1 /*
   2  * Copyright (c) 1995, 2013, Oracle and/or its affiliates. All rights reserved.
   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
   4  *
   5  * This code is free software; you can redistribute it and/or modify it
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   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
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  19  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
  20  *
  21  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
  22  * or visit www.oracle.com if you need additional information or have any
  23  * questions.
  24  */
  25 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  *
  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       JDK1.0
 103  */
 104 public 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>,&nbsp;<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>,&nbsp;<i>y</i>).
 143      * That is to say, the point (<code>0</code>,&nbsp;<code>0</code>) in the
 144      * new graphics context is the same as (<i>x</i>,&nbsp;<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>,&nbsp;<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>,&nbsp;<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>,&nbsp;<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,&nbsp;y1)</code> and <code>(x2,&nbsp;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&nbsp;+&nbsp;width&nbsp;-&nbsp;1</code>.
 401      * The top and bottom edges are at
 402      * <code>y</code> and <code>y&nbsp;+&nbsp;height&nbsp;-&nbsp;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&nbsp;+&nbsp;width</code>.
 422      * The top and bottom edges are at
 423      * <code>y</code> and <code>y&nbsp;+&nbsp;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&nbsp;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&nbsp;+&nbsp;width</code>,
 474      * respectively. The top and bottom edges of the rectangle are at
 475      * <code>y</code> and <code>y&nbsp;+&nbsp;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&nbsp;+&nbsp;width&nbsp;-&nbsp;1</code>,
 493      * respectively. The top and bottom edges of the rectangle are at
 494      * <code>y</code> and <code>y&nbsp;+&nbsp;height&nbsp;-&nbsp;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&nbsp;+&nbsp;1</code> pixels wide
 517      * by <code>height&nbsp;+&nbsp;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&nbsp;+&nbsp;1</code> pixels wide
 584      * and <code>height&nbsp;+&nbsp;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&nbsp;degrees
 615      * is at the 3&nbsp;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>,&nbsp;<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&nbsp;+&nbsp;1</code> pixels wide
 625      * by <code>height&nbsp;+&nbsp;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&nbsp;degrees
 654      * is at the 3&nbsp;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>,&nbsp;<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&nbsp;+&nbsp;1</code> pixels wide
 664      * by <code>height&nbsp;+&nbsp;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>,&nbsp;<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>,&nbsp;<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&nbsp;-&nbsp;1</code>
 709      * line segments are line segments from
 710      * <code>(xPoints[i&nbsp;-&nbsp;1],&nbsp;yPoints[i&nbsp;-&nbsp;1])</code>
 711      * to <code>(xPoints[i],&nbsp;yPoints[i])</code>, for
 712      * 1&nbsp;&le;&nbsp;<i>i</i>&nbsp;&le;&nbsp;<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&nbsp;-&nbsp;1</code>
 741      * line segments are line segments from
 742      * <code>(xPoints[i&nbsp;-&nbsp;1],&nbsp;yPoints[i&nbsp;-&nbsp;1])</code>
 743      * to <code>(xPoints[i],&nbsp;yPoints[i])</code>, for
 744      * 1&nbsp;&le;&nbsp;<i>i</i>&nbsp;&le;&nbsp;<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>,&nbsp;<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>,&nbsp;<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>,&nbsp;<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>,&nbsp;<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>,&nbsp;<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>,&nbsp;<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 }