Question

我在下面的代码中包含2个按钮，一个用于打开由我的D3 Force graph组成的模态，另一个用于捕获和下载我的模态图像。

问题是我的图形设置了Raleway字体，但是当我捕获它们并下载我的图形的图像时，由于某种原因它不呈现字体和字体大小，我不知道为什么会这样。

这就是我的图表的样子。

这就是它捕获它的方式。谁能告诉我为什么会这样吗？非常感谢！

<!DOCTYPE html>
<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.3.1/jquery.min.js"></script>
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css">
<script src="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/js/bootstrap.min.js"></script>
<html>

<head>
  <meta charset="utf-8" />
  <style>
    body {
      font-family: Raleway;
    }

    .modal-posit {
      position: relative;
    }

    .links line {
      stroke: #999;
      stroke-opacity: 0.6;
    }

    .nodes circle {
      stroke: #000;
      stroke-width: 1.5px;
    }

    text {
      font-size: 30px;
      font-weight: bold;
    }
  </style>
  <link rel="shortcut icon" href="//#" />
  <link rel="stylesheet" type="text/css" href="//fonts.googleapis.com/css?family=Raleway" />
  <script type="text/javascript" src="https://html2canvas.hertzen.com/dist/html2canvas.js"></script>
  <script type="text/javascript" src="https://html2canvas.hertzen.com/dist/html2canvas.min.js"></script>
</head>

<body>
  <div id="capture">



    <button class="modal-button" data-toggle="modal" data-target="#myModal2">MODAL BUTTON</button>


    <div class="modal fade" id="myModal2" role="dialog">
      <div class="modal-dialog modal-lg">
        <div class="modal-content">
          <div class="modal-header">
            <button type="button" class="close" data-dismiss="modal">&times;</button>
            <h2 class="modal-title center">GRAPH</h2>
          </div>
          <div class="modal-body">
            <svg width="798" height="400"></svg>

          </div>
        </div>
        <div class="modal-footer">
          <button type="button" class="btn btn-default" data-dismiss="modal">Close</button>
        </div>
      </div>
    </div>
  </div>
  </div>

  <button id="match-button" onclick="sendData();">capture</button>
  <a id="test" href="#"></a>
</body>

</html>
<script src="https://d3js.org/d3.v4.min.js"></script>

<script>
  var graph = {
    "nodes": [{ "id": "Apple", "group": 1 }, { "id": "Cherry", "group": 1 }, { "id": "Tomato", "group": 1 }, { "id": "Chilli", "group": 1 }, { "id": "Red Fruits", "group": 1 }],

    "links": [{ "source": "Apple", "target": "Red Fruits", "value": 10, "type": "A" },
    { "source": "Cherry", "target": "Red Fruits", "value": 10, "type": "A" },
    { "source": "Tomato", "target": "Red Fruits", "value": 10, "type": "A" },
    { "source": "Chilli", "target": "Red Fruits", "value": 10, "type": "A" }]


  };
  var fruits = ["Apple", "Cherry", "Tomato", "Chilli"];
  var color = ["Red Fruits"];

  var colorNodes = graph["nodes"];
  let greyNodes = colorNodes;
  greyNodes.forEach((obj) => {
    if (fruits.includes(obj.id.toString())) obj.group = "1"
  })

  let redNodes = greyNodes;
  redNodes.forEach((obj) => {
    if (color.includes(obj.id.toString())) obj.group = "2"
  })


  var colorLinks = graph["links"];
  let linksArray = colorLinks;
  linksArray.forEach((obj) => {
    if (color.includes(obj.target.toString())) obj.type = "B"
  })

  var svg = d3.select("svg"),
    width = +svg.attr("width"),
    height = +svg.attr("height");

  var zoom_handler = d3.zoom().on("zoom", zoom_actions);

  // zoom_handler(svg);

  var simulation = d3.forceSimulation()
    .force("link", d3.forceLink().distance(300).id(function (d) {
      return d.id;
    }))
    .force("charge", d3.forceManyBody().strength(-300))
    .force("center", d3.forceCenter(width / 2, height / 2));

  var g = svg.append("g")
    .attr("class", "everything");

  svg.call(zoom_handler)
    .call(zoom_handler.transform, d3.zoomIdentity.translate(100, 100).scale(1));

  var link = g.append("g")
    .attr("class", "links")
    .selectAll("line")
    .data(graph.links)
    .enter().append("line")
    .style("stroke", linkColour)
    .attr("stroke-width", function (d) {
      return Math.sqrt(d.value);
    });

  var nodeGroup = g.append("g")
    .attr("class", "nodes");

  var node = nodeGroup.selectAll("circle")
    .data(graph.nodes)
    .enter().append("circle")
    .attr("r", 8)
    .attr("fill", circleColour)
    .attr("id", function (d) { return d.id })
    .call(d3.drag()
      .on("start", dragstarted)
      .on("drag", dragged)
      .on("end", dragended));

  function cleanId(id) { return id.replace(/[^A-Z0-9]/ig, "_"); }

  node.append("title")
    .text(function (d) { return d.id; });

  node.each(d => {
    nodeGroup.append("text") // Labelling for nodes
      .attr("id", 't_' + cleanId(d.id))
      .text(d.id);
  });

  function ticked() {
    link
      .attr("x1", function (d) { return d.source.x; })
      .attr("y1", function (d) { return d.source.y; })
      .attr("x2", function (d) { return d.target.x; })
      .attr("y2", function (d) { return d.target.y; });
    node
      .attr("cx", function (d) { return d.x; })
      .attr("cy", function (d) { return d.y; })
      .each(d => { d3.select('#t_' + cleanId(d.id)).attr('x', d.x + 10).attr('y', d.y + 3); });
  };

  simulation
    .nodes(graph.nodes)
    .on("tick", ticked);

  simulation.force("link")
    .links(graph.links);

  function circleColour(d) {
    if (d.group == "1") {
      return "DimGrey";
    } else if (d.group == "2") {
      return "#81C784";
    }
    else {
      return "blue"
    }
  }

  function linkColour(d) {
    if (d.type == "A") {
      return "DimGrey";
    } else {
      return "SpringGreen";
    }
  }


  function zoom_actions() {
    g.attr("transform", d3.event.transform)
  }

  function dragstarted(d) {
    if (!d3.event.active) simulation.alphaTarget(0.3).restart();
    d.fx = d.x;
    d.fy = d.y;
  }

  function dragged(d) {
    d.fx = d3.event.x;
    d.fy = d3.event.y;
  }

  function dragended(d) {
    if (!d3.event.active) simulation.alphaTarget(0);
    d.fx = null;
    d.fy = null;
  }

  function sendData() {

    $('#myModal2').addClass('modal-posit');

    var modalButton = $('[data-target="#myModal2"]')[0];
    modalButton.click();
    var modal = $('#myModal2')[0];

    setTimeout(function () {
      html2canvas(document.getElementById('capture'), {
        allowTaint: false,
        useCORS: true
      }).then(function (canvas) {

        downloadCanvas(document.getElementById('test'), canvas, 'test.png');
        modalButton.click();
      });
    }, 1000);
  }

  function downloadCanvas(link, canvas, filename) {
    link.href = canvas.toDataURL();
    link.download = filename;
    link.click();
  }
</script>

Answer 1

问题是未加载字体。我不知道HTML2Canvas的内部结构，但可能将XML字符串化并创建一个数据URL，呈现一个图像，然后将其绘制在画布上。在这种情况下，将字体直接嵌入到svg中可以帮助我推测。您需要添加一个defs标签，然后在其中添加样式标签，如以下link所示：

<defs>
  <style type="text/css">
    @font-face {
      font-family: Delicious;
      src: url('../fonts/font.woff');
    }
  </style>
</defs>

我确定某些浏览器将无法正常运行。.

还有1件事，您可以通过设置responseType = "arraybuffer"并使用ajax将字体文件读取为带有ajax的数组缓冲区，而不是使用url相对的src来添加src，而不是将其转换为data-url。 MIME类型为application/font-woff的Blob，并将FileReader赋予readAsDataURL。比使用此数据网址代替'../ fonts / font.woff'

HTML2Canvas无法呈现D3字体和字体大小

1 个答案: