我有一个用D3.js编写的简单代码。
json数据采用以下格式：
{
"user_id": 0,
"name": "Buckner Carrillo",
"children": [
{
"user_id": 13,
"name": "Snider Barrett"
},
{
"user_id": 14,
"name": "Janice Atkins",
"children": [
{
"user_id": 11,
"name": "cdc dd"
}
]
}
]
}
这是工作代码：
// Get JSON data
treeJSON = d3.json("https://gist.githubusercontent.com/robschmuecker/7926762/raw/adfd3d8017f99d18497dc1592db9416c568353c9/manyNodes.json", function(error, treeData) {
// Calculate total nodes, max label length
var totalNodes = 0;
var maxLabelLength = 0;
// variables for drag/drop
var selectedNode = null;
var draggingNode = null;
// panning variables
var panSpeed = 200;
var panBoundary = 20; // Within 20px from edges will pan when dragging.
// Misc. variables
var i = 0;
var duration = 750;
var root;
// size of the diagram
var viewerWidth = $(document).width();
var viewerHeight = $(document).height();
var tree = d3.layout.tree()
.size([viewerHeight, viewerWidth]);
// define a d3 diagonal projection for use by the node paths later on.
var diagonal = d3.svg.diagonal()
.projection(function(d) {
return [d.y, d.x];
});
// A recursive helper function for performing some setup by walking through all nodes
function visit(parent, visitFn, childrenFn) {
if (!parent) return;
visitFn(parent);
var children = childrenFn(parent);
if (children) {
var count = children.length;
for (var i = 0; i < count; i++) {
visit(children[i], visitFn, childrenFn);
}
}
}
// Call visit function to establish maxLabelLength
visit(treeData, function(d) {
totalNodes++;
maxLabelLength = Math.max(d.name.length, maxLabelLength);
}, function(d) {
return d.children && d.children.length > 0 ? d.children : null;
});
// sort the tree according to the node names
function sortTree() {
tree.sort(function(a, b) {
return b.name.toLowerCase() < a.name.toLowerCase() ? 1 : -1;
});
}
// Sort the tree initially incase the JSON isn't in a sorted order.
sortTree();
// TODO: Pan function, can be better implemented.
function pan(domNode, direction) {
var speed = panSpeed;
if (panTimer) {
clearTimeout(panTimer);
translateCoords = d3.transform(svgGroup.attr("transform"));
if (direction == 'left' || direction == 'right') {
translateX = direction == 'left' ? translateCoords.translate[0] + speed : translateCoords.translate[0] - speed;
translateY = translateCoords.translate[1];
} else if (direction == 'up' || direction == 'down') {
translateX = translateCoords.translate[0];
translateY = direction == 'up' ? translateCoords.translate[1] + speed : translateCoords.translate[1] - speed;
}
scaleX = translateCoords.scale[0];
scaleY = translateCoords.scale[1];
scale = zoomListener.scale();
svgGroup.transition().attr("transform", "translate(" + translateX + "," + translateY + ")scale(" + scale + ")");
d3.select(domNode).select('g.node').attr("transform", "translate(" + translateX + "," + translateY + ")");
zoomListener.scale(zoomListener.scale());
zoomListener.translate([translateX, translateY]);
panTimer = setTimeout(function() {
pan(domNode, speed, direction);
}, 50);
}
}
// Define the zoom function for the zoomable tree
function zoom() {
svgGroup.attr("transform", "translate(" + d3.event.translate + ")scale(" + d3.event.scale + ")");
}
// define the zoomListener which calls the zoom function on the "zoom" event constrained within the scaleExtents
var zoomListener = d3.behavior.zoom().scaleExtent([0.1, 3]).on("zoom", zoom);
function initiateDrag(d, domNode) {
draggingNode = d;
d3.select(domNode).select('.ghostCircle').attr('pointer-events', 'none');
d3.selectAll('.ghostCircle').attr('class', 'ghostCircle show');
d3.select(domNode).attr('class', 'node activeDrag');
svgGroup.selectAll("g.node").sort(function(a, b) { // select the parent and sort the path's
if (a.id != draggingNode.id) return 1; // a is not the hovered element, send "a" to the back
else return -1; // a is the hovered element, bring "a" to the front
});
// if nodes has children, remove the links and nodes
if (nodes.length > 1) {
// remove link paths
links = tree.links(nodes);
nodePaths = svgGroup.selectAll("path.link")
.data(links, function(d) {
return d.target.id;
}).remove();
// remove child nodes
nodesExit = svgGroup.selectAll("g.node")
.data(nodes, function(d) {
return d.id;
}).filter(function(d, i) {
if (d.id == draggingNode.id) {
return false;
}
return true;
}).remove();
}
// remove parent link
parentLink = tree.links(tree.nodes(draggingNode.parent));
svgGroup.selectAll('path.link').filter(function(d, i) {
if (d.target.id == draggingNode.id) {
return true;
}
return false;
}).remove();
dragStarted = null;
}
// define the baseSvg, attaching a class for styling and the zoomListener
var baseSvg = d3.select("#tree-container").append("svg")
.attr("width", viewerWidth)
.attr("height", viewerHeight)
.attr("class", "overlay")
.call(zoomListener);
// Define the drag listeners for drag/drop behaviour of nodes.
dragListener = d3.behavior.drag()
.on("dragstart", function(d) {
if (d == root) {
return;
}
dragStarted = true;
nodes = tree.nodes(d);
d3.event.sourceEvent.stopPropagation();
// it's important that we suppress the mouseover event on the node being dragged. Otherwise it will absorb the mouseover event and the underlying node will not detect it d3.select(this).attr('pointer-events', 'none');
})
.on("drag", function(d) {
if (d == root) {
return;
}
if (dragStarted) {
domNode = this;
initiateDrag(d, domNode);
}
// get coords of mouseEvent relative to svg container to allow for panning
relCoords = d3.mouse($('svg').get(0));
if (relCoords[0] < panBoundary) {
panTimer = true;
pan(this, 'left');
} else if (relCoords[0] > ($('svg').width() - panBoundary)) {
panTimer = true;
pan(this, 'right');
} else if (relCoords[1] < panBoundary) {
panTimer = true;
pan(this, 'up');
} else if (relCoords[1] > ($('svg').height() - panBoundary)) {
panTimer = true;
pan(this, 'down');
} else {
try {
clearTimeout(panTimer);
} catch (e) {
}
}
d.x0 += d3.event.dy;
d.y0 += d3.event.dx;
var node = d3.select(this);
node.attr("transform", "translate(" + d.y0 + "," + d.x0 + ")");
updateTempConnector();
}).on("dragend", function(d) {
if (d == root) {
return;
}
domNode = this;
if (selectedNode) {
// now remove the element from the parent, and insert it into the new elements children
var index = draggingNode.parent.children.indexOf(draggingNode);
if (index > -1) {
draggingNode.parent.children.splice(index, 1);
}
if (typeof selectedNode.children !== 'undefined' || typeof selectedNode._children !== 'undefined') {
if (typeof selectedNode.children !== 'undefined') {
selectedNode.children.push(draggingNode);
} else {
selectedNode._children.push(draggingNode);
}
} else {
selectedNode.children = [];
selectedNode.children.push(draggingNode);
}
// Make sure that the node being added to is expanded so user can see added node is correctly moved
expand(selectedNode);
sortTree();
endDrag();
} else {
endDrag();
}
});
function endDrag() {
selectedNode = null;
d3.selectAll('.ghostCircle').attr('class', 'ghostCircle');
d3.select(domNode).attr('class', 'node');
// now restore the mouseover event or we won't be able to drag a 2nd time
d3.select(domNode).select('.ghostCircle').attr('pointer-events', '');
updateTempConnector();
if (draggingNode !== null) {
update(root);
centerNode(draggingNode);
draggingNode = null;
}
}
// Helper functions for collapsing and expanding nodes.
function collapse(d) {
if (d.children) {
d._children = d.children;
d._children.forEach(collapse);
d.children = null;
}
}
function expand(d) {
if (d._children) {
d.children = d._children;
d.children.forEach(expand);
d._children = null;
}
}
var overCircle = function(d) {
selectedNode = d;
updateTempConnector();
};
var outCircle = function(d) {
selectedNode = null;
updateTempConnector();
};
// Function to update the temporary connector indicating dragging affiliation
var updateTempConnector = function() {
var data = [];
if (draggingNode !== null && selectedNode !== null) {
// have to flip the source coordinates since we did this for the existing connectors on the original tree
data = [{
source: {
x: selectedNode.y0,
y: selectedNode.x0
},
target: {
x: draggingNode.y0,
y: draggingNode.x0
}
}];
}
var link = svgGroup.selectAll(".templink").data(data);
link.enter().append("path")
.attr("class", "templink")
.attr("d", d3.svg.diagonal())
.attr('pointer-events', 'none');
link.attr("d", d3.svg.diagonal());
link.exit().remove();
};
// Function to center node when clicked/dropped so node doesn't get lost when collapsing/moving with large amount of children.
function centerNode(source) {
scale = zoomListener.scale();
x = -source.y0;
y = -source.x0;
x = x * scale + viewerWidth / 2;
y = y * scale + viewerHeight / 2;
d3.select('g').transition()
.duration(duration)
.attr("transform", "translate(" + x + "," + y + ")scale(" + scale + ")");
zoomListener.scale(scale);
zoomListener.translate([x, y]);
}
// Toggle children function
function toggleChildren(d) {
if (d.children) {
d._children = d.children;
d.children = null;
} else if (d._children) {
d.children = d._children;
d._children = null;
}
return d;
}
// Toggle children on click.
function click(d) {
if (d3.event.defaultPrevented) return; // click suppressed
d = toggleChildren(d);
update(d);
centerNode(d);
}
function update(source) {
// Compute the new height, function counts total children of root node and sets tree height accordingly.
// This prevents the layout looking squashed when new nodes are made visible or looking sparse when nodes are removed
// This makes the layout more consistent.
var levelWidth = [1];
var childCount = function(level, n) {
if (n.children && n.children.length > 0) {
if (levelWidth.length <= level + 1) levelWidth.push(0);
levelWidth[level + 1] += n.children.length;
n.children.forEach(function(d) {
childCount(level + 1, d);
});
}
};
childCount(0, root);
var newHeight = d3.max(levelWidth) * 25; // 25 pixels per line
tree = tree.size([newHeight, viewerWidth]);
// Compute the new tree layout.
var nodes = tree.nodes(root).reverse(),
links = tree.links(nodes);
// Set widths between levels based on maxLabelLength.
nodes.forEach(function(d) {
d.y = (d.depth * (maxLabelLength * 10)); //maxLabelLength * 10px
// alternatively to keep a fixed scale one can set a fixed depth per level
// Normalize for fixed-depth by commenting out below line
// d.y = (d.depth * 500); //500px per level.
});
// Update the nodes…
node = svgGroup.selectAll("g.node")
.data(nodes, function(d) {
return d.id || (d.id = ++i);
});
// Enter any new nodes at the parent's previous position.
var nodeEnter = node.enter().append("g")
.call(dragListener)
.attr("class", "node")
.attr("transform", function(d) {
return "translate(" + source.y0 + "," + source.x0 + ")";
})
.on('click', click);
nodeEnter.append("circle")
.attr('class', 'nodeCircle')
.attr("r", 0)
.style("fill", function(d) {
return d._children ? "lightsteelblue" : "#fff";
});
nodeEnter.append("text")
.attr("x", function(d) {
return d.children || d._children ? -10 : 10;
})
.attr("dy", ".35em")
.attr('class', 'nodeText')
.attr("text-anchor", function(d) {
return d.children || d._children ? "end" : "start";
})
.text(function(d) {
return d.name;
})
.style("fill-opacity", 0);
// phantom node to give us mouseover in a radius around it
nodeEnter.append("circle")
.attr('class', 'ghostCircle')
.attr("r", 30)
.attr("opacity", 0.2) // change this to zero to hide the target area
.style("fill", "red")
.attr('pointer-events', 'mouseover')
.on("mouseover", function(node) {
overCircle(node);
})
.on("mouseout", function(node) {
outCircle(node);
});
// Update the text to reflect whether node has children or not.
node.select('text')
.attr("x", function(d) {
return d.children || d._children ? -10 : 10;
})
.attr("text-anchor", function(d) {
return d.children || d._children ? "end" : "start";
})
.text(function(d) {
return d.name;
});
// Change the circle fill depending on whether it has children and is collapsed
node.select("circle.nodeCircle")
.attr("r", 4.5)
.style("fill", function(d) {
return d._children ? "lightsteelblue" : "#fff";
});
// Transition nodes to their new position.
var nodeUpdate = node.transition()
.duration(duration)
.attr("transform", function(d) {
return "translate(" + d.y + "," + d.x + ")";
});
// Fade the text in
nodeUpdate.select("text")
.style("fill-opacity", 1);
// Transition exiting nodes to the parent's new position.
var nodeExit = node.exit().transition()
.duration(duration)
.attr("transform", function(d) {
return "translate(" + source.y + "," + source.x + ")";
})
.remove();
nodeExit.select("circle")
.attr("r", 0);
nodeExit.select("text")
.style("fill-opacity", 0);
// Update the links…
var link = svgGroup.selectAll("path.link")
.data(links, function(d) {
return d.target.id;
});
// Enter any new links at the parent's previous position.
link.enter().insert("path", "g")
.attr("class", "link")
.attr("d", function(d) {
var o = {
x: source.x0,
y: source.y0
};
return diagonal({
source: o,
target: o
});
});
// Transition links to their new position.
link.transition()
.duration(duration)
.attr("d", diagonal);
// Transition exiting nodes to the parent's new position.
link.exit().transition()
.duration(duration)
.attr("d", function(d) {
var o = {
x: source.x,
y: source.y
};
return diagonal({
source: o,
target: o
});
})
.remove();
// Stash the old positions for transition.
nodes.forEach(function(d) {
d.x0 = d.x;
d.y0 = d.y;
});
}
// Append a group which holds all nodes and which the zoom Listener can act upon.
var svgGroup = baseSvg.append("g");
// Define the root
root = treeData;
root.x0 = viewerHeight / 2;
root.y0 = 0;
// Collapse all children of roots children before rendering.
root.children.forEach(function(child){
collapse(child);
});
// Layout the tree initially and center on the root node.
update(root);
centerNode(root);
});<!DOCTYPE html>
<html lang="">
<head>
<style type="text/css">
.node {
cursor: pointer;
}
.overlay {
background-color: #EEE;
}
.node circle {
fill: #fff;
stroke: steelblue;
stroke-width: 1.5px;
}
.node text {
font-size: 10px;
font-family: sans-serif;
}
.link {
fill: none;
stroke: #ccc;
stroke-width: 1.5px;
}
.templink {
fill: none;
stroke: red;
stroke-width: 3px;
}
.ghostCircle.show {
display: block;
}
.ghostCircle, .activeDrag .ghostCircle {
display: none;
}
</style>
<title></title>
</head>
<body>
<script src="http://code.jquery.com/jquery-1.10.2.min.js"></script>
<script src="http://d3js.org/d3.v3.min.js"></script>
<div id="tree-container"></div>
</body>
</html>
问题在于，当我使用所有50,000个节点时，系统变慢并且在放大和缩小时会费力。
可以通过将JavaScript代码的最后7行从collapse(child);替换为expand(child);
还有其他可以支持它的库吗？还是应该更改代码？
我将Macbook Pro与Intel i5处理器和8GB RAM配合使用，因此不是由于系统要求。
答案 0 :(得分：0)
问题来自环境：扩展节点时，它是用DOM编写的。 因此，对于每个节点，您的DOM包含多个元素，例如圆圈，文本，链接。 当扩展50000个节点时，DOM包含超过100000个元素，这使大多数环境不稳定（请检查此：How many HTML elements can "modern" browsers "handle" at once?或此：how many div's can you have before the dom slows and becomes unstable?）。
对于您的问题“我应该更改代码吗？”和“还有其他图书馆吗”， 您应该考虑代码的终结性，为什么要向用户显示50000个节点？