我试图在d3 JS Sankey实现中使接收器节点在垂直方向上集中对齐。朝向顶部它（几乎）正确对齐 Correct Alignment
但是在底部，与输入相比，汇聚节点不再是中心对齐的
这里是代码`
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;
` 以下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);
};
`
到目前为止我一直在尝试
1）使中心（节点）功能节点返回0，这不能正常工作
2）尝试在nodes.sort中的表达式y0 = node.y + node.dy + nodePadding中删除+ node.dy，导致相反的情况发生，下半部分对齐，但顶部对齐不在订购。如何使接收器节点与相应源节点的中心对齐？
答案 0 :(得分：0)
好吧，我得到了（非常偶然），在relaxRightToLeft函数中，只需注释掉node.y + =（y - center（node））* alpha; line，导致sink节点未对齐