Hi,

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I am allowing the user to add and connect objects through several different views, one being powered by JGraph. When a vertex is added from another view I need to figure out a good location for it in the graph. Has anybody any suggestions?

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Currently I re-layout all the vertices as soon as a new vertex is created, but I know that will drive users crazy (if they have pain-stakenly arranged all the boxes and the layout mess it all up). Besides, the layout's are not (always) behaving well.

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What I would really like is something like an organic layout which locks all existing vertices and only optimizes the position of the new vertex.

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All the best!

asked 27 Feb '12, 05:01

Earthumb's gravatar image

Earthumb
2616
accept rate: 16%

edited 27 Feb '12, 05:06


It should be possible to implement this by overriding isVertexMovable in the layout and returning false for all vertices except the inserted one.

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answered 27 Feb '12, 06:24

Gaudenz's gravatar image

Gaudenz
80.1k1310
accept rate: 39%

Only a couple of the layouts respect isVertexMovable (in mxGraph). I am trying to get mxFastOrganicLayout to behave but I am having a real hard time.

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First of all, the layout will ignore all unconnected vertices, which would be the case for a new vertex, so I override the isVertexIgnored to return the reply of the superclass. Still the layout behaves very wierd. Will have another look tomorrow and post my findings if I make any progress.

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Thanks for the quick reply!

(27 Feb '12, 07:50) Earthumb

Ok, without knowing what I am doing with the layout parameters, this is what I ended up with:

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    public void createVertex(mxGraph graph, Object parent, Object id, Object value, int width, int height ) {\n    // Randomize an initial position to shake things about a bit\n    mxRectangle bounds = graph.getView().getGraphBounds();\n\n    int x = (int) (Math.random()*bounds.getHeight());\n    int y = (int) (Math.random()*bounds.getWidth());\n\n    // Create vertex\n    mxCell vertex = graph.insertVertex(parent, id, value, x, y, width, height);\n\n    // Find ideal spot for new vertex\n    FindRelaxingSpotLayout layout = new FindRelaxingSpotLayout(graph, vertex );\n    layout.execute( parent );\n}\n\npublic static class FindRelaxingSpotLayout extends mxFastOrganicLayout {\n    private final mxCell moveMe;\n    public FindRelaxingSpotLayout(mxGraph graph, Object vertex) {\n        super(graph);\n        this.moveMe = (mxCell) vertex;\n\n        setForceConstant(500);\n        setInitialTemp(10);\n        setMaxDistanceLimit(1);\n        setMinDistanceLimit(1);\n\n        setDisableEdgeStyle(false);\n        setResetEdges(false);\n    }\n            /** Overridden so that the only movable vertex is the newly created one */\n    @Override\n        public boolean isVertexMovable(Object vertex)\n    {\n        return vertex == moveMe;\n    }\n\n            /** Overridden so that also unconnected vertices are included in the layouting */\n            @Override\n            public boolean isVertexIgnored(Object vertex)\n    {                     \n        return !graph.getModel().isVertex(vertex) || !graph.isCellVisible(vertex);\n    }\n}\n
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answered 27 Feb '12, 23:00

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Earthumb
2616
accept rate: 16%

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Asked: 27 Feb '12, 05:01

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Last updated: 27 Feb '12, 23:00