Re: Take a screenshot from within Emacs

[joakim@verona.se]

Eli Zaretskii <eliz@gnu.org> writes:

>> From: joakim@verona.se
>> Date: Thu, 07 Jul 2016 21:57:41 +0200
>> Cc: Emacs developers <emacs-devel@gnu.org>
>> 
>> I don't think Emacs has the capability to access its internal rendering
>> data out of the box.
>
> Actually, it does, sort of.  Take a look at the dump-glyph-matrix
> function and the subroutines it calls.  There are also
> dump-frame-glyph-matrix (for TTY frames) and dump-tool-bar-row.  They
> describe the data structures Emacs uses to draw its windows and
> frames.  We could use them to provide some initial testing capability
> for the display engine.  The disadvantages of using these functions
> are that (a) they currently need Emacs build with GLYPH_DEBUG defined,
> and (b) they don't test the terminal-specific parts of the display
> engine (in xterm.c, w32term.c, nsterm.m, etc.) that actually write to
> the glass.

Yes you are right of course. I even used those routines while working
on the xwidget branch, but forgot.

-- 
Joakim Verona