javascript - 修复 d3 js Sankey 中接收器节点的垂直对齐

Question

我试图让接收器节点在 d3 JS Sankey 实现中在垂直方向居中对齐。朝向顶部，它（几乎）像这样 正确对齐正确对齐

但在底部，与输入相比，汇节点不再居中对齐

错误对齐

这是代码`

sankey.nodeWidth = function (_) {
    if (!arguments.length) return nodeWidth;
    nodeWidth = +_;
    return sankey;
};

sankey.nodePadding = function (_) {
    if (!arguments.length) return nodePadding;
    nodePadding = +_;
    return sankey;
};

sankey.nodes = function (_) {
    if (!arguments.length) return nodes;
    nodes = _;
    return sankey;
};

sankey.links = function (_) {
    if (!arguments.length) return links;
    links = _;
    return sankey;
};

sankey.size = function (_) {
    if (!arguments.length) return size;
    size = _;
    return sankey;
};

sankey.layout = function (iterations) {
    computeNodeLinks();
    computeNodeValues();
    computeNodeBreadths();
    computeNodeDepths(iterations);
    computeLinkDepths();
    return sankey;
};

sankey.relayout = function () {
    computeLinkDepths();
    return sankey;
};

sankey.link = function () {
  //Original value of 0.5
    var curvature = 0.5;

    function link(d) {
        var x0 = d.source.x + d.source.dx,
            x1 = d.target.x,
            xi = d3.interpolateNumber(x0, x1),
            x2 = xi(curvature),
            x3 = xi(1 - curvature),
            y0 = d.source.y + d.sy + d.dy / 2,
            y1 = d.target.y + d.ty + d.dy / 2;
        return "M" + x0 + "," + y0 + "C" + x2 + "," + y0 + " " + x3 + "," + y1 + " " + x1 + "," + y1;
    }

    link.curvature = function (_) {
        if (!arguments.length) return curvature;
        curvature = +_;
        return link;
    };

    return link;
};

// Populate the sourceLinks and targetLinks for each node.
// Also, if the source and target are not objects, assume they are indices.
function computeNodeLinks() {
    nodes.forEach(function (node) {
        node.sourceLinks = [];
        node.targetLinks = [];
    });
    links.forEach(function (link) {
        var source = link.source,
            target = link.target;
        if (typeof source == "number")
         source = link.source = nodes[link.source];
        if (typeof target == "number") 
        target = link.target = nodes[link.target];
        source.sourceLinks.push(link);
        target.targetLinks.push(link);
    });
}

// Compute the value (size) of each node by summing the associated links.
function computeNodeValues() {
    nodes.forEach(function (node) {
      node.value = 15;
         //Original code
        //node.value = Math.max(
        // d3.sum(node.sourceLinks, value),
        //d3.sum(node.targetLinks, value));
    });
}

// Iteratively assign the breadth (x-position) for each node.
// Nodes are assigned the maximum breadth of incoming neighbors plus one;
// nodes with no incoming links are assigned breadth zero, while
// nodes with no outgoing links are assigned the maximum breadth.
function computeNodeBreadths() {
    var remainingNodes = nodes,
        nextNodes,
        x = 0;

    while (remainingNodes.length) {
        nextNodes = [];
        remainingNodes.forEach(function (node) {
            node.x = x;
            node.dx = nodeWidth;
            node.sourceLinks.forEach(function (link) {
                nextNodes.push(link.target);
            });
        });
        remainingNodes = nextNodes;
        //Original value of x+=1
       x++;
    }

    //
    moveSinksRight(x);
    scaleNodeBreadths((size[0] - nodeWidth) / (x - 1));
}

function moveSourcesRight() {
    nodes.forEach(function (node) {
        if (!node.targetLinks.length) {
            node.x = d3.min(node.sourceLinks, function (d) {
                return d.target.x;
            }) - 1;
        }
    });
}

function moveSinksRight(x) {
    nodes.forEach(function (node) {
        if (!node.sourceLinks.length) {
            node.x = x - 1;
        }
    });
}

function scaleNodeBreadths(kx) {
    nodes.forEach(function (node) {
        node.x *= kx;
    });
}

function computeNodeDepths(iterations) {
    var nodesByBreadth = d3.nest()
        .key(function (d) {
        return d.x;
    })
        .sortKeys(d3.ascending)
        .entries(nodes)
        .map(function (d) {
        return d.values;
    });

    //
    initializeNodeDepth();
    resolveCollisions();
    for (var alpha = 1; iterations > 0; --iterations) {
        relaxRightToLeft(alpha *= .99);
        resolveCollisions();
        relaxLeftToRight(alpha);
        resolveCollisions();
    }

    function initializeNodeDepth() {
        var ky = d3.min(nodesByBreadth, function (nodes) {
            return (size[1] - (nodes.length - 1) * nodePadding) / d3.sum(nodes, value);
        });

        nodesByBreadth.forEach(function (nodes) {
            nodes.forEach(function (node, i) {
                node.y = i;
                node.dy = node.value * ky;
            });
        });

        links.forEach(function (link) {
            link.dy = link.value * ky;
        });
    }

    function relaxLeftToRight(alpha) {
        nodesByBreadth.forEach(function (nodes, breadth) {
            nodes.forEach(function (node) {
                if (node.targetLinks.length) {
                    var y = d3.sum(node.targetLinks, weightedSource) / d3.sum(node.targetLinks, value);
                    node.y += (y - center(node)) * alpha;
                }
            });
        });

        function weightedSource(link) {
            return center(link.source) * link.value;
        }
    }

    function relaxRightToLeft(alpha) {
        nodesByBreadth.slice().reverse().forEach(function (nodes) {
            nodes.forEach(function (node) {
                if (node.sourceLinks.length) {
                    var y = d3.sum(node.sourceLinks, weightedTarget) / d3.sum(node.sourceLinks, value);
                    node.y += (y - center(node)) * alpha;
                }
            });
        });

        function weightedTarget(link) {
            return center(link.target) * link.value;
        }
    }

    function resolveCollisions() {
        nodesByBreadth.forEach(function (nodes) {
            var node,
            dy,
            y0 = 0,
                n = nodes.length,
                i;

            // Push any overlapping nodes down.
            nodes.sort(ascendingDepth);
            for (i = 0; i < n; ++i) {
                node = nodes[i];
                dy = y0 - node.y;
                //Make some changes here
                //Originally there in code
                if (dy > 0) node.y += dy;
                y0 = node.y + node.dy + nodePadding;
            }

            // If the bottommost node goes outside the bounds, push it back up.
            dy = y0 - nodePadding - size[1];
            if (dy > 0) {
                y0 = node.y -= dy;

                // Push any overlapping nodes back up.
                for (i = n - 2; i >= 0; --i) {
                    node = nodes[i];
                    dy = node.y + node.dy + nodePadding - y0;
                    if (dy > 0) node.y -= dy;
                    y0 = node.y;
                }
            }
        });
    }

    function ascendingDepth(a, b) {
        return a.y - b.y;
    }
}

function computeLinkDepths() {
    nodes.forEach(function (node) {
        node.sourceLinks.sort(ascendingTargetDepth);
        node.targetLinks.sort(ascendingSourceDepth);
    });
    nodes.forEach(function (node) {
        var sy = 0,
            ty = 0;
        node.sourceLinks.forEach(function (link) {
            link.sy = sy;
            sy += link.dy;
        });
        node.targetLinks.forEach(function (link) {
            link.ty = ty;
            ty += link.dy;
        });
    });

    function ascendingSourceDepth(a, b) {
        return a.source.y - b.source.y;
    }

    function ascendingTargetDepth(a, b) {
        return a.target.y - b.target.y;
    }
}

function center(node) {
  //return 0;  
  //Original code +node.dy/2
  return node.y+node.dy/2 ;
 // return node.y ;
}

function value(link) {
    return link.value;
}

return sankey;

` 这里是通常设置的用户参数

var units = "Widgets";

var VariableHeight = graphData.nodes.length*25; //Change to suit the needs of the 
    graph,
//reduce factor of 100 for sleeker design
var margin = {top: 10, right: 10, bottom: 10, left: 10},
//Original Values are 700 and 300, 2700 is definitely a dangerous value for width
width = 1200 - margin.left - margin.right,
height = VariableHeight - margin.top - margin.bottom;

var formatNumber = d3.format(",.0f"),    // zero decimal places
    format = function(d) { return formatNumber(d) + " " + units; },
    color = d3.scale.category20();
    // append the svg canvas to the html page
var svg = d3.select("#sankeyContainer").append("svg")
    .attr("width", width + margin.left + margin.right)
    .attr("height", height + margin.top + margin.bottom)
  .append("g")
    .attr("transform", 
          "translate(" + margin.left + "," + margin.top + ")");

// Set the sankey diagram properties
var sankey = d3sankey()
    .nodeWidth(36)
    .nodePadding(40)
    .size([width, height]);
//Changes to connect links to centre of nodes
//Original Value
//var path = sankey.link();
var path = d3.svg.diagonal()
    .source(function(d) {
        return {"x":d.source.y + d.source.dy / 2,
                "y":d.source.x + sankey.nodeWidth()/2};
    })            
    .target(function(d) {
        return {"x":d.target.y + d.target.dy / 2,
                "y":d.target.x + sankey.nodeWidth()/2};
    })
    .projection(function(d) { return [d.y, d.x]; });
// load the data
var graph = graphData;

sankey.nodes(graph.nodes)
    .links(graph.links)
    .layout(32);

// add in the links
var link = svg.append("g").selectAll(".link")
    .data(graph.links)
    .enter().append("path")
    .attr("class", "link")
    .attr("d", path)
    .style("fill", "none")
    .style("stroke", "black")
    .style("stroke-opacity", ".1")
    //.style("stroke-opacity", ".2")
    .on("mouseover", function() { d3.select(this).style("stroke-opacity", ".4") } )
    .on("mouseout", function() { d3.select(this).style("stroke-opacity", ".1") } )
    .style("stroke-width", function (d) {
      return 15;
      //return Math.max(1, Math.sqrt(d.dy)); 
      //Original value
      //return Math.max(1, d.dy);
    })
    .sort(function (a, b) {
        return b.dy - a.dy;
    });

// add the link titles
link.append("title")
    .text(function (d) {
        return d.source.name + " → " + d.target.name + "\n" + format(d.value);
    });

// add in the nodes
var node = svg.append("g").selectAll(".node")
        .data(graph.nodes).enter().append("g").attr("class", "node")
        .attr("transform", function(d) { 
            return "translate(" + d.x + "," + d.y + ")"; 
        }).on("click",function(d){
            if (d3.event.defaultPrevented) {
                document.getElementById("ErrorDisplay").innerHTML="";
                return;}
            document.getElementById("ErrorDisplay").innerHTML="You Have Clicked "+ d.name;
        }).call(d3.behavior.drag().origin(function(d) { 
            return d; 
        }).on("dragstart", function() { 
            //Removing the following line's comment status will make nodes unclickable
            //this.parentNode.appendChild(this); 
        }).on("drag", dragmove));

// add the rectangles for the nodes, Original Code
/*
node.append("rect")
    .attr("height", function (d) {
      //Changed to make sure all node heights are the same
      //Original Value  
      //return d.dy;
      return 15;
    })
    .attr("width", sankey.nodeWidth())
    */// add the circles for the nodes
node.append("circle")
.attr("cx", sankey.nodeWidth()/2)
.attr("cy", function (d) {
    return d.dy/2;
})
.attr("r", function (d) {
    return Math.sqrt(d.dy);
})
.style("fill", function (d) {
        return d.color = color(d.name.replace(/ .*/, ""));
    })
    .style("fill-opacity", ".9")
    .style("shape-rendering", "crispEdges")
    .style("stroke", function (d) {
        return d3.rgb(d.color).darker(2);
    })
    .append("title")
    .text(function (d) {
        return d.name + "\n" + format(d.value);
    });

// add in the title for the nodes
node.append("text")
    .attr("x", -6)
    .attr("y", function (d) {
        return d.dy / 2+15;  //Original value of only d.dy/2
    })
    .attr("dy", ".35em")
    .attr("text-anchor", "end")
    .attr("text-shadow", "0 1px 0 #fff")
    .attr("transform", null)
    .text(function (d) {
        return d.name;
    })
    .filter(function (d) {
        return d.x < width / 2;
    })
    .attr("x", 6 + sankey.nodeWidth())
    .attr("text-anchor", "start");

// the function for moving the nodes
function dragmove(d) {
    d3.select(this).attr("transform",
        "translate(" + (
    d.x = Math.max(0, Math.min(width - d.dx, d3.event.x))) + "," + (
    d.y = Math.max(0, Math.min(height - d.dy, d3.event.y))) + ")");
    sankey.relayout();
    link.attr("d", path);
};

`

我到目前为止所尝试的

1）让center(node)函数node返回0，效果不好

2）尝试在nodes.sort中删除表达式y0 = node.y + node.dy + nodePadding中的+node.dy，这导致相反的情况发生，下半部分对齐，但顶部对齐无序。如何使汇节点与相应源节点的中心对齐？

标签： javascriptd3.js

Answer 1

好的，我明白了（很偶然），在relaxRightToLeft 函数中，只需注释掉 node.y += (y - center(node)) * alpha; 线，这会导致汇节点错位