustments appropriate
 211      *                  to antialiased rendering should be applied
 212      * @param consumer the {@code PathConsumer2D} instance to forward
 213      *                 the widened geometry to
 214      * @since 1.7
 215      */
 216     public abstract void strokeTo(Shape src,
 217                                   AffineTransform at,
 218                                   BasicStroke bs,
 219                                   boolean thin,
 220                                   boolean normalize,
 221                                   boolean antialias,
 222                                   PathConsumer2D consumer);
 223 
 224     /**
 225      * Construct an antialiased tile generator for the given shape with
 226      * the given rendering attributes and store the bounds of the tile
 227      * iteration in the bbox parameter.
 228      * The {@code at} parameter specifies a transform that should affect
 229      * both the shape and the {@code BasicStroke} attributes.
 230      * The {@code clip} parameter specifies the current clip in effect
 231      * in device coordinates and can be used to prune the data for the
 232      * operation, but the renderer is not required to perform any
 233      * clipping.
 234      * If the {@code BasicStroke} parameter is null then the shape
 235      * should be filled as is, otherwise the attributes of the
 236      * {@code BasicStroke} should be used to specify a draw operation.
 237      * The {@code thin} parameter indicates whether or not the
 238      * transformed {@code BasicStroke} represents coordinates smaller
 239      * than the minimum resolution of the antialiasing rasterizer as
 240      * specified by the {@code getMinimumAAPenWidth()} method.
 241      * <p>
 242      * Upon returning, this method will fill the {@code bbox} parameter
 243      * with 4 values indicating the bounds of the iteration of the
 244      * tile generator.
 245      * The iteration order of the tiles will be as specified by the
 246      * pseudo-code:
 247      * <pre>
 248      *     for (y = bbox[1]; y < bbox[3]; y += tileheight) {
 249      *         for (x = bbox[0]; x < bbox[2]; x += tilewidth) {
 250      *         }
 251      *     }
 252      * </pre>
 253      * If there is no output to be rendered, this method may return
 254      * null.
 255      *
 256      * @param s the shape to be rendered (fill or draw)
 257      * @param at the transform to be applied to the shape and the
 258      *           stroke attributes
 259      * @param clip the current clip in effect in device coordinates
 260      * @param bs if non-null, a {@code BasicStroke} whose attributes
 261      *           should be applied to this operation
 262      * @param thin true if the transformed stroke attributes are smaller
 263      *             than the minimum dropout pen width
 264      * @param normalize true if the {@code VALUE_STROKE_NORMALIZE}
 265      *                  {@code RenderingHint} is in effect
 266      * @param bbox returns the bounds of the iteration
 267      * @return the {@code AATileGenerator} instance to be consulted
 268      *         for tile coverages, or null if there is no output to render
 269      * @since 1.7
 270      */
 271     public abstract AATileGenerator getAATileGenerator(Shape s,
 272                                                        AffineTransform at,
 273                                                        Region clip,
 274                                                        BasicStroke bs,
 275                                                        boolean thin,
 276                                                        boolean normalize,
 277                                                        int bbox[]);
 278 
 279     /**
 280      * Construct an antialiased tile generator for the given parallelogram
 281      * store the bounds of the tile iteration in the bbox parameter.
 282      * The parallelogram is specified as a starting point and 2 delta
 283      * vectors that indicate the slopes of the 2 pairs of sides of the
 284      * parallelogram.
 285      * The 4 corners of the parallelogram are defined by the 4 points:
 286      * <ul>
 287      * <li> {@code x}, {@code y}
 288      * <li> {@code x+dx1}, {@code y+dy1}
 289      * <li> {@code x+dx1+dx2}, {@code y+dy1+dy2}
 290      * <li> {@code x+dx2}, {@code y+dy2}
 291      * </ul>
 292      * The {@code lw1} and {@code lw2} parameters provide a specification
 293      * for an optionally stroked parallelogram if they are positive numbers.
 294      * The {@code lw1} parameter is the ratio of the length of the {@code dx1},
 295      * {@code dx2} delta vector to half of the line width in that same
 296      * direction.
 297      * The {@code lw2} parameter provides the same ratio for the other delta
 298      * vector.
 299      * If {@code lw1} and {@code lw2} are both greater than zero, then
 300      * the parallelogram figure is doubled by both expanding and contracting
 301      * each delta vector by its corresponding {@code lw} value.
 302      * If either (@code lw1) or {@code lw2} are also greater than 1, then
 303      * the inner (contracted) parallelogram disappears and the figure is
 304      * simply a single expanded parallelogram.
 305      * The {@code clip} parameter specifies the current clip in effect
 306      * in device coordinates and can be used to prune the data for the
 307      * operation, but the renderer is not required to perform any
 308      * clipping.
 309      * <p>
 310      * Upon returning, this method will fill the {@code bbox} parameter
 311      * with 4 values indicating the bounds of the iteration of the
 312      * tile generator.
 313      * The iteration order of the tiles will be as specified by the
 314      * pseudo-code:
 315      * <pre>
 316      *     for (y = bbox[1]; y < bbox[3]; y += tileheight) {
 317      *         for (x = bbox[0]; x < bbox[2]; x += tilewidth) {
 318      *         }
 319      *     }
 320      * </pre>
 321      * If there is no output to be rendered, this method may return
 322      * null.
 323      *
 324      * @param x the X coordinate of the first corner of the parallelogram
 325      * @param y the Y coordinate of the first corner of the parallelogram
 326      * @param dx1 the X coordinate delta of the first leg of the parallelogram
 327      * @param dy1 the Y coordinate delta of the first leg of the parallelogram
 328      * @param dx2 the X coordinate delta of the second leg of the parallelogram
 329      * @param dy2 the Y coordinate delta of the second leg of the parallelogram
 330      * @param lw1 the line width ratio for the first leg of the parallelogram
 331      * @param lw2 the line width ratio for the second leg of the parallelogram
 332      * @param clip the current clip in effect in device coordinates
 333      * @param bbox returns the bounds of the iteration
 334      * @return the {@code AATileGenerator} instance to be consulted
 335      *         for tile coverages, or null if there is no output to render
 336      * @since 1.7
 337      */
 338     public abstract AATileGenerator getAATileGenerator(double x, double y,
 339                                                        double dx1, double dy1,
 340                                                        double dx2, double dy2,
 341                                                        double lw1, double lw2,
 342                                                        Region clip,
 343                                                        int bbox[]);
 344 
 345     /**
 346      * Returns the minimum pen width that the antialiasing rasterizer
 347      * can represent without dropouts occurring.
 348      * @since 1.7
 349      */
 350     public abstract float getMinimumAAPenSize();
 351 
 352     /**
 353      * Utility method to feed a {@link PathConsumer2D} object from a
 354      * given {@link PathIterator}.
 355      * This method deals with the details of running the iterator and
 356      * feeding the consumer a segment at a time.
 357      */
 358     public static void feedConsumer(PathIterator pi, PathConsumer2D consumer) {
 359         float coords[] = new float[6];
 360         while (!pi.isDone()) {
 361             switch (pi.currentSegment(coords)) {
 362             case PathIterator.SEG_MOVETO:
 363                 consumer.moveTo(coords[0], coords[1]);
 364                 break;
 365             case PathIterator.SEG_LINETO:
 366                 consumer.lineTo(coords[0], coords[1]);
 367                 break;
 368             case PathIterator.SEG_QUADTO:
 369                 consumer.quadTo(coords[0], coords[1],
 370                                 coords[2], coords[3]);
 371                 break;
 372             case PathIterator.SEG_CUBICTO:
 373                 consumer.curveTo(coords[0], coords[1],
 374                                  coords[2], coords[3],
 375                                  coords[4], coords[5]);
 376                 break;
 377             case PathIterator.SEG_CLOSE:
 378                 consumer.closePath();
 379                 break;
 380             }
 381             pi.next();
 382         }
 383     }
 384 
 385     static class Tracer extends RenderingEngine {
 386         RenderingEngine target;
 387         String name;
 388 
 389         public Tracer(RenderingEngine target) {
 390             this.target = target;
 391             name = target.getClass().getName();
 392         }
 393 
 394         public Shape createStrokedShape(Shape src,
 395                                         float width,
 396                                         int caps,
 397                                         int join,
 398                                         float miterlimit,
 399                                         float dashes[],
 400                                         float dashphase)
 401         {
 402             System.out.println(name+".createStrokedShape("+
 403                                src.getClass().getName()+", "+
 404                                "width = "+width+", "+
 405                                "caps = "+caps+", "+
 406                                "join = "+join+", "+
 407                                "miter = "+miterlimit+", "+
 408                                "dashes = "+dashes+", "+
 409                                "dashphase = "+dashphase+")");
 410             return target.createStrokedShape(src,
 411                                              width, caps, join, miterlimit,
 412                                              dashes, dashphase);
 413         }
 414 
 415         public void strokeTo(Shape src,
 416                              AffineTransform at,
 417                              BasicStroke bs,
 418                              boolean thin,
 419                              boolean normalize,
 420                              boolean antialias,
 421                              PathConsumer2D consumer)
 422         {
 423             System.out.println(name+".strokeTo("+
 424                                src.getClass().getName()+", "+
 425                                at+", "+
 426                                bs+", "+
 427                                (thin ? "thin" : "wide")+", "+
 428                                (normalize ? "normalized" : "pure")+", "+
 429                                (antialias ? "AA" : "non-AA")+", "+
 430                                consumer.getClass().getName()+")");
 431             target.strokeTo(src, at, bs, thin, normalize, antialias, consumer);
 432         }
 433 
 434         public float getMinimumAAPenSize() {
 435             System.out.println(name+".getMinimumAAPenSize()");
 436             return target.getMinimumAAPenSize();
 437         }
 438 
 439         public AATileGenerator getAATileGenerator(Shape s,
 440                                                   AffineTransform at,
 441                                                   Region clip,
 442                                                   BasicStroke bs,
 443                                                   boolean thin,
 444                                                   boolean normalize,
 445                                                   int bbox[])
 446         {
 447             System.out.println(name+".getAATileGenerator("+
 448                                s.getClass().getName()+", "+
 449                                at+", "+
 450                                clip+", "+
 451                                bs+", "+
 452                                (thin ? "thin" : "wide")+", "+
 453                                (normalize ? "normalized" : "pure")+")");
 454             return target.getAATileGenerator(s, at, clip,
 455                                              bs, thin, normalize,
 456                                              bbox);
 457         }
 458         public AATileGenerator getAATileGenerator(double x, double y,
 459                                                   double dx1, double dy1,
 460                                                   double dx2, double dy2,
 461                                                   double lw1, double lw2,
 462                                                   Region clip,
 463                                                   int bbox[])
 464         {
 465             System.out.println(name+".getAATileGenerator("+
 466                                x+", "+y+", "+
 467                                dx1+", "+dy1+", "+
 468                                dx2+", "+dy2+", "+
 469                                lw1+", "+lw2+", "+
 470                                clip+")");
 471             return target.getAATileGenerator(x, y,
 472                                              dx1, dy1,
 473                                              dx2, dy2,
 474                                              lw1, lw2,
 475                                              clip, bbox);
 476         }
 477     }
 478 }
--- EOF ---