workings-book/entries/2014-12-18.md

Thursday, December 18, 2014
===========================

screencast gifs
---------------

Looking to make some GIFs of things that happen on my screen, found `byzanz`.

    $ sudo apt-get install byzanz
    byzanz-record -x 1 -y 1 --delay=4 -h 150 -w 700 hello_world.gif

Options:

- `-x` and `-y` set origin of capture on screen
- `-h` and `-w` set height and width to capture

I think I need a more clever way to trigger / manage this than just fiddling
with CLI options, but it works really well and produces lightweight image
files.

I think it would be cool if there were a utility that let me use arrow keys /
hjkl / the mouse cursor to visually select a region of the screen.  It could
return x, y, height, and width, then I'd let byzanz handle the capture.

That can't be the _hardest_ thing in the world to do.

-> ☆ <-

[xdotool](http://www.semicomplete.com/projects/xdotool/) seems like kind of a
swiss army knife, and has a `getmouselocation` command.  Theoretically, at
least, you can have it respond to events, including a mouse click.  I can't
quite wrap my head around how this is supposed to work, and my first few
attempts fall flat.

[GNU xnee](https://www.gnu.org/software/xnee/) might also be promising, but I
don't really get anywhere with it.

Eventually I find an
[Ask Ubuntu](http://askubuntu.com/questions/107726/how-to-create-animated-gif-images-of-a-screencast)
thread on creating screencast gifs, which points to
[xrectsel](https://github.com/lolilolicon/xrectsel), a tool for
returning the coordinates and size of a screen region selected with the mouse:

    brennen@desiderata 22:06:28 /var/www/workings-book (master) ★  xrectsel "%x %y %w %h"
    432 130 718 575%

I wind up with [`gif_sel`](https://github.com/brennen/bpb-kit/blob/master/bin/gif_sel):

    #!/usr/bin/env bash

    # requires:
    # https://github.com/lolilolicon/xrectsel.git

    eval `xrectsel "BYZANZ_X=%x; BYZANZ_Y=%y; BYZANZ_WIDTH=%w; BYZANZ_HEIGHT=%h"`
    byzanz-record -x $BYZANZ_X -y $BYZANZ_Y --delay=4 -h $BYZANZ_HEIGHT -w $BYZANZ_WIDTH ~/screenshots/screencast-`date +"%Y-%m-%d-%T"`.gif

I'll probably wind up with a couple of wrappers for this for different lengths
of recording (for starting with dmenu), though it would be nice if I could just
have it record until I press some hotkey.