如何放大GraphStream视图? [英] How to zoom into a GraphStream View?

问题描述

在GraphStream可视化中，图可能很密集. enableAutoLayout方法提供了Graph的全局可视化，因此需要缩放.如何放大GraphStream视图?

In GraphStream visualizations Graphs can be dense. The enableAutoLayout method gives a global visualization of the Graph and so zooming is needed. How to zoom into a GraphStream View?

Graph go=...;
Viewer viewer = new Viewer(go, Viewer.ThreadingModel.GRAPH_IN_ANOTHER_THREAD);
viewer.enableAutoLayout();
View view = viewer.addDefaultView(false); 
swingNode.setContent((JComponent) view);

推荐答案

我试图找到一种使用鼠标滚轮缩放到鼠标光标的方法，偶然发现了该线程，希望找到答案.我想出了最终使用GraphStream放大鼠标的方法:

I tried to find a way to zoom to the mouse cursor using the mouse wheel and stumbled across this thread, hoping to find an answer. I figured out how to zoom to the mouse eventually with GraphStream:

在我的情况下，每个鼠标滚轮旋转的缩放系数为1.25(缩小时为0.8).该代码根据图形的原始中心，图形中的单击点，缩放以及最终可以从摄像机检索到的Px与Gu的比率来计算图形的新中心.

The zoom-factor for each mouse wheel rotation in my case is 1.25 (or 0.8 when zooming out). The code calculates the new center of the graph based on the original center of the graph, the clicked point in the graph, the zoom and eventually the ratio of Px to Gu which can be retrieved from the camera.

final Viewer viewer = new Viewer(graph, Viewer.ThreadingModel.GRAPH_IN_ANOTHER_THREAD);
viewer.enableAutoLayout();
final View view = viewer.addDefaultView(false);
view.getCamera().setViewPercent(1);
((Component) view).addMouseWheelListener(new MouseWheelListener() {
    @Override
    public void mouseWheelMoved(MouseWheelEvent e) {
        e.consume();
        int i = e.getWheelRotation();
        double factor = Math.pow(1.25, i);
        Camera cam = view.getCamera();
        double zoom = cam.getViewPercent() * factor;
        Point2 pxCenter  = cam.transformGuToPx(cam.getViewCenter().x, cam.getViewCenter().y, 0);
        Point3 guClicked = cam.transformPxToGu(e.getX(), e.getY());
        double newRatioPx2Gu = cam.getMetrics().ratioPx2Gu/factor;
        double x = guClicked.x + (pxCenter.x - e.getX())/newRatioPx2Gu;
        double y = guClicked.y - (pxCenter.y - e.getY())/newRatioPx2Gu;
        cam.setViewCenter(x, y, 0);
        cam.setViewPercent(zoom);
    }
});

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