1 /* 2 * Copyright (c) 1997, 2018, 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 java.awt; 27 28 import java.beans.ConstructorProperties; 29 30 import java.lang.annotation.Native; 31 32 /** 33 * The {@code BasicStroke} class defines a basic set of rendering 34 * attributes for the outlines of graphics primitives, which are rendered 35 * with a {@link Graphics2D} object that has its Stroke attribute set to 36 * this {@code BasicStroke}. 37 * The rendering attributes defined by {@code BasicStroke} describe 38 * the shape of the mark made by a pen drawn along the outline of a 39 * {@link Shape} and the decorations applied at the ends and joins of 40 * path segments of the {@code Shape}. 41 * These rendering attributes include: 42 * <dl> 43 * <dt><i>width</i> 44 * <dd>The pen width, measured perpendicularly to the pen trajectory. 45 * <dt><i>end caps</i> 46 * <dd>The decoration applied to the ends of unclosed subpaths and 47 * dash segments. Subpaths that start and end on the same point are 48 * still considered unclosed if they do not have a CLOSE segment. 49 * See {@link java.awt.geom.PathIterator#SEG_CLOSE SEG_CLOSE} 50 * for more information on the CLOSE segment. 51 * The three different decorations are: {@link #CAP_BUTT}, 52 * {@link #CAP_ROUND}, and {@link #CAP_SQUARE}. 53 * <dt><i>line joins</i> 54 * <dd>The decoration applied at the intersection of two path segments 55 * and at the intersection of the endpoints of a subpath that is closed 56 * using {@link java.awt.geom.PathIterator#SEG_CLOSE SEG_CLOSE}. 57 * The three different decorations are: {@link #JOIN_BEVEL}, 58 * {@link #JOIN_MITER}, and {@link #JOIN_ROUND}. 59 * <dt><i>miter limit</i> 60 * <dd>The limit to trim a line join that has a JOIN_MITER decoration. 61 * A line join is trimmed when the ratio of miter length to stroke 62 * width is greater than the miterlimit value. The miter length is 63 * the diagonal length of the miter, which is the distance between 64 * the inside corner and the outside corner of the intersection. 65 * The smaller the angle formed by two line segments, the longer 66 * the miter length and the sharper the angle of intersection. The 67 * default miterlimit value of 10.0f causes all angles less than 68 * 11 degrees to be trimmed. Trimming miters converts 69 * the decoration of the line join to bevel. 70 * <dt><i>dash attributes</i> 71 * <dd>The definition of how to make a dash pattern by alternating 72 * between opaque and transparent sections. 73 * </dl> 74 * All attributes that specify measurements and distances controlling 75 * the shape of the returned outline are measured in the same 76 * coordinate system as the original unstroked {@code Shape} 77 * argument. When a {@code Graphics2D} object uses a 78 * {@code Stroke} object to redefine a path during the execution 79 * of one of its {@code draw} methods, the geometry is supplied 80 * in its original form before the {@code Graphics2D} transform 81 * attribute is applied. Therefore, attributes such as the pen width 82 * are interpreted in the user space coordinate system of the 83 * {@code Graphics2D} object and are subject to the scaling and 84 * shearing effects of the user-space-to-device-space transform in that 85 * particular {@code Graphics2D}. 86 * For example, the width of a rendered shape's outline is determined 87 * not only by the width attribute of this {@code BasicStroke}, 88 * but also by the transform attribute of the 89 * {@code Graphics2D} object. Consider this code: 90 * <blockquote><pre>{@code 91 * // sets the Graphics2D object's Transform attribute 92 * g2d.scale(10, 10); 93 * // sets the Graphics2D object's Stroke attribute 94 * g2d.setStroke(new BasicStroke(1.5f)); 95 * }</pre></blockquote> 96 * Assuming there are no other scaling transforms added to the 97 * {@code Graphics2D} object, the resulting line 98 * will be approximately 15 pixels wide. 99 * As the example code demonstrates, a floating-point line 100 * offers better precision, especially when large transforms are 101 * used with a {@code Graphics2D} object. 102 * When a line is diagonal, the exact width depends on how the 103 * rendering pipeline chooses which pixels to fill as it traces the 104 * theoretical widened outline. The choice of which pixels to turn 105 * on is affected by the antialiasing attribute because the 106 * antialiasing rendering pipeline can choose to color 107 * partially-covered pixels. 108 * <p> 109 * For more information on the user space coordinate system and the 110 * rendering process, see the {@code Graphics2D} class comments. 111 * @see Graphics2D 112 * @author Jim Graham 113 */ 114 public class BasicStroke implements Stroke { 115 116 /** 117 * Joins path segments by extending their outside edges until 118 * they meet. 119 */ 120 @Native public static final int JOIN_MITER = 0; 121 122 /** 123 * Joins path segments by rounding off the corner at a radius 124 * of half the line width. 125 */ 126 @Native public static final int JOIN_ROUND = 1; 127 128 /** 129 * Joins path segments by connecting the outer corners of their 130 * wide outlines with a straight segment. 131 */ 132 @Native public static final int JOIN_BEVEL = 2; 133 134 /** 135 * Ends unclosed subpaths and dash segments with no added 136 * decoration. 137 */ 138 @Native public static final int CAP_BUTT = 0; 139 140 /** 141 * Ends unclosed subpaths and dash segments with a round 142 * decoration that has a radius equal to half of the width 143 * of the pen. 144 */ 145 @Native public static final int CAP_ROUND = 1; 146 147 /** 148 * Ends unclosed subpaths and dash segments with a square 149 * projection that extends beyond the end of the segment 150 * to a distance equal to half of the line width. 151 */ 152 @Native public static final int CAP_SQUARE = 2; 153 154 float width; 155 156 int join; 157 int cap; 158 float miterlimit; 159 160 float[] dash; 161 float dash_phase; 162 163 /** 164 * Constructs a new {@code BasicStroke} with the specified 165 * attributes. 166 * @param width the width of this {@code BasicStroke}. The 167 * width must be greater than or equal to 0.0f. If width is 168 * set to 0.0f, the stroke is rendered as the thinnest 169 * possible line for the target device and the antialias 170 * hint setting. 171 * @param cap the decoration of the ends of a {@code BasicStroke} 172 * @param join the decoration applied where path segments meet 173 * @param miterlimit the limit to trim the miter join. The miterlimit 174 * must be greater than or equal to 1.0f. 175 * @param dash the array representing the dashing pattern 176 * @param dash_phase the offset to start the dashing pattern 177 * @throws IllegalArgumentException if {@code width} is negative 178 * @throws IllegalArgumentException if {@code cap} is not either 179 * CAP_BUTT, CAP_ROUND or CAP_SQUARE 180 * @throws IllegalArgumentException if {@code miterlimit} is less 181 * than 1 and {@code join} is JOIN_MITER 182 * @throws IllegalArgumentException if {@code join} is not 183 * either JOIN_ROUND, JOIN_BEVEL, or JOIN_MITER 184 * @throws IllegalArgumentException if {@code dash_phase} 185 * is negative and {@code dash} is not {@code null} 186 * @throws IllegalArgumentException if the length of 187 * {@code dash} is zero 188 * @throws IllegalArgumentException if dash lengths are all zero. 189 */ 190 @ConstructorProperties({ "lineWidth", "endCap", "lineJoin", "miterLimit", "dashArray", "dashPhase" }) BasicStroke(float width, int cap, int join, float miterlimit, float[] dash, float dash_phase)191 public BasicStroke(float width, int cap, int join, float miterlimit, 192 float[] dash, float dash_phase) { 193 if (width < 0.0f) { 194 throw new IllegalArgumentException("negative width"); 195 } 196 if (cap != CAP_BUTT && cap != CAP_ROUND && cap != CAP_SQUARE) { 197 throw new IllegalArgumentException("illegal end cap value"); 198 } 199 if (join == JOIN_MITER) { 200 if (miterlimit < 1.0f) { 201 throw new IllegalArgumentException("miter limit < 1"); 202 } 203 } else if (join != JOIN_ROUND && join != JOIN_BEVEL) { 204 throw new IllegalArgumentException("illegal line join value"); 205 } 206 if (dash != null) { 207 if (dash_phase < 0.0f) { 208 throw new IllegalArgumentException("negative dash phase"); 209 } 210 boolean allzero = true; 211 for (int i = 0; i < dash.length; i++) { 212 float d = dash[i]; 213 if (d > 0.0) { 214 allzero = false; 215 } else if (d < 0.0) { 216 throw new IllegalArgumentException("negative dash length"); 217 } 218 } 219 if (allzero) { 220 throw new IllegalArgumentException("dash lengths all zero"); 221 } 222 } 223 this.width = width; 224 this.cap = cap; 225 this.join = join; 226 this.miterlimit = miterlimit; 227 if (dash != null) { 228 this.dash = dash.clone(); 229 } 230 this.dash_phase = dash_phase; 231 } 232 233 /** 234 * Constructs a solid {@code BasicStroke} with the specified 235 * attributes. 236 * @param width the width of the {@code BasicStroke} 237 * @param cap the decoration of the ends of a {@code BasicStroke} 238 * @param join the decoration applied where path segments meet 239 * @param miterlimit the limit to trim the miter join 240 * @throws IllegalArgumentException if {@code width} is negative 241 * @throws IllegalArgumentException if {@code cap} is not either 242 * CAP_BUTT, CAP_ROUND or CAP_SQUARE 243 * @throws IllegalArgumentException if {@code miterlimit} is less 244 * than 1 and {@code join} is JOIN_MITER 245 * @throws IllegalArgumentException if {@code join} is not 246 * either JOIN_ROUND, JOIN_BEVEL, or JOIN_MITER 247 */ BasicStroke(float width, int cap, int join, float miterlimit)248 public BasicStroke(float width, int cap, int join, float miterlimit) { 249 this(width, cap, join, miterlimit, null, 0.0f); 250 } 251 252 /** 253 * Constructs a solid {@code BasicStroke} with the specified 254 * attributes. The {@code miterlimit} parameter is 255 * unnecessary in cases where the default is allowable or the 256 * line joins are not specified as JOIN_MITER. 257 * @param width the width of the {@code BasicStroke} 258 * @param cap the decoration of the ends of a {@code BasicStroke} 259 * @param join the decoration applied where path segments meet 260 * @throws IllegalArgumentException if {@code width} is negative 261 * @throws IllegalArgumentException if {@code cap} is not either 262 * CAP_BUTT, CAP_ROUND or CAP_SQUARE 263 * @throws IllegalArgumentException if {@code join} is not 264 * either JOIN_ROUND, JOIN_BEVEL, or JOIN_MITER 265 */ BasicStroke(float width, int cap, int join)266 public BasicStroke(float width, int cap, int join) { 267 this(width, cap, join, 10.0f, null, 0.0f); 268 } 269 270 /** 271 * Constructs a solid {@code BasicStroke} with the specified 272 * line width and with default values for the cap and join 273 * styles. 274 * @param width the width of the {@code BasicStroke} 275 * @throws IllegalArgumentException if {@code width} is negative 276 */ BasicStroke(float width)277 public BasicStroke(float width) { 278 this(width, CAP_SQUARE, JOIN_MITER, 10.0f, null, 0.0f); 279 } 280 281 /** 282 * Constructs a new {@code BasicStroke} with defaults for all 283 * attributes. 284 * The default attributes are a solid line of width 1.0, CAP_SQUARE, 285 * JOIN_MITER, a miter limit of 10.0. 286 */ BasicStroke()287 public BasicStroke() { 288 this(1.0f, CAP_SQUARE, JOIN_MITER, 10.0f, null, 0.0f); 289 } 290 291 292 /** 293 * Returns a {@code Shape} whose interior defines the 294 * stroked outline of a specified {@code Shape}. 295 * @param s the {@code Shape} boundary be stroked 296 * @return the {@code Shape} of the stroked outline. 297 * @throws NullPointerException if {@code s} is {@code null} 298 */ createStrokedShape(Shape s)299 public Shape createStrokedShape(Shape s) { 300 sun.java2d.pipe.RenderingEngine re = 301 sun.java2d.pipe.RenderingEngine.getInstance(); 302 return re.createStrokedShape(s, width, cap, join, miterlimit, 303 dash, dash_phase); 304 } 305 306 /** 307 * Returns the line width. Line width is represented in user space, 308 * which is the default-coordinate space used by Java 2D. See the 309 * {@code Graphics2D} class comments for more information on 310 * the user space coordinate system. 311 * @return the line width of this {@code BasicStroke}. 312 * @see Graphics2D 313 */ getLineWidth()314 public float getLineWidth() { 315 return width; 316 } 317 318 /** 319 * Returns the end cap style. 320 * @return the end cap style of this {@code BasicStroke} as one 321 * of the static {@code int} values that define possible end cap 322 * styles. 323 */ getEndCap()324 public int getEndCap() { 325 return cap; 326 } 327 328 /** 329 * Returns the line join style. 330 * @return the line join style of the {@code BasicStroke} as one 331 * of the static {@code int} values that define possible line 332 * join styles. 333 */ getLineJoin()334 public int getLineJoin() { 335 return join; 336 } 337 338 /** 339 * Returns the limit of miter joins. 340 * @return the limit of miter joins of the {@code BasicStroke}. 341 */ getMiterLimit()342 public float getMiterLimit() { 343 return miterlimit; 344 } 345 346 /** 347 * Returns the array representing the lengths of the dash segments. 348 * Alternate entries in the array represent the user space lengths 349 * of the opaque and transparent segments of the dashes. 350 * As the pen moves along the outline of the {@code Shape} 351 * to be stroked, the user space 352 * distance that the pen travels is accumulated. The distance 353 * value is used to index into the dash array. 354 * The pen is opaque when its current cumulative distance maps 355 * to an even element of the dash array and transparent otherwise. 356 * @return the dash array. 357 */ getDashArray()358 public float[] getDashArray() { 359 if (dash == null) { 360 return null; 361 } 362 363 return dash.clone(); 364 } 365 366 /** 367 * Returns the current dash phase. 368 * The dash phase is a distance specified in user coordinates that 369 * represents an offset into the dashing pattern. In other words, the dash 370 * phase defines the point in the dashing pattern that will correspond to 371 * the beginning of the stroke. 372 * @return the dash phase as a {@code float} value. 373 */ getDashPhase()374 public float getDashPhase() { 375 return dash_phase; 376 } 377 378 /** 379 * Returns the hashcode for this stroke. 380 * @return a hash code for this stroke. 381 */ hashCode()382 public int hashCode() { 383 int hash = Float.floatToIntBits(width); 384 hash = hash * 31 + join; 385 hash = hash * 31 + cap; 386 hash = hash * 31 + Float.floatToIntBits(miterlimit); 387 if (dash != null) { 388 hash = hash * 31 + Float.floatToIntBits(dash_phase); 389 for (int i = 0; i < dash.length; i++) { 390 hash = hash * 31 + Float.floatToIntBits(dash[i]); 391 } 392 } 393 return hash; 394 } 395 396 /** 397 * Returns true if this BasicStroke represents the same 398 * stroking operation as the given argument. 399 */ 400 /** 401 * Tests if a specified object is equal to this {@code BasicStroke} 402 * by first testing if it is a {@code BasicStroke} and then comparing 403 * its width, join, cap, miter limit, dash, and dash phase attributes with 404 * those of this {@code BasicStroke}. 405 * @param obj the specified object to compare to this 406 * {@code BasicStroke} 407 * @return {@code true} if the width, join, cap, miter limit, dash, and 408 * dash phase are the same for both objects; 409 * {@code false} otherwise. 410 */ equals(Object obj)411 public boolean equals(Object obj) { 412 if (!(obj instanceof BasicStroke)) { 413 return false; 414 } 415 416 BasicStroke bs = (BasicStroke) obj; 417 if (width != bs.width) { 418 return false; 419 } 420 421 if (join != bs.join) { 422 return false; 423 } 424 425 if (cap != bs.cap) { 426 return false; 427 } 428 429 if (miterlimit != bs.miterlimit) { 430 return false; 431 } 432 433 if (dash != null) { 434 if (dash_phase != bs.dash_phase) { 435 return false; 436 } 437 438 if (!java.util.Arrays.equals(dash, bs.dash)) { 439 return false; 440 } 441 } 442 else if (bs.dash != null) { 443 return false; 444 } 445 446 return true; 447 } 448 } 449