CODEWITHSUNDEEP
javascriptd3.js
I3i0
I3i0

Reputation: 1191

Mouse position in D3

I just wanted to get the mouse position using D3 by using the following code:

var x = 0;

svg.on('mousemove', function () {
   x = d3.mouse(this)[0];         
});

but x is always equal to 0. By using console.log(), I can see that x value is getting changed just inside the function() but out of it x got its initial value of 0.

How can I save the x value and use it later in my application?

Upvotes: 60

Views: 108189

Answers (6)

devjc
devjc

Reputation: 113

I believe this is the V6 way to do the same:

var svg = d3.select('body').append('svg')
    .attr('width', 600)
    .attr('height', 600)
    .on('mousemove', function(event) {
      let coords = d3.pointer(event);
      console.log( coords[0], coords[1] ) // log the mouse x,y position
    });

Note - this is only called out for clarity - it is already listed above in a comment.

Upvotes: 0

feri
feri

Reputation: 171

As commented above by chkaiser and The Composer the approach is different in version 6;

var coordinates = d3.pointer(this);
var x = coordinates[0];
var y = coordinates[1];

var svg = d3.select('body').append('svg')
    .attr('width', 600)
    .attr('height', 600)
    .on('mousemove', (event) => {
      var coords = d3.pointer( event );
      console.log( coords[0], coords[1] ) // log the mouse x,y position
    });

Further details @ D3 v6 migration guide

Upvotes: 16

duhaime
duhaime

Reputation: 27594

V3:

var svg = d3.select('body').append('svg')
    .attr('width', 600)
    .attr('height', 600)
    .on('mousemove', function() {
      console.log( d3.mouse(this) ) // log the mouse x,y position
    });

V4 and V5:

var svg = d3.select('body').append('svg')
    .attr('width', 600)
    .attr('height', 600)
    .on('mousemove', function() {
      console.log( d3.event.pageX, d3.event.pageY ) // log the mouse x,y position
    });

Upvotes: 21

Sudarshan Tanwar
Sudarshan Tanwar

Reputation: 3607

You have to use an array. That will store x and y like: 

var coordinates= d3.mouse(this);
var x = coordinates[0];
var y = coordinates[1];

// D3 v4
var x = d3.event.pageX - document.getElementById(<id-of-your-svg>).getBoundingClientRect().x + 10
var y = d3.event.pageY - document.getElementById(<id-of-your-svg>).getBoundingClientRect().y + 10

Upvotes: 91

Eric
Eric

Reputation: 31

I suspect you might be trying some like:

var x = 0;

svg.on('mousemove', function () {
   x = d3.mouse(this)[0];         
});

console.log(x);

Unless you have super fast hands, this will always write "0" to the console because the whole script executes while you are reaching for the mouse. Try putting your snippet directly into the console, move the mouse around and then type "x" into the console. You should see the latest x value.

I hope this helps, but I may have misunderstood the question.

Upvotes: 1

user3603902
user3603902

Reputation: 193

You can understand the click and drag function through this example very well.Hope it will helps..

 var point = d3.mouse(this)
  , p = {x: point[0], y: point[1] };

http://jsfiddle.net/mdml/da37B/

Upvotes: 16

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