Java tutorial
/* * Copyright (c) 1995, 2018, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. Oracle designates this * particular file as subject to the "Classpath" exception as provided * by Oracle in the LICENSE file that accompanied this code. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. */ package java.awt; import java.io.*; import java.lang.*; import java.util.*; import java.awt.image.ImageObserver; import java.text.AttributedCharacterIterator; /** * The {@code Graphics} class is the abstract base class for * all graphics contexts that allow an application to draw onto * components that are realized on various devices, as well as * onto off-screen images. * <p> * A {@code Graphics} object encapsulates state information needed * for the basic rendering operations that Java supports. This * state information includes the following properties: * * <ul> * <li>The {@code Component} object on which to draw. * <li>A translation origin for rendering and clipping coordinates. * <li>The current clip. * <li>The current color. * <li>The current font. * <li>The current logical pixel operation function (XOR or Paint). * <li>The current XOR alternation color * (see {@link Graphics#setXORMode}). * </ul> * <p> * Coordinates are infinitely thin and lie between the pixels of the * output device. * Operations that draw the outline of a figure operate by traversing * an infinitely thin path between pixels with a pixel-sized pen that hangs * down and to the right of the anchor point on the path. * Operations that fill a figure operate by filling the interior * of that infinitely thin path. * Operations that render horizontal text render the ascending * portion of character glyphs entirely above the baseline coordinate. * <p> * The graphics pen hangs down and to the right from the path it traverses. * This has the following implications: * <ul> * <li>If you draw a figure that covers a given rectangle, that * figure occupies one extra row of pixels on the right and bottom edges * as compared to filling a figure that is bounded by that same rectangle. * <li>If you draw a horizontal line along the same <i>y</i> coordinate as * the baseline of a line of text, that line is drawn entirely below * the text, except for any descenders. * </ul><p> * All coordinates that appear as arguments to the methods of this * {@code Graphics} object are considered relative to the * translation origin of this {@code Graphics} object prior to * the invocation of the method. * <p> * All rendering operations modify only pixels which lie within the * area bounded by the current clip, which is specified by a {@link Shape} * in user space and is controlled by the program using the * {@code Graphics} object. This <i>user clip</i> * is transformed into device space and combined with the * <i>device clip</i>, which is defined by the visibility of windows and * device extents. The combination of the user clip and device clip * defines the <i>composite clip</i>, which determines the final clipping * region. The user clip cannot be modified by the rendering * system to reflect the resulting composite clip. The user clip can only * be changed through the {@code setClip} or {@code clipRect} * methods. * All drawing or writing is done in the current color, * using the current paint mode, and in the current font. * * @author Sami Shaio * @author Arthur van Hoff * @see java.awt.Component * @see java.awt.Graphics#clipRect(int, int, int, int) * @see java.awt.Graphics#setColor(java.awt.Color) * @see java.awt.Graphics#setPaintMode() * @see java.awt.Graphics#setXORMode(java.awt.Color) * @see java.awt.Graphics#setFont(java.awt.Font) * @since 1.0 */ public abstract class Graphics { /** * Constructs a new {@code Graphics} object. * This constructor is the default constructor for a graphics * context. * <p> * Since {@code Graphics} is an abstract class, applications * cannot call this constructor directly. Graphics contexts are * obtained from other graphics contexts or are created by calling * {@code getGraphics} on a component. * @see java.awt.Graphics#create() * @see java.awt.Component#getGraphics */ protected Graphics() { } /** * Creates a new {@code Graphics} object that is * a copy of this {@code Graphics} object. * @return a new graphics context that is a copy of * this graphics context. */ public abstract Graphics create(); /** * Creates a new {@code Graphics} object based on this * {@code Graphics} object, but with a new translation and clip area. * The new {@code Graphics} object has its origin * translated to the specified point (<i>x</i>, <i>y</i>). * Its clip area is determined by the intersection of the original * clip area with the specified rectangle. The arguments are all * interpreted in the coordinate system of the original * {@code Graphics} object. The new graphics context is * identical to the original, except in two respects: * * <ul> * <li> * The new graphics context is translated by (<i>x</i>, <i>y</i>). * That is to say, the point ({@code 0}, {@code 0}) in the * new graphics context is the same as (<i>x</i>, <i>y</i>) in * the original graphics context. * <li> * The new graphics context has an additional clipping rectangle, in * addition to whatever (translated) clipping rectangle it inherited * from the original graphics context. The origin of the new clipping * rectangle is at ({@code 0}, {@code 0}), and its size * is specified by the {@code width} and {@code height} * arguments. * </ul> * * @param x the <i>x</i> coordinate. * @param y the <i>y</i> coordinate. * @param width the width of the clipping rectangle. * @param height the height of the clipping rectangle. * @return a new graphics context. * @see java.awt.Graphics#translate * @see java.awt.Graphics#clipRect */ public Graphics create(int x, int y, int width, int height) { Graphics g = create(); if (g == null) return null; g.translate(x, y); g.clipRect(0, 0, width, height); return g; } /** * Translates the origin of the graphics context to the point * (<i>x</i>, <i>y</i>) in the current coordinate system. * Modifies this graphics context so that its new origin corresponds * to the point (<i>x</i>, <i>y</i>) in this graphics context's * original coordinate system. All coordinates used in subsequent * rendering operations on this graphics context will be relative * to this new origin. * @param x the <i>x</i> coordinate. * @param y the <i>y</i> coordinate. */ public abstract void translate(int x, int y); /** * Gets this graphics context's current color. * @return this graphics context's current color. * @see java.awt.Color * @see java.awt.Graphics#setColor(Color) */ public abstract Color getColor(); /** * Sets this graphics context's current color to the specified * color. All subsequent graphics operations using this graphics * context use this specified color. * @param c the new rendering color. * @see java.awt.Color * @see java.awt.Graphics#getColor */ public abstract void setColor(Color c); /** * Sets the paint mode of this graphics context to overwrite the * destination with this graphics context's current color. * This sets the logical pixel operation function to the paint or * overwrite mode. All subsequent rendering operations will * overwrite the destination with the current color. */ public abstract void setPaintMode(); /** * Sets the paint mode of this graphics context to alternate between * this graphics context's current color and the new specified color. * This specifies that logical pixel operations are performed in the * XOR mode, which alternates pixels between the current color and * a specified XOR color. * <p> * When drawing operations are performed, pixels which are the * current color are changed to the specified color, and vice versa. * <p> * Pixels that are of colors other than those two colors are changed * in an unpredictable but reversible manner; if the same figure is * drawn twice, then all pixels are restored to their original values. * @param c1 the XOR alternation color */ public abstract void setXORMode(Color c1); /** * Gets the current font. * @return this graphics context's current font. * @see java.awt.Font * @see java.awt.Graphics#setFont(Font) */ public abstract Font getFont(); /** * Sets this graphics context's font to the specified font. * All subsequent text operations using this graphics context * use this font. A null argument is silently ignored. * @param font the font. * @see java.awt.Graphics#getFont * @see java.awt.Graphics#drawString(java.lang.String, int, int) * @see java.awt.Graphics#drawBytes(byte[], int, int, int, int) * @see java.awt.Graphics#drawChars(char[], int, int, int, int) */ public abstract void setFont(Font font); /** * Gets the font metrics of the current font. * @return the font metrics of this graphics * context's current font. * @see java.awt.Graphics#getFont * @see java.awt.FontMetrics * @see java.awt.Graphics#getFontMetrics(Font) */ public FontMetrics getFontMetrics() { return getFontMetrics(getFont()); } /** * Gets the font metrics for the specified font. * @return the font metrics for the specified font. * @param f the specified font * @see java.awt.Graphics#getFont * @see java.awt.FontMetrics * @see java.awt.Graphics#getFontMetrics() */ public abstract FontMetrics getFontMetrics(Font f); /** * Returns the bounding rectangle of the current clipping area. * This method refers to the user clip, which is independent of the * clipping associated with device bounds and window visibility. * If no clip has previously been set, or if the clip has been * cleared using {@code setClip(null)}, this method returns * {@code null}. * The coordinates in the rectangle are relative to the coordinate * system origin of this graphics context. * @return the bounding rectangle of the current clipping area, * or {@code null} if no clip is set. * @see java.awt.Graphics#getClip * @see java.awt.Graphics#clipRect * @see java.awt.Graphics#setClip(int, int, int, int) * @see java.awt.Graphics#setClip(Shape) * @since 1.1 */ public abstract Rectangle getClipBounds(); /** * Intersects the current clip with the specified rectangle. * The resulting clipping area is the intersection of the current * clipping area and the specified rectangle. If there is no * current clipping area, either because the clip has never been * set, or the clip has been cleared using {@code setClip(null)}, * the specified rectangle becomes the new clip. * This method sets the user clip, which is independent of the * clipping associated with device bounds and window visibility. * This method can only be used to make the current clip smaller. * To set the current clip larger, use any of the setClip methods. * Rendering operations have no effect outside of the clipping area. * @param x the x coordinate of the rectangle to intersect the clip with * @param y the y coordinate of the rectangle to intersect the clip with * @param width the width of the rectangle to intersect the clip with * @param height the height of the rectangle to intersect the clip with * @see #setClip(int, int, int, int) * @see #setClip(Shape) */ public abstract void clipRect(int x, int y, int width, int height); /** * Sets the current clip to the rectangle specified by the given * coordinates. This method sets the user clip, which is * independent of the clipping associated with device bounds * and window visibility. * Rendering operations have no effect outside of the clipping area. * @param x the <i>x</i> coordinate of the new clip rectangle. * @param y the <i>y</i> coordinate of the new clip rectangle. * @param width the width of the new clip rectangle. * @param height the height of the new clip rectangle. * @see java.awt.Graphics#clipRect * @see java.awt.Graphics#setClip(Shape) * @see java.awt.Graphics#getClip * @since 1.1 */ public abstract void setClip(int x, int y, int width, int height); /** * Gets the current clipping area. * This method returns the user clip, which is independent of the * clipping associated with device bounds and window visibility. * If no clip has previously been set, or if the clip has been * cleared using {@code setClip(null)}, this method returns * {@code null}. * @return a {@code Shape} object representing the * current clipping area, or {@code null} if * no clip is set. * @see java.awt.Graphics#getClipBounds * @see java.awt.Graphics#clipRect * @see java.awt.Graphics#setClip(int, int, int, int) * @see java.awt.Graphics#setClip(Shape) * @since 1.1 */ public abstract Shape getClip(); /** * Sets the current clipping area to an arbitrary clip shape. * Not all objects that implement the {@code Shape} * interface can be used to set the clip. The only * {@code Shape} objects that are guaranteed to be * supported are {@code Shape} objects that are * obtained via the {@code getClip} method and via * {@code Rectangle} objects. This method sets the * user clip, which is independent of the clipping associated * with device bounds and window visibility. * @param clip the {@code Shape} to use to set the clip * @see java.awt.Graphics#getClip() * @see java.awt.Graphics#clipRect * @see java.awt.Graphics#setClip(int, int, int, int) * @since 1.1 */ public abstract void setClip(Shape clip); /** * Copies an area of the component by a distance specified by * {@code dx} and {@code dy}. From the point specified * by {@code x} and {@code y}, this method * copies downwards and to the right. To copy an area of the * component to the left or upwards, specify a negative value for * {@code dx} or {@code dy}. * If a portion of the source rectangle lies outside the bounds * of the component, or is obscured by another window or component, * {@code copyArea} will be unable to copy the associated * pixels. The area that is omitted can be refreshed by calling * the component's {@code paint} method. * @param x the <i>x</i> coordinate of the source rectangle. * @param y the <i>y</i> coordinate of the source rectangle. * @param width the width of the source rectangle. * @param height the height of the source rectangle. * @param dx the horizontal distance to copy the pixels. * @param dy the vertical distance to copy the pixels. */ public abstract void copyArea(int x, int y, int width, int height, int dx, int dy); /** * Draws a line, using the current color, between the points * <code>(x1, y1)</code> and <code>(x2, y2)</code> * in this graphics context's coordinate system. * @param x1 the first point's <i>x</i> coordinate. * @param y1 the first point's <i>y</i> coordinate. * @param x2 the second point's <i>x</i> coordinate. * @param y2 the second point's <i>y</i> coordinate. */ public abstract void drawLine(int x1, int y1, int x2, int y2); /** * Fills the specified rectangle. * The left and right edges of the rectangle are at * {@code x} and <code>x + width - 1</code>. * The top and bottom edges are at * {@code y} and <code>y + height - 1</code>. * The resulting rectangle covers an area * {@code width} pixels wide by * {@code height} pixels tall. * The rectangle is filled using the graphics context's current color. * @param x the <i>x</i> coordinate * of the rectangle to be filled. * @param y the <i>y</i> coordinate * of the rectangle to be filled. * @param width the width of the rectangle to be filled. * @param height the height of the rectangle to be filled. * @see java.awt.Graphics#clearRect * @see java.awt.Graphics#drawRect */ public abstract void fillRect(int x, int y, int width, int height); /** * Draws the outline of the specified rectangle. * The left and right edges of the rectangle are at * {@code x} and <code>x + width</code>. * The top and bottom edges are at * {@code y} and <code>y + height</code>. * The rectangle is drawn using the graphics context's current color. * @param x the <i>x</i> coordinate * of the rectangle to be drawn. * @param y the <i>y</i> coordinate * of the rectangle to be drawn. * @param width the width of the rectangle to be drawn. * @param height the height of the rectangle to be drawn. * @see java.awt.Graphics#fillRect * @see java.awt.Graphics#clearRect */ public void drawRect(int x, int y, int width, int height) { if ((width < 0) || (height < 0)) { return; } if (height == 0 || width == 0) { drawLine(x, y, x + width, y + height); } else { drawLine(x, y, x + width - 1, y); drawLine(x + width, y, x + width, y + height - 1); drawLine(x + width, y + height, x + 1, y + height); drawLine(x, y + height, x, y + 1); } } /** * Clears the specified rectangle by filling it with the background * color of the current drawing surface. This operation does not * use the current paint mode. * <p> * Beginning with Java 1.1, the background color * of offscreen images may be system dependent. Applications should * use {@code setColor} followed by {@code fillRect} to * ensure that an offscreen image is cleared to a specific color. * @param x the <i>x</i> coordinate of the rectangle to clear. * @param y the <i>y</i> coordinate of the rectangle to clear. * @param width the width of the rectangle to clear. * @param height the height of the rectangle to clear. * @see java.awt.Graphics#fillRect(int, int, int, int) * @see java.awt.Graphics#drawRect * @see java.awt.Graphics#setColor(java.awt.Color) * @see java.awt.Graphics#setPaintMode * @see java.awt.Graphics#setXORMode(java.awt.Color) */ public abstract void clearRect(int x, int y, int width, int height); /** * Draws an outlined round-cornered rectangle using this graphics * context's current color. The left and right edges of the rectangle * are at {@code x} and <code>x + width</code>, * respectively. The top and bottom edges of the rectangle are at * {@code y} and <code>y + height</code>. * @param x the <i>x</i> coordinate of the rectangle to be drawn. * @param y the <i>y</i> coordinate of the rectangle to be drawn. * @param width the width of the rectangle to be drawn. * @param height the height of the rectangle to be drawn. * @param arcWidth the horizontal diameter of the arc * at the four corners. * @param arcHeight the vertical diameter of the arc * at the four corners. * @see java.awt.Graphics#fillRoundRect */ public abstract void drawRoundRect(int x, int y, int width, int height, int arcWidth, int arcHeight); /** * Fills the specified rounded corner rectangle with the current color. * The left and right edges of the rectangle * are at {@code x} and <code>x + width - 1</code>, * respectively. The top and bottom edges of the rectangle are at * {@code y} and <code>y + height - 1</code>. * @param x the <i>x</i> coordinate of the rectangle to be filled. * @param y the <i>y</i> coordinate of the rectangle to be filled. * @param width the width of the rectangle to be filled. * @param height the height of the rectangle to be filled. * @param arcWidth the horizontal diameter * of the arc at the four corners. * @param arcHeight the vertical diameter * of the arc at the four corners. * @see java.awt.Graphics#drawRoundRect */ public abstract void fillRoundRect(int x, int y, int width, int height, int arcWidth, int arcHeight); /** * Draws a 3-D highlighted outline of the specified rectangle. * The edges of the rectangle are highlighted so that they * appear to be beveled and lit from the upper left corner. * <p> * The colors used for the highlighting effect are determined * based on the current color. * The resulting rectangle covers an area that is * <code>width + 1</code> pixels wide * by <code>height + 1</code> pixels tall. * @param x the <i>x</i> coordinate of the rectangle to be drawn. * @param y the <i>y</i> coordinate of the rectangle to be drawn. * @param width the width of the rectangle to be drawn. * @param height the height of the rectangle to be drawn. * @param raised a boolean that determines whether the rectangle * appears to be raised above the surface * or sunk into the surface. * @see java.awt.Graphics#fill3DRect */ public void draw3DRect(int x, int y, int width, int height, boolean raised) { Color c = getColor(); Color brighter = c.brighter(); Color darker = c.darker(); setColor(raised ? brighter : darker); drawLine(x, y, x, y + height); drawLine(x + 1, y, x + width - 1, y); setColor(raised ? darker : brighter); drawLine(x + 1, y + height, x + width, y + height); drawLine(x + width, y, x + width, y + height - 1); setColor(c); } /** * Paints a 3-D highlighted rectangle filled with the current color. * The edges of the rectangle will be highlighted so that it appears * as if the edges were beveled and lit from the upper left corner. * The colors used for the highlighting effect will be determined from * the current color. * @param x the <i>x</i> coordinate of the rectangle to be filled. * @param y the <i>y</i> coordinate of the rectangle to be filled. * @param width the width of the rectangle to be filled. * @param height the height of the rectangle to be filled. * @param raised a boolean value that determines whether the * rectangle appears to be raised above the surface * or etched into the surface. * @see java.awt.Graphics#draw3DRect */ public void fill3DRect(int x, int y, int width, int height, boolean raised) { Color c = getColor(); Color brighter = c.brighter(); Color darker = c.darker(); if (!raised) { setColor(darker); } fillRect(x + 1, y + 1, width - 2, height - 2); setColor(raised ? brighter : darker); drawLine(x, y, x, y + height - 1); drawLine(x + 1, y, x + width - 2, y); setColor(raised ? darker : brighter); drawLine(x + 1, y + height - 1, x + width - 1, y + height - 1); drawLine(x + width - 1, y, x + width - 1, y + height - 2); setColor(c); } /** * Draws the outline of an oval. * The result is a circle or ellipse that fits within the * rectangle specified by the {@code x}, {@code y}, * {@code width}, and {@code height} arguments. * <p> * The oval covers an area that is * <code>width + 1</code> pixels wide * and <code>height + 1</code> pixels tall. * @param x the <i>x</i> coordinate of the upper left * corner of the oval to be drawn. * @param y the <i>y</i> coordinate of the upper left * corner of the oval to be drawn. * @param width the width of the oval to be drawn. * @param height the height of the oval to be drawn. * @see java.awt.Graphics#fillOval */ public abstract void drawOval(int x, int y, int width, int height); /** * Fills an oval bounded by the specified rectangle with the * current color. * @param x the <i>x</i> coordinate of the upper left corner * of the oval to be filled. * @param y the <i>y</i> coordinate of the upper left corner * of the oval to be filled. * @param width the width of the oval to be filled. * @param height the height of the oval to be filled. * @see java.awt.Graphics#drawOval */ public abstract void fillOval(int x, int y, int width, int height); /** * Draws the outline of a circular or elliptical arc * covering the specified rectangle. * <p> * The resulting arc begins at {@code startAngle} and extends * for {@code arcAngle} degrees, using the current color. * Angles are interpreted such that 0 degrees * is at the 3 o'clock position. * A positive value indicates a counter-clockwise rotation * while a negative value indicates a clockwise rotation. * <p> * The center of the arc is the center of the rectangle whose origin * is (<i>x</i>, <i>y</i>) and whose size is specified by the * {@code width} and {@code height} arguments. * <p> * The resulting arc covers an area * <code>width + 1</code> pixels wide * by <code>height + 1</code> pixels tall. * <p> * The angles are specified relative to the non-square extents of * the bounding rectangle such that 45 degrees always falls on the * line from the center of the ellipse to the upper right corner of * the bounding rectangle. As a result, if the bounding rectangle is * noticeably longer in one axis than the other, the angles to the * start and end of the arc segment will be skewed farther along the * longer axis of the bounds. * @param x the <i>x</i> coordinate of the * upper-left corner of the arc to be drawn. * @param y the <i>y</i> coordinate of the * upper-left corner of the arc to be drawn. * @param width the width of the arc to be drawn. * @param height the height of the arc to be drawn. * @param startAngle the beginning angle. * @param arcAngle the angular extent of the arc, * relative to the start angle. * @see java.awt.Graphics#fillArc */ public abstract void drawArc(int x, int y, int width, int height, int startAngle, int arcAngle); /** * Fills a circular or elliptical arc covering the specified rectangle. * <p> * The resulting arc begins at {@code startAngle} and extends * for {@code arcAngle} degrees. * Angles are interpreted such that 0 degrees * is at the 3 o'clock position. * A positive value indicates a counter-clockwise rotation * while a negative value indicates a clockwise rotation. * <p> * The center of the arc is the center of the rectangle whose origin * is (<i>x</i>, <i>y</i>) and whose size is specified by the * {@code width} and {@code height} arguments. * <p> * The resulting arc covers an area * <code>width + 1</code> pixels wide * by <code>height + 1</code> pixels tall. * <p> * The angles are specified relative to the non-square extents of * the bounding rectangle such that 45 degrees always falls on the * line from the center of the ellipse to the upper right corner of * the bounding rectangle. As a result, if the bounding rectangle is * noticeably longer in one axis than the other, the angles to the * start and end of the arc segment will be skewed farther along the * longer axis of the bounds. * @param x the <i>x</i> coordinate of the * upper-left corner of the arc to be filled. * @param y the <i>y</i> coordinate of the * upper-left corner of the arc to be filled. * @param width the width of the arc to be filled. * @param height the height of the arc to be filled. * @param startAngle the beginning angle. * @param arcAngle the angular extent of the arc, * relative to the start angle. * @see java.awt.Graphics#drawArc */ public abstract void fillArc(int x, int y, int width, int height, int startAngle, int arcAngle); /** * Draws a sequence of connected lines defined by * arrays of <i>x</i> and <i>y</i> coordinates. * Each pair of (<i>x</i>, <i>y</i>) coordinates defines a point. * The figure is not closed if the first point * differs from the last point. * @param xPoints an array of <i>x</i> points * @param yPoints an array of <i>y</i> points * @param nPoints the total number of points * @see java.awt.Graphics#drawPolygon(int[], int[], int) * @since 1.1 */ public abstract void drawPolyline(int[] xPoints, int[] yPoints, int nPoints); /** * Draws a closed polygon defined by * arrays of <i>x</i> and <i>y</i> coordinates. * Each pair of (<i>x</i>, <i>y</i>) coordinates defines a point. * <p> * This method draws the polygon defined by {@code nPoint} line * segments, where the first <code>nPoint - 1</code> * line segments are line segments from * <code>(xPoints[i - 1], yPoints[i - 1])</code> * to <code>(xPoints[i], yPoints[i])</code>, for * 1 ≤ <i>i</i> ≤ {@code nPoints}. * The figure is automatically closed by drawing a line connecting * the final point to the first point, if those points are different. * @param xPoints a an array of {@code x} coordinates. * @param yPoints a an array of {@code y} coordinates. * @param nPoints a the total number of points. * @see java.awt.Graphics#fillPolygon * @see java.awt.Graphics#drawPolyline */ public abstract void drawPolygon(int[] xPoints, int[] yPoints, int nPoints); /** * Draws the outline of a polygon defined by the specified * {@code Polygon} object. * @param p the polygon to draw. * @see java.awt.Graphics#fillPolygon * @see java.awt.Graphics#drawPolyline */ public void drawPolygon(Polygon p) { drawPolygon(p.xpoints, p.ypoints, p.npoints); } /** * Fills a closed polygon defined by * arrays of <i>x</i> and <i>y</i> coordinates. * <p> * This method draws the polygon defined by {@code nPoint} line * segments, where the first <code>nPoint - 1</code> * line segments are line segments from * <code>(xPoints[i - 1], yPoints[i - 1])</code> * to <code>(xPoints[i], yPoints[i])</code>, for * 1 ≤ <i>i</i> ≤ {@code nPoints}. * The figure is automatically closed by drawing a line connecting * the final point to the first point, if those points are different. * <p> * The area inside the polygon is defined using an * even-odd fill rule, also known as the alternating rule. * @param xPoints a an array of {@code x} coordinates. * @param yPoints a an array of {@code y} coordinates. * @param nPoints a the total number of points. * @see java.awt.Graphics#drawPolygon(int[], int[], int) */ public abstract void fillPolygon(int[] xPoints, int[] yPoints, int nPoints); /** * Fills the polygon defined by the specified Polygon object with * the graphics context's current color. * <p> * The area inside the polygon is defined using an * even-odd fill rule, also known as the alternating rule. * @param p the polygon to fill. * @see java.awt.Graphics#drawPolygon(int[], int[], int) */ public void fillPolygon(Polygon p) { fillPolygon(p.xpoints, p.ypoints, p.npoints); } /** * Draws the text given by the specified string, using this * graphics context's current font and color. The baseline of the * leftmost character is at position (<i>x</i>, <i>y</i>) in this * graphics context's coordinate system. * @param str the string to be drawn. * @param x the <i>x</i> coordinate. * @param y the <i>y</i> coordinate. * @throws NullPointerException if {@code str} is {@code null}. * @see java.awt.Graphics#drawBytes * @see java.awt.Graphics#drawChars */ public abstract void drawString(String str, int x, int y); /** * Renders the text of the specified iterator applying its attributes * in accordance with the specification of the * {@link java.awt.font.TextAttribute TextAttribute} class. * <p> * The baseline of the leftmost character is at position * (<i>x</i>, <i>y</i>) in this graphics context's coordinate system. * @param iterator the iterator whose text is to be drawn * @param x the <i>x</i> coordinate. * @param y the <i>y</i> coordinate. * @throws NullPointerException if {@code iterator} is * {@code null}. * @see java.awt.Graphics#drawBytes * @see java.awt.Graphics#drawChars */ public abstract void drawString(AttributedCharacterIterator iterator, int x, int y); /** * Draws the text given by the specified character array, using this * graphics context's current font and color. The baseline of the * first character is at position (<i>x</i>, <i>y</i>) in this * graphics context's coordinate system. * @param data the array of characters to be drawn * @param offset the start offset in the data * @param length the number of characters to be drawn * @param x the <i>x</i> coordinate of the baseline of the text * @param y the <i>y</i> coordinate of the baseline of the text * @throws NullPointerException if {@code data} is {@code null}. * @throws IndexOutOfBoundsException if {@code offset} or * {@code length} is less than zero, or * {@code offset+length} is greater than the length of the * {@code data} array. * @see java.awt.Graphics#drawBytes * @see java.awt.Graphics#drawString */ public void drawChars(char[] data, int offset, int length, int x, int y) { drawString(new String(data, offset, length), x, y); } /** * Draws the text given by the specified byte array, using this * graphics context's current font and color. The baseline of the * first character is at position (<i>x</i>, <i>y</i>) in this * graphics context's coordinate system. * <p> * Use of this method is not recommended as each byte is interpreted * as a Unicode code point in the range 0 to 255, and so can only be * used to draw Latin characters in that range. * @param data the data to be drawn * @param offset the start offset in the data * @param length the number of bytes that are drawn * @param x the <i>x</i> coordinate of the baseline of the text * @param y the <i>y</i> coordinate of the baseline of the text * @throws NullPointerException if {@code data} is {@code null}. * @throws IndexOutOfBoundsException if {@code offset} or * {@code length} is less than zero, or {@code offset+length} * is greater than the length of the {@code data} array. * @see java.awt.Graphics#drawChars * @see java.awt.Graphics#drawString */ @SuppressWarnings("deprecation") public void drawBytes(byte[] data, int offset, int length, int x, int y) { drawString(new String(data, 0, offset, length), x, y); } /** * Draws as much of the specified image as is currently available. * The image is drawn with its top-left corner at * (<i>x</i>, <i>y</i>) in this graphics context's coordinate * space. Transparent pixels in the image do not affect whatever * pixels are already there. * <p> * This method returns immediately in all cases, even if the * complete image has not yet been loaded, and it has not been dithered * and converted for the current output device. * <p> * If the image has completely loaded and its pixels are * no longer being changed, then * {@code drawImage} returns {@code true}. * Otherwise, {@code drawImage} returns {@code false} * and as more of * the image becomes available * or it is time to draw another frame of animation, * the process that loads the image notifies * the specified image observer. * @param img the specified image to be drawn. This method does * nothing if {@code img} is null. * @param x the <i>x</i> coordinate. * @param y the <i>y</i> coordinate. * @param observer object to be notified as more of * the image is converted. * @return {@code false} if the image pixels are still changing; * {@code true} otherwise. * @see java.awt.Image * @see java.awt.image.ImageObserver * @see java.awt.image.ImageObserver#imageUpdate(java.awt.Image, int, int, int, int, int) */ public abstract boolean drawImage(Image img, int x, int y, ImageObserver observer); /** * Draws as much of the specified image as has already been scaled * to fit inside the specified rectangle. * <p> * The image is drawn inside the specified rectangle of this * graphics context's coordinate space, and is scaled if * necessary. Transparent pixels do not affect whatever pixels * are already there. * <p> * This method returns immediately in all cases, even if the * entire image has not yet been scaled, dithered, and converted * for the current output device. * If the current output representation is not yet complete, then * {@code drawImage} returns {@code false}. As more of * the image becomes available, the process that loads the image notifies * the image observer by calling its {@code imageUpdate} method. * <p> * A scaled version of an image will not necessarily be * available immediately just because an unscaled version of the * image has been constructed for this output device. Each size of * the image may be cached separately and generated from the original * data in a separate image production sequence. * @param img the specified image to be drawn. This method does * nothing if {@code img} is null. * @param x the <i>x</i> coordinate. * @param y the <i>y</i> coordinate. * @param width the width of the rectangle. * @param height the height of the rectangle. * @param observer object to be notified as more of * the image is converted. * @return {@code false} if the image pixels are still changing; * {@code true} otherwise. * @see java.awt.Image * @see java.awt.image.ImageObserver * @see java.awt.image.ImageObserver#imageUpdate(java.awt.Image, int, int, int, int, int) */ public abstract boolean drawImage(Image img, int x, int y, int width, int height, ImageObserver observer); /** * Draws as much of the specified image as is currently available. * The image is drawn with its top-left corner at * (<i>x</i>, <i>y</i>) in this graphics context's coordinate * space. Transparent pixels are drawn in the specified * background color. * <p> * This operation is equivalent to filling a rectangle of the * width and height of the specified image with the given color and then * drawing the image on top of it, but possibly more efficient. * <p> * This method returns immediately in all cases, even if the * complete image has not yet been loaded, and it has not been dithered * and converted for the current output device. * <p> * If the image has completely loaded and its pixels are * no longer being changed, then * {@code drawImage} returns {@code true}. * Otherwise, {@code drawImage} returns {@code false} * and as more of * the image becomes available * or it is time to draw another frame of animation, * the process that loads the image notifies * the specified image observer. * @param img the specified image to be drawn. This method does * nothing if {@code img} is null. * @param x the <i>x</i> coordinate. * @param y the <i>y</i> coordinate. * @param bgcolor the background color to paint under the * non-opaque portions of the image. * @param observer object to be notified as more of * the image is converted. * @return {@code false} if the image pixels are still changing; * {@code true} otherwise. * @see java.awt.Image * @see java.awt.image.ImageObserver * @see java.awt.image.ImageObserver#imageUpdate(java.awt.Image, int, int, int, int, int) */ public abstract boolean drawImage(Image img, int x, int y, Color bgcolor, ImageObserver observer); /** * Draws as much of the specified image as has already been scaled * to fit inside the specified rectangle. * <p> * The image is drawn inside the specified rectangle of this * graphics context's coordinate space, and is scaled if * necessary. Transparent pixels are drawn in the specified * background color. * This operation is equivalent to filling a rectangle of the * width and height of the specified image with the given color and then * drawing the image on top of it, but possibly more efficient. * <p> * This method returns immediately in all cases, even if the * entire image has not yet been scaled, dithered, and converted * for the current output device. * If the current output representation is not yet complete then * {@code drawImage} returns {@code false}. As more of * the image becomes available, the process that loads the image notifies * the specified image observer. * <p> * A scaled version of an image will not necessarily be * available immediately just because an unscaled version of the * image has been constructed for this output device. Each size of * the image may be cached separately and generated from the original * data in a separate image production sequence. * @param img the specified image to be drawn. This method does * nothing if {@code img} is null. * @param x the <i>x</i> coordinate. * @param y the <i>y</i> coordinate. * @param width the width of the rectangle. * @param height the height of the rectangle. * @param bgcolor the background color to paint under the * non-opaque portions of the image. * @param observer object to be notified as more of * the image is converted. * @return {@code false} if the image pixels are still changing; * {@code true} otherwise. * @see java.awt.Image * @see java.awt.image.ImageObserver * @see java.awt.image.ImageObserver#imageUpdate(java.awt.Image, int, int, int, int, int) */ public abstract boolean drawImage(Image img, int x, int y, int width, int height, Color bgcolor, ImageObserver observer); /** * Draws as much of the specified area of the specified image as is * currently available, scaling it on the fly to fit inside the * specified area of the destination drawable surface. Transparent pixels * do not affect whatever pixels are already there. * <p> * This method returns immediately in all cases, even if the * image area to be drawn has not yet been scaled, dithered, and converted * for the current output device. * If the current output representation is not yet complete then * {@code drawImage} returns {@code false}. As more of * the image becomes available, the process that loads the image notifies * the specified image observer. * <p> * This method always uses the unscaled version of the image * to render the scaled rectangle and performs the required * scaling on the fly. It does not use a cached, scaled version * of the image for this operation. Scaling of the image from source * to destination is performed such that the first coordinate * of the source rectangle is mapped to the first coordinate of * the destination rectangle, and the second source coordinate is * mapped to the second destination coordinate. The subimage is * scaled and flipped as needed to preserve those mappings. * @param img the specified image to be drawn. This method does * nothing if {@code img} is null. * @param dx1 the <i>x</i> coordinate of the first corner of the * destination rectangle. * @param dy1 the <i>y</i> coordinate of the first corner of the * destination rectangle. * @param dx2 the <i>x</i> coordinate of the second corner of the * destination rectangle. * @param dy2 the <i>y</i> coordinate of the second corner of the * destination rectangle. * @param sx1 the <i>x</i> coordinate of the first corner of the * source rectangle. * @param sy1 the <i>y</i> coordinate of the first corner of the * source rectangle. * @param sx2 the <i>x</i> coordinate of the second corner of the * source rectangle. * @param sy2 the <i>y</i> coordinate of the second corner of the * source rectangle. * @param observer object to be notified as more of the image is * scaled and converted. * @return {@code false} if the image pixels are still changing; * {@code true} otherwise. * @see java.awt.Image * @see java.awt.image.ImageObserver * @see java.awt.image.ImageObserver#imageUpdate(java.awt.Image, int, int, int, int, int) * @since 1.1 */ public abstract boolean drawImage(Image img, int dx1, int dy1, int dx2, int dy2, int sx1, int sy1, int sx2, int sy2, ImageObserver observer); /** * Draws as much of the specified area of the specified image as is * currently available, scaling it on the fly to fit inside the * specified area of the destination drawable surface. * <p> * Transparent pixels are drawn in the specified background color. * This operation is equivalent to filling a rectangle of the * width and height of the specified image with the given color and then * drawing the image on top of it, but possibly more efficient. * <p> * This method returns immediately in all cases, even if the * image area to be drawn has not yet been scaled, dithered, and converted * for the current output device. * If the current output representation is not yet complete then * {@code drawImage} returns {@code false}. As more of * the image becomes available, the process that loads the image notifies * the specified image observer. * <p> * This method always uses the unscaled version of the image * to render the scaled rectangle and performs the required * scaling on the fly. It does not use a cached, scaled version * of the image for this operation. Scaling of the image from source * to destination is performed such that the first coordinate * of the source rectangle is mapped to the first coordinate of * the destination rectangle, and the second source coordinate is * mapped to the second destination coordinate. The subimage is * scaled and flipped as needed to preserve those mappings. * @param img the specified image to be drawn. This method does * nothing if {@code img} is null. * @param dx1 the <i>x</i> coordinate of the first corner of the * destination rectangle. * @param dy1 the <i>y</i> coordinate of the first corner of the * destination rectangle. * @param dx2 the <i>x</i> coordinate of the second corner of the * destination rectangle. * @param dy2 the <i>y</i> coordinate of the second corner of the * destination rectangle. * @param sx1 the <i>x</i> coordinate of the first corner of the * source rectangle. * @param sy1 the <i>y</i> coordinate of the first corner of the * source rectangle. * @param sx2 the <i>x</i> coordinate of the second corner of the * source rectangle. * @param sy2 the <i>y</i> coordinate of the second corner of the * source rectangle. * @param bgcolor the background color to paint under the * non-opaque portions of the image. * @param observer object to be notified as more of the image is * scaled and converted. * @return {@code false} if the image pixels are still changing; * {@code true} otherwise. * @see java.awt.Image * @see java.awt.image.ImageObserver * @see java.awt.image.ImageObserver#imageUpdate(java.awt.Image, int, int, int, int, int) * @since 1.1 */ public abstract boolean drawImage(Image img, int dx1, int dy1, int dx2, int dy2, int sx1, int sy1, int sx2, int sy2, Color bgcolor, ImageObserver observer); /** * Disposes of this graphics context and releases * any system resources that it is using. * A {@code Graphics} object cannot be used after * {@code dispose} has been called. * <p> * When a Java program runs, a large number of {@code Graphics} * objects can be created within a short time frame. * Although the finalization process of the garbage collector * also disposes of the same system resources, it is preferable * to manually free the associated resources by calling this * method rather than to rely on a finalization process which * may not run to completion for a long period of time. * <p> * Graphics objects which are provided as arguments to the * {@code paint} and {@code update} methods * of components are automatically released by the system when * those methods return. For efficiency, programmers should * call {@code dispose} when finished using * a {@code Graphics} object only if it was created * directly from a component or another {@code Graphics} object. * @see java.awt.Graphics#finalize * @see java.awt.Component#paint * @see java.awt.Component#update * @see java.awt.Component#getGraphics * @see java.awt.Graphics#create */ public abstract void dispose(); /** * Disposes of this graphics context once it is no longer referenced. * * @deprecated The {@code finalize} method has been deprecated. * Subclasses that override {@code finalize} in order to perform cleanup * should be modified to use alternative cleanup mechanisms and * to remove the overriding {@code finalize} method. * When overriding the {@code finalize} method, its implementation must explicitly * ensure that {@code super.finalize()} is invoked as described in {@link Object#finalize}. * See the specification for {@link Object#finalize()} for further * information about migration options. * @see #dispose */ @Deprecated(since = "9") public void finalize() { dispose(); } /** * Returns a {@code String} object representing this * {@code Graphics} object's value. * @return a string representation of this graphics context. */ public String toString() { return getClass().getName() + "[font=" + getFont() + ",color=" + getColor() + "]"; } /** * Returns the bounding rectangle of the current clipping area. * @return the bounding rectangle of the current clipping area * or {@code null} if no clip is set. * @deprecated As of JDK version 1.1, * replaced by {@code getClipBounds()}. */ @Deprecated public Rectangle getClipRect() { return getClipBounds(); } /** * Returns true if the specified rectangular area might intersect * the current clipping area. * The coordinates of the specified rectangular area are in the * user coordinate space and are relative to the coordinate * system origin of this graphics context. * This method may use an algorithm that calculates a result quickly * but which sometimes might return true even if the specified * rectangular area does not intersect the clipping area. * The specific algorithm employed may thus trade off accuracy for * speed, but it will never return false unless it can guarantee * that the specified rectangular area does not intersect the * current clipping area. * The clipping area used by this method can represent the * intersection of the user clip as specified through the clip * methods of this graphics context as well as the clipping * associated with the device or image bounds and window visibility. * * @param x the x coordinate of the rectangle to test against the clip * @param y the y coordinate of the rectangle to test against the clip * @param width the width of the rectangle to test against the clip * @param height the height of the rectangle to test against the clip * @return {@code true} if the specified rectangle intersects * the bounds of the current clip; {@code false} * otherwise. */ public boolean hitClip(int x, int y, int width, int height) { // Note, this implementation is not very efficient. // Subclasses should override this method and calculate // the results more directly. Rectangle clipRect = getClipBounds(); if (clipRect == null) { return true; } return clipRect.intersects(x, y, width, height); } /** * Returns the bounding rectangle of the current clipping area. * The coordinates in the rectangle are relative to the coordinate * system origin of this graphics context. This method differs * from {@link #getClipBounds() getClipBounds} in that an existing * rectangle is used instead of allocating a new one. * This method refers to the user clip, which is independent of the * clipping associated with device bounds and window visibility. * If no clip has previously been set, or if the clip has been * cleared using {@code setClip(null)}, this method returns the * specified {@code Rectangle}. * @param r the rectangle where the current clipping area is * copied to. Any current values in this rectangle are * overwritten. * @return the bounding rectangle of the current clipping area. */ public Rectangle getClipBounds(Rectangle r) { // Note, this implementation is not very efficient. // Subclasses should override this method and avoid // the allocation overhead of getClipBounds(). Rectangle clipRect = getClipBounds(); if (clipRect != null) { r.x = clipRect.x; r.y = clipRect.y; r.width = clipRect.width; r.height = clipRect.height; } else if (r == null) { throw new NullPointerException("null rectangle parameter"); } return r; } }