Javadoc注释编写细则[转]
package example;import java.awt.Image;import java.awt.image.ImageObserver;/** * * Graphics is the abstract base class for all graphics contexts * * which allow an application to draw onto components realized on * * various devices or onto off-screen images. * * A Graphics object encapsulates the state information needed * * for the various rendering operations that Java supports. This * * state information includes: * * * * # * The Component to draw on * * # * A translation origin for rendering and clipping coordinates * * # * The current clip * * # * The current color * * # * The current font * * # * The current logical pixel operation function (XOR or Paint) * * # * The current XOR alternation color * * (see setXORMode) * * * * * * Coordinates are infinitely thin and lie between the pixels of the * * output device. * * Operations which draw the outline of a figure operate by traversing * * along the infinitely thin path with a pixel-sized pen that hangs * * down and to the right of the anchor point on the path. * * Operations which fill a figure operate by filling the interior * * of the infinitely thin path. * * Operations which render horizontal text render the ascending * * portion of the characters entirely above the baseline coordinate. * * * * Some important points to consider are that drawing a figure that * * covers a given rectangle will occupy one extra row of pixels on * * the right and bottom edges compared to filling a figure that is * * bounded by that same rectangle. * * Also, drawing a horizontal line along the same y coordinate as * * the baseline of a line of text will draw the line entirely below * * the text except for any descenders. * * Both of these properties are due to the pen hanging down and to * * the right from the path that it traverses. * * * * All coordinates which appear as arguments to the methods of this * * Graphics object are considered relative to the translation origin * * of this Graphics object prior to the invocation of the method. * * All rendering operations modify only pixels which lie within the * * area bounded by both the current clip of the graphics context * * and the extents of the Component used to create the Graphics object. * * * * @author Sami Shaio * * @author Arthur van Hoff * * @version %I%, %G% * * @since 1.0 */public abstract class Graphics {/** * * Draws as much of the specified image as is currently available * * with its northwest corner at the specified coordinate (x, y). * * This method will return 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 * * the method will return false and the indicated * * {@link ImageObserver} object will be notified as the * * conversion process progresses. * * * * @param img * the image to be drawn * * @param x * the x-coordinate of the northwest corner * * of the destination rectangle in pixels * * @param y * the y-coordinate of the northwest corner * * of the destination rectangle in pixels * * @param observer * the image observer to be notified as more * * of the image is converted. May be * * null * * @return true if the image is completely * * loaded and was painted successfully; * * false otherwise. * * @see Image * * @see ImageObserver * * @since 1.0 */public abstract boolean drawImage(Image img, int x, int y,ImageObserver observer);/** * * Dispose of the system resources used by this graphics context. * * The Graphics context cannot be used after being disposed of. * * While the finalization process of the garbage collector will * * also dispose of the same system resources, due to the number * * of Graphics objects that can be created in short time frames * * it is preferable to manually free the associated resources * * using this method rather than to rely on a finalization * * process which may not happen for a long period of time. * * * * Graphics objects which are provided as arguments to the paint * * and update methods of Components are automatically disposed * * by the system when those methods return. Programmers should, * * for efficiency, call the dispose method when finished using * * a Graphics object only if it was created directly from a * * Component or another Graphics object. * * * * @see #create(int, int, int, int) * * @see #finalize() * * @see Component#getGraphics() * * @see Component#paint(Graphics) * * @see Component#update(Graphics) * * @since 1.0 */public abstract void dispose();/** * * Disposes of this graphics context once it is no longer * * referenced. * * * * @see #dispose() * * @since 1.0 */public void finalize() {dispose();}}
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