feature request: z-index

[dfl]

I'd love to be able to have the equivalent of z-index, by using a :z attribute on elements.
Browsers don't support this natively, but the same effect could be done by sorting elements by :z attribute before rendering to string. I took a stab at this with a monkeypatch but was unsuccessful, as the sorting was not as simple as I'd imagined, due to nesting. A possible alternative is parsing the endpoint with Nokogiri, and sorting in that domain before rendering to string.

PS thanks for this cool library, it's really handy!

[DannyBen]

Victor only takes your Ruby DSL and converts it element-by-element to SVG.
Since this is ruby, you can sort it yourself if you want, although it would probably be easier to just draw the objects by order, as SVG normally handles Z.

The library does not aim to amend the SVG functionality, just to let you write it with code.

[dfl]

thanks. drawing by order was not so easy to do in my case (I'm making a very complicated astrology chart). I was confused about where exactly to do the custom sorting, as there are no easy hooks. Does this look like the right idea?

module Victor
  class SVGBase
    alias_method :original_tag, :tag

    def tag(name, value = nil, attributes = {}, &block)
      if value.is_a?(Hash)
        attributes = value
        value = nil
      end

      attributes[:z] = attributes[:z].to_i if attributes.key?(:z)

      original_tag(name, value, attributes, &block)
    end

    alias_method :original_build, :build

    def build(&block)
      original_build(&block)
      sort_by_z_index
    end
    
       private

    def sort_by_z_index
      # ...
    end
  end  
end

UPDATE: alternatively, I just searched discovered there is the #use element, which will just duplicate the stuff I want on top. I think that will be simpler! https://www.geeksforgeeks.org/how-to-use-z-index-in-svg-elements/

[DannyBen]

I don't think the duplication is the way to go - you are starting the life of your code with a patchy technical debt.

If you feel you must have that z index, perhaps inheriting would be cleaner than monkey patching:

class SortableSVG < Victtor::SVGBase
  def tag(...)
    # ...
    super
  end

  def build(...)
    # ...
    super
  end
end