缩放和居中 D3-Graphviz 图

Question

使用 d3-graphviz 缩放和居中图形的最佳方法是什么？我希望我可以使用 scale(0.5) 但这会使生成的图形不居中。

我可能会使用 .attributer() 并手动调整 <svg> 和 <g> 元素以获得我正在寻找的内容，但我认为可能有更好的方式？

d3.select("#graph")
  .graphviz()
    .width(300)
    .height(300)
    .fit(true)
    .scale(.5)
    .renderDot('digraph {a -> b}');

<script src="//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>

Answer 1

没有简单的内置方法，但您几乎可以使用 attributer 实现任何功能，如下所示：

const px2pt = 3 / 4;

function attributer(datum, index, nodes) {
    var selection = d3.select(this);
    if (datum.tag == "svg") {
        var width = datum.attributes.width;
        var height = datum.attributes.height;
        w = datum.attributes.viewBox.split(" ")[2];
        h = datum.attributes.viewBox.split(" ")[3];
        var x = (width * px2pt - w / 2) / 2;
        var y = (height * px2pt - h / 2) / 2;
        selection
            .attr("width", width)
            .attr("height", height)
            .attr("viewBox", -x + " " + -y + " " + (width * px2pt) + " " + (height * px2pt));
        datum.attributes.width = width;
        datum.attributes.height = height;
        datum.attributes.viewBox = -x + " " + -y + " " + (width * px2pt) + " " + (height * px2pt);
    }
}

d3.select("#graph").graphviz()
    .width(300)
    .height(300)
    .fit(true)
    .scale(.5)
    .attributer(attributer)
    .renderDot('digraph  {a -> b}');

<script src="//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>

Answer 2

根据 magjac 的评论，我跳过了 .fit()、.scale()、.width() 和 .height()，并在属性器中完成了所有操作。这使得该解决方案甚至适用于更大的图形。

注意几点：

将 <svg> 的高度和宽度设置为 100% 允许我们跳过 .width() 和 .height() 并让 <svg> 填充其容器 div.
引入了一个scale变量，可以设置（0-1）来确定图形的比例
添加评论以帮助找到这里的人

感谢 magjac 这个很棒的库！

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="//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>

缩放和居中 D3-Graphviz 图

Scale and Center D3-Graphviz Graph

d3.js

graphviz

d3-graphviz