java程序如何调用Graphviz

。java可以直接调用这个类实现画图功能，但是使用这个类的前提是你的电脑已经装了GraphViz软件，你可以在http://www.graphviz.org/Gallery.php下载windows版本，装完后，找到dot.exe所在的路径，我电脑上的是D:\Program Files\Graphviz2.30\bin\dot.exe,
将GraphViz.java中的这一路径改成你电脑上的路径，基本上就可以用了。
 
package Graphoutput;
// GraphViz.java - a simple API to call dot from Java programs
/*$Id$*/
/*
 ******************************************************************************
 *                                                                            *
 *              (c) Copyright 2003 Laszlo Szathmary                           *
 *                                                                            *
 * This program is free software; you can redistribute it and/or modify it    *
 * under the terms of the GNU Lesser General Public License as published by   *
 * the Free Software Foundation; either version 2.1 of the License, or        *
 * (at your option) any later version.                                        *
 *                                                                            *
 * This program 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 Lesser General Public    *
 * License for more details.                                                  *
 *                                                                            *
 * You should have received a copy of the GNU Lesser General Public License   *
 * along with this program; if not, write to the Free Software Foundation,    *
 * Inc., 675 Mass Ave, Cambridge, MA 02139, USA.                              *
 *                                                                            *
 ******************************************************************************
 */

import java.io.BufferedReader;
import java.io.DataInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.FileWriter;
import java.io.InputStreamReader;

/**
 * <dl>
 * <dt>Purpose: GraphViz Java API
 * <dd>
 *
 * <dt>Description:
 * <dd> With this Java class you can simply call dot
 *      from your Java programs
 * <dt>Example usage:
 * <dd>
 * <pre>
 *    GraphViz gv = new GraphViz();
 *    gv.addln(gv.start_graph());
 *    gv.addln("A -> B;");
 *    gv.addln("A -> C;");
 *    gv.addln(gv.end_graph());
 *    System.out.println(gv.getDotSource());
 *
 *    String type = "gif";
 *    File out = new File("out." + type);   // out.gif in this example
 *    gv.writeGraphToFile( gv.getGraph( gv.getDotSource(), type ), out );
 * </pre>
 * </dd>
 *
 * </dl>
 *
 * @version v0.4, 2011/02/05 (February) -- Patch of Keheliya Gallaba is added. Now you
 * can specify the type of the output file: gif, dot, fig, pdf, ps, svg, png, etc.
 * @version v0.3, 2010/11/29 (November) -- Windows support + ability 
 * to read the graph from a text file
 * @version v0.2, 2010/07/22 (July) -- bug fix
 * @version v0.1, 2003/12/04 (December) -- first release
 * @author  Laszlo Szathmary (<a href="[e-mail]">[e-mail]</a>)
 */
public class GraphViz
{
   /**
    * The dir. where temporary files will be created.
    */
   //private static String TEMP_DIR = "/tmp"; // Linux
   private static String TEMP_DIR = "c:/temp"; // Windows

/**
    * Where is your dot program located? It will be called externally.
    */
  // private static String DOT = "/usr/bin/dot"; // Linux
   private static String DOT = "D:\\Program Files\\Graphviz2.30\\bin\\dot.exe"; // Windows

/**
    * The source of the graph written in dot language.
    */
 private StringBuilder graph = new StringBuilder();

/**
    * Constructor: creates a new GraphViz object that will contain
    * a graph.
    */
   public GraphViz() {
   }

/**
    * Returns the graph's source description in dot language.
    * @return Source of the graph in dot language.
    */
   public String getDotSource() {
      return graph.toString();
   }

/**
    * Adds a string to the graph's source (without newline).
    */
   public void add(String line) {
      graph.append(line);
   }

/**
    * Adds a string to the graph's source (with newline).
    */
   public void addln(String line) {
      graph.append(line + "\n");
   }

/**
    * Adds a newline to the graph's source.
    */
   public void addln() {
      graph.append('\n');
   }

/**
    * Returns the graph as an image in binary format.
    * @param dot_source Source of the graph to be drawn.
    * @param type Type of the output image to be produced, e.g.: gif, dot, fig, pdf, ps, svg, png.
    * @return A byte array containing the image of the graph.
    */
   public byte[] getGraph(String dot_source, String type)
   {
      File dot;
      byte[] img_stream = null;
   
      try {
         dot = writeDotSourceToFile(dot_source);
         if (dot != null)
         {
            img_stream = get_img_stream(dot, type);
            if (dot.delete() == false) 
               System.err.println("Warning: " + dot.getAbsolutePath() + " could not be deleted!");
            return img_stream;
         }
         return null;
      } catch (java.io.IOException ioe) { return null; }
   }

/**
    * Writes the graph's image in a file.
    * @param img   A byte array containing the image of the graph.
    * @param file  Name of the file to where we want to write.
    * @return Success: 1, Failure: -1
    */
   public int writeGraphToFile(byte[] img, String file)
   {
      File to = new File(file);
      return writeGraphToFile(img, to);
   }

/**
    * Writes the graph's image in a file.
    * @param img   A byte array containing the image of the graph.
    * @param to    A File object to where we want to write.
    * @return Success: 1, Failure: -1
    */
   public int writeGraphToFile(byte[] img, File to)
   {
      try {
         FileOutputStream fos = new FileOutputStream(to);
         fos.write(img);
         fos.close();
      } catch (java.io.IOException ioe) { ioe.printStackTrace();return -1; }
      return 1;
   }

/**
    * It will call the external dot program, and return the image in
    * binary format.
    * @param dot Source of the graph (in dot language).
    * @param type Type of the output image to be produced, e.g.: gif, dot, fig, pdf, ps, svg, png.
    * @return The image of the graph in .gif format.
    */
   private byte[] get_img_stream(File dot, String type)
   {
      File img;
      byte[] img_stream = null;

try {
         img = File.createTempFile("graph_", "."+type, new File(GraphViz.TEMP_DIR));
         Runtime rt = Runtime.getRuntime();
         
         // patch by Mike Chenault
         String[] args = {DOT, "-T"+type, dot.getAbsolutePath(), "-o", img.getAbsolutePath()};
         Process p = rt.exec(args);
         
         p.waitFor();

FileInputStream in = new FileInputStream(img.getAbsolutePath());
         img_stream = new byte[in.available()];
         in.read(img_stream);
         // Close it if we need to
         if( in != null ) in.close();

if (img.delete() == false) 
            System.err.println("Warning: " + img.getAbsolutePath() + " could not be deleted!");
      }
      catch (java.io.IOException ioe) {
         System.err.println("Error:    in I/O processing of tempfile in dir " + GraphViz.TEMP_DIR+"\n");
         System.err.println("       or in calling external command");
         ioe.printStackTrace();
      }
      catch (java.lang.InterruptedException ie) {
         System.err.println("Error: the execution of the external program was interrupted");
         ie.printStackTrace();
      }

return img_stream;   }
   /**
    * Writes the source of the graph in a file, and returns the written file
    * as a File object.
    * @param str Source of the graph (in dot language).
    * @return The file (as a File object) that contains the source of the graph.
    */
   public File writeDotSourceToFile(String str) throws java.io.IOException
   {
      File temp;
      try {
         temp = File.createTempFile("graph_", ".dot.tmp", new File(GraphViz.TEMP_DIR));
         FileWriter fout = new FileWriter(temp);
         fout.write(str);
         fout.close();
      }
      catch (Exception e) {
         System.err.println("Error: I/O error while writing the dot source to temp file!");
         return null;
      }
      return temp;
   }

/**
    * Returns a string that is used to start a graph.
    * @return A string to open a graph.
    */
   public String start_graph() {
      return "digraph G {" ;
   }

/**
    * Returns a string that is used to end a graph.
    * @return A string to close a graph.
    */
   public String end_graph() {
      return "}";
   }

/**
    * Read a DOT graph from a text file.
    * 
    * @param input Input text file containing the DOT graph
    * source.
    */
   public void readSource(String input)
   {
    StringBuilder sb = new StringBuilder();
    
    try
    {
     FileInputStream fis = new FileInputStream(input);
     DataInputStream dis = new DataInputStream(fis);
     BufferedReader br = new BufferedReader(new InputStreamReader(dis));
     String line;
     while ((line = br.readLine()) != null) {
      sb.append(line);
     }
     dis.close();
    } 
    catch (Exception e) {
     System.err.println("Error: " + e.getMessage());
    }
    
    this.graph = sb;
   }
   
} // end of class GraphViz

通过下面这个类调用graphViz.java
 
import java.io.File;
public class Proba
{
   public static void main(String[] args)
   {
      Proba p = new Proba();
      p.start();
//      p.start2();
   }

/**
    * Construct a DOT graph in memory, convert it
    * to image and store the image in the file system.
    */
   private void start()
   {
      GraphViz gv = new GraphViz();
      gv.addln(gv.start_graph());
      gv.addln("A -> B;");
      gv.addln("A -> C;");
      gv.addln(gv.end_graph());
      System.out.println(gv.getDotSource());
      
      String type = "gif";
//      String type = "dot";
//      String type = "fig";    // open with xfig
//      String type = "pdf";
//      String type = "ps";
//      String type = "svg";    // open with inkscape
//      String type = "png";
//      String type = "plain";
      File out = new File("/tmp/out." + type);   // Linux
//      File out = new File("c:/eclipse.ws/graphviz-java-api/out." + type);    // Windows
      gv.writeGraphToFile( gv.getGraph( gv.getDotSource(), type ), out );
   }
   
   /**
    * Read the DOT source from a file,
    * convert to image and store the image in the file system.
    */
   private void start2()
   {
 //     String dir = "/home/jabba/eclipse2/laszlo.sajat/graphviz-java-api";     // Linux
 //     String input = dir + "/sample/simple.dot";
    String input = "c:/eclipse.ws/graphviz-java-api/sample/simple.dot";    // Windows
    
    GraphViz gv = new GraphViz();
    gv.readSource(input);
    System.out.println(gv.getDotSource());
     
      String type = "gif";
//    String type = "dot";
//    String type = "fig";    // open with xfig
//    String type = "pdf";
//    String type = "ps";
//    String type = "svg";    // open with inkscape
//    String type = "png";
//      String type = "plain";
    File out = new File("/tmp/simple." + type);   // Linux
//    File out = new File("c:/eclipse.ws/graphviz-java-api/tmp/simple." + type);   // Windows
    gv.writeGraphToFile( gv.getGraph( gv.getDotSource(), type ), out );
   }
}

Graphviz介绍

graphviz是贝尔实验室几个计算机牛人设计的一个开源 的图表(计算机科学中数据结构中的图)可视化项目，主要用C语言实现，主要实现了一些图布局算法。通过这些算法，可以将图中的节点在画布上比较均匀的分 布，缩短节点之间的边长，并且尽量的减少边的交叉。

 

graphviz提供命令式的绘图方式，它提供一个dot语言 用来编写绘图脚本，然后对这个脚本进行解析，分析出其中的定点，边以及子图，然后根据属性进行绘制。具体的可以看一个例子，这个例子来自官方的文档。

 

digraph G {
    main -> parse -> execute;
    main -> init;
    main -> cleanup;
    execute -> make_string;
    execute -> printf
    init -> make_string;
    main -> printf;
    execute -> compare;
}

 

digraph指定该图是一个有向图(directed graph)，->表示一条边，main,parse,execute等是顶点，运行出来的效果很好看，如下图：

 

需要注意的是，我在这个dot脚本中没有指定任何的关于图的位置的信息，布局器会自动的根据图形的类型进行布局，并最终展现出来。

再来看一个比较复杂，并且是程序员经常使用的功能，数据结构图：

 

digraph g {
    node [shape = record,height=.1];
    node0[label = "<f0> |<f1> G|<f2> "];
    node1[label = "<f0> |<f1> E|<f2> "];
    node2[label = "<f0> |<f1> B|<f2> "];
    node3[label = "<f0> |<f1> F|<f2> "];
    node4[label = "<f0> |<f1> R|<f2> "];
    node5[label = "<f0> |<f1> H|<f2> "];
    node6[label = "<f0> |<f1> Y|<f2> "];
    node7[label = "<f0> |<f1> A|<f2> "];
    node8[label = "<f0> |<f1> C|<f2> "];
    "node0":f2 -> "node4":f1;
    "node0":f0 -> "node1":f1;
    "node1":f0 -> "node2":f1;
    "node1":f2 -> "node3":f1;
    "node2":f2 -> "node8":f1;
    "node2":f0 -> "node7":f1;
    "node4":f2 -> "node6":f1;
    "node4":f0 -> "node5":f1;
}

 

运行后的效果如下图所示：

 

 

 

不知道其他的程序员怎样，反正我对命令行情有独钟，比较喜欢这一类的工具。最早接触的计算机系统正是一个没有图形系统的BSD，由此对命令行的，没 有界面的程序都特别感兴趣。

相关的想法

自从使用了graphviz以后，一直想着把这个好东西移植到java下来，大概的思想跟graphviz类似：

• 解析dot脚本，生成图的对象，这个图中包括节点，边以及子图等对象，这些对象上都绑定着相应的属性
• 将解析出来的图对象发送给layout engine进行处理，layout engine可以选择布局策略，比如流布局等
• 从layout engine中得到布局后的图对象，并交给image engine处理，得到最终结果，负责展示或者保存等

dot 的语法定义比较简单，我已经用javacc构造了一个dot的分析器，现在可以从dot文件中构建出图对象出来，不过还需要进一步完善，可以看看这个 BNF定义：

 

 

graph -> [strict] (digraph|graph) id '{' stmt-list '}'
stmt-list -> [stmt [';'] [stmt-list] ]
stmt -> attr-stmt | node-stmt | edge-stmt | subgraph | id '=' id
attr-stmt -> (graph | node | edge) attr-list
attr-list -> '[' [a-list] ']' [attr-list]
a-list -> id '=' id [','][a-list]
node-stmt -> node-id [attr-list]
node-id -> id [port]
port -> port-location [port-angle] | port-angle [port-location]
port-location -> ':' id | ':' '(' id ',' id ')'
port-angle ->'@' id
edge-stmt -> (node-id | subgraph) edgeRHS [attr-list]
edgeRHS -> edgeop (node-id | subgraph) [edgeRHS]
subgraph -> [subgraph id] '{' stmt-list '}' | subgraph id

 

(最近老是感觉时间不够用，有很多有意思的项目要做，比如要完善前几天说的那个bbms(Bus Based Message Service), 再比如修改用Swing和Smack做一个jabber的客户端jTalk，都是很有搞头的，唉，扯远了。)

 

当然graphviz的功能不至于此，它提供一个lib，可以用来将绘图引擎嵌入在自己的应用中。这是一个很有意义的事，我们可以不必掌握布局部分 的复杂算法，把精力放在业务逻辑部分，将最后的图对象交给这个引擎来处理即可。当然，如果你正好和我一样，想了解其神奇的布局算法，不妨翻翻它的源码，欢 迎交流之至。

 

我在周末分析了下graphviz的内部结构，并建立了一个java的项目jraph ，用来做简单的移植，主要是学习之用，其实，Java的图库还是相当丰富的，比如JGraph ，JGraphT，Prefuse，TouchGraph等等，用来做项目当然是很便捷的，但是我还是比较喜欢看着一个算法被自己实现的过程，特别是这种 比较神奇的算法，哈哈。

 

预期中的API如下：

 

public static void main(String[] args){
    Parser parser = new GCodeParser("file.g");
    GraphSet gs = parser.parse();
    GraphSet layouted =
        new GraphLayoutEngine(gs).layout();
    ImageEngine imgEngine =
        new GraphImageEngine(layouted);
    imgEngine.export(0);
}

 

 

同graphviz一样，先调用分析器构造出图的集合GraphSet(包括多个图，每个图中包括Vertex，Edge，及SubGraph)， 然后进行布局，最后将通过布局后的GraphSet绘制结果。目前完成了框架的设计部分，分析器部分基本完成，layout部分只实现了一个策略，即force-based 布局算法，不过layout engine被设计成可以插拔的模型，如果有了新的算法实现，可以很容易的整合起来。

 

dot.exe  -Tpng -o new.png -Kdot new.dot