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Asked: 2026-05-27T09:34:12+00:00

I’d like to build a function like fromHeretoThere(x1,y1,x2,y2){ //…. } So that I can

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I’d like to build a function like

fromHeretoThere(x1,y1,x2,y2){
  //....
}

So that I can move a <div> or an image from one point on the HTML page to another point in a curve.

Is this doable only using Canvas? HTML5? any plugin/scripts yo suggest?

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1 Answer

  1. Editorial Team

    Edit: Here’s a work in progress that packages up the second concept described below as a re-usable JS object. You can edit the code or visually drag the curve to see the resulting code:

    http://phrogz.net/SVG/animation_on_a_curve.html

    I’d personally use SVG, which makes this sort of thing (animating along an arbitrary Bézier curve) trivial using the <animateMotion> element. As a bonus, you can even cause it to calculate the rotation for you. Some examples:

    Note that you don’t even have to actually use SVG to display the result; you could simply create an off-screen SVG with this animation and sample the transform of the animated element to get your desired point/rotation.

    Alternatively (if you don’t want the rotation, or want to calculate it yourself while controlling the rate of traversal) you can create an SVG path and just use getPointAtLength()/getTotalLength() to find where you should be along the path at a given percentage of the total traversal distance. With this you don’t even need an SVG document:

    // Moving along an S curve from 0,0 to 250,450
var p = document.createElementNS('http://www.w3.org/2000/svg','path');
p.setAttribute('d','M0,0 C350,20 -200,400 250,450');
var len = p.getTotalLength();
for (var i=0;i<=100;i+=10){
  var pct = i/100;
  var pt = p.getPointAtLength(pct*len);
  console.log( i, pt.x, pt.y );
}

// 0 0 0
// 10 65.54324340820312 10.656576156616211
// 20 117.17988586425781 49.639259338378906
// 30 120.2674789428711 114.92564392089844
// 40 100.49604034423828 178.4400177001953
// 50 78.06965637207031 241.1177520751953
// 60 63.526206970214844 305.9412841796875
// 70 74.59959411621094 370.6294860839844
// 80 122.1227798461914 415.8912658691406
// 90 184.41302490234375 438.8457336425781
// 100 250 450

    Now all you have to do is set the .style.top and .style.left of your <div> or <img> appropriately. The only ‘hard’ part is deciding what you want to the curve to look like and defining where to put the handles.

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