# Vicious

Vicious is a modular widget library for window managers, but mostly
catering to users of the *awesome* window manager. It was derived from
the old *Wicked* widget library, and has some of the old *Wicked* widget
types, a few of them rewritten, and a good number of new ones:

* https://github.com/vicious-widgets/vicious

Vicious widget types are a framework for creating your own
widgets. Vicious contains modules that gather data about your system,
and a few *awesome* helper functions that make it easier to register
timers, suspend widgets and so on. Vicious doesn't depend on any third party
Lua libraries, but may depend on additional system utilities (see widget
description).

## Usage

When provided by an operating system package, or installed from source
into the Lua library path Vicious can be used as a regular Lua
library, to be used stand-alone or to feed widgets of any window
manager (e.g. Ion, WMII). It is compatible with both Lua v5.1 and v5.2.

```lua
> widgets = require("vicious.widgets.init")
> print(widgets.volume(nil, "Master")[1])
100
```

## Usage within Awesome

To use Vicious with Awesome, install the package from your operating
system provider, or download the source code and move it to your
awesome configuration directory in `$XDG_CONFIG_HOME` (usually `~/.config`):

```bash
$ mv vicious $XDG_CONFIG_HOME/awesome/
```

Vicious will only load modules for widget types you intend to use in
your awesome configuration, to avoid having useless modules sitting in
your memory.

Then add the following to the top of your `rc.lua`:

```lua
local vicious = require("vicious")
```

Once you create a widget (a textbox, graph or a progressbar) call
`vicious.register()` to register it with Vicious:

    vicious.register(widget, wtype, format, interval, warg)

### widget

*Awesome* widget created with `widget()` or `awful.widget()` (in case of a
graph or a progressbar).

### wtype

Type: Vicious widget or `function`:

* Vicious widget type: any of the available (default, or custom)
  [widget type provided by Vicious](#widgets).
* function: custom function from your own *Awesome* configuration can be
  registered as widget types (see [Custom widget types](#custom-widget)).

### format

Type: `string` or `function`:

* string: `$key` will be replaced by respective value in the table `t` returned
  by the widget type. I.e. use `$1`, `$2`, etc. to retrieve data from an
  integer-indexed table (a.k.a. array); `${foo bar}` will be substituted by
  `t["{foo bar}"]`.
* `function (widget, args)` can be used to manipulate data returned by the
  widget type (see [Format functions](#format-func)).

### interval

Number of seconds between updates of the widget (default: 2). Read section
[Power and Caching](#power) for more information.

### warg

Some widget types require an argument to be passed, for example the battery ID.

## Other functions

`vicious.register` alone is not much different from
[awful.widget.watch](https://awesomewm.org/doc/api/classes/awful.widget.watch.html),
which has been added to Awesome since version 4.0. However, Vicious offers more
advanced control of widgets' behavior by providing the following functions.

### Unregister a widget

    vicious.unregister(widget, keep)

If `keep == true`, `widget` will be suspended and wait for activation.

### Suspend all widgets

    vicious.suspend()

See [example automation script](http://sysphere.org/~anrxc/local/sources/lmt-vicious.sh)
for the "laptop-mode-tools" start-stop module.

### Restart suspended widgets

    vicious.activate(widget)

If `widget` is provided only that widget will be activated.

### Enable caching of a widget type

    vicious.cache(wtype)

Enable caching of values returned by a widget type.

### Force update of widgets

    vicious.force(wtable)

`wtable` is a table of one or more widgets to be updated.

### Get data from a widget

    vicious.call(wtype, format, warg)

Fetch data from `wtype` to use it outside from the wibox
([example](#call-example)).

## <a name="widgets"></a>Widget types

Widget types consist of worker functions that take two arguments `format` and
`warg` (in that order), which were previously passed to `vicious.register`, and
return a table of values to be formatted by `format`.

### vicious.widgets.bat

Provides state, charge, and remaining time for a requested battery.

Supported platforms: GNU/Linux (require `sysfs`), FreeBSD (require `acpiconf`), OpenBSD (no extra requirements).

* `warg` (from now on will be called *argument*):
    * On GNU/Linux: battery ID, e.g. `"BAT0"`
    * On FreeBSD (optional): battery ID, e.g. `"batt"` or `"0"`
    * On OpenBSD (optional): `bat` followed by battery index, e.g. `bat0` or `bat1` on systems with more than one battery
* Returns an array (integer-indexed table) consisting of:
    * `$1`: State of requested battery
    * `$2`: Charge level in percent
    * `$3`: Remaining (charging or discharging) time
    * `$4`: Wear level in percent
    * `$5`: Current (dis)charge rate in Watt

### vicious.widgets.cpu

Provides CPU usage for all available CPUs/cores. Since this widget type give
CPU utilization between two consecutive calls, it is recommended to enable
caching if it is used to register multiple widgets (#71).

Supported platforms: GNU/Linux, FreeBSD.

Returns an array containing:
* `$1`: usage of all CPUs/cores
* `$2`, `$3`, etc. are respectively the usage of 1st, 2nd, etc. CPU/core

### vicious.widgets.cpufreq

Provides freq, voltage and governor info for a requested CPU.

Supported platforms: GNU/Linux, FreeBSD.

* Argument: CPU ID, e.g. `"cpu0"` on GNU/Linux, `"0"` on FreeBSD
* Returns an array containing:
    * `$1`: Frequency in MHz
    * `$2`: Frequency in GHz
    * `$3`: Voltage in mV
    * `$4`: Voltage in V
    * `$5`: Governor state
    * On FreeBSD: only the first two are supported
      (other values will always be `"N/A"`)

### vicious.widgets.cpuinf

Provides speed and cache information for all available CPUs/cores.

Supported platforms: GNU/Linux.

Returns a table whose keys using CPU ID as a base, e.g. `${cpu0 mhz}`,
`${cpu0 ghz}`, `${cpu0 kb}`, `${cpu0 mb}`, `${cpu1 mhz}`, etc.

### vicious.widgets.date

Provides access to Lua's `os.date`, with optional settings for time format and
time offset.

Supported platforms: platform independent.

* `format` (optional): a [strftime(3)](https://linux.die.net/man/3/strftime)
  format specification string (format functions are not supported). If not
  provided, use the prefered representation for the current locale.
* Argument (optional): time offset in seconds, e.g. for different a time zone.
  If not provided, current time is used.
* Returns the output of `os.date` formatted by `format` *string*.

### vicious.widgets.dio

Provides I/O statistics for all available storage devices.

Supported platforms: GNU/Linux.

Returns a table with string keys: `${sda total_s}`, `${sda total_kb}`,
`${sda total_mb}`, `${sda read_s}`, `${sda read_kb}`, `${sda read_mb}`,
`${sda write_s}`, `${sda write_kb}`, `${sda write_mb}`, `${sda iotime_ms}`,
`${sda iotime_s}`, `${sdb1 total_s}`, etc.

### vicious.widget.fanspeed

Provides fanspeed information for specified fan.

Supported platforms: FreeBSD.

* Argument: full `sysctl` string to entry, e.g. `"dev.acpi_ibm.0.fan_speed"`
* Returns speed of specified fan in RPM, `-1` on error (probably wrong string)

### vicious.widgets.fs

Provides usage of disk space.

Supported platforms: platform independent.

* Argument (optional): if true includes remote filesystems, otherwise fallback
  to default, where only local filesystems are included.
* Returns a table with string keys, using mount points as a base, e.g.
  `${/ size_mb}`, `${/ size_gb}`, `${/ used_mb}`, `${/ used_gb}`, `${/ used_p}`,
  `${/ avail_mb}`, `${/ avail_gb}`, `${/ avail_p}`, `${/home size_mb}`, etc.

### vicious.widgets.gmail

Provides count of new and subject of last e-mail on Gmail.

Supported platform: platform independent, requiring `curl`.

This widget expects login information in your `~/.netrc` file, e.g.
`machine mail.google.com login user password pass` and you have to disable
[two step verification](https://support.google.com/accounts/answer/1064203).
[Allow access for less secure apps](https://www.google.com/settings/security/lesssecureapps)
afterwards.

**BE AWARE THAT MAKING THESE SETTINGS IS A SECURITY RISK!**

* Arguments (optional): either a number or a table
    * If it is a number, subject will be truncated.
    * If it is a table whose first field is the maximum length and second field
      is the widget name (e.g. `"gmailwidget"`), scrolling will be used.
* Returns a table with string keys: `${count}` and `${subject}`

### vicious.widgets.hddtemp

Provides hard drive temperatures using the hddtemp daemon.

Supported platforms: GNU/Linux, requiring `hddtemp` and `curl`.

* Argument (optional): `hddtemp` listening port (default: 7634)
* Returns a table with string keys, using hard drives as a base, e.g.
  `${/dev/sda}` and `${/dev/sdc}`.

### vicious.widgets.hwmontemp

Provides name-based access to hwmon devices via sysfs.

Supported platforms: GNU/Linux

* Argument: an array with sensor name and input number (optional, falling back
  to `1`), e.g. `{"radeon", 2}`
* Returns a table with just the temperature value: `$1`
* Usage example:
    ```lua
    gputemp = wibox.widget.textbox()
    vicious.register(gputemp, vicious.widgets.hwmontemp, " $1°C", 5, {"radeon"})
    ```

### vicious.widgets.mbox

Provides the subject of last e-mail in a mbox file.

Supported platforms: platform independent.

* Argument: either a string or a table:
    * A string representing the full path to the mbox, or
    * Array of the form `{path, maximum_length[, widget_name]}`.
      If the widget name is provided, scrolling will be used.
    * Note: the path will be escaped so special variables like `~` will not
      work, use `os.getenv` instead to access environment variables.
* Returns an array whose first value is the subject of the last e-mail.

### vicious.widgets.mboxc

Provides the count of total, old and new messages in mbox files.

Supported platforms: platform independent.

* Argument: an array full paths to mbox files.
* Returns an array containing:
    * `$1`: Total number of messages
    * `$2`: Number of old messages
    * `$3`: Number of new messages

### vicious.widgets.mdir

Provides the number of unread messages in Maildir structures/directories.

Supported platforms: platform independent.

* Argument: an array with full paths to Maildir structures.
* Returns an array containing:
    * `$1`: Number of new messages
    * `$2`: Number of *old* messages lacking the *Seen* flag

### vicious.widgets.mem

Provides RAM and Swap usage statistics.

Supported platforms: GNU/Linux, FreeBSD.

Returns (per platform):
* GNU/Linux: an array consisting of:
    * `$1`: Memory usage in percent
    * `$2`: Memory usage in MiB
    * `$3`: Total system memory in MiB
    * `$4`: Free memory in MiB
    * `$5`: Swap usage in percent
    * `$6`: Swap usage in MiB
    * `$7`: Total system swap in MiB
    * `$8`: Free swap in MiB
    * `$9`: Memory usage with buffers and cache, in MiB
* FreeBSD: an array including:
    * `$1`: Memory usage in percent
    * `$2`: Memory usage in MiB
    * `$3`: Total system memory in MiB
    * `$4`: Free memory in MiB
    * `$5`: Swap usage in percent
    * `$6`: Swap usage in MiB
    * `$7`: Total system swap in MiB
    * `$8`: Free swap in MiB
    * `$9`: Wired memory in percent
    * `$10`: Wired memory in MiB
    * `$11`: Unfreeable memory (basically active+inactive+wired) in percent
    * `$12`: Unfreeable memory in MiB

### vicious.widgets.mpd

Provides Music Player Daemon information.

Supported platforms: platform independent (required tools: `curl`).

* Argument: an array including password, hostname and port in that order. `nil`
  fields will be fallen back to default (`localhost:6600` without password).
* Returns a table with string keys: `${volume}`, `${bitrate}`, `${elapsed}` (in seconds),
  `${duration}` (in seconds), `${Elapsed}` (formatted as [hh:]mm:ss), `${Duration}` (formatted as [hh:]mm:ss),
  `${Progress}` (in percentage), ${random}`, `${repeat}`, `${state}`, `${Artist}`, `${Title}`, `${Album}`,
  `${Genre}` and optionally `${Name}` and `${file}`.

### vicious.widgets.net

Provides state and usage statistics of network interfaces.

Supported platforms: GNU/Linux, FreeBSD.

* Argument (FreeBSD only): desired interface, e.g. `"wlan0"`
* Returns (per platform):
  * GNU/Linux: a table with string keys, using net interfaces as a base, e.g.
    `${eth0 carrier}`, `${eth0 rx_b}`, `${eth0 tx_b}`, `${eth0 rx_kb}`,
    `${eth0 tx_kb}`, `${eth0 rx_mb}`, `${eth0 tx_mb}`, `${eth0 rx_gb}`,
    `${eth0 tx_gb}`, `${eth0 down_b}`, `${eth0 up_b}`, `${eth0 down_kb}`,
    `${eth0 up_kb}`, `${eth0 down_mb}`, `${eth0 up_mb}`, `${eth0 down_gb}`,
    `${eth0 up_gb}`, `${eth1 rx_b}`, etc.
  * FreeBSD: a table with string keys: `${carrier}`, `${rx_b}`, `${tx_b}`,
    `${rx_kb}`, `${tx_kb}`, `${rx_mb}`, `${tx_mb}`, `${rx_gb}`, `${tx_gb}`,
    `${down_b}`, `${up_b}`, `${down_kb}`, `${up_kb}`, `${down_mb}`, `${up_mb}`,
    `${down_gb}`, `${up_gb}`.

### vicious.widgets.org

Provides agenda statistics for Emacs org-mode.

Supported platforms: platform independent.

* Argument: an array of full paths to agenda files, which will be parsed as
  arguments.
* Returns an array consisting of
    * `$1`: Number of tasks you forgot to do
    * `$2`: Number of tasks for today
    * `$3`: Number of tasks for the next 3 days
    * `$4`: Number of tasks to do in the week

### vicious.widgets.os

Provides operating system information.

Supported platforms: platform independent.

Returns an array containing:
* `$1`: Operating system in use
* `$2`: Release version
* `$3`: Username
* `$4`: Hostname
* `$5`: Available system entropy
* `$6`: Available entropy in percent

### vicious.widgets.pkg

Provides number of pending updates on UNIX systems. Be aware that some package
managers need to update their local databases (as root) before showing the
correct number of updates.

Supported platforms: platform independent, although it requires Awesome
`awful.spawn` library for non-blocking spawning.

* Argument: distribution name, e.g. `"Arch"`, `"Arch C"`, `"Arch S"`,
  `"Debian"`, `"Ubuntu"`, `"Fedora"`, `"FreeBSD"`, `"Mandriva"`.
* Returns an array including:
    * `$1`: Number of available updates
    * `$2`: Packages available for update

### vicious.widgets.raid

Provides state information for a requested RAID array.

Supported platforms: GNU/Linux.

* Argument: the RAID array ID.
* Returns an array containing:
    * `$1`: Number of assigned devices
    * `$2`: Number of active devices

### vicious.widgets.thermal

Provides temperature levels of several thermal zones.

Supported platforms: GNU/Linux, FreeBSD.

* Argument (per platform):
    * GNU/Linux: either a string - the thermal zone, e.g. `"thermal_zone0"`,
      or a table of the form `{thermal_zone, data_source[, input_file]}`.
      Available `data_source`s and corresponding default `input_file` are given
      in the table below. For instance, if `"thermal_zone0"` is passed,
      temperature would be read from `/sys/class/thermal/thermal_zone0/temp`.
      This widget type is confusing and ugly but it is kept for backward
      compatibility.
    * FreeBSD: either a full `sysctl` path to a thermal zone, e.g.
      `"hw.acpi.thermal.tz0.temperature"`, or a table with multiple paths.
* Returns (per platform):
    * GNU/Linux: an array whose first value is the requested temperature.
    * FreeBSD: a table whose keys are provided paths thermal zones.

| `data_source` |           Path           | Default `input_file` |
| :-----------: | ------------------------ | :------------------: |
|   `"sys"`     | /sys/class/thermal/      |    `"temp"`          |
|   `"core"`    | /sys/devices/platform/   |    `"temp2_input"`   |
|   `"hwmon"`   | /sys/class/hwmon/        |    `"temp1_input"`   |
|   `"proc"`    | /proc/acpi/thermal_zone/ |    `"temperature"`   |

### vicious.widgets.uptime

Provides system uptime and load information.

Supported platforms: GNU/Linux, FreeBSD.

Returns an array containing:
* `$1`: Uptime in days
* `$2`: Uptime in hours
* `$3`: Uptime in minutes
* `$4`: Load average in the past minute
* `$5`: Load average in the past 5 minutes
* `$6`: Load average in the past 15 minutes

### vicious.widgets.volume

Provides volume levels and state of requested mixers.

Supported platforms: GNU/Linux (requiring `amixer`), FreeBSD.

* Argument (per platform):
    * GNU/Linux: either a string containing the ALSA mixer control
      (e.g. `"Master"`) or a table including command line arguments to be
      passed to [amixer(1)](https://linux.die.net/man/1/amixer),
      e.g. `{"PCM", "-c", "0"}` or `{"Master", "-D", "pulse"}`
    * FreeBSD: the mixer control, e.g. `"vol"`
* Returns an array consisting of (per platform):
    * GNU/Linux: `$1` as the volume level and `$2` as the mute state of
      the requested control
    * FreeBSD: `$1` as the volume level of the *left* channel, `$2` as the
      volume level of the *right* channel and `$3` as the mute state of the
      desired control

### vicious.widgets.weather

Provides weather information for a requested station.

Supported platforms: any having Awesome and `curl` installed.

* Argument: the ICAO station code, e.g. `"LDRI"`
* Returns a table with string keys: `${city}`, `${wind}`, `${windmph}`,
  `${windkmh}`, `${sky}`, `${weather}`, `${tempf}`, `${tempc}`, `${humid}`,
  `${dewf}`, `${dewc}` and `${press}`

### vicious.widgets.wifi

Provides wireless information for a requested interface.

Supported platforms: GNU/Linux.

* Argument: the network interface, e.g. `"wlan0"`
* Returns a table with string keys: `${ssid}`, `${mode}`, `${chan}`, `${rate}`,
  `${link}`, `${linp}` (link quality in percent) and `${sign}` (signal level)

### vicious.widgets.wifiiw

Provides wireless information for a requested interface (similar to
vicious.widgets.wifi, but uses `iw` instead of `iwconfig`).

Supported platforms: GNU/Linux.

* Argument: the network interface, e.g. `"wlan0"`
* Returns a table with string keys: `${ssid}`, `${mode}`, `${chan}`, `${rate}`,
  `${freq}`, `${linp}` (link quality in percent), `${txpw}` (tx power) and
  `${sign}` (signal level)


## <a name="custom-widget"></a>Custom widget types

Use any of the existing widget types as a starting point for your
own. Write a quick worker function that does the work and plug it
in. How data will be formatted, will it be red or blue, should be
defined in rc.lua (or somewhere else, outside the actual module).

Before writing a widget type you should check if there is already one in the
contrib directory of Vicious. The contrib directory contains extra widgets you
can use. Some are for less common hardware, and other were contributed by
Vicious users. Most of the contrib widgets are obsolete. Contrib widgets will
not be imported by init unless you explicitly enable it, or load them in your
rc.lua.

Some users would like to avoid writing new modules. For them Vicious
kept the old Wicked functionality, possibility to register their own
functions as widget types. By providing them as the second argument to
vicious.register. Your function can accept `format` and `warg`
arguments, just like workers.


## <a name="power"></a>Power and Caching

When a lot of widgets are in use they, and awesome, can generate a lot
of wake-ups and also be very expensive for system resources. This is
especially important when running on battery power. It was a big
problem with awesome v2 and widgets that used shell scripts to gather
data, and with widget libraries written in languages like Ruby.

Lua is an extremely fast and efficient programming language, and
Vicious takes advantage of that. But suspending Vicious widgets is one
way to prevent them from draining your battery, despite that.

Update intervals also play a big role, and you can save a lot of power
with a smart approach. Don't use intervals like: 5, 10, 30, 60, … to
avoid harmonics. If you take the 60-second mark as an example, all of
your widgets would be executed at that point. Instead think about
using only prime numbers, in that case you will have only a few
widgets executed at any given time interval. When choosing intervals
also consider what a widget actually does. Some widget types read
files that reside in memory, others call external utilities and some,
like the mbox widget, read big files.

Vicious can also cache values returned by widget types. Caching
enables you to have multiple widgets using the same widget type. With
caching its worker function gets executed only once - which is also
great for saving power.

* Some widget types keep internal data and if you call one multiple times
  without caching, the widget that executes it first would modify stored
  values. This can lead to problems and give you inconsistent data. Remember
  it for widget types like CPU and Network usage, which compare the old set of
  data with the new one to calculate current usage.

* Widget types that require a widget argument to be passed should be handled
  carefully. If you are requesting information for different devices then
  caching should not be used, because you could get inconsistent data.


## Security

At the moment only one widget type (Gmail) requires auth. information
in order to get to the data. In the future there could be more, and
you should give some thought to the issue of protecting your data. The
Gmail widget type by default stores login information in the ~/.netrc
file, and you are advised to make sure that file is only readable by
the owner. Other than that we can not force all users to conform to
one standard, one way of keeping it secure, like in some keyring.

First let's clear why we simply don't encrypt the login information
and store it in ciphertext. By exposing the algorithm anyone can
reverse the encryption steps. Some claim even that's better than
plaintext but it's just security trough obscurity.

Here are some ideas actually worth your time. Users that have KDE (or
parts of it) installed could store their login information into the
Kwallet service and request it via DBus from the widget type. It can
be done with tools like `dbus-send` and `qdbus`. The Gnome keyring
should support the same, so those with parts of Gnome installed could
use that keyring.

Users of GnuPG (and its agent) could consider encrypting the netrc
file with their GPG key. Trough the GPG Passphrase Agent they could
then decrypt the file transparently while their session is active.

## Usage examples

Start with a simple widget, like `date`. Then build your setup from
there, one widget at a time. Also remember that besides creating and
registering widgets you have to add them to a `wibox` (statusbar) in
order to actually display them.

### Date widget

Update every 2 seconds (the default interval), use standard date sequences as
the format string:

```lua
datewidget = wibox.widget.textbox()
vicious.register(datewidget, vicious.widgets.date, "%b %d, %R")
```

### Memory widget

Update every 13 seconds, append `MiB` to 2nd and 3rd returned values and
enables caching.

```lua
memwidget = wibox.widget.textbox()
vicious.cache(vicious.widgets.mem)
vicious.register(memwidget, vicious.widgets.mem, "$1 ($2MiB/$3MiB)", 13)
```

### HDD temperature widget

Update every 19 seconds, request the temperature level of the /dev/sda and
append *°C* to the returned value. Since the listening port is not provided,
default one is used.

```lua
hddtempwidget = wibox.widget.textbox()
vicious.register(hddtempwidget, vicious.widgets.hddtemp, "${/dev/sda} °C", 19)
```

### Mbox widget

Updated every 5 seconds, provide full path to the mbox as argument:

```lua
mboxwidget = wibox.widget.textbox()
vicious.register(mboxwidget, vicious.widgets.mbox, "$1", 5,
                 "/home/user/mail/Inbox")
```

### Battery widget

Update every 61 seconds, request the current battery charge level and displays
a progressbar, provides `"BAT0"` as battery ID:

```lua
batwidget = wibox.widget.progressbar()

-- Create wibox with batwidget
batbox = wibox.layout.margin(
    wibox.widget{{max_value = 1, widget = batwidget,
                  border_width = 0.5, border_color = "#000000",
                  color = {type = "linear",
                           from = {0, 0},
                           to = {0, 30},
                           stops = {{0, "#AECF96"}, {1, "#FF5656"}}}},
                 forced_height = 10, forced_width = 8,
                 direction = 'east', color = beautiful.fg_widget,
                 layout = wibox.container.rotate},
    1, 1, 3, 3)

-- Register battery widget
vicious.register(batwidget, vicious.widgets.bat, "$2", 61, "BAT0")
```

### CPU usage widget

Update every 3 seconds, feed the graph with total usage percentage of all
CPUs/cores:

```lua
cpuwidget = awful.widget.graph()
cpuwidget:set_width(50)
cpuwidget:set_background_color"#494B4F"
cpuwidget:set_color{type = "linear", from = {0, 0}, to = {50, 0},
                    stops = {{0, "#FF5656"}, {0.5, "#88A175"}, {1, "#AECF96"}}}
vicious.register(cpuwidget, vicious.widgets.cpu, "$1", 3)
```

## <a name="format-func"></a>Format functions

You can use a function instead of a string as the format parameter.
Then you are able to check the value returned by the widget type and
change it or perform some action. You can change the color of the
battery widget when it goes below a certain point, hide widgets when
they return a certain value or maybe use `string.format` for padding.

Do not confuse this with just coloring the widget, in those cases standard
Pango markup can be inserted into the format string.

The format function will get the widget as its first argument, table
with the values otherwise inserted into the format string as its
second argument, and will return the text/data to be used for the
widget.

### Examples

#### Hide mpd widget when no song is playing

```lua
mpdwidget = wibox.widget.textbox()
vicious.register(
    mpdwidget,
    vicious.widgets.mpd,
    function (widget, args)
        if args["{state}"] == "Stop" then
            return ''
        else
            return ('<span color="white">MPD:</span> %s - %s'):format(
                args["{Artist}"], args["{Title}"])
        end
    end)
```

#### Use string.format for padding

```lua
uptimewidget = wibox.widget.textbox()
vicious.register(uptimewidget, vicious.widgets.uptime,
                 function (widget, args)
                     return ("Uptime: %02d %02d:%02d "):format(
                         args[1], args[2], args[3])
                 end, 61)
```

When it comes to padding it is also useful to mention how a widget can be
configured to have a fixed width. You can set a fixed width on your textbox
widgets by changing their `width` field (by default width is automatically
adapted to text width). The following code forces a fixed width of 50 px to the
uptime widget, and aligns its text to the right:

```lua
uptimewidget = wibox.widget.textbox()
uptimewidget.width, uptimewidget.align = 50, "right"
vicious.register(uptimewidget, vicious.widgets.uptime, "$1 $2:$3", 61)
```

#### Stacked graph

Stacked graphs are handled specially by Vicious: `format` functions passed to
the corresponding widget types must return an array instead of a string.

```lua
cpugraph = wibox.widget.graph()
cpugraph:set_stack(true)
cpugraph:set_stack_colors({"red", "yellow", "green", "blue"})
vicious.register(cpugraph, vicious.widgets.cpu,
                 function (widget, args)
                     return {args[2], args[3], args[4], args[5]}
                 end, 3)
```

The snipet above enables graph stacking/multigraph and plots usage of all four
CPU cores on a single graph.

#### Substitute widget types' symbols

If you are not happy with default symbols used in volume, battery, cpufreq and
other widget types, use your own symbols without any need to modify modules.
The following example uses a custom table map to modify symbols representing
the mixer state: on or off/mute.

```lua
volumewidget = wibox.widget.textbox()
vicious.register(volumewidget, vicious.widgets.volume,
                 function (widget, args)
                     local label = {["♫"] = "O", ["♩"] = "M"}
                     return ("Volume: %d%% State: %s"):format(
                         args[1], label[args[2]])
                 end, 2, "PCM")
```

#### <a name="call-example"></a>Get data from the widget

`vicious.call` could be useful for naughty notification and scripts:

```lua
mybattery = wibox.widget.textbox()
vicious.register(mybattery, vicious.widgets.bat, "$2%", 17, "0")
mybattery:buttons(awful.util.table.join(
    awful.button(
        {}, 1,
        function ()
            naughty.notify{title = "Battery indicator",
                           text = vicious.call(vicious.widgets.bat,
                                               "Remaining time: $3", "0")}
        end)))
```

Format functions can be used as well:

```lua
mybattery:buttons(awful.util.table.join(
    awful.button(
        {}, 1,
        function ()
            naughty.notify{
                title = "Battery indicator",
                text = vicious.call(
                    vicious.widgets.bat,
                    function (widget, args)
                        return ("%s: %10sh\n%s: %14d%%\n%s: %12dW"):format(
                            "Remaining time", args[3],
                            "Wear level", args[4],
                            "Present rate", args[5])
                    end, "0")}
        end)))
```

## See also

* Manual pages: [awesome(1)](https://awesomewm.org/doc/manpages/awesome),
  [awesomerc(5)](https://awesomewm.org/doc/manpages/awesomerc.5.html)
* [Awesome declarative layout system](https://awesomewm.org/apidoc/documentation/03-declarative-layout.md.html)
* [Example *awesome* configuration](http://git.sysphere.org/awesome-configs/)
  (outdated)
* [My first awesome](https://awesomewm.org/doc/api/documentation/07-my-first-awesome.md.html)

## Authors

Wicked was written by:

* Lucas de Vries \<lucas glacicle.com\>

Vicious was originally written by:

* Adrian C. (anrxc) \<anrxc sysphere.org\>

Current maintainers:

* Jörg Thalheim (Mic92) \<joerg thalheim.io\>
* [mutlusun](https://github.com/mutlusun) (especially the FreeBSD port)
* Daniel Hahler (blueyed) \<github thequod.de\>
* Nguyễn Gia Phong (McSinyx) \<vn.mcsinyx gmail.com\>

Vicious major contributors:

* Benedikt Sauer \<filmor gmail.com\>
* Greg D. \<jabbas jabbas.pl\>
* Henning Glawe \<glaweh debian.org\>
* Rémy C. \<shikamaru mandriva.org\>
* Hiltjo Posthuma \<hiltjo codemadness.org\>
* Hagen Schink \<troja84 googlemail.com\>
* Arvydas Sidorenko \<asido4 gmail.com\>
* Dodo The Last \<dodo.the.last gmail.com\>
* …
* Consult git log for a complete list of contributors