D3.js removing element doesn't work as expected - d3.js

I am building a visualization of a popular brain teaser. So far there are 9 balls on SVG with drag behavior, collision detection and forceY.
I am trying to remove them by dragging. Which kinda works... But not the way it is supposed.
One of balls is yellow. When it is dragged, it should get removed. This works, but the bug is that another ball gets rendered yellow.
Here is the function that deals with the functionality and below is fiddle.
function dragended(d, i) {
balls.splice(i, 1);
var update = svgBalls.data(balls)
update.exit().remove()
simulation.alphaTarget(0.1);
}
http://jsfiddle.net/Anuar/21738t3g/

This is not a solution in the narrow sense of the term, but simply an explanation of your problem.
If we slightly change your data array...
var balls = [{id:0, color:false},{id:1, color:false},{id:2, color:false},
{id:3, color:false}, {id:4, color:false}, {id:5, color:false},
{id:6, color:false}, {id:7, color:false},{id:8, color:false}];
... in such a way that we can set a key function...
svgBalls.data(balls, d => d.id)
... you're gonna see that this line:
balls.splice(i, 1);
Is not correctly removing the dragged element. If you change for this:
balls = balls.filter(d => d.id != i);
It will work.
Here is your updated fiddle: http://jsfiddle.net/27sykjxd/

Related

Display Mesh On Top Of Another | Remove Overalapping | Render Order | Three.js

I have 2 obj meshes.
They both have some common areas but not completely.
I displayed them both by adding them to screen ..
Just like a mesh on top of another.
But the lower mesh overlaps the top mesh
But what I want to acheive is the lower mesh should always stay below without overlapping and giving the space to the entire top mesh.
I went through this fiddle..Fiddle with renderorder
And I tried something with this like..
var objLoader1 = new OBJLoader2();
objLoader1.load('assets/object1.obj', (root) => {
root.renderOrder = 0;
scene.add(root);
});
var objLoader2 = new OBJLoader2();
objLoader2.load('assets/object2.obj', (root) => {
root.renderOrder = 1;
scene.add(root);
});
But I don't know for what reason the overlap still stays ..
I tried...
var objLoader1 = new OBJLoader2();
objLoader1.load('assets/object1.obj', (root) => {
objLoader1.renderOrder = 0;
scene.add(root);
});
var objLoader2 = new OBJLoader2();
objLoader2.load('assets/object2.obj', (root) => {
objLoader2.renderOrder = 1;
scene.add(root);
});
Then I tried going through this Fiddle .. Another Fiddle
But when I run in I get only the lower or the upper mesh .
But I want to see both without any overlaps..
var layer1 = new Layer(camera);
composer.addPass(layer1.renderPass);
layer1.scene.add(new THREE.AmbientLight(0xFFFFFF));
var objLoader1 = new OBJLoader2();
objLoader1.load('assets/object1.obj', (root) => {
layer1.scene.add(root);
});
var layer2 = new Layer(camera);
composer.addPass(layer2.renderPass);
layer2.scene.add(new THREE.AmbientLight(0xFFFFFF));
var objLoader2 = new OBJLoader2();
objLoader2.load('assets/object2.obj', (root) => {
layer2.scene.add(root);
});
I made the material depthTest to False
But Nothing Helped..
Can anyone help me achieve what I wanted ..
If anyone couldn't figure what I mean by overlapping see the image below..
And Thanks to anyone who took time and effort to go through and help me...
You can use polygonOffset to achieve your goal, which modifies the depth value right before a fragment is written to help move polygons off of eachother without visually changing the position:
material.polygonOffset = true;
material.polygonOffsetUnit = 1;
material.polygonOffsetFactor = 1;
Here is a fiddle demonstrating the solution:
https://jsfiddle.net/5s8ey0ad/1/
Here is what the OpenGL Docs have to say about polygon offset:
When GL_POLYGON_OFFSET_FILL, GL_POLYGON_OFFSET_LINE, or GL_POLYGON_OFFSET_POINT is enabled, each fragment's depth value will be offset after it is interpolated from the depth values of the appropriate vertices. The value of the offset is factor×DZ+r×units, where DZ is a measurement of the change in depth relative to the screen area of the polygon, and r is the smallest value that is guaranteed to produce a resolvable offset for a given implementation. The offset is added before the depth test is performed and before the value is written into the depth buffer.
You're experiencing z-fighting, which is when two or more planes occupy the same space in the depthBuffer, so the renderer doesn't know which one to render on top of the other. Render order alone doesn't fix this because they're both still on the same plane, regardless of which one gets drawn first. You have a few options to resolve this:
Move one of the beams ever so slightly up in the y-axis. A tiny fraction would give one priority over the other, and this distance may not be noticeable to the eye.
I saw your fiddle, and you forgot to add depthTest: false to your material. However, this will cause issues when depth-testing the rest of the shape, since some white is on top of the red, but also some red is on top of the white. The approach in the fiddle works only when it's a simple plane, not more complex geometries.
You can use a boolean operation that removes one shape from the other, like CSG.
I think you'd save yourself a lot of headache by using approach #1.

How to apply brushing on a dynamically growing dataset?

I have a dynamically growing timeseries I need to display in a zoomable/panable chart.
Try it out here (in fact: my first jsFiddle ever :) ) :
https://jsfiddle.net/Herkules001/L12k5zwx/29/
I tried to do it the same way as described here: https://dc-js.github.io/dc.js/examples/replacing-data.html
However, each time the chart updates, the zoom and filter are lost on the focus chart. (The brush is preserved on the range chart however.)
How can I add data without resetting the views and losing the zoom?
var chart = dc.lineChart("#test");
var zoom = dc.lineChart("#zoom");
//d3.csv("morley.csv", function(error, experiments) {
var experiments = d3.csvParse(d3.select('pre#data').text());
experiments.forEach(function(x) {
x.Speed = +x.Speed;
});
var ndx = crossfilter(experiments),
runDimension = ndx.dimension(function(d) {return +d.Run;}),
speedSumGroup = runDimension.group().reduceSum(function(d) {return d.Speed * d.Run / 1000;});
chart
.width(768)
.height(400)
.x(d3.scaleLinear().domain([6,20]))
.brushOn(false)
.yAxisLabel("This is the Y Axis!")
.dimension(runDimension)
.group(speedSumGroup)
.rangeChart(zoom);
zoom
.width(768)
.height(80)
.x(d3.scaleLinear().domain([6,20]))
.brushOn(true)
.yAxisLabel("")
.dimension(runDimension)
.group(speedSumGroup);
zoom.render();
chart.render();
var run = 21;
setInterval(
() => {
var chartfilter = chart.filters();
var zoomfilter = zoom.filters();
chart.filter(null);
zoom.filter(null);
ndx.add([{Expt: 6, Run: run++, Speed: 100 + 5 * run}]);
chart.x(d3.scaleLinear().domain([6,run]));
zoom.x(d3.scaleLinear().domain([6,run]));
chart.filter([chartfilter]);
zoom.filter([zoomfilter]);
chart.render();
zoom.render();
},
1000);
//});
In this case, if you are just adding data, you don't need to do the complicated clearing and restoring of filters demonstrated in the example you cited.
That part is only necessary because crossfilter.remove() originally would remove the data that matched the current filters. An awkward interface, almost never what you want.
If you're only adding data, you don't have to worry about any of that:
setInterval(
() => {
ndx.add([{Expt: 6, Run: run++, Speed: 5000 + 5 * run}]);
chart.redraw();
zoom.redraw();
},
5000);
Note that you'll get less flicker, and decent animated transitions, by using redraw instead of render. I also added evadeDomainFilter to avoid lines being clipped before the edge of the chart.
Fork of your fiddle
Removing data
If you use the predicate form of crossfilter.remove() you don't have to worry about saving and restoring filters:
ndx.remove(d => d.Run < run-20);
However, this does expose other bugs in dc.js. Seems like elasticY does not work, similar to what's described in this issue. And you get some weird animations.
Here's a demo with remove enabled.
In the end, dc.js has some pretty neat features, and there is usually a way to get it to do what you want, but it sure is quirky. It's a very complicated domain and in my experience you are going to find some of these quirks in any fully featured charting library.
Update: I fixed the replacing data example, that one is just ndx.remove(() => true) now.
zooming issues
As Joerg pointed out in the comments,
when the chart is not zoomed, it would be nice to have it also grow to show new data as it arrives
the X domain was clipped or even reversed if the focus reached outside the original domain of the chart
We can address these issues by adding a preRedraw event handler. That's the ideal place to adjust the domain; for example you can implement elasticX manually if you need to. (As you'll see in a second, we do!)
First, a naive attempt that's easy to understand:
chart.on('preRedraw', () => {
chart.elasticX(!zoom.filters().length);
});
We can turn elasticX on and off based on whether the range chart has an active filter.
This works and it's nice and simple, but why does the chart get so confused when you try to focus on a domain that wasn't in the original chart?
Welp, it records the original domain (source). So that it can restore to that domain if the focus is cleared, and also to stop you from zooming or panning past the edge of the graph.
But notice from the source link above that we have an escape hatch. It records the original domain when the X scale is set. So, instead of setting elasticX, we can calculate the extent of the data, set the domain of the scale, and tell the chart that the scale is new:
chart.on('preRedraw', () => {
if(!zoom.filters().length) {
var xExtent = d3.extent(speedSumGroup.all(), kv => kv.key);
chart.x(chart.x().domain(xExtent));
}
});
New fiddle with zooming issues fixed.
There is still one glitch which Joerg points out: if you are moving the brush while data comes in, the brush handles occasionally will occasionally stray from the ends of the brush. In my experience, these kinds of glitches are pretty common in D3 (and dynamic charting in general), because it's difficult to think about data changing during user interaction. It probably could be fixed inside the library (perhaps an interrupted transition?) but I'm not going to get into that here.

Draw/update circles in rect - nested selections confusion

I am trying to get a layout that would, for each object in the data array:
append a rect or a g element that will serve as container
inside or on top of this, append a circle for each of the coordinates.
Below is a mock-up of how the data is massaged before I'm trying to append to the DOM (at the top of the update() function in the block below):
[{
label: 'foo',
circles: [
{ x: 0, y: 10 },
{ x: 10, y: 10 }
]
},{
...
}]
The drawing and updating of the rect elements seems to be working fine, but I am getting the selection and joins confused for the circles.
Here's the block: http://blockbuilder.org/basilesimon/91f75ab5209a62981f11d30a81f618b5
With
var dots = rects.selectAll('.dots')
I can select the right data below but can't draw it.
Could you help me getting the selections right so I can draw and update both the rect and the circle, please?
Thank you Gerard for your help. This is my current state, but I've pitted myself into a hole by running a for loop instead of d3 selections.
I wonder if I couldn't nest the circles in g elements after building a new data object like so:
var data = dataset.map(function(d) {
var circles = d3.range(d.amount).map(function(i) {
return {
x: (i % 5)*20,
y: (i / 5 >> 0)*20
}
});
return {
label: d.label,
dots: circles
};
});
From each object in data, we'll append a g, and inside each g we'll append the circles. Any help appreciated, since this will affect the dots + i used by the update pattern...
New question here
Here is the problem:
var dots = svg.selectAll('dots')
You're selecting something that doesn't exist. Because of that, your "enter" selection will always contain all the data, and your "exit" selection will always be empty.
The solution is changing it for something like this:
var dots = svg.selectAll(".dots" + i)
And, in the enter selection, setting the classes:
.attr("class", "dots" + i)
Here is your updated bl.ocks (with some other minor changes): https://bl.ocks.org/anonymous/4c2e1d66f1ab890da983465a4f84ca9b

How to create slow simultaneous transitions of multiple attributes in force directed graphs?

In a previous post called "D3: How to create slow transition of Circles for nodes in Force Directed Graphs FDG?", I got a great answer for how to transition a single element (e.g. the radius for "just circles") in D3.
My followup question is now about how to transition "multiple D3 attributes" at the same time...
As a reminder, I'm using D3 generated Radio Buttons to toggle the size of Nodes in a FDG Layout (on mouse click) from a default size to a scaled magnitude. You can find the Radio Buttons in the upper left hand of the Node Cluster Diagram (http://nounz.if4it.com/Nouns/Applications/A__Application_1.NodeCluster.html)
The code that toggles the node circles between a default number and a scaled magnitude (now using transitions) looks as follows...
var densityControlClick = function() {
var thisObject = d3.select(this);
var typeValue = thisObject.attr("density_type");
var oppositeTypeValue = (function() {
if(typeValue=="On") {
return "Off";
} else {
return "On";
}
})();
var densityBulletSelector = "." + "densityControlBullet-" + typeValue;
var selectedBullet = d3.selectAll(densityBulletSelector);
selectedBullet.style("fill", "Black")
var oppositeDensityBulletSelector = "." + "densityControlBullet-" + oppositeTypeValue;
var selectedOppositeBullet = d3.selectAll(oppositeDensityBulletSelector);
selectedOppositeBullet.style("fill", "White")
if(typeValue=="On") {
var selectedNodeCircles = d3.selectAll("#NODE");
selectedNodeCircles.transition().duration(500).attr("r", function(d){ return rRange(d.rSize); });
}
else {
var selectedNodeCircles = d3.selectAll("#NODE"); selectedNodeCircles.transition().duration(500).attr("r", function(d) { if (d.id==focalNodeID) { return centerNodeSize; } else { return defaultNodeSize; } } );
}
}
Everything works great and you can see the slower node transitions when you select the radio buttons. However, I'd now like to learn how to transition multiple elements, such as the the radius and the edge lengths simultaneously, along with the theory behind doing so, in order to show off D3's dynamic nature.
My question is: Given that I already can successfully transition the radius of circles, how would I also transition other elements like the edge lengths based on attributes like "alpha", "friction", etc., and... what's the theory behind transitioning multiple elements (in other words, what does the code mean, in English)? The D3 API doesn't appear to clearly get into the theory behind transitioning multiple attributes, simultaneously.
So transitioning multiple attributes is the simple part of this question. Just like a regular selection you can set multiple attributes at a time on your transition:
selectedNodeCircles.transition().duration(500)
.attr("r", function(d){ return rRange(d.rSize); })
.attr("stroke", 'red');
This will transition your radius and your line colour. The transition is a property of the DOM element (in this case the circle) and it will transition as many DOM attributes as you like. The thing to remember is that there is only only one transition object on each DOM element. So if you create another you will overwrite the old one.
// This will NOT work
circles.transition().duration(1000).attr('r', 50);
// The radius transition will be overridden by the fill
// transition and so will not complete
circles.transition().duration(1000).attr('fill', 'red');
This can actually be quite useful because you don't have to worry about interrupting animations that are in progress and figure out how far along they are and then starting a new animation - this will generally be handled automatically.
In your case you want to transition edge lengths in your graph. These are determined by the positional attributes of the nodes. Judging by your finished product, these attributes are already being animated because you are updating the DOM on every iteration of the layout algorithm (not through transitions) probably in the tick() callback.
So you could use transitions inside your tick callback, which might look odd and may be a hassle to keep in synch with the radius transitions (you will have to set both attributes in the transition). But it might be just what you need.
Alternatively, if you can wait, don't update the DOM in the tick callback. Let the layout complete - it runs a lot faster when it is not rendering on each tick - and once it is complete you can animate the radius and x and y attributes to their final positions. Of course this means you'll want good starting positions.

Is it possible to create pie charts with object consistency?

the pie chart update example on the bl.ocks site doesn't update the elements 'in place':
http://bl.ocks.org/j0hnsmith/5591116
function change() {
clearTimeout(timeout);
path = path.data(pie(dataset[this.value])); // update the data
// set the start and end angles to Math.PI * 2 so we can transition
// anticlockwise to the actual values later
path.enter().append("path")
.attr("fill", function (d, i) {
return color(i);
})
.attr("d", arc(enterAntiClockwise))
.each(function (d) {
this._current = {
data: d.data,
value: d.value,
startAngle: enterAntiClockwise.startAngle,
endAngle: enterAntiClockwise.endAngle
};
}); // store the initial values
path.exit()
.transition()
.duration(750)
.attrTween('d', arcTweenOut)
.remove() // now remove the exiting arcs
path.transition().duration(750).attrTween("d", arcTween); // redraw the arcs
}
Instead, it just treats the new array of value as brand new data and resizes the chart accordingly.
I've created a fiddle demonstrating the issue very simply:
http://jsfiddle.net/u9GBq/23/
If you press 'add', it add a random int to the array: this works as intended.
If you press 'remove', the only element getting transitioned out is always the last element to have entered the pie. In short, it behaves like a LIFO stack.
The expected behaviour is for the relevant pie arc to get transitioned out instead.
Is it possible to apply object consistency to pies? I've also tried adding a key function (not demonstrated on the fiddle) but that just breaks (oddly enough it works fine with my stacked graphs).
Thank you.
The easiest solution to this problem is to set missing values to zero, rather than removing them entirely, as in Part III of the Pie Chart Update series of examples. Then you get object constancy for free: you have the same number of elements, in the same order, across updates.
Alternatively, if you want a data join as in Part IV, you have to tell D3 where the entering arcs should enter from, and where the exiting arcs should exit to. A reasonable strategy is to find the closest neighboring arc from the opposite data: for a given entering arc, find the closest neighboring arc in the old data (pre-transition); likewise for a given exiting arc, find the closest neighboring arc in the new data (post-transition).
To continue the example, say you’re showing sales of apples in different regions, and want to switch to show oranges. You could use the following key function to maintain object constancy:
function key(d) {
return d.data.region;
}
(This assumes you’re using d3.layout.pie, which wraps your original data and exposes it as d.data.)
Now say when you transition to oranges, you have the following old data and new data:
var data0 = path.data(), // retrieve the old data
data1 = pie(region.values); // compute the new data
For each entering arc at index i (where d is data1[i]), you can step sequentially through preceding data in data1, and see if you can find a match in data0:
var m = data0.length;
while (--i >= 0) {
var k = key(data1[i]);
for (var j = 0; j < m; ++j) {
if (key(data0[j]) === k) return data0[j]; // a match!
}
}
If you find a match, your entering arcs can start from the matching arc’s end angle. If you don’t find a preceding match, you can then look for a following matching arc instead. If there are no matches, then there’s no overlap between the two datasets, so you might enter the arcs from angle 0°, or do a crossfade. You can likewise apply this technique to exiting arcs.
Putting it all together, here’s Part V:
Ok, found the solution.
The trick was to pass the key this way:
path = path.data(pie(dataset), function (d) {return d.data}); // this is good
as opposed to not passing it, or passing it the wrong way:
path = path.data(pie(dataset, function (d) {return d.data})); // this is bad
And here's an updated fiddle with a working transition on the right arc! :)
http://jsfiddle.net/StephanTual/PA7WD/1/

Resources