07000

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The rendering effect of a marker is as if the contents of the referenced ‘marker’ element were deeply cloned into a separate non-exposed DOM tree for each instance of the marker. Because the cloned DOM tree is non-exposed,the SVG DOM does not show the cloned instance of the marker.

当指针事件发生时,将通过遍历SVG的DOM树来执行命中测试,从而省略任何未暴露的阴影DOM树.这就是为什么标记实例不可能成为指针事件的目标的原因.

为了澄清,可能有趣的是,在通过CSS规则设置标记实例时也是如此,这是不可行的.只有原始标记元素,即声明<标记>元素,可以使用CSS进行样式化,而通过属性marker-start,marker-mid或marker-end引用的克隆实例不可访问,因此不能单独设置样式.

CSS2 selectors can be applied to the original (i.e.,referenced) elements because they are part of the formal document structure. CSS2 selectors cannot be applied to the (conceptually) cloned DOM tree because its contents are not part of the formal document structure.