java - 将 JUNG 图写入图像 : can't reliably render complete graph

Question

我一直在使用 JUNG 可视化一些简单的图形，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，这意味着我得到的图形不完整——也就是说，只有少数边缘或节点被绘制的图形——大约有一半的时间。渲染到屏幕效果很好，这就是我如此困惑的部分原因。正如您将在下面看到的，我尝试了一些解决方法，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会很有用——我尝试这样做时只会得到一个黑色图像。

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);
    }
}

Answer 1

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

你的代码会是这样的:

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();
}