Develop Reference

Giving border-radius to svg and changing the font size

I'm currently working on a circular progress bar. I've been able to create the progress bar but I need to at border-radius to the end and start of the progress and also change de font-size of the % number. I've searched around and in theory, the border-radius is added with stroke-linecap="round", but that doesn't seem to work for me. I haven't been able to find anything regarding the font-size.Adding a shadow to the bar would also be great, but that's not truly necessary.
I have already looked at this answer but I can't seem to get it right.
function drawProgress(percentage, element, svg) {
if (svg) {
svg.selectAll("*").remove();
}
var wrapper = element;
var start = 0;
var colours = {
fill: '#3F88FB',
track: '#DDDDDD',
text: '#444444',
}
var radius = 34;
var border = 8;
var strokeSpacing = 4;
var endAngle = Math.PI * 2;
var formatText = d3.format('.0%');
var boxSize = radius * 2;
var count = percentage;
var progress = start;
var step = percentage < start ? -0.01 : 0.01;
//Define the circle
var circle = d3.svg.arc()
.startAngle(0)
.innerRadius(radius)
.outerRadius(radius - border);
//setup SVG wrapper
svg = d3.select(wrapper)
.append('svg')
.attr('width', boxSize)
.attr('height', boxSize);
// ADD Group container
var g = svg.append('g')
.attr('transform', 'translate(' + boxSize / 2 + ',' + boxSize / 2 + ')');
//Setup track
var track = g.append('g').attr('class', 'radial-progress');
track.append('path')
.attr('fill', colours.track)
.attr('stroke-width', strokeSpacing + 'px')
.attr('d', circle.endAngle(endAngle));
//Add colour fill
var value = track.append('path')
.attr('fill', colours.fill)
.attr('stroke-width', strokeSpacing + 'px')
.attr('stroke-linecap', 'round');
//Add text value
var numberText = track.append('text')
.attr('fill', colours.text)
.attr('text-anchor', 'middle')
.attr('dy', '0.5rem');
//update position of endAngle
value.attr('d', circle.endAngle(endAngle * percentage));
//update text value
numberText.text(formatText(percentage));}
var svgVisitas;
drawProgress(50 / 100, document.getElementById('radialprogressVisitas'), svgVisitas);
<script src="https://cdnjs.cloudflare.com/ajax/libs/d3/3.4.11/d3.min.js"></script>
<div id="radialprogressVisitas"></div>
Thank you. If you need anything else, please specify it in the comments and I'll edit the question. The project is run on Visual Basic.

First zoom glitches after page load using D3

I'm using D3 to zoom onto an image on click and on Mousewheel. Everything is working fine but the first zoom glitches a lot.
Here is the demo of the app.
This is how I'm zooming towards the objects:
const star = "https://gmg-world-media.github.io/skymap-v1dev/static/media/star.19b34dbf.svg";
const galaxy = "https://gmg-world-media.github.io/skymap-v1dev/static/media/galaxy.c5e7b011.svg";
const nebula = "https://gmg-world-media.github.io/skymap-v1dev/static/media/nebula.d65f45e5.svg";
const exotic = "https://gmg-world-media.github.io/skymap-v1dev/static/media/exotic.21ad5d39.svg";
const sWidth = window.innerWidth;
const sHeight = window.innerHeight;
const x = d3.scaleLinear().range([0, sWidth]).domain([-180, 180]);
const y = d3.scaleLinear().range([0, sHeight]).domain([-90, 90]);
const svg = d3.select("#render_map").append("svg").attr("width", sWidth).attr("height", sHeight);
const node = svg.append("g").attr('class', 'scale-holder');
const zoom = d3
.zoom()
.scaleExtent([1, 30])
.translateExtent([
[0, 0],
[sWidth, sHeight]
])
svg.call(zoom);
const imgG = node.append("g");
imgG
.insert("svg:image")
.attr("preserveAspectRatio", "none")
.attr("x", 0)
.attr("y", 0)
.attr("width", sWidth)
.attr("height", sHeight)
.attr("xlink:href", "https://gmg-world-media.github.io/skymap-v1dev/img-set/image-1.jpg");
imgG
.insert("svg:image")
.attr("preserveAspectRatio", "none")
.attr("x", 0)
.attr("y", 0)
.attr("width", sWidth)
.attr("height", sHeight)
.attr("xlink:href", "https://gmg-world-media.github.io/skymap-v1dev/img-set/image.jpg");
// Draw objects on map with icon size 8
drawObjects(8)
function drawObjects(size) {
const dataArray = [];
const to = -180;
const from = 180;
const fixed = 3;
const objectType = ["ST", "G", "N", "E"];
// Following loop is just for demo.
// Actual data comes from a JSON file.
for (let i = 0; i < 350; i++) {
const latitude = (Math.random() * (to - from) + from).toFixed(fixed) * 1;
const longitude = (Math.random() * (to - from) + from).toFixed(fixed) * 1;
const random = Math.floor(Math.random() * objectType.length);
dataArray.push({
"Longitude": longitude,
"Latitude": latitude,
"Category": objectType[random]
})
}
for (let index = 0; index < dataArray.length; index++) {
// Loop over the data
const item = dataArray[index]
const mY = y(Number(item.Latitude))
const mX = x(Number(item.Longitude))
if (node.select(".coords[index='" + index + "']").size() === 0) {
let shape = star;
// Plot various icons based on Category
switch (item.Category) {
case "ST":
shape = star;
break;
case "G":
shape = galaxy;
break;
case "N":
shape = nebula;
break;
case "E":
shape = exotic;
break;
}
const rect = node
.insert("svg:image")
.attr("class", "coords")
.attr("preserveAspectRatio", "none")
.attr("x", mX)
.attr("y", mY)
.attr("width", size)
.attr("height", size)
.attr("cursor", "pointer")
.attr("index", index)
.attr("xlink:href", shape)
.attr("opacity", "0")
.on("click", function() {
handleObjectClick(index, mX, mY)
})
// Add the objects on the map
rect.transition().duration(Math.random() * (2000 - 500) + 500).attr("opacity", "1")
}
}
}
function boxZoom(x, y) {
// Zoom towards the selected object
// This is the part responsible for zooming
svg
.transition()
.duration(1000)
.call(
zoom.transform,
d3.zoomIdentity
.translate(sWidth / 2, sHeight / 2)
.scale(6)
.translate(-x, -y)
);
}
function handleObjectClick(currentSelect, x, y) {
// Appending some thumbnails to the clicked object here...
//Call the zoom function
boxZoom(x, y)
}
#render_map {
width: 100vw;
height: 100vh;
margin: 0 auto;
overflow: hidden;
}
<script src="https://cdnjs.cloudflare.com/ajax/libs/react/16.6.3/umd/react.production.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/react-dom/16.6.3/umd/react-dom.production.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/d3/5.7.0/d3.min.js"></script>
<div id="render_map">
</div>
This zoom doesn't seem to be working here. But it does definitely work in the app. I've not modified the piece of code responsible for zooming. (See this demo instead.)
The problem is that zoom jumps when you do it for the first time after a page load, and then it fixes itself.
I don't understand what I'm doing wrong here. Any hints would be lovely.
TIA!

The issue seems caused by a very expensive CSS repaint cycle. I tested this in Firefox by going to Performance in the DEV tools and starting a recording, then zooming for the first time.
I saw the fps drop enormously, and that the repaint took as much as 250ms. Normally, that is 10-50ms.
I have some pointers:
Why do you have two images behind each other? Big images are definitely the reason why repainting takes this long, and your image is 8000x4000 pixels! Start by removing the image that we're not even seeing;
Try adding an initial value of transform="translate(0, 0) scale(1)" to .scale-holder. I have a feeling that adding this the first time is what forces the entire screen to be repainted. Maybe changing an existing scale value is an easier mathematical operation than applying a scale value to something that was not scaled before;
If that doesn't help, compress the image to at most 1600 or even 1080 pixels wide. Us mortals should not even be able to see the difference.

d3.js change zoom behavior to semantic zoom

I'm doing some tests with d3.js regarding zooming. At the moment, I have successfully implemented geometric zoom in my test, but it has a drawback: the elements under the zoomed g are being scaled. As I understood it, this could be solved by using semantic zooming.
The problem is that I need scale in my test, as I'm syncing it with a jQuery.UI slider value.
On the other hand, I would like the text elements being resized to maintain their size after a zoom operation.
I have an example of my current attempt here.
I'm having trouble changing my code to fit this purpose. Can any one share some insight/ideas?

For your solution I have merged 2 examples:
Semantic Zooming
Programmatic Zooming
Code snippets:
function zoom() {
text.attr("transform", transform);
var scale = zoombehavior.scale();
//to make the scale rounded to 2 decimal digits
scale = Math.round(scale * 100) / 100;
//setting the slider to the new value
$("#slider").slider( "option", "value", scale );
//setting the slider text to the new value
$("#scale").val(scale);
}
//note here we are not handling the scale as its Semantic Zoom
function transform(d) {
//translate string
return "translate(" + x(d[0]) + "," + y(d[1]) + ")";
}
function interpolateZoom(translate, scale) {
zoombehavior
.scale(scale)//we are setting this zoom only for detecting the scale for slider..we are not zoooming using scale.
.translate(translate);
zoom();
}
var slider = $(function() {
$("#slider").slider({
value: zoombehavior.scaleExtent()[0],//setting the value
min: zoombehavior.scaleExtent()[0],//setting the min value
max: zoombehavior.scaleExtent()[1],//settinng the ax value
step: 0.01,
slide: function(event, ui) {
var newValue = ui.value;
var center = [centerX, centerY],
extent = zoombehavior.scaleExtent(),
translate = zoombehavior.translate(),
l = [],
view = {
x: translate[0],
y: translate[1],
k: zoombehavior.scale()
};
//translate w.r.t the center
translate0 = [(center[0] - view.x) / view.k, (center[1] - view.y) / view.k];
view.k = newValue;//the scale as per the slider
//the translate after the scale(so we are multiplying the translate)
l = [translate0[0] * view.k + view.x, translate0[1] * view.k + view.y];
view.x += center[0] - l[0];
view.y += center[1] - l[1];
interpolateZoom([view.x, view.y], view.k);
}
});
});
I am zooming w.r.t. 250,250 which is the center of the clip circle.
Working code here (have added necessary comments)
Hope this helps!

To do what you want, you need to refactor the code first a little bit. With d3, it is good practice to use data() to append items to a selection, rather than using for loops.
So this :
for(i=0; i<7; i++){
pointsGroup.append("text")
.attr("x", function(){
var plusOrMinus = Math.random() < 0.5 ? -1 : 1;
var randx = Math.random();
return Math.floor(plusOrMinus*randx*75)+centerx;
})
.attr("y", function(){
var plusOrMinus = Math.random() < 0.5 ? -1 : 1;
var randy = Math.random();
return Math.floor(plusOrMinus*randy*75)+centery;
})
.html("star")
.attr("class", "point material-icons")
.on("click", function(){console.log("click!");});
}
Becomes this
var arr = [];
for(i=0; i<7; i++){
var plusOrMinus = Math.random() < 0.5 ? -1 : 1;
var randx = Math.random();
var x = Math.floor(plusOrMinus*randx*75)+centerx;
var plusOrMinus = Math.random() < 0.5 ? -1 : 1;
var randy = Math.random();
var y = Math.floor(plusOrMinus*randy*75)+centery;
arr.push({"x":x,"y":y});
}
pointsGroup.selectAll("text")
.data(arr)
.enter()
.append("text")
.attr("x", function(d,i){
return d.x;// This corresponds to arr[i].x
})
.attr("y", function(d,i){
return d.y;// This corresponds to arr[i].y
})
.html("star")
.attr("class", "point material-icons")
.on("click", function(){console.log("click!");});
This way, you can access individual coordinates using for instance.attr("x",function(d,i){ //d.x is equal to arr.x, i is item index in the selection});
Then, to achieve your goal, rather than changing the scale of your items, you should use a linear scale to change each star position.
First, add linear scales to your fiddle and apply them to the zoom:
var scalex = d3.scale.linear();
var scaley = d3.scale.linear();
var zoom = d3.behavior.zoom().x(scalex).y(scaley).scaleExtent([1, 5]).on('zoom', onZoom);
And finally on zoom event apply the scale to each star's x and y
function onZoom(){
d3.selectAll("text")
.attr("x",function(d,i){
return scalex(d.x);
})
.attr("y",function(d,i){
return scaley(d.y);
});
}
At this point, zoom will work without the slider. To add the slider, simply change manually the zoom behavior scale value during onSlide event, then call onZoom.
function onSlide(scale){
var sc = $("#slider").slider("value");
zoom.scale(sc);
onZoom();
}
Note: I used this config for the slider:
var slider = $(function() {
$( "#slider" ).slider({
value: 1,
min: 1,
max: 5,
step: 0.1,
slide: function(event, ui){
onSlide(5/ui.value);
}
});
});
Please note that at this point the zoom from the ui is performed relative to (0,0) at this point, and not your "circle" window center. To fix it I simplified the following function from the programmatic example, that computes valid translate and scale to feed to the zoom behavior.
// To handle center zooming
var width = 500;
var height = 600;
function zoomClick(sliderValue) {
var center = [width / 2, height / 2],
extent = zoom.scaleExtent(),
translate = zoom.translate();
var view = {
x: zoom.translate()[0],
y: zoom.translate()[1],
k: zoom.scale()
};
var target_zoom = sliderValue;
if (target_zoom < extent[0] || target_zoom > extent[1]) {
return false;
}
var translate0 = [(center[0] - view.x) / view.k, (center[1] - view.y) / view.k];
view.k = target_zoom;
var l = [];
l = [translate0[0] * view.k + view.x, translate0[1] * view.k + view.y];
view.x += center[0] - l[0];
view.y += center[1] - l[1];
// [view.x view.y] is valid translate
// view.k is valid scale
// Then, simply feed them to the zoom behavior
zoom
.scale(view.k)
.translate([view.x, view.y]);
// and call onZoom to update points position
onZoom();
}
then just change onSlide to use this new function every time slider moves
function onSlide(scale){
var sc = $("#slider").slider("value");
zoomClick(sc);
}
Full snippet
function onZoom(){
d3.selectAll("text")
.attr("x",function(d,i){
return scalex(d.x);
})
.attr("y",function(d,i){
return scaley(d.y);
});
}
function onSlide(scale){
var sc = $("#slider").slider("value");
zoomClick(sc);
}
var scalex = d3.scale.linear();
var scaley = d3.scale.linear();
var zoom = d3.behavior.zoom().x(scalex).y(scaley).scaleExtent([1, 5]).on('zoom', onZoom);
var svg = d3.select("body").append("svg")
.attr("height", "500px")
.attr("width", "500px")
.call(zoom)
.on("mousedown.zoom", null)
.on("touchstart.zoom", null)
.on("touchmove.zoom", null)
.on("touchend.zoom", null);
var centerx = 250,
centery = 250;
var circleGroup = svg.append("g")
.attr("id", "circleGroup");
var circle = circleGroup.append("circle")
.attr("cx", "50%")
.attr("cy", "50%")
.attr("r", 150)
.attr("class", "circle");
var pointsParent = svg.append("g").attr("clip-path", "url(#clip)").attr("id", "pointsParent");
var pointsGroup = pointsParent.append("g")
.attr("id", "pointsGroup");
var arr = [];
for(i=0; i<7; i++){
var plusOrMinus = Math.random() < 0.5 ? -1 : 1;
var randx = Math.random();
var x = Math.floor(plusOrMinus*randx*75)+centerx;
var plusOrMinus = Math.random() < 0.5 ? -1 : 1;
var randy = Math.random();
var y = Math.floor(plusOrMinus*randy*75)+centery;
arr.push({"x":x,"y":y});
}
pointsGroup.selectAll("text")
.data(arr)
.enter()
.append("text")
.attr("x", function(d,i){
return d.x;// This corresponds to arr[i].x
})
.attr("y", function(d,i){
return d.y;// This corresponds to arr[i].y
})
.html("star")
.attr("class", "point material-icons")
.on("click", function(){console.log("click!");});
zoom(pointsGroup);
var clip = svg.append("defs").append("svg:clipPath")
.attr("id", "clip")
.append("svg:circle")
.attr("id", "clip-circ")
.attr("cx", centerx)
.attr("cy", centery)
.attr("r", 149);
var slider = $(function() {
$( "#slider" ).slider({
value: 1,
min: 1,
max: 5,
step: 0.1,
slide: function(event, ui){
onSlide(5/ui.value);
}
});
});
// To handle center zooming
var width = 500;
var height = 600;
function zoomClick(sliderValue) {
var target_zoom = 1,
center = [width / 2, height / 2],
extent = zoom.scaleExtent(),
translate = zoom.translate();
var view = {x: zoom.translate()[0], y: zoom.translate()[1], k: zoom.scale()};
target_zoom = sliderValue;
if (target_zoom < extent[0] || target_zoom > extent[1]) { return false; }
var translate0 = [];
translate0 = [(center[0] - view.x) / view.k, (center[1] - view.y) / view.k];
view.k = target_zoom;
var l = [];
l = [translate0[0] * view.k + view.x, translate0[1] * view.k + view.y];
view.x += center[0] - l[0];
view.y += center[1] - l[1];
zoom
.scale(view.k)
.translate([view.x, view.y]);
onZoom();
}
body {
font: 10px sans-serif;
}
text {
font: 10px sans-serif;
}
.circle{
stroke: black;
stroke-width: 2px;
fill: white;
}
.point{
fill: goldenrod;
cursor: pointer;
}
.blip{
fill: black;
}
#slider{
width: 200px;
margin: auto;
}
<!DOCTYPE html>
<html>
<head>
<link href="https://fonts.googleapis.com/icon?family=Material+Icons"
rel="stylesheet">
<link href="https://code.jquery.com/ui/1.11.4/themes/smoothness/jquery-ui.css" rel="stylesheet" type="text/css" />
<script src="https://code.jquery.com/jquery-1.11.3.js"></script>
<script src="https://code.jquery.com/ui/1.11.4/jquery-ui.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/d3/3.5.6/d3.min.js"></script>
<meta charset=utf-8 />
<title>d3.JS slider zoom</title>
</head>
<body>
<div id="slider"></div>
</body>
</html>

Set position of polygons and paths in d3

I have several external SVG files I want to read in and position. Some of the SVG files are polygons, others are paths. For most of them, I specific a random amount to translate the files when I read them in. But I want to specifically assign a position for a couple of the shapes. (JSFiddle).
var width = 300, height = 300;
var sampleSVG = d3.select("body")
.append("svg")
.attr( {width: width, height: height} );
var shapes = [
{url:"https://dl.dropboxusercontent.com/u/2467665/shapes/shapes-01.svg", number: 1, color: 'red'},
{url:"https://dl.dropboxusercontent.com/u/2467665/shapes/shapes-02.svg", number: 2, color: 'yellow'},
{url:"https://dl.dropboxusercontent.com/u/2467665/shapes/shapes-03.svg", number: 3, color: 'orange'},
{url:"https://dl.dropboxusercontent.com/u/2467665/shapes/shapes-04.svg", number: 4, color: 'green'},
{url:"https://dl.dropboxusercontent.com/u/2467665/shapes/shapes-05.svg", number: 5, color: 'blue'},
{url:"https://dl.dropboxusercontent.com/u/2467665/shapes/shapes-06.svg", number: 6, color: 'purple'},
{url:"https://dl.dropboxusercontent.com/u/2467665/shapes/shapes-07.svg", number: 7, color: 'red'},
{url:"https://dl.dropboxusercontent.com/u/2467665/shapes/shapes-08.svg", number: 8, color: 'orange'}];
var q = queue();
shapes.forEach(function(shape) {
q.defer(d3.xml, shape.url, "image/svg+xml");
});
q.awaitAll(function (error, results) {
sampleSVG.selectAll('g.shape').data(shapes)
// g tag is created for positioning the shape at random location
.enter().append('g').attr('class', 'shape')
.attr('transform', function () {
return 'translate(' + Math.random() * (w - 50) + ',' + Math.random() * (h - 50) + ')'
})
.each(function (d, i) {
// the loaded svg file is then appended inside the g tag
this.appendChild(results[i].documentElement);
d3.select(this).select('svg').select("*")
.attr("stroke", function () {return d.color;})
.attr('transform', function () {
if (d.number > 6) {
var newX = 200,
newY = 200;
//This is where I want to set the position
return 'scale(0.3) translate(0,0)'}
else {return 'scale(0.1)'}
;})
})
});
Basically, I want the shapes to have different random positions except for two shapes (those with d.number > 6) which I want to appear at (200,200).
Is there a way to either reset translate and then run it again with new amounts, or specifically set the position of both paths and polygons?

Still unclear, but I think this is what you're looking for:
q.awaitAll(function (error, results) {
sampleSVG.selectAll('g.shape')
.data(shapes)
.enter()
.append('g')
.attr('class', 'shape')
.each(function (d, i) {
// the loaded svg file is then appended inside the g tag
this.appendChild(results[i].documentElement);
d3.select(this).select('svg').select("*")
.attr("stroke", d.color);
})
.attr('transform', function (d, i) {
// In general, in here we're setting the transform of a <g>, which contains an svg. So:
if (d.number > 6) {
var newX = 200,
newY = 200;
// What you return here will scale and translate the <g> (and the svg inside it)
return 'scale(0.3) translate(0,0)';
}
else {
return 'translate(' + Math.random() * (w - 50) + ',' + Math.random() * (h - 50) + ') scale(0.1)';
}
});
});

d3.js time series infinite scroll

I am working on a time series line chart that lets the user scroll back from the present. I can find tutorials on real-time d3.js charts, I can find tutorials on zooming and panning, and I can find tutorials on using external data sources. I'm having trouble putting all this knowledge together.
Here is the behavior that I am looking for:
The chart can pan backward in time (meaning that the lines, data points, and axes move with dragging of the mouse or finger)
Panning should only effect the x-axis, and no zooming should occur.
As the user pans the chart, more data loads in, giving an experience of infinite scrolling
I plan on buffering in at least one extra "page" worth of data for the user to scroll into (already got this part figured out)
I don't think I need transitions, because the panning of the chart will already smoothly translate it
This is what I have working so far:
// set up a zoom handler only for panning
// by limiting the scaleExtent
var zoom = d3.behavior.zoom()
.x(x)
.y(y)
.scaleExtent([1, 1])
.on("zoom", pan);
var loadedPage = 1; // begin with one page of data loaded
var nextPage = 2; // next page will be page 2
var panX = 0;
function pan()
{
if (d3.event)
{
panX = d3.event ? d3.event.translate[0] : 0;
// is there a better way to determine when
// to load the next page?
nextPage = panX / (width + margin.left + margin.right) + 2;
nextPage = Math.floor(nextPage);
// if we haven't loaded in the next page's data
// load it in so that the user can scroll into it
if (nextPage > loadedPage) {
console.log("Load a new page");
loadedPage += 1;
// load more data
Chart.query( /*params will be here*/ ).then(
function(response) {
// append the new data onto the front of the array
data = data.concat(response);
console.log(data.length);
// I need to add the new data into the line chart
// but how do I make that work with the pan
// logic from zoom?
}
);
}
// is this where I update the axes and scroll the chart?
// What's the best way to do that?
}
}
In this code, I can know when to pull more data from the server, but I'm not sure how to insert the data into the chart in a way that works with the pan offset. Do I use transform translate, or can I update the d value of the path of my line?
Any suggestions would be welcome... also, if anyone knows of any demos which already show panning infinitely through time series data, that would be much appreciated.

As mentioned in the other answer, I know this is a very old post but hopefully the following will help someone...
I made a pen that I think hits all the requirements mentioned. As I didn't have a real API to use, I created some data using a json-generator (great tool), included it, and sorted it in descending order. Then I use the built in slice and concat methods to take bits of the array, data, and add to the chart_data variable (similarly to how one might use an api).
Important Sections:
Once you've created your scales, axes, and points (lines, bars, etc.), you need to create the zoom behavior. As mentioned in the question, keeping the scaleExtent limited to the same number on both sides prevents zooming:
var pan = d3.behavior.zoom()
.x(x_scale)
.scale(scale)
.size([width, height])
.scaleExtent([scale, scale])
.on('zoom', function(e) { ... });
Now that we've created the behavior, we need to call it. I'm also calculating what the x translation will be for this moment in time, now, and programmatically panning there:
// Apply the behavior
viz.call(pan);
// Now that we've scaled in, find the farthest point that
// we'll allow users to pan forward in time (to the right)
max_translate_x = width - x_scale(new Date(now));
viz.call(pan.translate([max_translate_x, 0]).event);
Both preventing the user from scrolling past now and loading more data is all done in the zoom event handler:
...
.scaleExtent([scale, scale])
.on('zoom', function(e) {
var current_domain = x_scale.domain(),
current_max = current_domain[1].getTime();
// If we go past the max (i.e. now), reset translate to the max
if (current_max > now)
pan.translate([max_translate_x, 0]);
// Update the data & points once user hits the point where current data ends
if (pan.translate()[0] > min_translate_x) {
updateData();
addNewPoints();
}
// Redraw any components defined by the x axis
x_axis.call(x_axis_generator);
circles.attr('cx', function(d) {
return x_scale(new Date(d.registered));
});
});
The other functions are pretty straightforward and can be found at the bottom of the pen. I'm not aware of any built in D3 function to prevent panning past the present but I'm definitely open to feedback if I've missed an easier way to do some of this.
Let me know if you have trouble viewing the pen or need clarification on something. If I have time I'll update this with another version demoing an infinite scrolling line chart.
P.S. In the pen, I'm consoling out the selection and data as they update. I suggest opening the console to see exactly what's happening.

This is too late, but answering just in case somebody needs again. I was having most of the code ready for my scatterplot so uploading that. Hope it helps you. The code is created as a trial when I was learning this features. So please check before you use.
Note:
D3js panning implemented with zoom behavior,
zooming disabled with scaleExtent,
Y panning restricted.
Data loaded when x extremes are reached.
Please check the Plunkr link
// Code goes here
window.chartBuilder = {};
(function(ns) {
function getMargin() {
var margin = {
top: 20,
right: 15,
bottom: 60,
left: 60
};
var width = 960 - margin.left - margin.right;
var height = 500 - margin.top - margin.bottom;
return {
margin: margin,
width: width,
height: height
};
}
function getData() {
var data = [
[5, 3],
[10, 17],
[15, 4],
[2, 8]
];
return data;
}
//function defineScales(data, width, height) {
// var x = d3.scale.linear()
// .domain([0, d3.max(data, function (d) {
// return d[0];
// })])
// .range([0, width]);
//
// var y = d3.scale.linear()
// .domain([0, d3.max(data, function (d) {
// return d[1];
// })])
// .range([height, 0]);
// return {x: x, y: y};
//}
function defineYScale(data, domain, range) {
var domainArr = domain;
if (!domain || domain.length == 0) {
domainArr = [0, d3.max(data, function(d) {
return d[1];
})];
}
var y = d3.scale.linear()
.domain(domainArr)
.range(range);
return y;
}
function defineXScale(data, domain, range) {
var domainArr = domain;
if (!domain || domain.length == 0) {
domainArr = [d3.min(data, function(d) {
return d[0];
}), d3.max(data, function(d) {
return d[0];
})];
}
var x = d3.scale.linear()
.domain(domainArr)
.range(range);
return x;
}
function getSvg(width, margin, height) {
var chart = d3.select('body')
.append('svg:svg')
.attr('width', width + margin.right + margin.left)
.attr('height', height + margin.top + margin.bottom)
.attr('class', 'chart');
return chart;
}
function getContainerGroup(chart, margin, width, height) {
var main = chart.append('g')
.attr('transform', 'translate(' + margin.left + ',' + margin.top + ')')
.attr('width', width)
.attr('height', height)
.attr('class', 'main');
return main;
}
function renderXAxis(x, main, height) {
var xAxis = d3.svg.axis()
.scale(x)
.orient('bottom');
var xAxisElement = main.select('.x.axis');
if (xAxisElement.empty()) {
xAxisElement = main.append('g')
.attr('transform', 'translate(0,' + height + ')')
.attr('class', 'x axis')
}
xAxisElement.call(xAxis);
return xAxis;
}
function renderYAxis(y, main) {
var yAxis = d3.svg.axis()
.scale(y)
.orient('left');
var yAxisElement = main.select('.y.axis');
if (yAxisElement.empty()) {
yAxisElement = main.append('g')
.attr('transform', 'translate(0,0)')
.attr('class', 'y axis');
}
yAxisElement.call(yAxis);
return yAxis;
}
function renderScatterplot(main, data, scales) {
var g = main.append("svg:g");
var divTooltip = d3.select('.tooltip1');
if (divTooltip.empty()) {
divTooltip = d3.select('body').append('div')
.attr('class', 'tooltip1')
.style('opacity', 0);
}
g.selectAll("scatter-dots")
.data(data, function(d, i) {
return i;
})
.enter().append("svg:circle")
.attr("cx", function(d, i) {
return scales.x(d[0]);
})
.attr("cy", function(d) {
return scales.y(d[1]);
})
.on('click', function(d) {
// log(d.toString());
})
.attr("r", 8);
}
function addZoomRect(main, scales, zoom) {
var zoomRect = main.append('rect')
.attr('width', function() {
return scales.x(d3.max(scales.x.domain()));
})
.attr('height', function() {
return scales.y(d3.min(scales.y.domain()));
})
.attr('x', 0)
.attr('y', 0)
.attr('fill', 'transparent')
.attr('stroke', 'red');
if (zoom) {
zoomRect.call(zoom);
}
return zoomRect;
}
function restrictYPanning(zoom) {
var zoomTranslate = this.translate();
this.translate([zoomTranslate[0], 0]);
}
function addXScrollEndEvent(scales, direction, data) {
var zoomTranslate = this.translate();
var condition;
var currentDomainMax = d3.max(scales.x.domain());
var dataMax = d3.max(data, function(d) {
return d[0];
});
var currentDomainMin = d3.min(scales.x.domain());
var dataMin =
d3.min(data, function(d) {
return d[0];
});
if (currentDomainMax > dataMax && direction === 'right') {
//log('currentDomainMax ', currentDomainMax);
//log('dataMax ', dataMax);
//log('----------------');
condition = true;
}
if (dataMin > currentDomainMin && direction === 'left') {
//log('currentDomainMin ', currentDomainMin);
//log('dataMin ', dataMin);
//log('----------------');
condition = true;
}
//var xRightLimit, xTranslate;
//if (direction === 'right') {
// xRightLimit = scales.x(d3.max(scales.x.domain())) - (getMargin().width + 60);
//
// xTranslate = 0 - zoomTranslate[0];// + scales.x(d3.min(scales.x.domain()));
//
// condition = xTranslate > xRightLimit;
//} else {
// xRightLimit = scales.x(d3.min(scales.x.domain()));
//
// xTranslate = zoomTranslate[0];// + scales.x(d3.min(scales.x.domain()));
//
// condition = xTranslate > xRightLimit;
//}
return condition;
}
function onZoom(zoom, main, xAxis, yAxis, scales, data) {
//var xAxis = d3.svg.axis()
// .scale(scales.x)
// .orient('bottom');
//var yAxis = d3.svg.axis()
// .scale(scales.y)
// .orient('left');
//alert(data);
var translate = zoom.translate();
var direction = '';
if (translate[0] < ns.lastTranslate[0]) {
direction = 'right';
} else {
direction = 'left';
}
ns.lastTranslate = translate; //d3.transform(main.attr('transform')).translate ;
// log('zoom translate', ns.lastTranslate);
// log('d3 Event translate', d3.event.translate);
window.scales = scales;
window.data = data;
// ns.lastTranslate = translate;
var divTooltip = d3.select('.tooltip1');
if (divTooltip.empty()) {
divTooltip = d3.select('body').append('div')
.attr('class', 'tooltip1')
.style('opacity', 0);
}
restrictYPanning.call(zoom);
var xScrollEndCondition = addXScrollEndEvent.call(zoom, scales, direction, data);
if (xScrollEndCondition) {
if (zoom.onXScrollEnd) {
zoom.onXScrollEnd.call(this, {
'translate': translate,
'direction': direction
});
}
}
main.select(".x.axis").call(xAxis);
main.select(".y.axis").call(yAxis);
var dataElements = main.selectAll("circle")
.data(data, function(d, i) {
return i;
});
dataElements.attr("cx", function(d, i) {
return scales.x(d[0]);
})
.attr("cy", function(d) {
return scales.y(d[1]);
}).attr("r", 8);
dataElements.enter().append("svg:circle")
.attr("cx", function(d, i) {
return scales.x(d[0]);
})
.attr("cy", function(d) {
return scales.y(d[1]);
}).on('click', function(d) {
// log(d.toString());
})
.attr("r", 8);
// log(direction);
}
//var xRangeMax;
//var xRangeMin;
ns.lastTranslate = [0, 0];
/**
* Created by Lenovo on 7/4/2015.
*/
function log(titlee, msgg) {
var msg = msgg;
var title;
if (titlee) {
title = titlee + ':-->';
}
if (!msgg) {
msg = titlee;
title = '';
} else {
if (Array.isArray(msgg)) {
msg = msgg.toString();
}
if ((typeof msg === "object") && (msg !== null)) {
msg = JSON.stringify(msg);
}
}
var tooltip = d3.select('.tooltip1');
var earlierMsg = tooltip.html();
var num = tooltip.attr('data-serial') || 0;
num = parseInt(num) + 1;
msg = '<div style="border-bottom:solid 1px green"><span style="color:white">' + num + ')</span><strong>' + title + '</strong> ' + decodeURIComponent(msg) + ' </div>';
tooltip.html('<br>' + msg + '<br>' + earlierMsg).style({
'color': 'lightGray',
'background': 'darkGray',
'font-family': 'courier',
'opacity': 1,
'max-height': '200px',
'overflow': 'auto'
})
.attr('data-serial', num);
}
function addLoggerDiv() {
var divTooltip = d3.select('.tooltip1');
if (divTooltip.empty()) {
divTooltip = d3.select('body').append('div')
.attr('class', 'tooltip1')
.style({
'opacity': 0,
'position': 'relative'
});
d3.select('body').append('div')
.text('close')
.style({
'top': 0,
'right': 0,
'position': 'absolute',
'background': 'red',
'color': 'white',
'cursor': 'pointer'
})
.on('click', function() {
var thisItem = divTooltip;
var txt = thisItem.text();
var display = 'none';
if (txt === 'close') {
thisItem.text('open');
display = 'none';
} else {
thisItem.text('close');
display = 'block';
}
devTooltip.style('display', display);
});
d3.select('body').append('div')
.text('clear')
.style({
'top': 0,
'right': 20,
'position': 'absolute',
'background': 'red',
'color': 'white',
'cursor': 'pointer'
})
.on('click', function() {
divTooltip.html('');
divTooltip.attr('data-serial', '0');
});
}
}
$(document).ready(function() {
var data = getData();
var __ret = getMargin();
var margin = __ret.margin;
var width = __ret.width;
var height = __ret.height;
var scales = {};
var xRangeMax = width;
scales.x = defineXScale(data, [], [0, xRangeMax]);
scales.y = defineYScale(data, [], [height, 0]);
addLoggerDiv();
var svg = getSvg(width, margin, height);
var main = getContainerGroup(svg, margin, width, height);
// draw the x axis
var xAxis = renderXAxis(scales.x, main, height);
// draw the y axis
var yAxis = renderYAxis(scales.y, main);
var thisobj = this;
var zoom = d3.behavior.zoom().x(scales.x).y(scales.y).scaleExtent([1, 1]).on('zoom', function() {
onZoom.call(null, zoom, main, xAxis, yAxis, scales, data);
});
zoom.onXScrollEnd = function(e) {
var maxX = d3.max(data, function(d) {
return d[0];
});
var minX = d3.min(data, function(d) {
return d[0];
});
var incrementX = Math.floor((Math.random() * 3) + 1);
var maxY = d3.max(data, function(d) {
return d[1];
})
var minY = d3.min(data, function(d) {
return d[1];
})
var incrementY = Math.floor((Math.random() * 1) + 16);
var xRangeMin1, xRangeMax1, dataPoint;
if (e.direction === 'left') {
incrementX = incrementX * -1;
dataPoint = minX + incrementX;
// log('dataPoint ', dataPoint);
//xRangeMin1 = d3.min(scales.x.range()) - Math.abs(scales.x(minX) - scales.x(dataPoint));
xRangeMin1 = scales.x(dataPoint);
xRangeMax1 = d3.max(scales.x.range());
} else {
dataPoint = maxX + incrementX;
// log('dataPoint ', dataPoint);
//xRangeMax1 = d3.max(scales.x.range()) + (scales.x(dataPoint) - scales.x(maxX));
xRangeMax1 = d3.max(scales.x.range()) + 20; //scales.x(dataPoint);
xRangeMin1 = d3.min(scales.x.range()) //e.translate[0];
}
data.push([dataPoint, incrementY]);
//scales = defineScales(data, width + incrementX, height );
// scales.x = defineXScale(data, [], [xRangeMin1, xRangeMax1]);
// scales.y = defineYScale(data, [], [height, 0]);
scales.x.domain(d3.extent(data, function(d) {
return d[0];
}));
x = scales.x;
y = scales.y;
xAxis = renderXAxis(scales.x, main, height);
// draw the y axis
yAxis = renderYAxis(scales.y, main);
zoom.x(scales.x).y(scales.y);
}
var zoomRect = addZoomRect(main, scales, zoom);
renderScatterplot(main, data, scales);
});
})(window.chartBuilder);
/* Styles go here */
.chart {
font-family: Arial, sans-serif;
font-size: 10px;
}
.axis path, .axis line {
fill: none;
stroke: #000;
shape-rendering: crispEdges;
}
.bar {
fill: steelblue;
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.js"></script>
<script src="https://cdnjs.cloudflare.com/ajax/libs/d3/3.4.11/d3.min.js"></script>
I have created zoom.onXScrollEnd function to add new points to data.
Hope it helps.