5

我一直在使用 JUNG 来可视化一些简单的图表,我想将其中的几个写入 PNG 文件。不幸的是,图像通常在图形完成绘制之前呈现,这意味着我得到不完整的图形 - 即仅绘制少量边或节点的图形 - 大约有一半的时间。渲染到屏幕效果很好,这也是我如此困惑的部分原因。正如您将在下面看到的,我尝试了几种解决方法,但它们没有帮助。知道我正在使用的 basicVisualizationServer 不会直接为 BufferedImage 绘制任何有用的东西可能很有用——当我尝试这样做时,我只会得到一个黑色的图像。

谢谢!

  public void writeImage(String filename) {
    Layout layout = new CircleLayout<V, E>(jungGraph);
    layout.setSize(innerSize);
    bvs = new BasicVisualizationServer<V,E>(layout);
    float strokeWidth = 8f;
    bvs.getRenderContext().setVertexShapeTransformer(new ConstantTransformer(new Ellipse2D.Float(-24,-24,48,48)));
    bvs.getRenderContext().setArrowDrawPaintTransformer(new ConstantTransformer(Color.black));
    bvs.getRenderContext().setEdgeStrokeTransformer(new ConstantTransformer(new BasicStroke(strokeWidth)));
    bvs.getRenderContext().setEdgeArrowStrokeTransformer(new ConstantTransformer(new BasicStroke(strokeWidth)));
    bvs.getRenderContext().setEdgeLabelTransformer(new ToStringLabeller<E>());
    bvs.getRenderContext().setVertexLabelTransformer(new ToStringLabeller<V>());
    bvs.setPreferredSize(viewSize);
    //int width = bvs.getWidth(); // Always returns zero
    int width = viewFrame.getWidth();
    //int height = bvs.getHeight(); // Always returns zero
    int height = viewFrame.getHeight();

    BufferedImage bim = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
    Graphics2D g = bim.createGraphics();
    viewFrame.paintAll(g);

    g.dispose();
    //this.viewFrame.paintComponents(g);
    //try{Thread.sleep(1000);} catch(Exception e) {throw new RuntimeException(e);} // Sleeping doesn't help.
    try {
        File f = new File(filename);
        ImageIO.write(bim,"png",f);
        System.out.println("wrote image for " + jungGraph + " to "+ filename+ ":" + f.toString());
        //try{Thread.sleep(500);} catch(Exception e) {throw new RuntimeException(e);} // Doesn't help
    } catch (Exception e) {
        throw new RuntimeException(e);
    }
}
4

2 回答 2

2

您还可以使用VisualizationImageServer。它是 BasicVisualizationServer 的子类型,它添加了一个 getImage 方法。我在正确渲染图形方面没有遇到任何问题。

您的代码将如下所示:

public void writeImage(String filename) {
    Layout layout = new CircleLayout<V, E>(jungGraph);
    layout.setSize(innerSize);
    bvs = new VisualizationImageServer<V,E>(layout);
    // [...]
    BufferedImage image = (BufferedImage)bvs.getImage();
}
于 2011-07-03T23:11:23.607 回答
1

我们通常希望保存操作图的状态。我们以我们喜欢的方式缩放和定位组件,然后制作容器的图片。这可以这样实现:

  1. 从优秀的 Rob Camick 的博客中获取 ScreenImage 类
  2. 将 JScrollPane 中的 JPanel 或托管 JUNG2 图形的任何组件传递给 ScreenImage.createImage 以创建图像。

    private void writeToImageFile(String imageFileName) {
    
       BufferedImage bufImage = ScreenImage.createImage((JComponent) jPanel1);
       try {
           File outFile = new File(imageFileName);
           ImageIO.write(bufImage, "png", outFile);
           System.out.println("wrote image to " + imageFileName);
       } catch (Exception e) {
           System.out.println("writeToImageFile(): " + e.getMessage());
       }
    }
    
  3. 另请阅读上述博客的其他主题:-)

于 2011-03-01T10:19:45.253 回答