Request: The ability to layout arbitrary boxes in line with text

[nicoburns]

It's often the case that UIs want to intersperse non-textual content in line with text. Examples of this would include inline images and form fields. But in theory this extends to arbitrary content. It seems to me that:

• A UI framework wanting to implement such functionality would not be able to build it on top of the text-only functionality that cosmic-text currently offers.
• It would be relatively easy for cosmic-text to offer support for laying out boxes (rectangles) in line with text.

I don't really care what the API looks like, but I would suggest something like:

• Cosmic text takes a Vec<InlineBox> as input in addition to it's existing inputs
• Each InlineBox consists of:
  • a unique identifier
  • a width
  • a height
  • an index into the text string specifying the position at which the box should be laid out
  • Possibly some kind of baseline/alignment specifying for vertical alignment
• Cosmic text output a Vec of box positions for each line consisting of:
  • the unique identifier
  • an x position
  • a y position