corejava第10版

corejava第10版/v2ch03/write/RectangleComponent.java

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+package write;
+
+import java.awt.*;
+import java.awt.geom.*;
+import java.util.*;
+import javax.swing.*;
+import javax.xml.parsers.*;
+import javax.xml.stream.*;
+import org.w3c.dom.*;
+
+/**
+ * A component that shows a set of colored rectangles
+ */
+public class RectangleComponent extends JComponent
+{
+   private static final Dimension PREFERRED_SIZE = new Dimension(300, 200);   
+
+   private java.util.List<Rectangle2D> rects;
+   private java.util.List<Color> colors;
+   private Random generator;
+   private DocumentBuilder builder;
+
+   public RectangleComponent()
+   {
+      rects = new ArrayList<>();
+      colors = new ArrayList<>();
+      generator = new Random();
+
+      DocumentBuilderFactory factory = DocumentBuilderFactory.newInstance();
+      factory.setNamespaceAware(true);
+      try
+      {
+         builder = factory.newDocumentBuilder();
+      }
+      catch (ParserConfigurationException e)
+      {
+         e.printStackTrace();
+      }
+   }
+
+   /**
+    * Create a new random drawing.
+    */
+   public void newDrawing()
+   {
+      int n = 10 + generator.nextInt(20);
+      rects.clear();
+      colors.clear();
+      for (int i = 1; i <= n; i++)
+      {
+         int x = generator.nextInt(getWidth());
+         int y = generator.nextInt(getHeight());
+         int width = generator.nextInt(getWidth() - x);
+         int height = generator.nextInt(getHeight() - y);
+         rects.add(new Rectangle(x, y, width, height));
+         int r = generator.nextInt(256);
+         int g = generator.nextInt(256);
+         int b = generator.nextInt(256);
+         colors.add(new Color(r, g, b));
+      }
+      repaint();
+   }
+
+   public void paintComponent(Graphics g)
+   {
+      if (rects.size() == 0) newDrawing();
+      Graphics2D g2 = (Graphics2D) g;
+
+      // draw all rectangles
+      for (int i = 0; i < rects.size(); i++)
+      {
+         g2.setPaint(colors.get(i));
+         g2.fill(rects.get(i));
+      }
+   }
+
+   /**
+    * Creates an SVG document of the current drawing.
+    * @return the DOM tree of the SVG document
+    */
+   public Document buildDocument()
+   {      
+      String namespace = "http://www.w3.org/2000/svg";
+      Document doc = builder.newDocument();
+      Element svgElement = doc.createElementNS(namespace, "svg");
+      doc.appendChild(svgElement);
+      svgElement.setAttribute("width", "" + getWidth());
+      svgElement.setAttribute("height", "" + getHeight());
+      for (int i = 0; i < rects.size(); i++)
+      {
+         Color c = colors.get(i);
+         Rectangle2D r = rects.get(i);
+         Element rectElement = doc.createElementNS(namespace, "rect");
+         rectElement.setAttribute("x", "" + r.getX());
+         rectElement.setAttribute("y", "" + r.getY());
+         rectElement.setAttribute("width", "" + r.getWidth());
+         rectElement.setAttribute("height", "" + r.getHeight());
+         rectElement.setAttribute("fill", String.format("#%06x",
+               c.getRGB() & 0xFFFFFF));
+         svgElement.appendChild(rectElement);
+      }
+      return doc;
+   }
+
+   /**
+    * Writes an SVG document of the current drawing.
+    * @param writer the document destination
+    */
+   public void writeDocument(XMLStreamWriter writer) throws XMLStreamException
+   {
+      writer.writeStartDocument();
+      writer.writeDTD("<!DOCTYPE svg PUBLIC \"-//W3C//DTD SVG 20000802//EN\" " 
+            + "\"http://www.w3.org/TR/2000/CR-SVG-20000802/DTD/svg-20000802.dtd\">");
+      writer.writeStartElement("svg");
+      writer.writeDefaultNamespace("http://www.w3.org/2000/svg");
+      writer.writeAttribute("width", "" + getWidth());
+      writer.writeAttribute("height", "" + getHeight());
+      for (int i = 0; i < rects.size(); i++)
+      {
+         Color c = colors.get(i);
+         Rectangle2D r = rects.get(i);
+         writer.writeEmptyElement("rect");
+         writer.writeAttribute("x", "" + r.getX());
+         writer.writeAttribute("y", "" + r.getY());
+         writer.writeAttribute("width", "" + r.getWidth());
+         writer.writeAttribute("height", "" + r.getHeight());
+         writer.writeAttribute("fill", String.format("#%06x",
+               c.getRGB() & 0xFFFFFF));         
+      }
+      writer.writeEndDocument(); // closes svg element
+   }  
+
+   public Dimension getPreferredSize() { return PREFERRED_SIZE; }
+}