d3.jsgraphvizd3-graphviz

Scale and Center D3-Graphviz Graph


What is the best way to scale and center a graph using d3-graphviz? I was hopeful that I could use scale(0.5) but this leaves the resulting graph uncentered.

I could probably go in with an .attributer() and manually adjust the <svg> and <g> elements to get what I'm looking for, but I figured there was probably a better way?

d3.select("#graph")
  .graphviz()
    .width(300)
    .height(300)
    .fit(true)
    .scale(.5)
    .renderDot('digraph {a -> b}');
<script src="https://d3js.org/d3.v5.min.js"></script>
<script src="https://unpkg.com/@hpcc-js/wasm@0.3.11/dist/index.min.js"></script>
<script src="https://unpkg.com/d3-graphviz@3.0.5/build/d3-graphviz.js"></script>
  
<div id="graph" style="width: 300px; height: 300px; border: 1px solid black"></div>


Solution

  • Based on magjac's comment, I skipped .fit(), .scale(), .width(), and .height() and did it all in the attributer. This allows the solution to work even for larger graphs.

    A few things to note:

    const scale = 0.8;
    
    function attributer(datum, index, nodes) {
        var selection = d3.select(this);
        if (datum.tag == "svg") {
            datum.attributes = {
                ...datum.attributes,
                width: '100%',
                height: '100%',
            };
            // svg is constructed by hpcc-js/wasm, which uses pt instead of px, so need to convert
            const px2pt = 3 / 4;
    
            // get graph dimensions in px. These can be grabbed from the viewBox of the svg
            // that hpcc-js/wasm generates
            const graphWidth = datum.attributes.viewBox.split(' ')[2] / px2pt;
            const graphHeight = datum.attributes.viewBox.split(' ')[3] / px2pt;
    
            // new viewBox width and height
            const w = graphWidth / scale;
            const h = graphHeight / scale;
    
            // new viewBox origin to keep the graph centered
            const x = -(w - graphWidth) / 2;
            const y = -(h - graphHeight) / 2;
    
            const viewBox = `${x * px2pt} ${y * px2pt} ${w * px2pt} ${h * px2pt}`;
            selection.attr('viewBox', viewBox);
            datum.attributes.viewBox = viewBox;
        }
    }
    
    d3.select("#graph").graphviz()
        .attributer(attributer)
        .renderDot('digraph  {a -> b -> c ->d -> e}');
    <script src="https://d3js.org/d3.v5.min.js"></script>
    <script src="https://unpkg.com/@hpcc-js/wasm@0.3.11/dist/index.min.js"></script>
    <script src="https://unpkg.com/d3-graphviz@3.0.5/build/d3-graphviz.js"></script>
      
    <div id="graph" style="width: 300px; height: 300px; border: 1px solid black"></div>