Jump to content
Search Community

Wrong x/y positioning in Firefox

48DESIGN test
Moderator Tag

Go to solution Solved by GreenSock,

Warning: Please note

This thread was started before GSAP 3 was released. Some information, especially the syntax, may be out of date for GSAP 3. Please see the GSAP 3 migration guide and release notes for more information about how to update the code to GSAP 3's syntax. 

Recommended Posts

Hi everybody,


I'm trying to animate an SVG (that I didn't create) for client project. It works well in Chrome and even Internet Explorer (9-11), however, I'm running into trouble with Firefox. The y positioning of the elements is completely incorrect, some parts move up instead of down and parts that should visually "stick" together end up shifted.



Interestingly, I found out that if I use "yPercent:" instead of "y:" and adjust the values accordingly, the animation works as intended throughout all browsers. Take a look at this modified codepen:


See the Pen xGQEXr by anon (@anon) on CodePen


I don't feel comfortable using yPercent. On the one hand, it's not "semantically" correct in my view, because I actually don't need and don't want to rely on the elements' heights for just moving them around. And on the other hand, if I want to move two elements around that visually represent the back and front side of one single object, I have to find the correct percentage values for each of them, which doubles my work. (I should add that I will have to animate several similiar SVGs for the project.)


I'm aware of the fact that the SVG could be cleaner (e.g. not using <use>, the various transforms and the viewBox attributes on the symbols...), but I want to avoid having to clean up and effectively rebuild every single SVG file. And apart from that, I would really like to know what causes these browser inconsistencies that GSAP isn't able to compensate and would be glad if anyone could come up with a way to fix it.


Thanks in advance for any help


See the Pen zGMKPN by anon (@anon) on CodePen

Link to comment
Share on other sites

Hi 48DESIGN  :-) ,


I just took a look at your CodePen in Chrome, FF and IE and I'm seeing the exact same animation in each browser. No strange y positioning is showing up in Firefox. Maybe you've changed something since your original post, but at this time, I don't see any browser differences.

Link to comment
Share on other sites

Correction - after Carl's post, I tried the Codepen again on a different PC with the latest version of FF(39)  and it is indeed showing some y positioning problems. The other PC I tried has an older version of FF (30) and works perfectly fine. 

  • Like 1
Link to comment
Share on other sites

From what I can tell, the issue has to do with a bug in the way Firefox reports getBBox() on <use> elements. It includes the "x" and "y" attributes in the computed value whereas other browsers don't. One solution would be to adjust your SVG so that you just merge those values into the "transform". In other words, currently you're using two different values to affect position - x/y attributes AND a transform matrix, but you could just use the transform matrix instead so that the x/y don't taint the getBBox(). I'll try finding another solution but I wanted to at least get back to you about what I believe the problem is and how you could avoid it in the short term. 

  • Like 4
Link to comment
Share on other sites

Thanks so much for taking the time for an evaluation! I will try merging the x/y and transform - if that works, maybe I can automate it with a script.

I will also file a bug report with Mozilla, but I will await your final response on this matter first.



Link to comment
Share on other sites

  • Solution

Here's a solution - just add this to your JS:

//test for SVG bug that causes SVG <use> elements to include "x" and "y" attribute values in the results of getBBox(). Firefox 39, for example. If the bug is found, overwrite the getBBox() method with a new one that corrects the behavior. 
(function testSVGBug() {
  var useNodes = document.querySelectorAll("use"),
      i = useNodes.length,
      node = useNodes[0], 
      x = parseFloat(node.getAttribute("x")) || 0,
      bbox = node.getBBox(), 
  node.setAttribute("x", x + 20);
  hasBug = (node.getBBox().x !== bbox.x);
  node.setAttribute("x", x);
  if (hasBug) {
    while (--i > -1) {
      node = useNodes[i];
      node.originalGetBBox = node.getBBox;
      node.getBBox = function() {
        var bbox = this.originalGetBBox();
        bbox.x -= parseFloat(this.getAttribute("x")) || 0;
        bbox.y -= parseFloat(this.getAttribute("y")) || 0;
        return bbox;


  • Like 3
Link to comment
Share on other sites

That's awesome. You, Sir, are awesome. And GSAP is awesome. Did I forget anything? ;-)

Thanks a lot, the fix will save us quite som time and nerves...


Here's an updated codepen that includes the fix:

See the Pen LVXBxY by anon (@anon) on CodePen




P.S: If anyone's interested, here's the bug report at Mozilla's Bugzilla:


Edited by 48DESIGN
  • Like 1
Link to comment
Share on other sites

Here's an update: Mozilla devs feel they are following the specs, so the other browsers are behaving wrong. I'm not taking on the hassle of either getting the spec changed or filing bug reports with several other vendors, but rather live with yet another browser inconsistency.


Thanks to your fix, that won't be a problem, and you might consider including it in a future update.

Link to comment
Share on other sites

I guess I can see what they're saying, but of course we just want consistency among browsers. Another problem I noticed in Firefox is that it throws an exception when you try to call getBBox() on an element in a <symbol>. Here's a simple codepen that shows some of the behavior in various browsers (you'll need to crack open the console and see the differences in what gets reported)


  • Like 1
Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Recently Browsing   0 members

    • No registered users viewing this page.
  • Create New...