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How to get the position of element transformed with css rotate

How to get the position of element transformed with css rotate


I'm having a problem with getting the position of a div after rotate filter is applied to it. I have the position of one end, its height, and the angle by which it is rotated, but after checking what this filter actually does on MDN ("[cos(angle) sin(angle) -sin(angle) cos(angle) 0 0]") I still don't know how to crack it.

Example :

The div I'm interested in is the dashed line. Its styling at that moment was :

left: 80px; top: 12px; height: 69.5122px; width: 2px; -moz-transform: rotate(-1.21366rad);

(top/left describe the position of its beginning.) I'm trying to get the top/left position of its end.

Problem courtesy of: owca


Per your current Question and your requested confirmation of:

var x = + Math.cos(angle) * div.height;
var y = div.left + Math.sin(angle) * div.height;

The solution can be found in this other SO Answer for a different question, enhanced here:

// return an object with full width/height (including borders), top/bottom coordinates
var getPositionData = function(el) {
    return $.extend({
        width: el.outerWidth(false),
        height: el.outerHeight(false)
    }, el.offset());

// get rotated dimensions   
var transformedDimensions = function(el, angle) {
    var dimensions = getPositionData(el);
    return {
        width: dimensions.width + Math.ceil(dimensions.width * Math.cos(angle)),
        height: dimensions.height + Math.ceil(dimensions.height * Math.cos(angle))

Here's an interactive jsFiddle that provides real-time updates for getPositionData(); function.
You'll be able to see the top and left values at the end of the CSS3 Rotation process you control.

Reference:   jsFiddle

Status Update: The above jsFiddle works great for 0-90deg and can be approved upon for all angles and different units such as rad, grad, and turn.

Solution courtesy of: arttronics


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This post first appeared on CSS3 Recipes - The Solution To All Your Style Problems, please read the originial post: here

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How to get the position of element transformed with css rotate


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