如何获取已分组的svg元素的全局坐标? [英] How do I get the global coordinates of a grouped svg element?

问题描述

假设我有以下文档(小提琴):

<svg>
    <g transform="translate(50,50)">
        <rect width="20" height="20" style="fill:black;">
    </g>
</svg>

假设我不知道它在一个组中，如何获取rect元素的全局坐标?

How do I get the global coordinates of the rect element assuming I don't know that it's in a group?

推荐答案

实际上很难找到.搜索SVGElement的方法将导致页面显示SVGElement没有方法！实际上，它确实有很多方法，但是它们是继承的:

It was actually kind of hard to find. Searching for methods of SVGElement results in pages saying SVGElement has no methods! It does in fact have a ton of methods, but they are inherited:

http://www.w3.org/TR/SVG/types. html#InterfaceSVGLocatable

根据需要，可以使用getCTM或getScreenCTM的结果来转换SVGPoint，从而了解元素的位置:

Depending on what you want you can use the result of getCTM or getScreenCTM to transform a SVGPoint, and thus learn where you element is:

root = document.getElementById('root')
rec = document.getElementById('rec')
point = root.createSVGPoint()
# This is the top-left relative to the SVG element
ctm = rec.getCTM()
console.log point.matrixTransform(ctm)
# This is the top-left relative to the document
ctm = rec.getScreenCTM()
console.log point.matrixTransform(ctm)

http://jsfiddle.net/kitsu_eb/ZXVAX/3/

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