[00:00.000 --> 00:24.560]  Back in 2006, I was a user of Gert Hoffman's Linux framebuffer image viewer, FBI.
[00:24.560 --> 00:34.560]  At some point, I wanted to add Veeam-styled keys for movement, so I came up with a patch for FBI.
[00:34.560 --> 00:41.560]  Soon after, I wanted a simple command line and shortcuts to jump around.
[00:41.560 --> 00:50.560]  And then commands came, and a parser, and auto-completion, inspiration came from Veeam,
[00:50.560 --> 00:58.560]  mutt, the shell, and so Veeam grew, hack after hack.
[00:58.560 --> 01:02.560]  What is Veeam now?
[01:02.560 --> 01:08.560]  Veeam is a Unix tool specialized in viewing image files.
[01:08.560 --> 01:14.560]  Let me stress this, viewing, not editing.
[01:14.560 --> 01:22.560]  Veeam is customizable via configuration files, and is interoperable with other Unix tools.
[01:22.560 --> 01:30.560]  Veeam adheres to the Perl's logon, there's more than one way to do it.
[01:30.560 --> 01:37.560]  Thanks to caching and prefetching, Veeam plays well with slower computers.
[01:37.560 --> 01:41.560]  It spares discrete time.
[01:41.560 --> 01:48.560]  It has a minimalistic user interface, no buttons, no menus, and it's flexible.
[01:48.560 --> 01:59.560]  It displays images as pixels or characters via SSH, under screen.
[01:59.560 --> 02:05.560]  If invoked in the Linux framebuffer, Veeam uses it.
[02:05.560 --> 02:11.560]  Under X11, Veeam runs in a window or full screen.
[02:11.560 --> 02:19.560]  Another option is to display images as ASCII art, even in color.
[02:19.560 --> 02:24.560]  Runtime auto-detection will try choosing the most appropriate mode.
[02:24.560 --> 02:30.560]  You can also specify one yourself via the command line.
[02:30.560 --> 02:38.560]  Veeam offers a consistent look and feel across those different graphical modes.
[02:38.560 --> 02:47.560]  Invoking Veeam from the shell to open image files works as you expect.
[02:47.560 --> 02:52.560]  File decoding depends on file contents, not on the file name.
[02:52.560 --> 02:59.560]  You can also load directories, even recursively, or in the background.
[02:59.560 --> 03:04.560]  In scanning a directory, a file name-based selection occurs,
[03:04.560 --> 03:12.560]  and this is to avoid opening and inspecting contents of too many files.
[03:12.560 --> 03:16.560]  Interactive usage is keyboard-oriented.
[03:16.560 --> 03:22.560]  Arrow keys for movement, plus, minus for scale,
[03:22.560 --> 03:31.560]  N for next, P for previous, or pitch down to do what you expect.
[03:31.560 --> 03:36.560]  Each one of those keys is bound to an action.
[03:36.560 --> 03:41.560]  An action may be invoking a simple command
[03:41.560 --> 03:47.560]  or a command with expressions as arguments.
[03:47.560 --> 03:51.560]  An action can also contain control flow,
[03:51.560 --> 03:56.560]  as the one associated with pitch down on the bottom of the slide.
[03:56.560 --> 04:01.560]  The thing is, under the hood, there is a language interpreter.
[04:01.560 --> 04:06.560]  Just as in Veeam, you access it with the column key.
[04:06.560 --> 04:12.560]  And just as in Veeam, or the shell, there is auto-completion.
[04:12.560 --> 04:20.560]  Configuration files are scripts written in this language.
[04:20.560 --> 04:34.560]  Veeam's language consists of commands, aliases, variables, control constructs, and special shortcuts.
[04:34.560 --> 04:41.560]  I develop Veeam for my daily use to occasionally open files
[04:41.560 --> 04:45.560]  or to load a collected collection of photographs.
[04:45.560 --> 04:49.560]  Sometimes I come up with more tricky use cases,
[04:49.560 --> 04:54.560]  perhaps updating the configuration file with new aliases,
[04:54.560 --> 05:03.560]  or updating my shell configuration with new aliases using Veeam.
[05:04.560 --> 05:08.560]  So far, I talked about introductory topics.
[05:08.560 --> 05:13.560]  I'm also presenting another talk at this FOSDEM.
[05:13.560 --> 05:16.560]  That talk is about general interactive usage,
[05:16.560 --> 05:19.560]  and it may be of your interest too.
[05:19.560 --> 05:25.560]  But now, we will cover language-specific topics.
[05:25.560 --> 05:30.560]  Of the theme commands, the most important ones
[05:30.560 --> 05:35.560]  are those to move around, scale the image, and get help.
[05:35.560 --> 05:42.560]  The purpose of the help go-to, scale, pen commands is self-explanatory.
[05:42.560 --> 05:49.560]  Other important commands, like list or limit, manipulate the file list.
[05:49.560 --> 05:56.560]  Please check out my talk on interactive theme usage for that.
[05:56.560 --> 06:01.560]  How to start using theme commands effectively?
[06:01.560 --> 06:07.560]  You usually pick the functionality you like, experiment a bit,
[06:07.560 --> 06:10.560]  and express it as an alias.
[06:10.560 --> 06:17.560]  This can be a command with argument, like pan left, or go 2 plus 1.
[06:17.560 --> 06:21.560]  Or it can be a more complicated statement.
[06:21.560 --> 06:27.560]  Here you have next 10 for a simple slideshow loop.
[06:27.560 --> 06:33.560]  Notice how their arguments are quoted.
[06:33.560 --> 06:38.560]  The idea is to streamline your work.
[06:38.560 --> 06:40.560]  Do a workflow.
[06:40.560 --> 06:45.560]  No matter how complex an action, you should be able to encapsulate it.
[06:45.560 --> 06:57.560]  As Larry Wall said, easy things should be easy, and hard things should be possible.
[06:57.560 --> 07:03.560]  Theme has each of its commands and variables documented.
[07:03.560 --> 07:07.560]  The manual pages are generated from the help command.
[07:07.560 --> 07:10.560]  The help command is also dynamic.
[07:10.560 --> 07:17.560]  So you can use it to get the actual key bindings and aliases.
[07:17.560 --> 07:24.560]  Now certain frequent actions have direct language shortcuts.
[07:24.560 --> 07:31.560]  You may want to use those occasionally via the interactive command line.
[07:31.560 --> 07:37.560]  One is jumping to a specific position in the files list.
[07:37.560 --> 07:47.560]  So for the third position, enter the command line with colon, enter digit 3, and hit enter.
[07:47.560 --> 07:59.560]  For the first or the last one, you may recognize the carrot and dollar syntax as familiar here.
[07:59.560 --> 08:09.560]  The shortcuts of this slide instead are for rescaling images by specifying factors.
[08:09.560 --> 08:17.560]  As you see, this exploits the fine-grained control that the scale command offers.
[08:17.560 --> 08:25.560]  What you see are standalone theme statements, of course.
[08:25.560 --> 08:32.560]  Another shortcut syntax prefixes a command by a number.
[08:32.560 --> 08:39.560]  The command, or a block, will be repeatedly executed that specific number of times.
[08:39.560 --> 08:47.560]  One can interrupt the iterations by hitting escape, for instance.
[08:47.560 --> 08:56.560]  You can use a so-called range syntax to repeat an action on a filename interval.
[08:56.560 --> 09:02.560]  Just specify number, comma, number before a command.
[09:02.560 --> 09:13.560]  Use this to invoke commands on filenames, which will be substituted to open, close curly brackets.
[09:13.560 --> 09:24.560]  This usage of the brackets substitution mimics the syntax of the Unix find utility.
[09:24.560 --> 09:29.560]  FIM uses dynamic variables and a weak type system.
[09:29.560 --> 09:36.560]  Internally, a variable can be an integer, a floating point number, or a string.
[09:36.560 --> 09:42.560]  You can combine expressions with several operators.
[09:42.560 --> 09:46.560]  Strings concatenate with dot.
[09:46.560 --> 09:49.560]  There are two quoting styles for strings.
[09:49.560 --> 09:56.560]  Within single quotes, you only have to escape using backslash, single quotes.
[09:56.560 --> 10:02.560]  Within double quotes, we escape double quotes.
[10:02.560 --> 10:09.560]  FIM sets several variables, many meant to be used or internally.
[10:09.560 --> 10:15.560]  Some other variables are meant to be controlled by the user.
[10:15.560 --> 10:21.560]  These are the configuration variables, and may, for instance, control caching behavior,
[10:21.560 --> 10:27.560]  or customize, the status line, or the window manager caption.
[10:27.560 --> 10:37.560]  In the case of the special variable random, think of it as it were a function.
[10:37.560 --> 10:45.560]  Certain variables prefixed by i colon are contextual to the current image.
[10:45.560 --> 10:52.560]  They may hold its filename, size, or the current width.
[10:52.560 --> 10:58.560]  But also special information, like exif metadata.
[10:58.560 --> 11:09.560]  I, for instance, really like to have those being displayed in the status line.
[11:09.560 --> 11:12.560]  Variables are the glue of the language.
[11:12.560 --> 11:19.560]  But auto commands are the glue of the FIM internals.
[11:19.560 --> 11:26.560]  Auto commands, inspired by VIM, are actions that trigger
[11:26.560 --> 11:32.560]  if the current filename matches a pattern on a specific event.
[11:32.560 --> 11:38.560]  There is a dozen of specific events defined in FIM.
[11:38.560 --> 11:44.560]  You have a list of them in demand FIM or C.
[11:44.560 --> 11:50.560]  Auto commands are tricky, but also very powerful.
[11:50.560 --> 11:54.560]  Now, remember the special range syntax?
[11:54.560 --> 12:06.560]  One must say one can also use it to rudimentarily interact with the shell from within FIM.
[12:06.560 --> 12:13.560]  The example here repeats the copy command with a changing first argument.
[12:13.560 --> 12:17.560]  It copies each file into a specific directory.
[12:17.560 --> 12:25.560]  You can think the open-closed brackets as the i colon filename variable.
[12:25.560 --> 12:33.560]  This feature is to be used with lots of care.
[12:33.560 --> 12:42.560]  By now, you know enough of the language that you can experiment in the internal command line.
[12:42.560 --> 12:49.560]  You can also make FIM run custom scripts or customize the configuration.
[12:49.560 --> 12:54.560]  It would be useful to know that FIM has command-recording functionality.
[12:54.560 --> 12:57.560]  See the right script out option, for instance.
[12:57.560 --> 13:02.560]  With it, when terminating your usage session,
[13:02.560 --> 13:10.560]  FIM can save all the executed actions, along with timings, into a text file, a script.
[13:10.560 --> 13:16.560]  You can then replay that session by executing that output script.
[13:16.560 --> 13:21.560]  Just remember that only executed commands are saved.
[13:21.560 --> 13:28.560]  The actual invocation arguments to FIM will not be there.
[13:28.560 --> 13:34.560]  Also worth to know, in your scripts, you can control the exit status.
[13:34.560 --> 13:38.560]  This is good for interaction with shell scripts.
[13:38.560 --> 13:44.560]  You can signal success or failure of a script.
[13:44.560 --> 13:50.560]  Indeed, so far, we have mostly seen internal scriptability.
[13:50.560 --> 13:53.560]  But FIM has several command-line options.
[13:53.560 --> 13:56.560]  There are many things you can do with them.
[13:56.560 --> 14:05.560]  And interacting with shell pipes, you can read and execute a script via the standard input.
[14:05.560 --> 14:09.560]  You can read images via the standard input.
[14:09.560 --> 14:15.560]  Or perhaps print filename lists as output of one FIM instance.
[14:16.560 --> 14:26.560]  And back, reading back as input in another FIM instance.
[14:26.560 --> 14:28.560]  We are approaching the end of the talk.
[14:28.560 --> 14:34.560]  You might be curious and want to know that FIM consists of
[14:34.560 --> 14:40.560]  about 42,000 lines of C++ code.
[14:40.560 --> 14:44.560]  The language parser has been written in Bison and Flex.
[14:44.560 --> 14:54.560]  And, well, details of the grammar are in Man, FIM or C.
[14:54.560 --> 14:59.560]  FIM's language offers many possibilities.
[14:59.560 --> 15:02.560]  But this can still be improved a lot.
[15:02.560 --> 15:06.560]  Variable identifiers are not always clear.
[15:06.560 --> 15:10.560]  The technique mistakes in a program can be difficult.
[15:10.560 --> 15:14.560]  Output could be escaped or quoted better.
[15:14.560 --> 15:18.560]  Sometimes I wish less quoting were possible.
[15:18.560 --> 15:21.560]  Autocompletion could be richer.
[15:21.560 --> 15:28.560]  And wouldn't it be awesome to use your favorite extension or customization language
[15:28.560 --> 15:33.560]  instead of this one here?
[15:33.560 --> 15:40.560]  Well, this is the end of our tour of FIM's internal language.
[15:40.560 --> 15:43.560]  FIM is packaged on several Linux distributions.
[15:43.560 --> 15:48.560]  So you can check out yours to obtain FIM.
[15:48.560 --> 15:53.560]  The documentation is mostly inside two Man pages.
[15:53.560 --> 15:58.560]  And perhaps the other FIM talk I'm giving at this FOSDEM,
[15:58.560 --> 16:04.560]  specific about interactive usage, can be of your interest too.
[16:04.560 --> 16:10.560]  So I hope you will be enjoying FIM as much as I do.
[16:10.560 --> 16:12.560]  Thanks for your attention.
[16:28.560 --> 16:32.560]  We are live now.
[16:32.560 --> 16:35.560]  We don't seem to have any questions.
[16:35.560 --> 16:43.560]  You could add something if you have anything to add beyond the talk itself.
[16:58.560 --> 17:05.560]  Maybe I could ask questions.
[17:05.560 --> 17:11.560]  Did you consider using a Lisp-like language for FIM?
[17:11.560 --> 17:17.560]  And why did you choose a specific kind of syntax?
[17:17.560 --> 17:26.560]  I don't know if Lisp is a minimalistic language
[17:26.560 --> 17:33.560]  in that it requires a certain degree of parenthesis as far as I know.
[17:33.560 --> 17:39.560]  And that is already too much or more than what I wanted.
[17:39.560 --> 17:47.560]  I don't exclude the idea of having Lisp to interact with FIM in the future.
[17:47.560 --> 17:52.560]  But still I wanted to have minimalistic syntax,
[17:52.560 --> 17:58.560]  like the one that you have seen with the shortcut jump command.
[17:58.560 --> 18:03.560]  I think you cannot have that in Lisp.
[18:03.560 --> 18:11.560]  So you wanted a little bit of really short syntax.
[18:11.560 --> 18:21.560]  I am referring to slide 17 and 18.
[18:21.560 --> 18:38.560]  Okay.
[18:38.560 --> 18:40.560]  There is a question by Piotr.
[18:40.560 --> 18:43.560]  Perhaps I can answer it straight away.
[18:43.560 --> 18:48.560]  Yeah, good.
[18:48.560 --> 18:53.560]  I am not enough an Emacs user to have...
[18:53.560 --> 18:56.560]  Could you read up the question next?
[18:56.560 --> 19:01.560]  Piotr asks, do you have mappings for Emacs?
[19:01.560 --> 19:07.560]  And my answer is, I am not that much of an Emacs user to know it.
[19:07.560 --> 19:13.560]  However, the mappings, I mean, already if you tell me, Piotr,
[19:13.560 --> 19:18.560]  what is Emacs style in interactive usage,
[19:18.560 --> 19:24.560]  it's no problem for me, even to me, for me to come up with a few key mappings,
[19:24.560 --> 19:31.560]  because this is configurable as you will also see in the using FIM presentation this afternoon,
[19:31.560 --> 19:34.560]  which is less nerdy than this one.
[19:34.560 --> 19:38.560]  And when it comes to the language, the command line,
[19:38.560 --> 19:45.560]  I didn't say it, or I didn't put much emphasis on this,
[19:45.560 --> 19:54.560]  but FIM uses autocompletion based on libredline.
[19:54.560 --> 20:00.560]  Libredline is what you use in many shells
[20:00.560 --> 20:04.560]  and allows you to have autocompletion.
[20:04.560 --> 20:14.560]  So that has interactive autocompletion with Emacs style.
[20:14.560 --> 20:19.560]  However, that works under the frame buffer and not in X11,
[20:19.560 --> 20:22.560]  so it's not exactly as we should.
[20:22.560 --> 20:25.560]  Perhaps can be fixed.
[20:25.560 --> 20:35.560]  I hope I answered the two aspects of Emacs style working with FIM.
[20:35.560 --> 20:52.560]  Please come up with another question, please.
[20:52.560 --> 20:59.560]  So could you say something about your motivation for writing FIM?
[20:59.560 --> 21:02.560]  Why did you want to take on this project?
[21:02.560 --> 21:08.560]  Thanks, Arun.
[21:08.560 --> 21:18.560]  I wanted to be able to suit my very personal style of opening files
[21:18.560 --> 21:23.560]  and browsing files, especially PDFs at the beginning.
[21:23.560 --> 21:31.560]  I liked to have PDFs and I wanted to use a style which is more VIM oriented.
[21:31.560 --> 21:37.560]  At the time, I didn't have a suitable alternative that I liked.
[21:37.560 --> 21:44.560]  It's mostly to suit my own needs, and it continues this way.
[21:44.560 --> 21:52.560]  So for the fun, these are the motivations behind FIM.
[21:52.560 --> 21:54.560]  Okay, yeah, that makes sense.
[21:54.560 --> 22:00.560]  So you wanted a PDF reader and an image reader that can be used with FIM.
[22:00.560 --> 22:04.560]  Yeah, when it comes to the PDFs, because I didn't stick here in this talk,
[22:04.560 --> 22:16.560]  but there is a script which transforms images into PDFs or similar files into PNGs.
[22:16.560 --> 22:22.560]  It's called FIMGS, and it's nothing else than the translation of FBIGS,
[22:22.560 --> 22:32.560]  because FIM means to be an improvement on FBI.
[22:32.560 --> 22:45.560]  It can also open CBZ or tar balls to extract stuff.
[22:45.560 --> 22:50.560]  The extraction is not recursive, unfortunately.
[22:50.560 --> 22:53.560]  It's something that I wish to have at some point.
[22:53.560 --> 23:01.560]  It's a recursive extraction of tar balls or PDFs into images, or archives.
[23:01.560 --> 23:07.560]  Archives also can be opened, by the way, somewhere, yeah.
[23:07.560 --> 23:16.560]  Do we have any other questions? I don't see any.
[23:16.560 --> 23:25.560]  There seems to be a bit of lag in my question-score box, but there are no questions.
[23:25.560 --> 23:27.560]  So I'll ask one more.
[23:27.560 --> 23:34.560]  So when you convert these PDFs to images for viewing in FIM,
[23:34.560 --> 23:38.560]  can you search through the PDF, I mean, search through the text of the PDF?
[23:38.560 --> 23:40.560]  No, no.
[23:40.560 --> 23:44.560]  The PDF will become an image, and that's all.
[23:44.560 --> 23:52.560]  I think in principle, yeah, by using Poplar, which is one library which FIM uses,
[23:52.560 --> 23:58.560]  might be possible in the future, but I don't plan this at the moment.
[23:58.560 --> 24:00.560]  For now, it's about images.
[24:00.560 --> 24:06.560]  Use something else if you really need to use fully the F functionality.
[24:06.560 --> 24:08.560]  For now, stick to FIM for images.
[24:08.560 --> 24:13.560]  People use FIM for image frames, good for them,
[24:13.560 --> 24:19.560]  but I think it's a bit not using FIM at the full potential.
[24:19.560 --> 24:22.560]  I think FIM should be used interactively for images.
[24:22.560 --> 24:30.560]  And when one wants to have some special custom command, then you are welcome to configure FIM,
[24:30.560 --> 24:34.560]  but mostly it's meant for interactive usage, so don't take me wrong here.
[24:34.560 --> 24:38.560]  It's not something for programming stuff, use a library for that.
[24:38.560 --> 24:42.560]  This is just for viewing and viewing on steroids, hopefully.
[24:42.560 --> 24:44.560]  What do you mean by image frames?
[24:44.560 --> 24:46.560]  You said something about image frames.
[24:46.560 --> 24:53.560]  I mean small devices, which usually have a small screen, a very weak processor,
[24:53.560 --> 25:00.560]  which every five minutes, perhaps, changes an image and does a slideshow, which is very low,
[25:00.560 --> 25:03.560]  but it's usually not interactive.
[25:03.560 --> 25:09.560]  I think people use it a lot for this, and for the Raspberry PI, for instance,
[25:09.560 --> 25:15.560]  because I think there is no X there, or, let's say, it's good to use the frame buffer there.
[25:15.560 --> 25:26.560]  But I encourage using FIM interactively every day, if you like this style of keyboard-oriented usage, of course.
[25:26.560 --> 25:32.560]  I wish to have menus, and I'm working on that, but that's not the spirit of FIM.
[25:32.560 --> 25:35.560]  Okay, I think the time is over.
[25:36.560 --> 25:38.560]  We still have two and a half minutes.
[25:38.560 --> 25:41.560]  I mean, two hours, 45 seconds.
[25:41.560 --> 25:44.560]  Sorry, two minutes, 45 seconds.
[25:54.560 --> 25:56.560]  I still don't see any more questions.
[25:56.560 --> 25:58.560]  It's probably a bit early in the morning.
[25:58.560 --> 26:00.560]  Yes.
[26:06.560 --> 26:08.560]  Okay.
[26:21.560 --> 26:26.560]  I asked the question about the PDFs, because Emax has something very similar to look at PDFs,
[26:26.560 --> 26:29.560]  and it has the same problem with the search.
[26:29.560 --> 26:36.560]  It converts the PDFs to images, and then you can't really do much with the image.
[26:36.560 --> 26:40.560]  It's not a substitute for a PDF reader, that's the point.
[26:47.560 --> 26:51.560]  Can you play the SVG images using FIM?
[26:51.560 --> 26:53.560]  Sorry, can you repeat, please?
[26:53.560 --> 26:56.560]  Can you handle SVG images in FIM?
[26:56.560 --> 26:58.560]  Which images?
[26:58.560 --> 27:01.560]  SVG, scalable vector graphics?
[27:01.560 --> 27:04.560]  Yes, yes, yes.
[27:04.560 --> 27:17.560]  There is an internal conversion which uses Inkscape to render an internally pixel map out of the SVG.
[27:17.560 --> 27:20.560]  You have different converters inside FIM.
[27:20.560 --> 27:27.560]  Sorry, not inside, being invoked by FIM to make out of even your custom format.
[27:28.560 --> 27:30.560]  A pixel map.
[27:30.560 --> 27:35.560]  I invite those who wish to use this FIM, this afternoon, my other talk.
[27:35.560 --> 27:39.560]  I think it's at 3.30 or something like this.
[27:39.560 --> 27:41.560]  It will be most about usage.
[27:43.560 --> 27:48.560]  I think, guys, you should prepare for the next recording.
[27:50.560 --> 27:53.560]  The next talk, I think someone else will be handy.
[27:57.560 --> 27:58.560]  Good.
[27:58.560 --> 28:00.560]  So, we are almost done.
[28:00.560 --> 28:02.560]  Thanks, Arun.
[28:02.560 --> 28:05.560]  If you want to add something, you have 20 seconds more.
[28:05.560 --> 28:10.560]  No, I welcome to follow me live in Brussels this afternoon.
[28:10.560 --> 28:13.560]  Who is in Brussels? Otherwise, virtually.
[28:15.560 --> 28:16.560]  Thanks, Arun.
[28:16.560 --> 28:19.560]  Thanks to organizer Manolis and Piotr.
[28:19.560 --> 28:21.560]  Thank you, Mr.
[28:21.560 --> 28:22.560]  Ciao.
[28:22.560 --> 28:24.560]  Bye.
[28:27.560 --> 28:29.560]  Thank you.
[28:57.560 --> 28:59.560]  Thank you.
[29:27.560 --> 29:29.560]  Thank you.
[29:57.560 --> 29:59.560]  Thank you.