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<html><!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Keywords" name="Keywords"content="JavaScript, examples, JavaScript: The Definitive Guide"><title>Example 22-14 from JavaScript: The Definitive Guide, Fifth Edition</title><style>body { font-family: arial, sans-serif}.lefttitle { font: bold x-small arial, sans-serif; margin: 5px; letter-spacing: .15em; text-transform:uppercase;}.leftcaption { font: italic x-small sans-serif; margin-bottom: 20px;}#banner { font-family:sans-serif; color:#333; font-size:x-large; font-weight:normal; padding:15px; padding-top: 3px; border-bottom:4px double #666;}#banner h1 { font-size: x-large; margin: 0px; padding: 0px;}#banner .description { font-size:large; margin-left: 2px;}pre { border: solid black 1px; background-color: #ddd; padding: 10px; margin: 0px;} </style></script></head><body><div id="banner"><h1>davidflanagan.com/javascript5</h1><span class="description">Example 22-14 from<i>JavaScript: The Definitive Guide, Fifth Edition</i></span></div><div style="float: left; 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text-align: right"><a href="index.html" tppabs="http://www.davidflanagan.com/javascript5/index.html">Table of Examples</a></div><pre>import java.applet.*;import java.awt.*;import java.awt.geom.*;import java.awt.image.*;/** * This simple applet does nothing by itself: it simply exports an API * for the use of client-side JavaScript code. */public class Canvas extends Applet { BufferedImage image; // We draw into this offscreen image Graphics2D g; // using this graphics context // The browser calls this method to initialize the applet public void init() { // Find out how big the applet is and create an offscreen image // that size. int w = getWidth(); int h = getHeight(); image = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB); // Get a graphics context for drawing into the image g = image.createGraphics(); // Start with a pure white background g.setPaint(Color.WHITE); g.fillRect(0, 0, w, h); // Turn on antialiasing g.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON); } // The browser automatically calls this method when the applet needs // to be redrawn. We copy the offscreen image onscreen. // JavaScript code drawing to this applet must call the inherited // repaint() method to request a redraw. public void paint(Graphics g) { g.drawImage(image, 0, 0, this); } // These methods set basic drawing parameters // This is just a subset: the Java2D API supports many others public void setLineWidth(float w) { g.setStroke(new BasicStroke(w)); } public void setColor(int color) { g.setPaint(new Color(color)); } public void setFont(String fontfamily, int pointsize) { g.setFont(new Font(fontfamily, Font.PLAIN, pointsize)); } // These are simple drawing primitives public void fillRect(int x, int y, int w, int h) { g.fillRect(x,y,w,h); } public void drawRect(int x, int y, int w, int h) { g.drawRect(x,y,w,h); } public void drawString(String s, int x, int y) { g.drawString(s, x, y); } // These methods fill and draw arbitrary shapes public void fill(Shape shape) { g.fill(shape); } public void draw(Shape shape) { g.draw(shape); } // These methods return simple Shape objects // This is just a sampler. The Java2D API supports many others public Shape createRectangle(double x, double y, double w, double h) { return new Rectangle2D.Double(x, y, w, h); } public Shape createEllipse(double x, double y, double w, double h) { return new Ellipse2D.Double(x, y, w, h); } public Shape createWedge(double x, double y, double w, double h, double start, double extent) { return new Arc2D.Double(x, y, w, h, start, extent, Arc2D.PIE); }}</pre><div class="lefttitle" style="padding:0px; text-align: right"><a href="index.html" tppabs="http://www.davidflanagan.com/javascript5/index.html">Table of Examples</a></div><p><script type="text/javascript">amazon_ad_tag="davidflanagancom"; amazon_ad_width="300"; amazon_ad_height="250"; amazon_ad_logo="hide";</script><script type="text/javascript" src="../../www.assoc-amazon.com/s/ads.js" tppabs="http://www.assoc-amazon.com/s/ads.js"></script></div></body></html>⌨️ 快捷键说明
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