addEventListener在Canvas标记中 [英] addEventListener in Canvas tag

问题描述

我有一个canvas标签来创建图形。在我的行的每个部分，我有一个点来启用鼠标悬停并显示更多细节。

I have a canvas tag to create a graphic. At each section of my line, I have a "dot" to enable a 'mouseover' and display more detail.

当我不添加事件侦听器到此点。

Everything works fine when I don't add an event listener to this dot.

Firebug警告我：s.addEventListener不是函数...

Firebug is warning me : s.addEventListener is not a function...

是否可以创建动态事件侦听器？ （我是新的Javascript）

Is it possible to create dynamic event listener? (I'm new to Javascript)

推荐答案

不能将DOM事件附加到DOM对象（元素）之外的东西。 canvas 是一个DOM元素，你正在绘制到画布上的东西不是。他们成为画布的一部分作为img的像素。

You cannot attach DOM events to things other than DOM objects (elements). The canvas is a DOM element, the things you are drawing to the canvas are not. They become a part of the canvas as pixels of an img.

为了检测对画布上的特定点的点击，您必须在画布上附加点击事件元素，然后将点击事件的x / y坐标与画布的坐标进行比较。

In order to detect a click on a specific point on your canvas you must attach the click event on the canvas element, and then compare the x/y coordinates of the click event with the coordinates of your canvas.

这回答为如何获取鼠标点击的坐标canvas元素？

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