Jquery draggable with zoom problem

Question

I am working on a page in witch all its contents are scaled by using zoom. The problem is that when I drag something in the page the dragging item gets a bad position that s

Answer 1

If CSS Zoom is performed specifically on the html body, there is a very easy fix, but it does require you to modify the source. That's a no-go for some, but I'll post the solution here anyway.

So the draggable functionality of jQuery UI figures out the mouseposition using a method called _generatePosition. The problem is that it doesn't take zoom into account (duh), so we merely have to divide its outcome by the zoom level and everything will work.

So turn this:

    return {
        top: (

            // The absolute mouse position
            pageY -

            // Click offset (relative to the element)
            this.offset.click.top -

            // Only for relative positioned nodes: Relative offset from element to offset parent
            this.offset.relative.top -

            // The offsetParent's offset without borders (offset + border)
            this.offset.parent.top +
            ( this.cssPosition === "fixed" ?
                -this.offset.scroll.top :
                ( scrollIsRootNode ? 0 : this.offset.scroll.top ) )
        )/ ,
        left: (

            // The absolute mouse position
            pageX -

            // Click offset (relative to the element)
            this.offset.click.left -

            // Only for relative positioned nodes: Relative offset from element to offset parent
            this.offset.relative.left -

            // The offsetParent's offset without borders (offset + border)
            this.offset.parent.left +
            ( this.cssPosition === "fixed" ?
                -this.offset.scroll.left :
                ( scrollIsRootNode ? 0 : this.offset.scroll.left ) )
        )
    };

in

    var zoomLevel = parseFloat($('body').css("zoom") || "1.0");

    return {
        top: (

            // The absolute mouse position
            pageY -

            // Click offset (relative to the element)
            this.offset.click.top -

            // Only for relative positioned nodes: Relative offset from element to offset parent
            this.offset.relative.top -

            // The offsetParent's offset without borders (offset + border)
            this.offset.parent.top +
            ( this.cssPosition === "fixed" ?
                -this.offset.scroll.top :
                ( scrollIsRootNode ? 0 : this.offset.scroll.top ) )
        ) / zoomLevel,
        left: (

            // The absolute mouse position
            pageX -

            // Click offset (relative to the element)
            this.offset.click.left -

            // Only for relative positioned nodes: Relative offset from element to offset parent
            this.offset.relative.left -

            // The offsetParent's offset without borders (offset + border)
            this.offset.parent.left +
            ( this.cssPosition === "fixed" ?
                -this.offset.scroll.left :
                ( scrollIsRootNode ? 0 : this.offset.scroll.left ) )
        ) / zoomLevel
    };

That's all. I suggest saving it under a specific name so it's easily recognized that it has been modified. E.g.: jquery-ui.ZOOMFIX.js

I used the jquery-ui.js file from the following package: https://jqueryui.com/resources/download/jquery-ui-1.12.1.zip