graphics.java

《移动Agent技术》一书的所有章节源代码。

     * Draws the outline of an oval.
     * The result is a circle or ellipse that fits within the
     * rectangle specified by the <code>x</code>, <code>y</code>,
     * <code>width</code>, and <code>height</code> arguments.
     * <p>
     * The oval covers an area that is
     * <code>width&nbsp;+&nbsp;1</code> pixels wide
     * and <code>height&nbsp;+&nbsp;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
     * @since       JDK1.0
     */
    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
     * @since       JDK1.0
     */
    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</code> and extends
     * for <code>arcAngle</code> degrees, using the current color.
     * Angles are interpreted such that 0&nbsp;degrees
     * is at the 3&nbsp;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>,&nbsp;<i>y</i>) and whose size is specified by the
     * <code>width</code> and <code>height</code> arguments.
     * <p>
     * The resulting arc covers an area
     * <code>width&nbsp;+&nbsp;1</code> pixels wide
     * by <code>height&nbsp;+&nbsp;1</code> pixels tall.
     * @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
     * @since       JDK1.0
     */
    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</code> and extends
     * for <code>arcAngle</code> degrees.
     * Angles are interpreted such that 0&nbsp;degrees
     * is at the 3&nbsp;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>,&nbsp;<i>y</i>) and whose size is specified by the
     * <code>width</code> and <code>height</code> arguments.
     * <p>
     * The resulting arc covers an area
     * <code>width&nbsp;+&nbsp;1</code> pixels wide
     * by <code>height&nbsp;+&nbsp;1</code> pixels tall.
     * @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
     * @since       JDK1.0
     */
    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>,&nbsp;<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       JDK1.1
     */
    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>,&nbsp;<i>y</i>) coordinates defines a point.
     * <p>
     * This method draws the polygon defined by <code>nPoint</code> line
     * segments, where the first <code>nPoint&nbsp;-&nbsp;1</code>
     * line segments are line segments from
     * <code>(xPoints[i&nbsp;-&nbsp;1],&nbsp;yPoints[i&nbsp;-&nbsp;1])</code>
     * to <code>(xPoints[i],&nbsp;yPoints[i])</code>, for
     * 1&nbsp;&le;&nbsp;<i>i</i>&nbsp;&le;&nbsp;<code>nPoints</code>.
     * 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</code> coordinates.
     * @param        yPoints   a an array of <code>y</code> coordinates.
     * @param        nPoints   a the total number of points.
     * @see          java.awt.Graphics#fillPolygon
     * @see          java.awt.Graphics#drawPolyline
     * @since        JDK1.0
     */
    public abstract void drawPolygon(int xPoints[], int yPoints[],
				     int nPoints);

    /**
     * Draws the outline of a polygon defined by the specified
     * <code>Polygon</code> object.
     * @param        p the polygon to draw.
     * @see          java.awt.Graphics#fillPolygon
     * @see          java.awt.Graphics#drawPolyline
     * @since        JDK1.0
     */
    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</code> line
     * segments, where the first <code>nPoint&nbsp;-&nbsp;1</code>
     * line segments are line segments from
     * <code>(xPoints[i&nbsp;-&nbsp;1],&nbsp;yPoints[i&nbsp;-&nbsp;1])</code>
     * to <code>(xPoints[i],&nbsp;yPoints[i])</code>, for
     * 1&nbsp;&le;&nbsp;<i>i</i>&nbsp;&le;&nbsp;<code>nPoints</code>.
     * 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</code> coordinates.
     * @param        yPoints   a an array of <code>y</code> coordinates.
     * @param        nPoints   a the total number of points.
     * @see          java.awt.Graphics#drawPolygon(int[], int[], int)
     * @since        JDK1.0
     */
    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)
     * @since        JDK1.0
     */
    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
     * first character is at position (<i>x</i>,&nbsp;<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.
     * @see         java.awt.Graphics#drawBytes
     * @see         java.awt.Graphics#drawChars
     * @since       JDK1.0
     */
    public abstract void drawString(String str, 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>,&nbsp;<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
     * @see         java.awt.Graphics#drawBytes
     * @see         java.awt.Graphics#drawString
     * @since       JDK1.0
     */
    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>,&nbsp;<i>y</i>) in this
     * graphics context's coordinate system.
     * @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
     * @see         java.awt.Graphics#drawChars
     * @see         java.awt.Graphics#drawString
     * @since       JDK1.0
     */
    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>,&nbsp;<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 not yet been completely loaded, then
     * <code>drawImage</code> returns <code>false</code>. As more of
     * the image becomes available, the process that draws the image notifies
     * the specified image observer.
     * @param    img the specified image to be drawn.
     * @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.
     * @see      java.awt.Image
     * @see      java.awt.image.ImageObserver
     * @see      java.awt.image.ImageObserver#imageUpdate(java.awt.Image, int, int, int, int, int)
     * @since    JDK1.0
     */
    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.