When slide contents have exceeded from the size of a page in Markdown preview, it is helpful to indicate the contents has overflowed.

const overflowed =
  section.scrollHeight > section.clientHeight ||
  section.scrollWidth > section.clientWidth

I have seen many Marp slides with a page that is including overflowed contents, e.g. the image was cropped within the slide size, the text had been overlaped with the footer contents, and so on.

A new slide-content-overflow diagnostic may be helpful for making better and beautiful slide pages with Marp.

For existing Marp slides, this diagnostic may indicate many errors more than expected, and users may feel obtrusive. So we should implement it as opt-in diagnostic, and collect feedback from users.

• Related
  • Marp Core's safe centering (Changes in new Marp Core v4 🚀 marp#533)