CODEWITHSUNDEEP
javascriptjqueryd3.js
IlludiumPu36
IlludiumPu36

Reputation: 4304

d3.js tree - paging for many vertical child nodes?

I'm finding that the number of child nodes in a d3.js tree need to be constrained to prevent tight clustering of many nodes.

An extreme example:

enter image description here

I have been attempting to do this by grouping the child nodes where possible, but it gets to a point where this is no longer feasible.

It would be useful to have a layout where the number of child nodes to be displayed can be set, and a node (or whatever) at the end of the vertical list of nodes can be clicked to show the next lot of child nodes, which would also hide the upper batch of child nodes.

Another expanding node would then display at the top of that batch to show the previous batch of nodes and so on, with the number of child nodes displayed always constrained by the set value.

enter image description here

This is to show/hide nodes already in the JSON data. How would this be achieved?

See fiddle.

// Set the dimensions and margins of the diagram
var margin = {top: 20, right: 90, bottom: 30, left: 90},
    width = 960 - margin.left - margin.right,
    height = 500 - margin.top - margin.bottom;

// append the svg object to the body of the page
// appends a 'group' element to 'svg'
// moves the 'group' element to the top left margin
var svg = d3.select("body").append("svg")
    .attr("width", width + margin.right + margin.left)
    .attr("height", height + margin.top + margin.bottom)
  .append("g")
    .attr("transform", "translate("
          + margin.left + "," + margin.top + ")");

var i = 0,
    duration = 750,
    root;

// declares a tree layout and assigns the size
var treemap = d3.tree().size([height, width]);

// Assigns parent, children, height, depth
root = d3.hierarchy(treeData, function(d) { return d.children; });
root.x0 = height / 2;
root.y0 = 0;

// Collapse after the second level
root.children.forEach(collapse);

update(root);

// Collapse the node and all it's children
function collapse(d) {
  if(d.children) {
    d._children = d.children
    d._children.forEach(collapse)
    d.children = null
  }
}


function update(source) {

const colourScale = d3.scaleOrdinal()
.domain( [ "Parent", "Child 1", "Child 2" ] )
.range( [ "#abacab", "#b67a4e", "#5a6fbb" ] );

  // Assigns the x and y position for the nodes
  var treeData = treemap(root);

  // Compute the new tree layout.
  var nodes = treeData.descendants(),
      links = treeData.descendants().slice(1);

  // Normalize for fixed-depth.
  nodes.forEach(function(d){ d.y = d.depth * 180});

  // ****************** Nodes section ***************************

  // Update the nodes...
  var node = svg.selectAll('g.node')
      .data(nodes, function(d) {return d.id || (d.id = ++i); });

  // Enter any new modes at the parent's previous position.
  var nodeEnter = node.enter().append('g')
      .attr('class', 'node')
      .attr("transform", function(d) {
        return "translate(" + source.y0 + "," + source.x0 + ")";
    })
    .on('click', click);

  // Add Circle for the nodes
  nodeEnter.append('circle')
      .attr('class', 'node')
      .attr('r', 1e-6)
      .style("fill", function(d) {
           return colourScale(findParent(d))
      });

  // Add labels for the nodes
  nodeEnter.append('text')
      .attr("dy", ".35em")
      .attr("x", function(d) {
          return d.children || d._children ? -13 : 13;
      })
      .attr("text-anchor", function(d) {
          return d.children || d._children ? "end" : "start";
      })
      .text(function(d) { return d.data.name; });

  // UPDATE
  var nodeUpdate = nodeEnter.merge(node);

  // Transition to the proper position for the node
  nodeUpdate.transition()
    .duration(duration)
    .attr("transform", function(d) { 
        return "translate(" + d.y + "," + d.x + ")";
     });

  // Update the node attributes and style
  nodeUpdate.select('circle.node')
    .attr('r', 6)
    .style("fill", function(d) {
         return colourScale(findParent(d));
    });


  // Remove any exiting nodes
  var nodeExit = node.exit().transition()
      .duration(duration)
      .attr("transform", function(d) {
          return "translate(" + source.y + "," + source.x + ")";
      })
      .remove();

  // On exit reduce the node circles size to 0
  nodeExit.select('circle')
    .attr('r', 1e-6);

  // On exit reduce the opacity of text labels
  nodeExit.select('text')
    .style('fill-opacity', 1e-6);

  // ****************** links section ***************************

  // Update the links...
  var link = svg.selectAll('path.link')
      .data(links, function(d) { return d.id; });

  // Enter any new links at the parent's previous position.
  var linkEnter = link.enter().insert('path', "g")
      .attr("class", "link")
      .attr("stroke-width", function(d) {
           return 1;
        })
      .attr('d', function(d){
        var o = {
            x: source.x0,
            y: source.y0
        }
        return diagonal(o, o)
      })
  .attr("opacity", "0.3")
   .style("stroke", function(d) {
                //return colourScale(findParentLinks(d));
            });

  // UPDATE
  var linkUpdate = linkEnter.merge(link);

  // Transition back to the parent element position
  linkUpdate.transition()
      .duration(duration)
      .attr('d', function(d){ return diagonal(d, d.parent) });

  // Remove any exiting links
  var linkExit = link.exit().transition()
      .duration(duration)
      .attr('d', function(d) {
        var o = {x: source.x, y: source.y}
        return diagonal(o, o)
      })
      .remove();

  // Store the old positions for transition.
  nodes.forEach(function(d){
    d.x0 = d.x;
    d.y0 = d.y;
  });

  // Creates a curved (diagonal) path from parent to the child nodes
  function diagonal(s, d) {

    path = `M ${s.y} ${s.x}
            C ${(s.y + d.y) / 2} ${s.x},
              ${(s.y + d.y) / 2} ${d.x},
              ${d.y} ${d.x}`

    return path
  }
  
  function findParent(datum) {
  if (datum.depth < 2) {
    return datum.data.name
  } else {
    return findParent(datum.parent)
  }
}

function findParentLinks(datum) {
  if (datum.target.depth < 2) {
    return datum.target.name
  } else {
    return findParent(datum.target.parent)
  }
}

  // Toggle children on click.
  function click(event, d) {
    if (d.children) {
        d._children = d.children;
        d.children = null;
      } else {
        d.children = d._children;
        d._children = null;
      }
    update(d);
  }
}

Upvotes: 1

Views: 749

Answers (1)

Chandan
Chandan

Reputation: 11797

var treeData = {
  "name": "Top Level",
  "children": [{
      "name": "Child 1",
      "children": [{
          "name": "C1"
        },
        {
          "name": "C2"
        },
        {
          "name": "C3"
        },
        {
          "name": "C4"
        },
        {
          "name": "C5"
        },
        {
          "name": "C6"
        },
        {
          "name": "C7"
        },
        {
          "name": "C8"
        },
        {
          "name": "C9"
        },
        {
          "name": "C10"
        },
        {
          "name": "C11"
        },
        {
          "name": "C12"
        },
        {
          "name": "C13"
        },
        {
          "name": "C14"
        },
        {
          "name": "C15"
        },
        {
          "name": "C16"
        },
        {
          "name": "C17"
        },
        {
          "name": "C18"
        },
        {
          "name": "C19"
        },
        {
          "name": "C20"
        },
        {
          "name": "C21"
        },
      ]
    },
    {
      "name": "Child 2",
      "children": [{
          "name": "Son of Child 2"
        },
        {
          "name": "Daughter of Child 2"
        }
      ]
    }
  ]
};

// Set the dimensions and margins of the diagram
var margin = {
    top: 20,
    right: 90,
    bottom: 30,
    left: 90
  },
  width = 960 - margin.left - margin.right,
  height = 500 - margin.top - margin.bottom;

// append the svg object to the body of the page
// appends a 'group' element to 'svg'
// moves the 'group' element to the top left margin
var svg = d3.select("body").append("svg")
  .attr("width", width + margin.right + margin.left)
  .attr("height", height + margin.top + margin.bottom)
  .append("g")
  .attr("transform", "translate(" +
    margin.left + "," + margin.top + ")");

var i = 0,
  duration = 750,
  root;

// declares a tree layout and assigns the size
var treemap = d3.tree().size([height, width]);

// Assigns parent, children, height, depth
root = d3.hierarchy(treeData, function(d) {
  return d.children;
});
root.x0 = height / 2;
root.y0 = 0;

function pageNodes(d, maxNode) {
  if (d.children) {
    d.children.forEach(c => pageNodes(c, maxNode));
    if (d.children.length > maxNode) {
      d.pages = {}
      const count = maxNode - 2;
      const l = Math.ceil(d.children.length / count);
      for (let i = 0; i < l; i++) {
        let startRange = i * count;
        let endRange = i * count + count;
        d.pages[i] = d.children.slice(startRange, endRange);
        d.pages[i].unshift({
          ...d.pages[i][0],
          data: {
            name: "..."
          },
          page: i == 0 ? l - 1 : i - 1
        })

        // console.log(i, d.pages[i]);
        d.pages[i].push({
          ...d.pages[i][0],
          data: {
            name: "..."
          },
          page: i != (l - 1) ? i + 1 : 0,
        });
      }
      d.children = d.pages[0];
    }
  }
}

root.children.forEach(c => pageNodes(c, 10));

// Collapse after the second level
root.children.forEach(collapse);

update(root);

// Collapse the node and all it's children
function collapse(d) {
  if (d.children) {
    d._children = d.children
    d._children.forEach(collapse)
    d.children = null
  }
}


function update(source) {

  const colourScale = d3.scaleOrdinal()
    .domain(["Parent", "Child 1", "Child 2"])
    .range(["#abacab", "#b67a4e", "#5a6fbb"]);

  // Assigns the x and y position for the nodes
  var treeData = treemap(root);

  // Compute the new tree layout.
  var nodes = treeData.descendants(),
    links = treeData.descendants().slice(1);

  // Normalize for fixed-depth.
  nodes.forEach(function(d) {
    d.y = d.depth * 180
  });

  // ****************** Nodes section ***************************

  // Update the nodes...
  var node = svg.selectAll('g.node')
    .data(nodes, function(d) {
      return d.id || (d.id = ++i);
    });

  // Enter any new modes at the parent's previous position.
  var nodeEnter = node.enter().append('g')
    .attr('class', 'node')
    .attr("transform", function(d) {
      return "translate(" + source.y0 + "," + source.x0 + ")";
    })
    .on('click', click);

  // Add Circle for the nodes
  nodeEnter.append('circle')
    .attr('class', 'node')
    .attr('r', 1e-6)
    .style("fill", function(d) {
      return colourScale(findParent(d))
    });

  // Add labels for the nodes
  nodeEnter.append('text')
    .attr("dy", ".35em")
    .attr("x", function(d) {
      return d.children || d._children ? -13 : 13;
    })
    .attr("text-anchor", function(d) {
      return d.children || d._children ? "end" : "start";
    })
    .text(function(d) {
      return d.data.name;
    });

  // UPDATE
  var nodeUpdate = nodeEnter.merge(node);

  // Transition to the proper position for the node
  nodeUpdate.transition()
    .duration(duration)
    .attr("transform", function(d) {
      return "translate(" + d.y + "," + d.x + ")";
    });

  // Update the node attributes and style
  nodeUpdate.select('circle.node')
    .attr('r', 6)
    .style("fill", function(d) {
      return colourScale(findParent(d));
    });


  // Remove any exiting nodes
  var nodeExit = node.exit().transition()
    .duration(duration)
    .attr("transform", function(d) {
      return "translate(" + source.y + "," + source.x + ")";
    })
    .remove();

  // On exit reduce the node circles size to 0
  nodeExit.select('circle')
    .attr('r', 1e-6);

  // On exit reduce the opacity of text labels
  nodeExit.select('text')
    .style('fill-opacity', 1e-6);

  // ****************** links section ***************************

  // Update the links...
  var link = svg.selectAll('path.link')
    .data(links, function(d) {
      return d.id;
    });

  // Enter any new links at the parent's previous position.
  var linkEnter = link.enter().insert('path', "g")
    .attr("class", "link")
    .attr("stroke-width", function(d) {
      return 1;
    })
    .attr('d', function(d) {
      var o = {
        x: source.x0,
        y: source.y0
      }
      return diagonal(o, o)
    })
    .attr("opacity", "0.3")
    .style("stroke", function(d) {
      //return colourScale(findParentLinks(d));
    });

  // UPDATE
  var linkUpdate = linkEnter.merge(link);

  // Transition back to the parent element position
  linkUpdate.transition()
    .duration(duration)
    .attr('d', function(d) {
      return diagonal(d, d.parent)
    });

  // Remove any exiting links
  var linkExit = link.exit().transition()
    .duration(duration)
    .attr('d', function(d) {
      var o = {
        x: source.x,
        y: source.y
      }
      return diagonal(o, o)
    })
    .remove();

  // Store the old positions for transition.
  nodes.forEach(function(d) {
    d.x0 = d.x;
    d.y0 = d.y;
  });

  // Creates a curved (diagonal) path from parent to the child nodes
  function diagonal(s, d) {

    path = `M ${s.y} ${s.x}
            C ${(s.y + d.y) / 2} ${s.x},
              ${(s.y + d.y) / 2} ${d.x},
              ${d.y} ${d.x}`

    return path
  }

  function findParent(datum) {
    if (datum.depth < 2) {
      return datum.data.name
    } else {
      return findParent(datum.parent)
    }
  }

  function findParentLinks(datum) {
    if (datum.target.depth < 2) {
      return datum.target.name
    } else {
      return findParent(datum.target.parent)
    }
  }

  // Toggle children on click.
  function click(event, d) {
    if (d.hasOwnProperty('page')) {
      d.parent.children = d.parent.pages[d.page];
    } else if (d.children) {
      d._children = d.children;
      d.children = null;
    } else {
      d.children = d._children;
      d._children = null;
    }
    update(d);
  }
}

Here working example

Upvotes: 3

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