Re: Render a buffer or string to a simpler string?

[Dmitry Gutov <dgutov@yandex.ru>]

esabof@gmail.com writes:
>> Obviously, some ERT tests could use such a feature, but things like
>> 
>> htmlfontify could probably also make use of it.
>
> Another primitive which I think doesn't exist, is given a position,
> return it's pixel coordinates. From this one could construct things
> like region-pixel-width and region-pixel-height.

See `posn-at-point'.

> It might also be useful to be able to store frame renderings as images
> and compare them. This would also allow a somewhat grotesque way to do
> transparency. (Save the image (which I think is already possible),
> overlay the buffer with a SVG, include the rendering in the SVG and
> render whatever necessary ontop of it).

The main problem as I see it, is how to output the difference
information in case of mismatch. Saying "these pics are different, go
look at them yourself" isn't very helpful for test-driven development.

This would extend to arrays of glyphs, too, maybe even to a larger
degree (haven't thought of that before).