Graphics.java revision 10444:f08705540498
1/* 2 * Copyright (c) 1995, 2014, 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 */ 25package java.awt; 26 27import java.io.*; 28import java.lang.*; 29import java.util.*; 30import java.awt.image.ImageObserver; 31import java.text.AttributedCharacterIterator; 32 33/** 34 * The <code>Graphics</code> class is the abstract base class for 35 * all graphics contexts that allow an application to draw onto 36 * components that are realized on various devices, as well as 37 * onto off-screen images. 38 * <p> 39 * A <code>Graphics</code> object encapsulates state information needed 40 * for the basic rendering operations that Java supports. This 41 * state information includes the following properties: 42 * 43 * <ul> 44 * <li>The <code>Component</code> object on which to draw. 45 * <li>A translation origin for rendering and clipping coordinates. 46 * <li>The current clip. 47 * <li>The current color. 48 * <li>The current font. 49 * <li>The current logical pixel operation function (XOR or Paint). 50 * <li>The current XOR alternation color 51 * (see {@link Graphics#setXORMode}). 52 * </ul> 53 * <p> 54 * Coordinates are infinitely thin and lie between the pixels of the 55 * output device. 56 * Operations that draw the outline of a figure operate by traversing 57 * an infinitely thin path between pixels with a pixel-sized pen that hangs 58 * down and to the right of the anchor point on the path. 59 * Operations that fill a figure operate by filling the interior 60 * of that infinitely thin path. 61 * Operations that render horizontal text render the ascending 62 * portion of character glyphs entirely above the baseline coordinate. 63 * <p> 64 * The graphics pen hangs down and to the right from the path it traverses. 65 * This has the following implications: 66 * <ul> 67 * <li>If you draw a figure that covers a given rectangle, that 68 * figure occupies one extra row of pixels on the right and bottom edges 69 * as compared to filling a figure that is bounded by that same rectangle. 70 * <li>If you draw a horizontal line along the same <i>y</i> coordinate as 71 * the baseline of a line of text, that line is drawn entirely below 72 * the text, except for any descenders. 73 * </ul><p> 74 * All coordinates that appear as arguments to the methods of this 75 * <code>Graphics</code> object are considered relative to the 76 * translation origin of this <code>Graphics</code> object prior to 77 * the invocation of the method. 78 * <p> 79 * All rendering operations modify only pixels which lie within the 80 * area bounded by the current clip, which is specified by a {@link Shape} 81 * in user space and is controlled by the program using the 82 * <code>Graphics</code> object. This <i>user clip</i> 83 * is transformed into device space and combined with the 84 * <i>device clip</i>, which is defined by the visibility of windows and 85 * device extents. The combination of the user clip and device clip 86 * defines the <i>composite clip</i>, which determines the final clipping 87 * region. The user clip cannot be modified by the rendering 88 * system to reflect the resulting composite clip. The user clip can only 89 * be changed through the <code>setClip</code> or <code>clipRect</code> 90 * methods. 91 * All drawing or writing is done in the current color, 92 * using the current paint mode, and in the current font. 93 * 94 * @author Sami Shaio 95 * @author Arthur van Hoff 96 * @see java.awt.Component 97 * @see java.awt.Graphics#clipRect(int, int, int, int) 98 * @see java.awt.Graphics#setColor(java.awt.Color) 99 * @see java.awt.Graphics#setPaintMode() 100 * @see java.awt.Graphics#setXORMode(java.awt.Color) 101 * @see java.awt.Graphics#setFont(java.awt.Font) 102 * @since 1.0 103 */ 104public abstract class Graphics { 105 106 /** 107 * Constructs a new <code>Graphics</code> object. 108 * This constructor is the default constructor for a graphics 109 * context. 110 * <p> 111 * Since <code>Graphics</code> is an abstract class, applications 112 * cannot call this constructor directly. Graphics contexts are 113 * obtained from other graphics contexts or are created by calling 114 * <code>getGraphics</code> on a component. 115 * @see java.awt.Graphics#create() 116 * @see java.awt.Component#getGraphics 117 */ 118 protected Graphics() { 119 } 120 121 /** 122 * Creates a new <code>Graphics</code> object that is 123 * a copy of this <code>Graphics</code> object. 124 * @return a new graphics context that is a copy of 125 * this graphics context. 126 */ 127 public abstract Graphics create(); 128 129 /** 130 * Creates a new <code>Graphics</code> object based on this 131 * <code>Graphics</code> object, but with a new translation and clip area. 132 * The new <code>Graphics</code> object has its origin 133 * translated to the specified point (<i>x</i>, <i>y</i>). 134 * Its clip area is determined by the intersection of the original 135 * clip area with the specified rectangle. The arguments are all 136 * interpreted in the coordinate system of the original 137 * <code>Graphics</code> object. The new graphics context is 138 * identical to the original, except in two respects: 139 * 140 * <ul> 141 * <li> 142 * The new graphics context is translated by (<i>x</i>, <i>y</i>). 143 * That is to say, the point (<code>0</code>, <code>0</code>) in the 144 * new graphics context is the same as (<i>x</i>, <i>y</i>) in 145 * the original graphics context. 146 * <li> 147 * The new graphics context has an additional clipping rectangle, in 148 * addition to whatever (translated) clipping rectangle it inherited 149 * from the original graphics context. The origin of the new clipping 150 * rectangle is at (<code>0</code>, <code>0</code>), and its size 151 * is specified by the <code>width</code> and <code>height</code> 152 * arguments. 153 * </ul> 154 * 155 * @param x the <i>x</i> coordinate. 156 * @param y the <i>y</i> coordinate. 157 * @param width the width of the clipping rectangle. 158 * @param height the height of the clipping rectangle. 159 * @return a new graphics context. 160 * @see java.awt.Graphics#translate 161 * @see java.awt.Graphics#clipRect 162 */ 163 public Graphics create(int x, int y, int width, int height) { 164 Graphics g = create(); 165 if (g == null) return null; 166 g.translate(x, y); 167 g.clipRect(0, 0, width, height); 168 return g; 169 } 170 171 /** 172 * Translates the origin of the graphics context to the point 173 * (<i>x</i>, <i>y</i>) in the current coordinate system. 174 * Modifies this graphics context so that its new origin corresponds 175 * to the point (<i>x</i>, <i>y</i>) in this graphics context's 176 * original coordinate system. All coordinates used in subsequent 177 * rendering operations on this graphics context will be relative 178 * to this new origin. 179 * @param x the <i>x</i> coordinate. 180 * @param y the <i>y</i> coordinate. 181 */ 182 public abstract void translate(int x, int y); 183 184 /** 185 * Gets this graphics context's current color. 186 * @return this graphics context's current color. 187 * @see java.awt.Color 188 * @see java.awt.Graphics#setColor(Color) 189 */ 190 public abstract Color getColor(); 191 192 /** 193 * Sets this graphics context's current color to the specified 194 * color. All subsequent graphics operations using this graphics 195 * context use this specified color. 196 * @param c the new rendering color. 197 * @see java.awt.Color 198 * @see java.awt.Graphics#getColor 199 */ 200 public abstract void setColor(Color c); 201 202 /** 203 * Sets the paint mode of this graphics context to overwrite the 204 * destination with this graphics context's current color. 205 * This sets the logical pixel operation function to the paint or 206 * overwrite mode. All subsequent rendering operations will 207 * overwrite the destination with the current color. 208 */ 209 public abstract void setPaintMode(); 210 211 /** 212 * Sets the paint mode of this graphics context to alternate between 213 * this graphics context's current color and the new specified color. 214 * This specifies that logical pixel operations are performed in the 215 * XOR mode, which alternates pixels between the current color and 216 * a specified XOR color. 217 * <p> 218 * When drawing operations are performed, pixels which are the 219 * current color are changed to the specified color, and vice versa. 220 * <p> 221 * Pixels that are of colors other than those two colors are changed 222 * in an unpredictable but reversible manner; if the same figure is 223 * drawn twice, then all pixels are restored to their original values. 224 * @param c1 the XOR alternation color 225 */ 226 public abstract void setXORMode(Color c1); 227 228 /** 229 * Gets the current font. 230 * @return this graphics context's current font. 231 * @see java.awt.Font 232 * @see java.awt.Graphics#setFont(Font) 233 */ 234 public abstract Font getFont(); 235 236 /** 237 * Sets this graphics context's font to the specified font. 238 * All subsequent text operations using this graphics context 239 * use this font. A null argument is silently ignored. 240 * @param font the font. 241 * @see java.awt.Graphics#getFont 242 * @see java.awt.Graphics#drawString(java.lang.String, int, int) 243 * @see java.awt.Graphics#drawBytes(byte[], int, int, int, int) 244 * @see java.awt.Graphics#drawChars(char[], int, int, int, int) 245 */ 246 public abstract void setFont(Font font); 247 248 /** 249 * Gets the font metrics of the current font. 250 * @return the font metrics of this graphics 251 * context's current font. 252 * @see java.awt.Graphics#getFont 253 * @see java.awt.FontMetrics 254 * @see java.awt.Graphics#getFontMetrics(Font) 255 */ 256 public FontMetrics getFontMetrics() { 257 return getFontMetrics(getFont()); 258 } 259 260 /** 261 * Gets the font metrics for the specified font. 262 * @return the font metrics for the specified font. 263 * @param f the specified font 264 * @see java.awt.Graphics#getFont 265 * @see java.awt.FontMetrics 266 * @see java.awt.Graphics#getFontMetrics() 267 */ 268 public abstract FontMetrics getFontMetrics(Font f); 269 270 271 /** 272 * Returns the bounding rectangle of the current clipping area. 273 * This method refers to the user clip, which is independent of the 274 * clipping associated with device bounds and window visibility. 275 * If no clip has previously been set, or if the clip has been 276 * cleared using <code>setClip(null)</code>, this method returns 277 * <code>null</code>. 278 * The coordinates in the rectangle are relative to the coordinate 279 * system origin of this graphics context. 280 * @return the bounding rectangle of the current clipping area, 281 * or <code>null</code> if no clip is set. 282 * @see java.awt.Graphics#getClip 283 * @see java.awt.Graphics#clipRect 284 * @see java.awt.Graphics#setClip(int, int, int, int) 285 * @see java.awt.Graphics#setClip(Shape) 286 * @since 1.1 287 */ 288 public abstract Rectangle getClipBounds(); 289 290 /** 291 * Intersects the current clip with the specified rectangle. 292 * The resulting clipping area is the intersection of the current 293 * clipping area and the specified rectangle. If there is no 294 * current clipping area, either because the clip has never been 295 * set, or the clip has been cleared using <code>setClip(null)</code>, 296 * the specified rectangle becomes the new clip. 297 * This method sets the user clip, which is independent of the 298 * clipping associated with device bounds and window visibility. 299 * This method can only be used to make the current clip smaller. 300 * To set the current clip larger, use any of the setClip methods. 301 * Rendering operations have no effect outside of the clipping area. 302 * @param x the x coordinate of the rectangle to intersect the clip with 303 * @param y the y coordinate of the rectangle to intersect the clip with 304 * @param width the width of the rectangle to intersect the clip with 305 * @param height the height of the rectangle to intersect the clip with 306 * @see #setClip(int, int, int, int) 307 * @see #setClip(Shape) 308 */ 309 public abstract void clipRect(int x, int y, int width, int height); 310 311 /** 312 * Sets the current clip to the rectangle specified by the given 313 * coordinates. This method sets the user clip, which is 314 * independent of the clipping associated with device bounds 315 * and window visibility. 316 * Rendering operations have no effect outside of the clipping area. 317 * @param x the <i>x</i> coordinate of the new clip rectangle. 318 * @param y the <i>y</i> coordinate of the new clip rectangle. 319 * @param width the width of the new clip rectangle. 320 * @param height the height of the new clip rectangle. 321 * @see java.awt.Graphics#clipRect 322 * @see java.awt.Graphics#setClip(Shape) 323 * @see java.awt.Graphics#getClip 324 * @since 1.1 325 */ 326 public abstract void setClip(int x, int y, int width, int height); 327 328 /** 329 * Gets the current clipping area. 330 * This method returns the user clip, which is independent of the 331 * clipping associated with device bounds and window visibility. 332 * If no clip has previously been set, or if the clip has been 333 * cleared using <code>setClip(null)</code>, this method returns 334 * <code>null</code>. 335 * @return a <code>Shape</code> object representing the 336 * current clipping area, or <code>null</code> if 337 * no clip is set. 338 * @see java.awt.Graphics#getClipBounds 339 * @see java.awt.Graphics#clipRect 340 * @see java.awt.Graphics#setClip(int, int, int, int) 341 * @see java.awt.Graphics#setClip(Shape) 342 * @since 1.1 343 */ 344 public abstract Shape getClip(); 345 346 /** 347 * Sets the current clipping area to an arbitrary clip shape. 348 * Not all objects that implement the <code>Shape</code> 349 * interface can be used to set the clip. The only 350 * <code>Shape</code> objects that are guaranteed to be 351 * supported are <code>Shape</code> objects that are 352 * obtained via the <code>getClip</code> method and via 353 * <code>Rectangle</code> objects. This method sets the 354 * user clip, which is independent of the clipping associated 355 * with device bounds and window visibility. 356 * @param clip the <code>Shape</code> to use to set the clip 357 * @see java.awt.Graphics#getClip() 358 * @see java.awt.Graphics#clipRect 359 * @see java.awt.Graphics#setClip(int, int, int, int) 360 * @since 1.1 361 */ 362 public abstract void setClip(Shape clip); 363 364 /** 365 * Copies an area of the component by a distance specified by 366 * <code>dx</code> and <code>dy</code>. From the point specified 367 * by <code>x</code> and <code>y</code>, this method 368 * copies downwards and to the right. To copy an area of the 369 * component to the left or upwards, specify a negative value for 370 * <code>dx</code> or <code>dy</code>. 371 * If a portion of the source rectangle lies outside the bounds 372 * of the component, or is obscured by another window or component, 373 * <code>copyArea</code> will be unable to copy the associated 374 * pixels. The area that is omitted can be refreshed by calling 375 * the component's <code>paint</code> method. 376 * @param x the <i>x</i> coordinate of the source rectangle. 377 * @param y the <i>y</i> coordinate of the source rectangle. 378 * @param width the width of the source rectangle. 379 * @param height the height of the source rectangle. 380 * @param dx the horizontal distance to copy the pixels. 381 * @param dy the vertical distance to copy the pixels. 382 */ 383 public abstract void copyArea(int x, int y, int width, int height, 384 int dx, int dy); 385 386 /** 387 * Draws a line, using the current color, between the points 388 * <code>(x1, y1)</code> and <code>(x2, y2)</code> 389 * in this graphics context's coordinate system. 390 * @param x1 the first point's <i>x</i> coordinate. 391 * @param y1 the first point's <i>y</i> coordinate. 392 * @param x2 the second point's <i>x</i> coordinate. 393 * @param y2 the second point's <i>y</i> coordinate. 394 */ 395 public abstract void drawLine(int x1, int y1, int x2, int y2); 396 397 /** 398 * Fills the specified rectangle. 399 * The left and right edges of the rectangle are at 400 * <code>x</code> and <code>x + width - 1</code>. 401 * The top and bottom edges are at 402 * <code>y</code> and <code>y + height - 1</code>. 403 * The resulting rectangle covers an area 404 * <code>width</code> pixels wide by 405 * <code>height</code> pixels tall. 406 * The rectangle is filled using the graphics context's current color. 407 * @param x the <i>x</i> coordinate 408 * of the rectangle to be filled. 409 * @param y the <i>y</i> coordinate 410 * of the rectangle to be filled. 411 * @param width the width of the rectangle to be filled. 412 * @param height the height of the rectangle to be filled. 413 * @see java.awt.Graphics#clearRect 414 * @see java.awt.Graphics#drawRect 415 */ 416 public abstract void fillRect(int x, int y, int width, int height); 417 418 /** 419 * Draws the outline of the specified rectangle. 420 * The left and right edges of the rectangle are at 421 * <code>x</code> and <code>x + width</code>. 422 * The top and bottom edges are at 423 * <code>y</code> and <code>y + height</code>. 424 * The rectangle is drawn using the graphics context's current color. 425 * @param x the <i>x</i> coordinate 426 * of the rectangle to be drawn. 427 * @param y the <i>y</i> coordinate 428 * of the rectangle to be drawn. 429 * @param width the width of the rectangle to be drawn. 430 * @param height the height of the rectangle to be drawn. 431 * @see java.awt.Graphics#fillRect 432 * @see java.awt.Graphics#clearRect 433 */ 434 public void drawRect(int x, int y, int width, int height) { 435 if ((width < 0) || (height < 0)) { 436 return; 437 } 438 439 if (height == 0 || width == 0) { 440 drawLine(x, y, x + width, y + height); 441 } else { 442 drawLine(x, y, x + width - 1, y); 443 drawLine(x + width, y, x + width, y + height - 1); 444 drawLine(x + width, y + height, x + 1, y + height); 445 drawLine(x, y + height, x, y + 1); 446 } 447 } 448 449 /** 450 * Clears the specified rectangle by filling it with the background 451 * color of the current drawing surface. This operation does not 452 * use the current paint mode. 453 * <p> 454 * Beginning with Java 1.1, the background color 455 * of offscreen images may be system dependent. Applications should 456 * use <code>setColor</code> followed by <code>fillRect</code> to 457 * ensure that an offscreen image is cleared to a specific color. 458 * @param x the <i>x</i> coordinate of the rectangle to clear. 459 * @param y the <i>y</i> coordinate of the rectangle to clear. 460 * @param width the width of the rectangle to clear. 461 * @param height the height of the rectangle to clear. 462 * @see java.awt.Graphics#fillRect(int, int, int, int) 463 * @see java.awt.Graphics#drawRect 464 * @see java.awt.Graphics#setColor(java.awt.Color) 465 * @see java.awt.Graphics#setPaintMode 466 * @see java.awt.Graphics#setXORMode(java.awt.Color) 467 */ 468 public abstract void clearRect(int x, int y, int width, int height); 469 470 /** 471 * Draws an outlined round-cornered rectangle using this graphics 472 * context's current color. The left and right edges of the rectangle 473 * are at <code>x</code> and <code>x + width</code>, 474 * respectively. The top and bottom edges of the rectangle are at 475 * <code>y</code> and <code>y + height</code>. 476 * @param x the <i>x</i> coordinate of the rectangle to be drawn. 477 * @param y the <i>y</i> coordinate of the rectangle to be drawn. 478 * @param width the width of the rectangle to be drawn. 479 * @param height the height of the rectangle to be drawn. 480 * @param arcWidth the horizontal diameter of the arc 481 * at the four corners. 482 * @param arcHeight the vertical diameter of the arc 483 * at the four corners. 484 * @see java.awt.Graphics#fillRoundRect 485 */ 486 public abstract void drawRoundRect(int x, int y, int width, int height, 487 int arcWidth, int arcHeight); 488 489 /** 490 * Fills the specified rounded corner rectangle with the current color. 491 * The left and right edges of the rectangle 492 * are at <code>x</code> and <code>x + width - 1</code>, 493 * respectively. The top and bottom edges of the rectangle are at 494 * <code>y</code> and <code>y + height - 1</code>. 495 * @param x the <i>x</i> coordinate of the rectangle to be filled. 496 * @param y the <i>y</i> coordinate of the rectangle to be filled. 497 * @param width the width of the rectangle to be filled. 498 * @param height the height of the rectangle to be filled. 499 * @param arcWidth the horizontal diameter 500 * of the arc at the four corners. 501 * @param arcHeight the vertical diameter 502 * of the arc at the four corners. 503 * @see java.awt.Graphics#drawRoundRect 504 */ 505 public abstract void fillRoundRect(int x, int y, int width, int height, 506 int arcWidth, int arcHeight); 507 508 /** 509 * Draws a 3-D highlighted outline of the specified rectangle. 510 * The edges of the rectangle are highlighted so that they 511 * appear to be beveled and lit from the upper left corner. 512 * <p> 513 * The colors used for the highlighting effect are determined 514 * based on the current color. 515 * The resulting rectangle covers an area that is 516 * <code>width + 1</code> pixels wide 517 * by <code>height + 1</code> pixels tall. 518 * @param x the <i>x</i> coordinate of the rectangle to be drawn. 519 * @param y the <i>y</i> coordinate of the rectangle to be drawn. 520 * @param width the width of the rectangle to be drawn. 521 * @param height the height of the rectangle to be drawn. 522 * @param raised a boolean that determines whether the rectangle 523 * appears to be raised above the surface 524 * or sunk into the surface. 525 * @see java.awt.Graphics#fill3DRect 526 */ 527 public void draw3DRect(int x, int y, int width, int height, 528 boolean raised) { 529 Color c = getColor(); 530 Color brighter = c.brighter(); 531 Color darker = c.darker(); 532 533 setColor(raised ? brighter : darker); 534 drawLine(x, y, x, y + height); 535 drawLine(x + 1, y, x + width - 1, y); 536 setColor(raised ? darker : brighter); 537 drawLine(x + 1, y + height, x + width, y + height); 538 drawLine(x + width, y, x + width, y + height - 1); 539 setColor(c); 540 } 541 542 /** 543 * Paints a 3-D highlighted rectangle filled with the current color. 544 * The edges of the rectangle will be highlighted so that it appears 545 * as if the edges were beveled and lit from the upper left corner. 546 * The colors used for the highlighting effect will be determined from 547 * the current color. 548 * @param x the <i>x</i> coordinate of the rectangle to be filled. 549 * @param y the <i>y</i> coordinate of the rectangle to be filled. 550 * @param width the width of the rectangle to be filled. 551 * @param height the height of the rectangle to be filled. 552 * @param raised a boolean value that determines whether the 553 * rectangle appears to be raised above the surface 554 * or etched into the surface. 555 * @see java.awt.Graphics#draw3DRect 556 */ 557 public void fill3DRect(int x, int y, int width, int height, 558 boolean raised) { 559 Color c = getColor(); 560 Color brighter = c.brighter(); 561 Color darker = c.darker(); 562 563 if (!raised) { 564 setColor(darker); 565 } 566 fillRect(x+1, y+1, width-2, height-2); 567 setColor(raised ? brighter : darker); 568 drawLine(x, y, x, y + height - 1); 569 drawLine(x + 1, y, x + width - 2, y); 570 setColor(raised ? darker : brighter); 571 drawLine(x + 1, y + height - 1, x + width - 1, y + height - 1); 572 drawLine(x + width - 1, y, x + width - 1, y + height - 2); 573 setColor(c); 574 } 575 576 /** 577 * Draws the outline of an oval. 578 * The result is a circle or ellipse that fits within the 579 * rectangle specified by the <code>x</code>, <code>y</code>, 580 * <code>width</code>, and <code>height</code> arguments. 581 * <p> 582 * The oval covers an area that is 583 * <code>width + 1</code> pixels wide 584 * and <code>height + 1</code> pixels tall. 585 * @param x the <i>x</i> coordinate of the upper left 586 * corner of the oval to be drawn. 587 * @param y the <i>y</i> coordinate of the upper left 588 * corner of the oval to be drawn. 589 * @param width the width of the oval to be drawn. 590 * @param height the height of the oval to be drawn. 591 * @see java.awt.Graphics#fillOval 592 */ 593 public abstract void drawOval(int x, int y, int width, int height); 594 595 /** 596 * Fills an oval bounded by the specified rectangle with the 597 * current color. 598 * @param x the <i>x</i> coordinate of the upper left corner 599 * of the oval to be filled. 600 * @param y the <i>y</i> coordinate of the upper left corner 601 * of the oval to be filled. 602 * @param width the width of the oval to be filled. 603 * @param height the height of the oval to be filled. 604 * @see java.awt.Graphics#drawOval 605 */ 606 public abstract void fillOval(int x, int y, int width, int height); 607 608 /** 609 * Draws the outline of a circular or elliptical arc 610 * covering the specified rectangle. 611 * <p> 612 * The resulting arc begins at <code>startAngle</code> and extends 613 * for <code>arcAngle</code> degrees, using the current color. 614 * Angles are interpreted such that 0 degrees 615 * is at the 3 o'clock position. 616 * A positive value indicates a counter-clockwise rotation 617 * while a negative value indicates a clockwise rotation. 618 * <p> 619 * The center of the arc is the center of the rectangle whose origin 620 * is (<i>x</i>, <i>y</i>) and whose size is specified by the 621 * <code>width</code> and <code>height</code> arguments. 622 * <p> 623 * The resulting arc covers an area 624 * <code>width + 1</code> pixels wide 625 * by <code>height + 1</code> pixels tall. 626 * <p> 627 * The angles are specified relative to the non-square extents of 628 * the bounding rectangle such that 45 degrees always falls on the 629 * line from the center of the ellipse to the upper right corner of 630 * the bounding rectangle. As a result, if the bounding rectangle is 631 * noticeably longer in one axis than the other, the angles to the 632 * start and end of the arc segment will be skewed farther along the 633 * longer axis of the bounds. 634 * @param x the <i>x</i> coordinate of the 635 * upper-left corner of the arc to be drawn. 636 * @param y the <i>y</i> coordinate of the 637 * upper-left corner of the arc to be drawn. 638 * @param width the width of the arc to be drawn. 639 * @param height the height of the arc to be drawn. 640 * @param startAngle the beginning angle. 641 * @param arcAngle the angular extent of the arc, 642 * relative to the start angle. 643 * @see java.awt.Graphics#fillArc 644 */ 645 public abstract void drawArc(int x, int y, int width, int height, 646 int startAngle, int arcAngle); 647 648 /** 649 * Fills a circular or elliptical arc covering the specified rectangle. 650 * <p> 651 * The resulting arc begins at <code>startAngle</code> and extends 652 * for <code>arcAngle</code> degrees. 653 * Angles are interpreted such that 0 degrees 654 * is at the 3 o'clock position. 655 * A positive value indicates a counter-clockwise rotation 656 * while a negative value indicates a clockwise rotation. 657 * <p> 658 * The center of the arc is the center of the rectangle whose origin 659 * is (<i>x</i>, <i>y</i>) and whose size is specified by the 660 * <code>width</code> and <code>height</code> arguments. 661 * <p> 662 * The resulting arc covers an area 663 * <code>width + 1</code> pixels wide 664 * by <code>height + 1</code> pixels tall. 665 * <p> 666 * The angles are specified relative to the non-square extents of 667 * the bounding rectangle such that 45 degrees always falls on the 668 * line from the center of the ellipse to the upper right corner of 669 * the bounding rectangle. As a result, if the bounding rectangle is 670 * noticeably longer in one axis than the other, the angles to the 671 * start and end of the arc segment will be skewed farther along the 672 * longer axis of the bounds. 673 * @param x the <i>x</i> coordinate of the 674 * upper-left corner of the arc to be filled. 675 * @param y the <i>y</i> coordinate of the 676 * upper-left corner of the arc to be filled. 677 * @param width the width of the arc to be filled. 678 * @param height the height of the arc to be filled. 679 * @param startAngle the beginning angle. 680 * @param arcAngle the angular extent of the arc, 681 * relative to the start angle. 682 * @see java.awt.Graphics#drawArc 683 */ 684 public abstract void fillArc(int x, int y, int width, int height, 685 int startAngle, int arcAngle); 686 687 /** 688 * Draws a sequence of connected lines defined by 689 * arrays of <i>x</i> and <i>y</i> coordinates. 690 * Each pair of (<i>x</i>, <i>y</i>) coordinates defines a point. 691 * The figure is not closed if the first point 692 * differs from the last point. 693 * @param xPoints an array of <i>x</i> points 694 * @param yPoints an array of <i>y</i> points 695 * @param nPoints the total number of points 696 * @see java.awt.Graphics#drawPolygon(int[], int[], int) 697 * @since 1.1 698 */ 699 public abstract void drawPolyline(int xPoints[], int yPoints[], 700 int nPoints); 701 702 /** 703 * Draws a closed polygon defined by 704 * arrays of <i>x</i> and <i>y</i> coordinates. 705 * Each pair of (<i>x</i>, <i>y</i>) coordinates defines a point. 706 * <p> 707 * This method draws the polygon defined by <code>nPoint</code> line 708 * segments, where the first <code>nPoint - 1</code> 709 * line segments are line segments from 710 * <code>(xPoints[i - 1], yPoints[i - 1])</code> 711 * to <code>(xPoints[i], yPoints[i])</code>, for 712 * 1 ≤ <i>i</i> ≤ <code>nPoints</code>. 713 * The figure is automatically closed by drawing a line connecting 714 * the final point to the first point, if those points are different. 715 * @param xPoints a an array of <code>x</code> coordinates. 716 * @param yPoints a an array of <code>y</code> coordinates. 717 * @param nPoints a the total number of points. 718 * @see java.awt.Graphics#fillPolygon 719 * @see java.awt.Graphics#drawPolyline 720 */ 721 public abstract void drawPolygon(int xPoints[], int yPoints[], 722 int nPoints); 723 724 /** 725 * Draws the outline of a polygon defined by the specified 726 * <code>Polygon</code> object. 727 * @param p the polygon to draw. 728 * @see java.awt.Graphics#fillPolygon 729 * @see java.awt.Graphics#drawPolyline 730 */ 731 public void drawPolygon(Polygon p) { 732 drawPolygon(p.xpoints, p.ypoints, p.npoints); 733 } 734 735 /** 736 * Fills a closed polygon defined by 737 * arrays of <i>x</i> and <i>y</i> coordinates. 738 * <p> 739 * This method draws the polygon defined by <code>nPoint</code> line 740 * segments, where the first <code>nPoint - 1</code> 741 * line segments are line segments from 742 * <code>(xPoints[i - 1], yPoints[i - 1])</code> 743 * to <code>(xPoints[i], yPoints[i])</code>, for 744 * 1 ≤ <i>i</i> ≤ <code>nPoints</code>. 745 * The figure is automatically closed by drawing a line connecting 746 * the final point to the first point, if those points are different. 747 * <p> 748 * The area inside the polygon is defined using an 749 * even-odd fill rule, also known as the alternating rule. 750 * @param xPoints a an array of <code>x</code> coordinates. 751 * @param yPoints a an array of <code>y</code> coordinates. 752 * @param nPoints a the total number of points. 753 * @see java.awt.Graphics#drawPolygon(int[], int[], int) 754 */ 755 public abstract void fillPolygon(int xPoints[], int yPoints[], 756 int nPoints); 757 758 /** 759 * Fills the polygon defined by the specified Polygon object with 760 * the graphics context's current color. 761 * <p> 762 * The area inside the polygon is defined using an 763 * even-odd fill rule, also known as the alternating rule. 764 * @param p the polygon to fill. 765 * @see java.awt.Graphics#drawPolygon(int[], int[], int) 766 */ 767 public void fillPolygon(Polygon p) { 768 fillPolygon(p.xpoints, p.ypoints, p.npoints); 769 } 770 771 /** 772 * Draws the text given by the specified string, using this 773 * graphics context's current font and color. The baseline of the 774 * leftmost character is at position (<i>x</i>, <i>y</i>) in this 775 * graphics context's coordinate system. 776 * @param str the string to be drawn. 777 * @param x the <i>x</i> coordinate. 778 * @param y the <i>y</i> coordinate. 779 * @throws NullPointerException if <code>str</code> is <code>null</code>. 780 * @see java.awt.Graphics#drawBytes 781 * @see java.awt.Graphics#drawChars 782 */ 783 public abstract void drawString(String str, int x, int y); 784 785 /** 786 * Renders the text of the specified iterator applying its attributes 787 * in accordance with the specification of the 788 * {@link java.awt.font.TextAttribute TextAttribute} class. 789 * <p> 790 * The baseline of the leftmost character is at position 791 * (<i>x</i>, <i>y</i>) in this graphics context's coordinate system. 792 * @param iterator the iterator whose text is to be drawn 793 * @param x the <i>x</i> coordinate. 794 * @param y the <i>y</i> coordinate. 795 * @throws NullPointerException if <code>iterator</code> is 796 * <code>null</code>. 797 * @see java.awt.Graphics#drawBytes 798 * @see java.awt.Graphics#drawChars 799 */ 800 public abstract void drawString(AttributedCharacterIterator iterator, 801 int x, int y); 802 803 /** 804 * Draws the text given by the specified character array, using this 805 * graphics context's current font and color. The baseline of the 806 * first character is at position (<i>x</i>, <i>y</i>) in this 807 * graphics context's coordinate system. 808 * @param data the array of characters to be drawn 809 * @param offset the start offset in the data 810 * @param length the number of characters to be drawn 811 * @param x the <i>x</i> coordinate of the baseline of the text 812 * @param y the <i>y</i> coordinate of the baseline of the text 813 * @throws NullPointerException if <code>data</code> is <code>null</code>. 814 * @throws IndexOutOfBoundsException if <code>offset</code> or 815 * <code>length</code>is less than zero, or 816 * <code>offset+length</code> is greater than the length of the 817 * <code>data</code> array. 818 * @see java.awt.Graphics#drawBytes 819 * @see java.awt.Graphics#drawString 820 */ 821 public void drawChars(char data[], int offset, int length, int x, int y) { 822 drawString(new String(data, offset, length), x, y); 823 } 824 825 /** 826 * Draws the text given by the specified byte array, using this 827 * graphics context's current font and color. The baseline of the 828 * first character is at position (<i>x</i>, <i>y</i>) in this 829 * graphics context's coordinate system. 830 * <p> 831 * Use of this method is not recommended as each byte is interpreted 832 * as a Unicode code point in the range 0 to 255, and so can only be 833 * used to draw Latin characters in that range. 834 * @param data the data to be drawn 835 * @param offset the start offset in the data 836 * @param length the number of bytes that are drawn 837 * @param x the <i>x</i> coordinate of the baseline of the text 838 * @param y the <i>y</i> coordinate of the baseline of the text 839 * @throws NullPointerException if <code>data</code> is <code>null</code>. 840 * @throws IndexOutOfBoundsException if <code>offset</code> or 841 * <code>length</code>is less than zero, or <code>offset+length</code> 842 * is greater than the length of the <code>data</code> array. 843 * @see java.awt.Graphics#drawChars 844 * @see java.awt.Graphics#drawString 845 */ 846 public void drawBytes(byte data[], int offset, int length, int x, int y) { 847 drawString(new String(data, 0, offset, length), x, y); 848 } 849 850 /** 851 * Draws as much of the specified image as is currently available. 852 * The image is drawn with its top-left corner at 853 * (<i>x</i>, <i>y</i>) in this graphics context's coordinate 854 * space. Transparent pixels in the image do not affect whatever 855 * pixels are already there. 856 * <p> 857 * This method returns immediately in all cases, even if the 858 * complete image has not yet been loaded, and it has not been dithered 859 * and converted for the current output device. 860 * <p> 861 * If the image has completely loaded and its pixels are 862 * no longer being changed, then 863 * <code>drawImage</code> returns <code>true</code>. 864 * Otherwise, <code>drawImage</code> returns <code>false</code> 865 * and as more of 866 * the image becomes available 867 * or it is time to draw another frame of animation, 868 * the process that loads the image notifies 869 * the specified image observer. 870 * @param img the specified image to be drawn. This method does 871 * nothing if <code>img</code> is null. 872 * @param x the <i>x</i> coordinate. 873 * @param y the <i>y</i> coordinate. 874 * @param observer object to be notified as more of 875 * the image is converted. 876 * @return <code>false</code> if the image pixels are still changing; 877 * <code>true</code> otherwise. 878 * @see java.awt.Image 879 * @see java.awt.image.ImageObserver 880 * @see java.awt.image.ImageObserver#imageUpdate(java.awt.Image, int, int, int, int, int) 881 */ 882 public abstract boolean drawImage(Image img, int x, int y, 883 ImageObserver observer); 884 885 /** 886 * Draws as much of the specified image as has already been scaled 887 * to fit inside the specified rectangle. 888 * <p> 889 * The image is drawn inside the specified rectangle of this 890 * graphics context's coordinate space, and is scaled if 891 * necessary. Transparent pixels do not affect whatever pixels 892 * are already there. 893 * <p> 894 * This method returns immediately in all cases, even if the 895 * entire image has not yet been scaled, dithered, and converted 896 * for the current output device. 897 * If the current output representation is not yet complete, then 898 * <code>drawImage</code> returns <code>false</code>. As more of 899 * the image becomes available, the process that loads the image notifies 900 * the image observer by calling its <code>imageUpdate</code> method. 901 * <p> 902 * A scaled version of an image will not necessarily be 903 * available immediately just because an unscaled version of the 904 * image has been constructed for this output device. Each size of 905 * the image may be cached separately and generated from the original 906 * data in a separate image production sequence. 907 * @param img the specified image to be drawn. This method does 908 * nothing if <code>img</code> is null. 909 * @param x the <i>x</i> coordinate. 910 * @param y the <i>y</i> coordinate. 911 * @param width the width of the rectangle. 912 * @param height the height of the rectangle. 913 * @param observer object to be notified as more of 914 * the image is converted. 915 * @return <code>false</code> if the image pixels are still changing; 916 * <code>true</code> otherwise. 917 * @see java.awt.Image 918 * @see java.awt.image.ImageObserver 919 * @see java.awt.image.ImageObserver#imageUpdate(java.awt.Image, int, int, int, int, int) 920 */ 921 public abstract boolean drawImage(Image img, int x, int y, 922 int width, int height, 923 ImageObserver observer); 924 925 /** 926 * Draws as much of the specified image as is currently available. 927 * The image is drawn with its top-left corner at 928 * (<i>x</i>, <i>y</i>) in this graphics context's coordinate 929 * space. Transparent pixels are drawn in the specified 930 * background color. 931 * <p> 932 * This operation is equivalent to filling a rectangle of the 933 * width and height of the specified image with the given color and then 934 * drawing the image on top of it, but possibly more efficient. 935 * <p> 936 * This method returns immediately in all cases, even if the 937 * complete image has not yet been loaded, and it has not been dithered 938 * and converted for the current output device. 939 * <p> 940 * If the image has completely loaded and its pixels are 941 * no longer being changed, then 942 * <code>drawImage</code> returns <code>true</code>. 943 * Otherwise, <code>drawImage</code> returns <code>false</code> 944 * and as more of 945 * the image becomes available 946 * or it is time to draw another frame of animation, 947 * the process that loads the image notifies 948 * the specified image observer. 949 * @param img the specified image to be drawn. This method does 950 * nothing if <code>img</code> is null. 951 * @param x the <i>x</i> coordinate. 952 * @param y the <i>y</i> coordinate. 953 * @param bgcolor the background color to paint under the 954 * non-opaque portions of the image. 955 * @param observer object to be notified as more of 956 * the image is converted. 957 * @return <code>false</code> if the image pixels are still changing; 958 * <code>true</code> otherwise. 959 * @see java.awt.Image 960 * @see java.awt.image.ImageObserver 961 * @see java.awt.image.ImageObserver#imageUpdate(java.awt.Image, int, int, int, int, int) 962 */ 963 public abstract boolean drawImage(Image img, int x, int y, 964 Color bgcolor, 965 ImageObserver observer); 966 967 /** 968 * Draws as much of the specified image as has already been scaled 969 * to fit inside the specified rectangle. 970 * <p> 971 * The image is drawn inside the specified rectangle of this 972 * graphics context's coordinate space, and is scaled if 973 * necessary. Transparent pixels are drawn in the specified 974 * background color. 975 * This operation is equivalent to filling a rectangle of the 976 * width and height of the specified image with the given color and then 977 * drawing the image on top of it, but possibly more efficient. 978 * <p> 979 * This method returns immediately in all cases, even if the 980 * entire image has not yet been scaled, dithered, and converted 981 * for the current output device. 982 * If the current output representation is not yet complete then 983 * <code>drawImage</code> returns <code>false</code>. As more of 984 * the image becomes available, the process that loads the image notifies 985 * the specified image observer. 986 * <p> 987 * A scaled version of an image will not necessarily be 988 * available immediately just because an unscaled version of the 989 * image has been constructed for this output device. Each size of 990 * the image may be cached separately and generated from the original 991 * data in a separate image production sequence. 992 * @param img the specified image to be drawn. This method does 993 * nothing if <code>img</code> is null. 994 * @param x the <i>x</i> coordinate. 995 * @param y the <i>y</i> coordinate. 996 * @param width the width of the rectangle. 997 * @param height the height of the rectangle. 998 * @param bgcolor the background color to paint under the 999 * non-opaque portions of the image. 1000 * @param observer object to be notified as more of 1001 * the image is converted. 1002 * @return <code>false</code> if the image pixels are still changing; 1003 * <code>true</code> otherwise. 1004 * @see java.awt.Image 1005 * @see java.awt.image.ImageObserver 1006 * @see java.awt.image.ImageObserver#imageUpdate(java.awt.Image, int, int, int, int, int) 1007 */ 1008 public abstract boolean drawImage(Image img, int x, int y, 1009 int width, int height, 1010 Color bgcolor, 1011 ImageObserver observer); 1012 1013 /** 1014 * Draws as much of the specified area of the specified image as is 1015 * currently available, scaling it on the fly to fit inside the 1016 * specified area of the destination drawable surface. Transparent pixels 1017 * do not affect whatever pixels are already there. 1018 * <p> 1019 * This method returns immediately in all cases, even if the 1020 * image area to be drawn has not yet been scaled, dithered, and converted 1021 * for the current output device. 1022 * If the current output representation is not yet complete then 1023 * <code>drawImage</code> returns <code>false</code>. As more of 1024 * the image becomes available, the process that loads the image notifies 1025 * the specified image observer. 1026 * <p> 1027 * This method always uses the unscaled version of the image 1028 * to render the scaled rectangle and performs the required 1029 * scaling on the fly. It does not use a cached, scaled version 1030 * of the image for this operation. Scaling of the image from source 1031 * to destination is performed such that the first coordinate 1032 * of the source rectangle is mapped to the first coordinate of 1033 * the destination rectangle, and the second source coordinate is 1034 * mapped to the second destination coordinate. The subimage is 1035 * scaled and flipped as needed to preserve those mappings. 1036 * @param img the specified image to be drawn. This method does 1037 * nothing if <code>img</code> is null. 1038 * @param dx1 the <i>x</i> coordinate of the first corner of the 1039 * destination rectangle. 1040 * @param dy1 the <i>y</i> coordinate of the first corner of the 1041 * destination rectangle. 1042 * @param dx2 the <i>x</i> coordinate of the second corner of the 1043 * destination rectangle. 1044 * @param dy2 the <i>y</i> coordinate of the second corner of the 1045 * destination rectangle. 1046 * @param sx1 the <i>x</i> coordinate of the first corner of the 1047 * source rectangle. 1048 * @param sy1 the <i>y</i> coordinate of the first corner of the 1049 * source rectangle. 1050 * @param sx2 the <i>x</i> coordinate of the second corner of the 1051 * source rectangle. 1052 * @param sy2 the <i>y</i> coordinate of the second corner of the 1053 * source rectangle. 1054 * @param observer object to be notified as more of the image is 1055 * scaled and converted. 1056 * @return <code>false</code> if the image pixels are still changing; 1057 * <code>true</code> otherwise. 1058 * @see java.awt.Image 1059 * @see java.awt.image.ImageObserver 1060 * @see java.awt.image.ImageObserver#imageUpdate(java.awt.Image, int, int, int, int, int) 1061 * @since 1.1 1062 */ 1063 public abstract boolean drawImage(Image img, 1064 int dx1, int dy1, int dx2, int dy2, 1065 int sx1, int sy1, int sx2, int sy2, 1066 ImageObserver observer); 1067 1068 /** 1069 * Draws as much of the specified area of the specified image as is 1070 * currently available, scaling it on the fly to fit inside the 1071 * specified area of the destination drawable surface. 1072 * <p> 1073 * Transparent pixels are drawn in the specified background color. 1074 * This operation is equivalent to filling a rectangle of the 1075 * width and height of the specified image with the given color and then 1076 * drawing the image on top of it, but possibly more efficient. 1077 * <p> 1078 * This method returns immediately in all cases, even if the 1079 * image area to be drawn has not yet been scaled, dithered, and converted 1080 * for the current output device. 1081 * If the current output representation is not yet complete then 1082 * <code>drawImage</code> returns <code>false</code>. As more of 1083 * the image becomes available, the process that loads the image notifies 1084 * the specified image observer. 1085 * <p> 1086 * This method always uses the unscaled version of the image 1087 * to render the scaled rectangle and performs the required 1088 * scaling on the fly. It does not use a cached, scaled version 1089 * of the image for this operation. Scaling of the image from source 1090 * to destination is performed such that the first coordinate 1091 * of the source rectangle is mapped to the first coordinate of 1092 * the destination rectangle, and the second source coordinate is 1093 * mapped to the second destination coordinate. The subimage is 1094 * scaled and flipped as needed to preserve those mappings. 1095 * @param img the specified image to be drawn. This method does 1096 * nothing if <code>img</code> is null. 1097 * @param dx1 the <i>x</i> coordinate of the first corner of the 1098 * destination rectangle. 1099 * @param dy1 the <i>y</i> coordinate of the first corner of the 1100 * destination rectangle. 1101 * @param dx2 the <i>x</i> coordinate of the second corner of the 1102 * destination rectangle. 1103 * @param dy2 the <i>y</i> coordinate of the second corner of the 1104 * destination rectangle. 1105 * @param sx1 the <i>x</i> coordinate of the first corner of the 1106 * source rectangle. 1107 * @param sy1 the <i>y</i> coordinate of the first corner of the 1108 * source rectangle. 1109 * @param sx2 the <i>x</i> coordinate of the second corner of the 1110 * source rectangle. 1111 * @param sy2 the <i>y</i> coordinate of the second corner of the 1112 * source rectangle. 1113 * @param bgcolor the background color to paint under the 1114 * non-opaque portions of the image. 1115 * @param observer object to be notified as more of the image is 1116 * scaled and converted. 1117 * @return <code>false</code> if the image pixels are still changing; 1118 * <code>true</code> otherwise. 1119 * @see java.awt.Image 1120 * @see java.awt.image.ImageObserver 1121 * @see java.awt.image.ImageObserver#imageUpdate(java.awt.Image, int, int, int, int, int) 1122 * @since 1.1 1123 */ 1124 public abstract boolean drawImage(Image img, 1125 int dx1, int dy1, int dx2, int dy2, 1126 int sx1, int sy1, int sx2, int sy2, 1127 Color bgcolor, 1128 ImageObserver observer); 1129 1130 /** 1131 * Disposes of this graphics context and releases 1132 * any system resources that it is using. 1133 * A <code>Graphics</code> object cannot be used after 1134 * <code>dispose</code>has been called. 1135 * <p> 1136 * When a Java program runs, a large number of <code>Graphics</code> 1137 * objects can be created within a short time frame. 1138 * Although the finalization process of the garbage collector 1139 * also disposes of the same system resources, it is preferable 1140 * to manually free the associated resources by calling this 1141 * method rather than to rely on a finalization process which 1142 * may not run to completion for a long period of time. 1143 * <p> 1144 * Graphics objects which are provided as arguments to the 1145 * <code>paint</code> and <code>update</code> methods 1146 * of components are automatically released by the system when 1147 * those methods return. For efficiency, programmers should 1148 * call <code>dispose</code> when finished using 1149 * a <code>Graphics</code> object only if it was created 1150 * directly from a component or another <code>Graphics</code> object. 1151 * @see java.awt.Graphics#finalize 1152 * @see java.awt.Component#paint 1153 * @see java.awt.Component#update 1154 * @see java.awt.Component#getGraphics 1155 * @see java.awt.Graphics#create 1156 */ 1157 public abstract void dispose(); 1158 1159 /** 1160 * Disposes of this graphics context once it is no longer referenced. 1161 * @see #dispose 1162 */ 1163 public void finalize() { 1164 dispose(); 1165 } 1166 1167 /** 1168 * Returns a <code>String</code> object representing this 1169 * <code>Graphics</code> object's value. 1170 * @return a string representation of this graphics context. 1171 */ 1172 public String toString() { 1173 return getClass().getName() + "[font=" + getFont() + ",color=" + getColor() + "]"; 1174 } 1175 1176 /** 1177 * Returns the bounding rectangle of the current clipping area. 1178 * @return the bounding rectangle of the current clipping area 1179 * or <code>null</code> if no clip is set. 1180 * @deprecated As of JDK version 1.1, 1181 * replaced by <code>getClipBounds()</code>. 1182 */ 1183 @Deprecated 1184 public Rectangle getClipRect() { 1185 return getClipBounds(); 1186 } 1187 1188 /** 1189 * Returns true if the specified rectangular area might intersect 1190 * the current clipping area. 1191 * The coordinates of the specified rectangular area are in the 1192 * user coordinate space and are relative to the coordinate 1193 * system origin of this graphics context. 1194 * This method may use an algorithm that calculates a result quickly 1195 * but which sometimes might return true even if the specified 1196 * rectangular area does not intersect the clipping area. 1197 * The specific algorithm employed may thus trade off accuracy for 1198 * speed, but it will never return false unless it can guarantee 1199 * that the specified rectangular area does not intersect the 1200 * current clipping area. 1201 * The clipping area used by this method can represent the 1202 * intersection of the user clip as specified through the clip 1203 * methods of this graphics context as well as the clipping 1204 * associated with the device or image bounds and window visibility. 1205 * 1206 * @param x the x coordinate of the rectangle to test against the clip 1207 * @param y the y coordinate of the rectangle to test against the clip 1208 * @param width the width of the rectangle to test against the clip 1209 * @param height the height of the rectangle to test against the clip 1210 * @return <code>true</code> if the specified rectangle intersects 1211 * the bounds of the current clip; <code>false</code> 1212 * otherwise. 1213 */ 1214 public boolean hitClip(int x, int y, int width, int height) { 1215 // Note, this implementation is not very efficient. 1216 // Subclasses should override this method and calculate 1217 // the results more directly. 1218 Rectangle clipRect = getClipBounds(); 1219 if (clipRect == null) { 1220 return true; 1221 } 1222 return clipRect.intersects(x, y, width, height); 1223 } 1224 1225 /** 1226 * Returns the bounding rectangle of the current clipping area. 1227 * The coordinates in the rectangle are relative to the coordinate 1228 * system origin of this graphics context. This method differs 1229 * from {@link #getClipBounds() getClipBounds} in that an existing 1230 * rectangle is used instead of allocating a new one. 1231 * This method refers to the user clip, which is independent of the 1232 * clipping associated with device bounds and window visibility. 1233 * If no clip has previously been set, or if the clip has been 1234 * cleared using <code>setClip(null)</code>, this method returns the 1235 * specified <code>Rectangle</code>. 1236 * @param r the rectangle where the current clipping area is 1237 * copied to. Any current values in this rectangle are 1238 * overwritten. 1239 * @return the bounding rectangle of the current clipping area. 1240 */ 1241 public Rectangle getClipBounds(Rectangle r) { 1242 // Note, this implementation is not very efficient. 1243 // Subclasses should override this method and avoid 1244 // the allocation overhead of getClipBounds(). 1245 Rectangle clipRect = getClipBounds(); 1246 if (clipRect != null) { 1247 r.x = clipRect.x; 1248 r.y = clipRect.y; 1249 r.width = clipRect.width; 1250 r.height = clipRect.height; 1251 } else if (r == null) { 1252 throw new NullPointerException("null rectangle parameter"); 1253 } 1254 return r; 1255 } 1256} 1257