javascript - 關於trasform後的座標計算的問題

Question

我在做了一個圖片在父容器內拖曳的功能後，將父容器用transform變化了一下，旋轉啊拉伸啊什麼的，之後坐標的計算就開始紊亂了，我想問一下如果想讓他正常工作的話該怎麼做？
拖曳的程式碼如下：
$(function(){

#

 var dragging = false;
        var iX, iY;
        var qX, qY;
        var tempid;
         $(".dragcontain").mousedown(function(e) {
            dragging = true;
            iX = accSub(e.clientX,this.offsetLeft);
            iY = accSub(e.clientY,this.offsetTop);                
            qX = $(e.target).children().position().left;
            qY = $(e.target).children().position().top;
            console.log(qX,qY);
            console.log(iX,iY);
            this.setCapture && this.setCapture();
             return false;
        });
        document.onmousemove = function(e) {
            if (dragging) {
            var e = e || window.event;
            console.log("sX:",e.clientX,"sY:",e.clientY);
            var nX = accSub(e.clientX,e.target.offsetLeft);
            var nY = accSub(e.clientY,e.target.offsetTop);
            console.log(e.clientX,e.target.offsetLeft)
            var mX = accSub(nX,iX);
            var mY = accSub(nY,iY);
            var oX = accAdd(qX,mX);
            var oY = accAdd(qY,mY);
            $(e.target).children().css({"left":oX + "px", "top":oY + "px"});
            console.log("iX:",iX,"iY:",iY);
            console.log("oX:",oX,"oY:",oY);
            console.log("nX:",nX,"nY:",nY);
            console.log("mX:",mX,"mY:",mY);
            console.log("qX:",qX,"qY:",qY);
            console.log("");
            return false;
            }
        };
        $(document).mouseup(function(e) {
            dragging = false;
            e.cancelBubble = true;
            iX=0;
            iY=0;
        })    

})

光光是將dragcontain給rotate（45deg）旋轉後就開始亂了，座標直接到-1000多去了

Answer 1

transform旋轉縮放都是有基點的，transform-origin