Question

我有以下代码通过简单地从一个节点拖动到另一个节点来动态地在圆之间绘制边。

在单击SVG时，将添加一个新节点，可以通过从一个节点拖动到另一个节点来绘制新连接。添加此边缘时，有一种方法可以使用svg text元素向此边添加标签吗？

我尝试添加以下代码：

drag_line.append('svg:text')
                        .attr('x', 50)
                        .attr('y', 20)
                        .attr('class', 'id')
                        .text(function(d) {
                            return "Label";
                        });

添加该行的mousedown函数中的

。但似乎没有用？我做错了什么？

可以执行以下操作：

从一个节点拖动到另一个节点以创建边

cntrl +拖动以单独移动节点。

＆＃13;

// Code goes here
console.log("init");
console.log(d3);
// set up SVG for D3
var width  = 960,
    height = 500,
    colors = d3.scale.category10();

var svg = d3.select('body')
  .append('svg')
  .attr('oncontextmenu', 'return false;')
  .attr('width', width)
  .attr('height', height);

// set up initial nodes and links
//  - nodes are known by 'id', not by index in array.
//  - reflexive edges are indicated on the node (as a bold black circle).
//  - links are always source < target; edge directions are set by 'left' and 'right'.
var nodes = [
    {id: 0, reflexive: false},
    {id: 1, reflexive: true },
    {id: 2, reflexive: false}
  ],
  lastNodeId = 2,
  links = [
    {source: nodes[0], target: nodes[1], left: false, right: true },
    {source: nodes[1], target: nodes[2], left: false, right: true }
  ];

// init D3 force layout
var force = d3.layout.force()
    .nodes(nodes)
    .links(links)
    .size([width, height])
    .linkDistance(150)
    .charge(-500)
    .on('tick', tick)

// define arrow markers for graph links
svg.append('svg:defs').append('svg:marker')
    .attr('id', 'end-arrow')
    .attr('viewBox', '0 -5 10 10')
    .attr('refX', 6)
    .attr('markerWidth', 3)
    .attr('markerHeight', 3)
    .attr('orient', 'auto')
  .append('svg:path')
    .attr('d', 'M0,-5L10,0L0,5')
    .attr('fill', '#000');

svg.append('svg:defs').append('svg:marker')
    .attr('id', 'start-arrow')
    .attr('viewBox', '0 -5 10 10')
    .attr('refX', 4)
    .attr('markerWidth', 3)
    .attr('markerHeight', 3)
    .attr('orient', 'auto')
  .append('svg:path')
    .attr('d', 'M10,-5L0,0L10,5')
    .attr('fill', '#000');

// line displayed when dragging new nodes
var drag_line = svg.append('svg:path')
  .attr('class', 'link dragline hidden')
  .attr('d', 'M0,0L0,0');

// handles to link and node element groups
var path = svg.append('svg:g').selectAll('path'),
    circle = svg.append('svg:g').selectAll('g');

// mouse event vars
var selected_node = null,
    selected_link = null,
    mousedown_link = null,
    mousedown_node = null,
    mouseup_node = null;

function resetMouseVars() {
  mousedown_node = null;
  mouseup_node = null;
  mousedown_link = null;
}

// update force layout (called automatically each iteration)
function tick() {
  // draw directed edges with proper padding from node centers
  path.attr('d', function(d) {
    var deltaX = d.target.x - d.source.x,
        deltaY = d.target.y - d.source.y,
        dist = Math.sqrt(deltaX * deltaX + deltaY * deltaY),
        normX = deltaX / dist,
        normY = deltaY / dist,
        sourcePadding = d.left ? 42 : 37,
        targetPadding = d.right ? 42 : 37,
        sourceX = d.source.x + (sourcePadding * normX),
        sourceY = d.source.y + (sourcePadding * normY),
        targetX = d.target.x - (targetPadding * normX),
        targetY = d.target.y - (targetPadding * normY);
    return 'M' + sourceX + ',' + sourceY + 'L' + targetX + ',' + targetY;
  });

  circle.attr('transform', function(d) {
    return 'translate(' + d.x + ',' + d.y + ')';
  });
}

// update graph (called when needed)
function restart() {
  // path (link) group
  path = path.data(links);

  // update existing links
  path.classed('selected', function(d) { return d === selected_link; })
    .style('marker-start', function(d) { return d.left ? 'url(#start-arrow)' : ''; })
    .style('marker-end', function(d) { return d.right ? 'url(#end-arrow)' : ''; });


  // add new links
  path.enter().append('svg:path')
    .attr('class', 'link')
    .classed('selected', function(d) { return d === selected_link; })
    .style('marker-start', function(d) { return d.left ? 'url(#start-arrow)' : ''; })
    .style('marker-end', function(d) { return d.right ? 'url(#end-arrow)' : ''; })
    .on('mousedown', function(d) {
      if(d3.event.ctrlKey) return;

      // select link
      mousedown_link = d;
      if(mousedown_link === selected_link) selected_link = null;
      else selected_link = mousedown_link;
      selected_node = null;
      restart();
    });

  // remove old links
  path.exit().remove();


  // circle (node) group
  // NB: the function arg is crucial here! nodes are known by id, not by index!
  circle = circle.data(nodes, function(d) { return d.id; });

  // update existing nodes (reflexive & selected visual states)
  circle.selectAll('circle')
    .style('fill', function(d) { return (d === selected_node) ? d3.rgb(colors(d.id)).brighter().toString() : colors(d.id); })
    .classed('reflexive', function(d) { return d.reflexive; })
    .classed("fixed", function(d){ return d.fixed = true});

  // add new nodes
  var g = circle.enter().append('svg:g');

  g.append('svg:circle')
    .attr('class', 'node')
    .attr('r', 40)
    .style('fill', function(d) { return (d === selected_node) ? d3.rgb(colors(d.id)).brighter().toString() : colors(d.id); })
    .style('stroke', function(d) { return d3.rgb(colors(d.id)).darker().toString(); })
    .classed('reflexive', function(d) { return d.reflexive; })
    .on('mouseover', function(d) {
      if(!mousedown_node || d === mousedown_node) return;
      // enlarge target node
      d3.select(this).attr('transform', 'scale(1.1)');
    })
    .on('mouseout', function(d) {
      if(!mousedown_node || d === mousedown_node) return;
      // unenlarge target node
      d3.select(this).attr('transform', '');
    })
    .on('mousedown', function(d) {
      if(d3.event.ctrlKey) return;

      // select node
      mousedown_node = d;
      if(mousedown_node === selected_node) selected_node = null;
      else selected_node = mousedown_node;
      selected_link = null;

      // reposition drag line
      drag_line
        .style('marker-end', 'url(#end-arrow)')
        .classed('hidden', false)
        .attr('d', 'M' + mousedown_node.x + ',' + mousedown_node.y + 'L' + mousedown_node.x + ',' + mousedown_node.y);

      restart();
    })
    .on('mouseup', function(d) {
      if(!mousedown_node) return;

      // needed by FF
      drag_line
        .classed('hidden', true)
        .style('marker-end', '');

      // check for drag-to-self
      mouseup_node = d;
      if(mouseup_node === mousedown_node) { resetMouseVars(); return; }

      // unenlarge target node
      d3.select(this).attr('transform', '');

      // add link to graph (update if exists)
      // NB: links are strictly source < target; arrows separately specified by booleans
      var source, target, direction;
      if(mousedown_node.id < mouseup_node.id) {
        source = mousedown_node;
        target = mouseup_node;
        direction = 'right';
      } else {
        source = mouseup_node;
        target = mousedown_node;
        direction = 'left';
      }

      var link;
      link = links.filter(function(l) {
        return (l.source === source && l.target === target);
      })[0];

      if(link) {
        link[direction] = true;
      } else {
        link = {source: source, target: target, left: false, right: false};
        link[direction] = true;
        links.push(link);
      }

      // select new link
      selected_link = link;
      selected_node = null;
      restart();
    });

  // show node IDs
  g.append('svg:text')
      .attr('x', 0)
      .attr('y', 4)
      .attr('class', 'id')
      .text(function(d) { return d.id; });

  // remove old nodes
  circle.exit().remove();

  // set the graph in motion
  force.start();
}

function mousedown() {
  // prevent I-bar on drag
  //d3.event.preventDefault();

  // because :active only works in WebKit?
  svg.classed('active', true);

  if(d3.event.ctrlKey || mousedown_node || mousedown_link) return;

  // insert new node at point
  var point = d3.mouse(this),
      node = {id: ++lastNodeId, reflexive: false};
  node.x = point[0];
  node.y = point[1];
  nodes.push(node);

  restart();
}

function mousemove() {
  if(!mousedown_node) return;

  // update drag line
  drag_line.attr('d', 'M' + mousedown_node.x + ',' + mousedown_node.y + 'L' + d3.mouse(this)[0] + ',' + d3.mouse(this)[1]);

  restart();
}

function mouseup() {
  if(mousedown_node) {
    // hide drag line
    drag_line
      .classed('hidden', true)
      .style('marker-end', '');
  }

  // because :active only works in WebKit?
  svg.classed('active', false);

  // clear mouse event vars
  resetMouseVars();
}

function spliceLinksForNode(node) {
  var toSplice = links.filter(function(l) {
    return (l.source === node || l.target === node);
  });
  toSplice.map(function(l) {
    links.splice(links.indexOf(l), 1);
  });
}

// only respond once per keydown
var lastKeyDown = -1;

function keydown() {
  d3.event.preventDefault();

  if(lastKeyDown !== -1) return;
  lastKeyDown = d3.event.keyCode;

  // ctrl
  if(d3.event.keyCode === 17) {
    circle.call(force.drag);
    svg.classed('ctrl', true);
  }

  if(!selected_node && !selected_link) return;
  switch(d3.event.keyCode) {
    case 8: // backspace
    case 46: // delete
      if(selected_node) {
        nodes.splice(nodes.indexOf(selected_node), 1);
        spliceLinksForNode(selected_node);
      } else if(selected_link) {
        links.splice(links.indexOf(selected_link), 1);
      }
      selected_link = null;
      selected_node = null;
      restart();
      break;
    case 66: // B
      if(selected_link) {
        // set link direction to both left and right
        selected_link.left = true;
        selected_link.right = true;
      }
      restart();
      break;
    case 76: // L
      if(selected_link) {
        // set link direction to left only
        selected_link.left = true;
        selected_link.right = false;
      }
      restart();
      break;
    case 82: // R
      if(selected_node) {
        // toggle node reflexivity
        selected_node.reflexive = !selected_node.reflexive;
      } else if(selected_link) {
        // set link direction to right only
        selected_link.left = false;
        selected_link.right = true;
      }
      restart();
      break;
  }
}

function keyup() {
  lastKeyDown = -1;

  // ctrl
  if(d3.event.keyCode === 17) {
    circle
      .on('mousedown.drag', null)
      .on('touchstart.drag', null);
    svg.classed('ctrl', false);
  }
}

// app starts here
svg.on('mousedown', mousedown)
  .on('mousemove', mousemove)
  .on('mouseup', mouseup);
d3.select(window)
  .on('keydown', keydown)
  .on('keyup', keyup);
restart();

＆＃13;

/* Styles go here */

svg {
  background-color: #FFF;
  cursor: default;
  -webkit-user-select: none;
  -moz-user-select: none;
  -ms-user-select: none;
  -o-user-select: none;
  user-select: none;
}

svg:not(.active):not(.ctrl) {
  cursor: crosshair;
}

path.link {
  fill: none;
  stroke: #000;
  stroke-width: 4px;
  cursor: default;
}

svg:not(.active):not(.ctrl) path.link {
  cursor: pointer;
}

path.link.selected {
  stroke-dasharray: 10,2;
}

path.link.dragline {
  pointer-events: none;
}

path.link.hidden {
  stroke-width: 0;
}

circle.node {
  stroke-width: 1.5px;
  cursor: pointer;
}

circle.node.reflexive {
  stroke: #000 !important;
  stroke-width: 2.5px;
}

text {
  font: 12px sans-serif;
  pointer-events: none;
}

text.id {
  text-anchor: middle;
  font-weight: bold;
}

＆＃13;

<script src="https://cdnjs.cloudflare.com/ajax/libs/d3/3.4.11/d3.min.js"></script>

＆＃13;

Answer 1

首先，创建另一个组：

labels = svg.append('svg:g')
    .selectAll('.labels');

然后，在restart函数内：

labels = labels.data(links);

labels.exit().remove();

labels.enter()
    .append("text")
    .attr("text-anchor", "middle")
    .attr("x", 0)
    .attr("dy", 16)
    .append("textPath")
    .attr("startOffset", "50%")
    .attr("xlink:href", function(d,i){ return "#id" + i})
    .text("label");

这是一个非常粗略的解决方案，因为当路径从右向左移动时，您必须翻转文本（否则，文本将被反转）：

0到2之间的标签位置正确，但是当它从右向左（如1到3）时，你必须将其反转。

这是你的小提琴：https://jsfiddle.net/Lonbvdd4/

我对不透明度进行了硬编码，因此初始标签（0到1和1到2）不显示，只显示添加链接的标签。

Answer 2

由于@Gerardo Furtado和@Sooraj Chandran已经提到过无法向text添加path。如果您更改此设置并将text添加到包含g的{{1}}，则会显示该path。使用path的坐标并计算中间位置（或您想要的位置）并将其用于x和y值。

只需在drag_line_text

旁边添加drag_line个全局变量即可

var drag_line = svg.append('svg:path')
  .attr('class', 'link dragline hidden')
  .attr('d', 'M0,0L0,0');
var drag_line_text = svg.append('svg:text')
  .attr('class', 'link draglinetext hidden')
  .attr('x', '0');  
  .attr('y', '0');

然后附加您的mousedown函数以在需要时显示此文本元素

  drag_line
        .style('marker-end', 'url(#end-arrow)')
        .classed('hidden', false)
        .attr('d', 'M' + mousedown_node.x + ',' + mousedown_node.y + 'L' + mousedown_node.x + ',' + mousedown_node.y);
  drag_line_text
        .classed('hidden', false)
        .attr('x', mousedown_node.x)
        .attr('y', mousedown_node.y);

在此之后，您还必须更改mouseup功能以在拖动后隐藏文本

  drag_line
    .classed('hidden', true)
    .style('marker-end', '');
  drag_line_text
    .classed('hidden', true);

现在，当您在结束拖动时开始拖动和淡出时，将显示文本。现在你必须调整位置

function mousemove() {
  if(!mousedown_node) return;

  // update drag line
  drag_line.attr('d', 'M' + mousedown_node.x + ',' + mousedown_node.y + 'L' + d3.mouse(this)[0] + ',' + d3.mouse(this)[1]);
  // update drag line text
  drag_line_text
    .attr('x', (mousedown_node.x + d3.mouse(this)[0]) / 2)
    .attr('y', (mousedown_node.y + d3.mouse(this)[1]) / 2);

  restart();
}

这将显示该行中间的文字。拖动后（鼠标向上）隐藏drag_line和drag_line_text。

function mouseup() {
  if(mousedown_node) {
    // hide drag line
    drag_line
      .classed('hidden', true)
      .style('marker-end', '');
    // hide drag line text
    drag_line_text
      .classed('hidden', true);
  }

  // because :active only works in WebKit?
  svg.classed('active', false);

  // clear mouse event vars
  resetMouseVars();
}

BTW：您想要在drag_line添加一个文字吗？因为在建立连接后此文本将消失。

添加标签以动态添加边缘d3js强制布局

2 个答案: