1 /*
2 * Copyright 1995-2006 Sun Microsystems, Inc. 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. Sun designates this
8 * particular file as subject to the "Classpath" exception as provided
9 * by Sun 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
22 * CA 95054 USA or visit www.sun.com if you need additional information or
23 * have any questions.
24 */
25 package java.awt;
26
27 import java.io;
28 import java.lang;
29 import java.util;
30 import java.awt.image.ImageObserver;
31 import 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 * <p>
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 * <p><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 JDK1.0
103 */
104 public abstract class Graphics {
105
106 /**
107 * Constructs a new <code>Graphics</code> object.
108 * This constructor is the default contructor 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 * <p>
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 * <p>
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 JDK1.1
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 JDK1.1
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 JDK1.1
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 JDK1.1
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 JDK1.1
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 JDK1.1
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 JDK1.1
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 }
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