javascript - 如何在 Canvas 中查找坐标

Question

我有一张拉斐尔论文，我想找到相对于我的论文的坐标

我的html:

<div style='width:100%;'>
  <div id='mycanvas' class='canvas'></div>
</div>

我的Javascript:

var mypaper = Raphael(mycanvas, '100%', '100%');
...
document.getElementById('mycanvas').onmouseover=function(event) {
    var canvasPos = {
        x: this.offsetLeft,
        y: this.offsetTop
    };
    var coord = {
        x: event.pageX-canvasPos.x,
        y: event.pageY-canvasPos.y
    };
};

我希望 mypaper 左上角的 coord.x 和 coord.y 为零，但事实并非如此

Answer 1

最后，我找到了一个answer

function getCursorPosition(canvas, event) {
var rect = canvas.getBoundingClientRect();
var x = event.clientX - rect.left;
var y = event.clientY - rect.top;
console.log("x: " + x + " y: " + y);

}