问题描述
我正在为此使用d3.v4.当我有
var treemap = d3.tree().size([height, width])
树正好居中
但是(因为我想指定节点之间的垂直间距),当我将其更改为
var treemap = d3.tree().size([height, width]).nodeSize([40]);
树移到左上方:
有人知道为什么会这样吗?
我相信d3.tree().size()
和d3.tree().nodeSize()
是互斥的.设置一个会使另一个无效. v3文档(此处)在这方面是明确的,而v4文档(这里)可能暗示这仍然是正确的.快速测试表明,v4在这方面与v4相同. (另请参见:此答案,或这一个.)更重要的是,指定节点大小时,根节点始终位于⟨0,0⟩". ( API文档).
使用size
时,每个节点的定位都利用了可用空间-相对于指定的宽度/高度进行定位,而无需考虑节点密度.使用nodeSize
时,位置是相对于其他节点的,而不是该图的可用区域(尽管它将锚定在[0,0]).通过最初使用.size
,您不必担心定位.使用.nodeSize
,您必须为节点设置一个转换,以使它们正确居中.
要正确放置它,您需要在容器上设置一个转换,以便更适当地放置[0,0]和根节点(如下面的无边距示例中的[0,高度/2]):
var data = { "name": "Parent", "children": [ { "name": "Child A", "children": [ { "name": "Grandchild" } ] }, { "name": "Child B", } ] };
var width = 500;
var height = 500;
var svg = d3.select("body").append("svg")
.attr("width", width)
.attr("height", height);
var g = svg.append("g").attr('transform','translate(0,'+ (height/2) +')');
var root = d3.hierarchy(data);
var tree = d3.tree()
.nodeSize([width/2,height/2]);
var link = g.selectAll(".link")
.data(tree(root).links())
.enter().append("path")
.attr("class", "link")
.attr("d", d3.linkHorizontal()
.x(function(d) { return d.y; })
.y(function(d) { return d.x; }));
var node = g.selectAll(".node")
.data(root.descendants())
.enter().append("g")
.attr("class", function(d) { return "node" + (d.children ? " node--internal" : " node--leaf"); })
.attr("transform", function(d) { return "translate(" + d.y + "," + d.x + ")"; })
node.append("circle")
.attr("r", 2.5);
.node circle {
fill: #fff;
stroke: steelblue;
stroke-width: 3px;
}
.link {
fill: none;
stroke: #ccc;
stroke-width: 2px;
}
svg {
background: #eee;
}
<script src="https://cdnjs.cloudflare.com/ajax/libs/d3/4.9.1/d3.min.js"></script>
与d3.tree().size()
的自动间距相比:
var data = { "name": "Parent", "children": [ { "name": "Child A", "children": [ { "name": "Grandchild" } ] }, { "name": "Child B", } ] };
var width = 500;
var height = 500;
var svg = d3.select("body").append("svg")
.attr("width", width)
.attr("height", height);
var g = svg.append("g");
var root = d3.hierarchy(data);
var tree = d3.tree()
.size([width,height]);
var link = g.selectAll(".link")
.data(tree(root).links())
.enter().append("path")
.attr("class", "link")
.attr("d", d3.linkHorizontal()
.x(function(d) { return d.y; })
.y(function(d) { return d.x; }));
var node = g.selectAll(".node")
.data(root.descendants())
.enter().append("g")
.attr("class", function(d) { return "node" + (d.children ? " node--internal" : " node--leaf"); })
.attr("transform", function(d) { return "translate(" + d.y + "," + d.x + ")"; })
node.append("circle")
.attr("r", 2.5);
.node circle {
fill: #fff;
stroke: steelblue;
stroke-width: 3px;
}
.link {
fill: none;
stroke: #ccc;
stroke-width: 2px;
}
svg {
background: #eee;
}
<script src="https://cdnjs.cloudflare.com/ajax/libs/d3/4.9.1/d3.min.js"></script>
I'm using d3.v4 for this. When I have
var treemap = d3.tree().size([height, width])
the tree is nicely centred
but (because I want to specify the vertical spacing between nodes) when I change this to
var treemap = d3.tree().size([height, width]).nodeSize([40]);
the tree moves to the top left:
Does anyone know why this might be happening?
I believe that d3.tree().size()
and d3.tree().nodeSize()
are exclusive in relation to one another. Setting one nullifies the other. The v3 documentation (here) is explicit in this regard , while the v4 documentation (here) might suggest that this is still true. Quick testing suggests v4 is the same as v4 in regards to this. (see also: this answer, or this one.)
More importantly, "When a node size is specified, the root node is always positioned at ⟨0, 0⟩." (API documentation).
When using size
, the positioning of each node takes advantage of available space - positioning in relation to the specified width/height with no consideration for node density. When using nodeSize
, positioning is relative to other nodes, not the available area for the diagram (though it will be anchored at [0,0]). By initially using .size
, you didn't have to worry about positioning. Using .nodeSize
, you'll have to set a transform for your nodes so that they are centered properly.
To position it properly, you'll need to set a transform on your container so that [0,0], and the root node, is more appropriately placed (as in the margin-less example below, at [0,height/2]):
var data = { "name": "Parent", "children": [ { "name": "Child A", "children": [ { "name": "Grandchild" } ] }, { "name": "Child B", } ] };
var width = 500;
var height = 500;
var svg = d3.select("body").append("svg")
.attr("width", width)
.attr("height", height);
var g = svg.append("g").attr('transform','translate(0,'+ (height/2) +')');
var root = d3.hierarchy(data);
var tree = d3.tree()
.nodeSize([width/2,height/2]);
var link = g.selectAll(".link")
.data(tree(root).links())
.enter().append("path")
.attr("class", "link")
.attr("d", d3.linkHorizontal()
.x(function(d) { return d.y; })
.y(function(d) { return d.x; }));
var node = g.selectAll(".node")
.data(root.descendants())
.enter().append("g")
.attr("class", function(d) { return "node" + (d.children ? " node--internal" : " node--leaf"); })
.attr("transform", function(d) { return "translate(" + d.y + "," + d.x + ")"; })
node.append("circle")
.attr("r", 2.5);
.node circle {
fill: #fff;
stroke: steelblue;
stroke-width: 3px;
}
.link {
fill: none;
stroke: #ccc;
stroke-width: 2px;
}
svg {
background: #eee;
}
<script src="https://cdnjs.cloudflare.com/ajax/libs/d3/4.9.1/d3.min.js"></script>
As compared with the automatic spacing of d3.tree().size()
:
var data = { "name": "Parent", "children": [ { "name": "Child A", "children": [ { "name": "Grandchild" } ] }, { "name": "Child B", } ] };
var width = 500;
var height = 500;
var svg = d3.select("body").append("svg")
.attr("width", width)
.attr("height", height);
var g = svg.append("g");
var root = d3.hierarchy(data);
var tree = d3.tree()
.size([width,height]);
var link = g.selectAll(".link")
.data(tree(root).links())
.enter().append("path")
.attr("class", "link")
.attr("d", d3.linkHorizontal()
.x(function(d) { return d.y; })
.y(function(d) { return d.x; }));
var node = g.selectAll(".node")
.data(root.descendants())
.enter().append("g")
.attr("class", function(d) { return "node" + (d.children ? " node--internal" : " node--leaf"); })
.attr("transform", function(d) { return "translate(" + d.y + "," + d.x + ")"; })
node.append("circle")
.attr("r", 2.5);
.node circle {
fill: #fff;
stroke: steelblue;
stroke-width: 3px;
}
.link {
fill: none;
stroke: #ccc;
stroke-width: 2px;
}
svg {
background: #eee;
}
<script src="https://cdnjs.cloudflare.com/ajax/libs/d3/4.9.1/d3.min.js"></script>
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