I'm using Svelte and D3 to create a scatter-point graph.
I need it to dynamically show and hide data points depending on the length of an array of years.
If the array is empty, I want to show all of the points.
If the array is populated, I want to show only the data points which occur on years which are present in the array.
The array is coming from a parent component, I've logged it with a reactive statement and the array is correctly updated in the child component as it needs to be.
My component is currently set up as follows:
onMount(() => {
drawGraph();
plotPoints();
});
$: filterYears.length,
destroyPoints();
plotPoints();
function drawGraph() {
logic to render the graph with axis and titles relevant to the data input.
this works fine.
}
function plotPoints() {
svg.selectAll("dot")
.data(dataArray2)
.enter()
.append("circle")
.attr("r", 3)
.attr("cx", function(d) { return x(d.year); })
.attr("cy", function(d) { return yRight(d.value); })
.style("stroke", "#f8ff2a")
.style('stroke-width', '1px')
.style("fill", "#f8ff2a55")
.style("display", d => (filterYears.length > 0 && !filterYears.includes(d.year)) ? "none" : "inline")
.on('mouseover', function (event, datum) {
d3.select(this).transition()
.duration('100')
.attr("r", 7);
div2.transition()
.duration(100)
.style("opacity", 1)
div2.html((datum.value).toFixed(2))
.style("left", (event.offsetX + 25) + "px")
.style("top", (event.offsetY - 10) + "px")
})
.on('mouseout', function (event, datum) {
d3.select(this).transition()
.duration('200')
.attr("r", 3);
div2.transition()
.duration('200')
.style("opacity", 0);
});
console.log('plot point');
}
I have 2 sets of data being rendered, the above is one of them.
function destroyPoints() {
console.log('destroying points');
svg.selectAll("dot").remove()
}
All variables are correctly scoped and all functions have access to what they need.
The reactive statement seems to be called initially on component render and was triggering destroyPoints() which was trying to access svg before initialisation, causing an error, I have gotten around this with a really hacky setTimeout. If somebody could shed some light on why this happens and a better workaround I would love to hear it.
The real issue is that on change of filterYears, the points are not updating in the graph.
Could somebody give me a hand here?
Thanks!
Regular component code, including reactive statements, is executed before anything it mounted at which point DOM elements will not exist yet. It is common to just add a condition to reactive statements that depend on DOM bindings:
$: if (svg) {
filterYears;
destroyPoints();
plotPoints();
}
There seems to be another error here which is obfuscated by deceptive formatting, the correct format of the original code is:
$: filterYears.length,
destroyPoints();
plotPoints();
plotPoints() is not part of the reactive statement due to the ;.
(Also, in case you modify filterYears using functions like push: An assignment has to be used to trigger reactivity.)
I am new to d3.js, but wouldnt a pre-refinement of the inputdata be more straight forward?
svg.selectAll("dot")
.remove()
.data(filteredDataArray.any() ? filteredDataArray : dataArray2)
.enter()
.append("circle")
or maybe even more outside. just filter the dataArray
I am trying to create a force layout where nodes will have different images (icons) based on some condition in the .data(). I can understand that we can set other attributes such as style, class etc easily following the standard approach:
nodeSelction.data(...)
.enter()
.append("circle")
.attr("class", function(d) { return xxx; })
Is it possible to do the same thing for deciding whether to add a svg:circle, or some image icon? I tried doing the same thing to append method, but it doesn't take a function. That is,
the following snippet doesn't work.
nodeSelction.data(...)
.enter()
.append(function(d) { return d.group==0?"circle" : "usr.png"})
.attr("class", function { return xxx; })
So, what is the correct way to achieve the above?
What is an effective way to bring an SVG element to the top of the z-order, using the D3 library?
My specific scenario is a pie chart which highlights (by adding a stroke to the path) when the mouse is over a given piece. The code block for generating my chart is below:
svg.selectAll("path")
.data(d)
.enter().append("path")
.attr("d", arc)
.attr("class", "arc")
.attr("fill", function(d) { return color(d.name); })
.attr("stroke", "#fff")
.attr("stroke-width", 0)
.on("mouseover", function(d) {
d3.select(this)
.attr("stroke-width", 2)
.classed("top", true);
//.style("z-index", 1);
})
.on("mouseout", function(d) {
d3.select(this)
.attr("stroke-width", 0)
.classed("top", false);
//.style("z-index", -1);
});
I've tried a few options, but no luck so far. Using style("z-index") and calling classed both did not work.
The "top" class is defined as follows in my CSS:
.top {
fill: red;
z-index: 100;
}
The fill statement is there to make sure I knew it was turning on/off correctly. It is.
I've heard using sort is an option, but I'm unclear on how it would be implemented for bringing the "selected" element to the top.
UPDATE:
I fixed my particular situation with the following code, which adds a new arc to the SVG on the mouseover event to show a highlight.
svg.selectAll("path")
.data(d)
.enter().append("path")
.attr("d", arc)
.attr("class", "arc")
.style("fill", function(d) { return color(d.name); })
.style("stroke", "#fff")
.style("stroke-width", 0)
.on("mouseover", function(d) {
svg.append("path")
.attr("d", d3.select(this).attr("d"))
.attr("id", "arcSelection")
.style("fill", "none")
.style("stroke", "#fff")
.style("stroke-width", 2);
})
.on("mouseout", function(d) {
d3.select("#arcSelection").remove();
});
As explained in the other answers, SVG does not have a notion of a z-index. Instead, the order of elements in the document determines the order in the drawing.
Apart from reordering the elements manually, there is another way for certain situations:
Working with D3 you often have certain types of elements that should always be drawn on top of other types of elements.
For example, when laying out graphs, links should always be placed below nodes. More generally, some background elements usually need to be placed below everything else, while some highlights and overlays should be placed above.
If you have this kind of situation, I found that creating parent group elements for those groups of elements is the best way to go. In SVG, you can use the g element for that. For example, if you have links that should be always placed below nodes, do the following:
svg.append("g").attr("id", "links")
svg.append("g").attr("id", "nodes")
Now, when you paint your links and nodes, select as follows (the selectors starting with # reference the element id):
svg.select("#links").selectAll(".link")
// add data, attach elements and so on
svg.select("#nodes").selectAll(".node")
// add data, attach elements and so on
Now, all links will always be appended structurally before all node elements. Thus, the SVG will show all links below all nodes, no matter how often and in what order you add or remove elements. Of course, all elements of the same type (i.e. within the same container) will still be subject to the order in which they were added.
One of the solutions presented by the developer is: "use D3's sort operator to reorder the elements." (see https://github.com/mbostock/d3/issues/252)
In this light, one might sort the elements by comparing their data, or positions if they were dataless elements:
.on("mouseover", function(d) {
svg.selectAll("path").sort(function (a, b) { // select the parent and sort the path's
if (a.id != d.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
});
})
Since SVG doesn't have Z-index but use the order of the DOM elements, you can bring it to front by:
this.parentNode.appendChild(this);
You can then e.g. make use of insertBefore to put it back on mouseout. This however requires you to be able to target the sibling-node your element should be inserted before.
DEMO: Take a look at this JSFiddle
The simple answer is to use d3 ordering methods. In addition to d3.select('g').order(), there is .lower() and .raise() in version 4. This changes how your elements appear. Please consult the docs for more information - https://github.com/d3/d3/blob/master/API.md#selections-d3-selection
SVG doesn't do z-index. Z-order is dictated by the order of the SVG DOM elements in their container.
As far as I could tell (and I've tried this a couple of times in the past), D3 doesn't provide methods for detaching and reattaching a single element in order to bring it to the front or whatnot.
There is an .order() method, which reshuffles the nodes to match the order they appear in the selection. In your case, you need to bring a single element to the front. So, technically, you could resort the selection with the desired element in front (or at the end, can't remember which is topmost), and then call order() on it.
Or, you could skip d3 for this task and use plain JS (or jQuery) to re-insert that single DOM element.
I implemented futurend's solution in my code and it worked, but with the large number of elements I was using, it was very slow. Here's the alternative method using jQuery that worked faster for my particular visualization. It relies on the svgs you want on top having a class in common (in my example the class is noted in my data set as d.key). In my code there is a <g> with the class "locations" that contains all of the SVGs I'm re-organizing.
.on("mouseover", function(d) {
var pts = $("." + d.key).detach();
$(".locations").append(pts);
});
So when you hover on a particular data point, the code finds all the other data points with SVG DOM elements with that particular class. Then it detaches and re-inserts the SVG DOM elements associated with those data points.
Wanted to expand on what #notan3xit answered rather than write out an entire new answer (but I don't have enough reputation).
Another way to solve the element order problem is to use 'insert' rather than 'append' when drawing . That way the paths will always be placed together before the other svg elements(this assumes your code already does the enter() for links before the enter() for the other svg elements).
d3 insert api: https://github.com/mbostock/d3/wiki/Selections#insert
It took me ages to find how to tweak the Z-order in an existing SVG. I really needed it in the context of d3.brush with tooltip behavior. In order to have the two features work nicely together (http://wrobstory.github.io/2013/11/D3-brush-and-tooltip.html), you need the d3.brush to be the first in Z-order (1st to be drawn on the canvas, then covered by the rest of the SVG elements) and it will capture all mouse events, no matter what is on top of it (with higher Z indices).
Most forum comments say that you should add the d3.brush first in your code, then your SVG "drawing" code. But for me it was not possible as I loaded an external SVG file. You can easily add the brush at any time and alter the Z-order later on with:
d3.select("svg").insert("g", ":first-child");
In the context of a d3.brush setup it will look like:
brush = d3.svg.brush()
.x(d3.scale.identity().domain([1, width-1]))
.y(d3.scale.identity().domain([1, height-1]))
.clamp([true,true])
.on("brush", function() {
var extent = d3.event.target.extent();
...
});
d3.select("svg").insert("g", ":first-child");
.attr("class", "brush")
.call(brush);
d3.js insert() function API: https://github.com/mbostock/d3/wiki/Selections#insert
Hope this helps!
You can Do like this On Mouse Over You can Pull it to top.
d3.selection.prototype.bringElementAsTopLayer = function() {
return this.each(function(){
this.parentNode.appendChild(this);
});
};
d3.selection.prototype.pushElementAsBackLayer = function() {
return this.each(function() {
var firstChild = this.parentNode.firstChild;
if (firstChild) {
this.parentNode.insertBefore(this, firstChild);
}
});
};
nodes.on("mouseover",function(){
d3.select(this).bringElementAsTopLayer();
});
If You want To Push To Back
nodes.on("mouseout",function(){
d3.select(this).pushElementAsBackLayer();
});
Version 1
In theory, the following should work fine.
The CSS code :
path:hover {
stroke: #fff;
stroke-width : 2;
}
This CSS code will add a stroke to the selected path.
The JS code :
svg.selectAll("path").on("mouseover", function(d) {
this.parentNode.appendChild(this);
});
This JS code first removes the path from the DOM tree and then adds it as the last child of its parent. This makes sure the path is drawn on top of all other children of the same parent.
In practice, this code works fine in Chrome but breaks in some other browsers. I tried it in Firefox 20 on my Linux Mint machine and couldn't get it to work. Somehow, Firefox fails to trigger the :hover styles and I haven't found a way to fix this.
Version 2
So I came up with an alternative. It may be a bit 'dirty', but at least it works and it doesn't require looping over all elements (as some of the other answers).
The CSS code :
path.hover {
stroke: #fff;
stroke-width : 2;
}
Instead of using the :hover pseudoselector, I use a .hover class
The JS code :
svg.selectAll(".path")
.on("mouseover", function(d) {
d3.select(this).classed('hover', true);
this.parentNode.appendChild(this);
})
.on("mouseout", function(d) {
d3.select(this).classed('hover', false);
})
On mouseover, I add the .hover class to my path. On mouseout, I remove it.
As in the first case, the code also removes the path from the DOM tree and then adds it as the last child of its parent.
I solved it by using the raise function.
const raise = (d) => {
d3.select(d).raise()
}
And in the component that you need to raise on hover (along with all its children, just place this.
.on("mouseover", (d) => raise(d.srcElement.parentNode))
Depending on your structure, maybe parentNode is not needed. In this example they used "this" but that didn't work in React. https://codepen.io/_cselig/pen/KKgOppo
I've been looking for a solution for this but no luck. I can't get rid of this error, yet every example for d3 in Meteor that I've seen has it.
Array Getting Passed to d3:
{categoryName:"Shooter", count:"19"}
{categoryName:"Action",
count:"23"}
Error Encountered in Console:
"TypeError: slice.transition is not a function"
"TypeError: slice.duration is not a function"
Guide I've Been Following:
http://bl.ocks.org/dbuezas/9306799
Code:
https://gist.github.com/mayvn10/83d062eb7fd257b07c33
If anyone can shed some light on why transition and duration don't work, I'm all ears!
Thanks!
Move the enter like this...
var slice = svg.select(".slices")
.selectAll("path")
.data(pie(resultArray), function(d) { return d.data.categoryName; });
slice.enter()
.append("path")
.attr("class", "slice")
.attr("d", arc)
.attr("fill", function(d) {
return color(d.data.categoryName);
});
The enter object has reduced functionality, it doesn't have a .transition property for example. The object returned by .data() is a normal selection object and has all selection.prototype methods, including transition.
I have an odd problem that I can't seem to figure out. I have a stacked area chart with a smaller context chart below where I can brush similar to this: http://bl.ocks.org/mbostock/1667367
The brush is working, but only for the first layer (I have left the clipping off as it is easier to see what is happening).
If I check the data in the console the brush function does only have that first key and if I change the order of the data the key in the chart changes so it is always whatever the first key happens to be.
Here is a JSFiddle: http://jsfiddle.net/goodspeedj/7Qzt4/
Here is the brushed function - the 3rd line in the function has the console.log statement showing the data only has the 'ABORTED' key (first layer).
function brushed() {
main_x.domain(brush.empty() ? mini_x.domain() : brush.extent());
//main.select(".layer").attr("d", main_area);
main.select(".layer").attr("d", function(d) { console.log(d); return main_area(d.values); })
main.select(".x.axis").call(main_xAxis);
}
I'm guessing this is something really simple - I just can't seem to see it. Thanks!
I figured this out. I should have been calling selectAll instead of select in the brushed function.
This:
main.selectAll(".layer").attr("d", function(d) { console.log(d); return main_area(d.values); })
Instead of this:
main.select(".layer").attr("d", function(d) { console.log(d); return main_area(d.values); })