More information about the Underscore mailing list

[_] adding notes/overlay to web video

Oliver Humpage oliver at
Thu Nov 29 15:43:06 GMT 2018

> On 29 Nov 2018, at 15:36, Tom Spencer <fiznool at> wrote:
> Very nice.
> I’d be particularly interested how you got this working responsively? I had
> a requirement recently for layering user-editable annotations (text and
> arrows) on top of a responsive image (i.e. one that grew/shrunk to fit the
> viewport width), but couldn’t for the life of me figure out how to
> implement it.

Not exactly this, but I’ve done something similar that ought to work: a few lines of javascript on a resize event trigger which adjusts the “zoom” CSS value of the overlay.

This has the advantage that when created/drawn, elements in the overlay should have the correct absolute position for you to save off (assuming measured within the zoomed container).