Awesome 4.0 changelog

# Awesome window manager framework version 4.0 changes

Awesome 4.0 is the first release of the v4 API level, breaking the proven
v3.5 API level after 4 years.  This requires to port existing user
configuration and extensions to the new API.

This document offer an overview of the new features and required changes for
existing users.

## New features

### Inputs related

#### Mouse move and resize handlers

The code used to resize and move clients has been refactored to allow plugins
to be attached.  This includes:

 * display the client geometry in the wibar
 * implement a resize grid
 * implement delayed resizing (like Windows 3.11 and TWM)
 * have touch-friendly resize handles (implemented by the Collision extension)
 * allow window snapping (implemented)
 * allow edge tiling (like Windows 7+ (AeroSnap) , KDE and Gnome) (implemented)
 * move to the next tag when dragged to the edge (like KDE3) (disabled by default)

##### Edge tiling (AeroSnap)

Clients are now resized when dragged to the screen edge similar to other window
managers. The width of the border can be controlled by the
`beautiful.snap_border_width` theme variable. The edge shape with
`beautiful.snap_shape` (see `gears.shape`) and can be disabled by setting
`awful.mouse.snap.edge_enabled = false`.

##### Edge snapping

While this was already supported, this feature has been extensively extended.
It can be disabled by setting `awful.mouse.snap.client_enabled = false`.

#### Hotkey popup

It is now possible to display the list of active keyboard shortcuts by pressing
`mod4 + s` (`hotkeys_popup.show_help`).

### New tag and layout properties

#### Generic useless gap

Adds an empty space between clients.

#### Master fill policies

Allows the layout to optionally take all the space when there is no "slave"
client or to use a smaller screen area.  TODO: not clear.

#### Volatile

Tags can now be `volatile`. A volatile tag will be destroyed when its last
client has been untagged. This is useful for temporary layouts or tags
dedicated to a single client.

### New client properties

- `focusable` is now read/write (compared to read only in the previous
  versions)
- `valid` tells if the client still really exist or if the object is waiting to
  be deleted
- `floating` is now a client property
- `x` / `y` / `width` / `height` are `client.geometry` aliases
- `first_tag` is a convenience wrapper for `c:tags()[1]`

#### Client signaling

There is now an `awesome.unix_signal` signal table with all platform specific
signals and their indices. There is also an `awesome.kill()` function to send
signals to clients. This can be used, among other thing, to pause and resume
clients.

### New client rules (`awful.rules`)

All of the new client properties can be used in rules. In addition, the
following ones have been added:

- `placement`: use the `awful.placement` method (or combinations) to place the
  client. While older version of Awesome allowed to use callbacks here, it
  didn't support all corner cases such as titlebar offsets and border_width.
- `titlebars_enabled`: older versions of Awesome had a global variable to
  enable or disable titlebars. This is now delegated to the rules.
- `new_tag`: allows to create a tag for the client instead of using an existing
  one.
- The `tag` property has been expanded to also find tags from their name.
- The `tags` property now tries to merge the current tags into the array to fix
  some other properties.
- All geometry properties are now executed at once to avoid side effects.
- The `focus` is now going through the focus filters instead of being applied
  as-is (see the focus filter section).

Rules execution has been re-ordered to minimize the race conditions (one rule
affecting the outcome of another). This may create a slightly different
behavior for some users, but is usually considered to be an improvement.

#### User rules

It is now possible to register new rules by adding them to some `awful.rules`
arrays. This can be used by modules to add extra functionalities or to avoid
boilerplate code in callbacks.

 * `rules.high_priority_properties`: before most other rules are executed.
 * `rules.extra_properties`: together with normal rules.
 * `rules.delayed_properties`: after most other rules, but before `focus`.

Those extra rules also have the capability to mutate the current rule array.

### New widgets
- pie chart
- arc chart
- radial progressbar
- shaped progressbar
- bar graph
- ratio layout
- stack layout
- placement container
- shaped widget (in the background container)
- checkbox
- slider

Other widgets, like the `taglist` and `tasklist`, gained many new
configuration features such as empty colors and shape.

See http://new.awesomewm.org/apidoc/documentation/03-declarative-layout.md.html

### New APIs

#### The new and streamlined property system

Previously some core objects, such as clients or tags, were static. It wasn't
possible to directly set new properties on them. This is now supported:

```
c.my_new_property = "bar"
```

Also all properties previously accessible from the `awful` module are now
directly accessible on the object:

```lua
-- Before
awful.client.floating.set(c, true)

-- Now
c.floating = true
```

See the "deprecated" section below for the list of functions that have been
replaced by properties or methods.

The widgets API also received a similar overhaul. Both getters/setters and
the property APIs are now supported.

```lua
-- Before
mytextbox:set_text("Foobar")
myimagebox:set_resize(not myimagebox:get_resize())

-- Now
mytextbox.text = "Foobar"
myimagebox.resize = not myimagebox.resize
```

Awesome 4.0 restores a feature found in older versions of Awesome.
All widgets now have properties again. While all `:set_foo(bar)` type accessors
are still fully (and forever) supported, it is now possible to do `.foo = bar`
and `obj.foo = not obj.foo` . This is supported for all official widgets,
containers and layouts.

#### Declarative widget syntax is supported again

Awesome 4.0 re-introduces the declarative widget syntax. This feature was lost
when Awesome 3.5 introduced the new (and much, much better) widget system. It
is possible to do it again.

http://new.awesomewm.org/apidoc/documentation/03-declarative-layout.md.html

Most documentation examples have been adapted to use this syntax instead of the
imperative one. Both syntaxes are fully supported.

For example:

```lua

-- Imperative
local l = wibox.layout.fized.horizontal()
local i = wibox.widget.imagebox()
local t = wibox.widget.textbox()

i:set_image("/path/to/awesomeness.png")
t:set_text("is awesome")

l:add(i)
l:add(t)

-- Declarative
local l = wibox.layout {
     {
         image  = "/path/to/awesomeness.png",
         widget = wibox.widget.imagebox
     }.
     {
         text   = "is awesome",
         widget = wibox.widget.textbox
     }.
     layout = wibox.layout.fized.horizontal
}
```

#### The request API

Awesome used to blindly allow requests from clients to steal focus or move
them around. There are now handlers to block such requests.
The `request::` API is also used internally in Awesome itself to make
previously hard-coded behavior more flexible.

* `request::activate`: When a client requests focus and/or being raised.
* `request::geometry`: When a client requests a position.
* `request::screen`: When a client needs a screen.
* `request::select`: When a tag wants to be selected.
* `request::tag`: When a client needs a tag.
* `request::titlebars`: When a client needs a titlebar.
* `request::urgent`: When a client requests attention.

The defaults handlers are mostly located in the `awful.ewmh` module and comply
with what the specification defines.

#### The placement API

While Awesome already had some basic placement function, the new API makes it
possible to remove most hard-coded geometry handling code. From a user's point
of view this API allows for rich floating window management using
`awful.rules`.

http://new.awesomewm.org/apidoc/libraries/awful.placement.html

It provides generic placement functions that work with:
- clients
- wibox
- the mouse
- anything with a `:geometry()` method

#### The shape API

This new API allows nicer visuals and more complex themes.

http://new.awesomewm.org/apidoc/libraries/gears.shape.html

Also note that the client shape functionality was broken in 3.5 and has been
fixed.

#### The hierarchy API

The widget framework now produces a persistent model of its content rather than
a volatile one during the wibox drawing. This allows for better introspection
into the widget tree.
This model is now exposed through the `mouse::enter`, `mouse::press`,
`mouse.current_widget` and other APIs. This tree model also includes various
matrices to convert positions from the screen coordinates to the one of the
widgets (think of scaling and rotations).

This allows for interactive widgets such as a slider.

### New themes

A new `xresources` theme has been added. It uses native X11 assets such as
colors.

### Spawn and launcher improvements

#### Spawn

The newly renamed `awful.spawn` (previously `awful.util.spawn`) has been
extended into a whole API. It is now possible to define rules directly through
the spawn function.
Note that this only works if the client properly supports the freedesktop.org
startup notifications protocol. For example, to open a new `urxvt` in a new tag
from the command line, use:

```
awesome-client  "require('awful.spawn')('urxvt', {new_tag=true})"
```

As another example, to launch a centered floating terminal in the currently
selected tag of screen number 2:

 ```
awful.spawn("urxvt", {
    tag       = screen[2].selected_tag,
    placement = awful.placement.centered,
    floating  = true
})
```

All rule properties can be used, including the newly introduced placement ones
(like above).

#### Launcher

`awful.prompt` gained many new features. One of them is the ability to add
custom keyboard shortcuts and mutate the command.
Paired with the new spawn features, it can be used to create `mod4 + r`
shortcuts to spawn the clients with arguments and callbacks.

### Focus stealing filters.

It is now possible to add and manage filters to restrict what kind of focus
stealing is allowed. It can be used to mute noisy applications or to implement
tag level policies.
Every way a client could claim focus, including those from within Awesome
itself, now goes through the request filters.

### Notification actions

Awesome now supports XDG notification (aka, naughty) actions.

### Custom xproperties support

Awesome can now save some data in the X11 server itself. This allows to
communicate with external applications or so save state across restarts.

There is also supported/used for persistent client properties.

### Better XKB keyboard layout support

Awesome now has native support for keyboard layout detection and setting. Using
`setxkbmap` is no longer necessary. This also includes a widget to view the
current layout.

See:
- `awesome.xkb_set_layout_group`
- `awesome.xkb_get_layout_group`
- `awesome.xkb_get_group_names`
- `wibox.widget.keyboardlayout`

### Other minor features
- `awesome.composite_manager_running` allows to detect if a compositor is
  running
- a new `--replace` command line option is available (similar to other window
  managers)
- clients now have an unified `maximized` property additionally to only
  _horizontal and _vertical
- `awful.layout.layouts` is now where the client layout array is stored
- the `systray` elements order can be reversed and spacing can be added
- it is now possible to get the layout of unselected tags (use with caution)
- tags can be swapped, former XMonad users with multiple screens can rejoice
- whole screens can now be swapped
- virtual screens can be created, moved and resized
- paths can be added to Lua's search path via the `--search` argument
- RandR 1.5 MONITOR support
- access to the X resource management database
- titlebars are now controlled using `awful.rules` and enabled by default
- `awesome-client` now supports Lua code as its first argument (instead of
  reading from stdin)
- preferred client icon size can now be configured (see
  `awesome.set_preferred_icon_size`)
- there is now an `awesome.startup_errors` string with the startup error (if
  any)
- Initial support for HiDPI monitors / different DPI per screen
- early support for stateful client layouts
- the `--version` command line option now provides more details and system
  information

## Breaking changes

Awesome 4.0 is a major release.
As with all other major release, the API was broken to accommodate for new
capabilities. It isn't as different as 3.5 was from 3.4 however.
Many changes now cause a deprecation warning instead of breaking hard.
However, it is important to take note of these changes in order to avoid new
bugs.

### There can be off-screen clients unless rc.lua is adapted

```
# To fix from bash/zsh without a config change
echo 'for _,c in ipairs(client.get()) do require("awful.placement").no_offscreen(c) end' | awesome-client
```

And add the following to the global rc.lua `awful.rule` section:

```
 placement = awful.placement.no_overlap+awful.placement.no_offscreen
```

Also note that this is the new official syntax for placement functions in
rules. It is recommended to remove existing ones that are used as callbacks and
move them to the `placement` rule property.

### Screens are no longer static

Replace rc.lua `for s=1, screen.count() do` with
`awful.screen.connect_for_each_screen(function(s)` and add a `)` after the
section `end`.
All global widget tables should be adapted to avoid memory leaks.
Static code should not use `screen.count()` anymore. It should also always use
the screen object, as the integer representation is mostly deprecated.

### Screens are now objects

Previously: `type(s) == "number"`, now: `type(s) == "screen"`.
Doing `screen[1].geometry` is now partially deprecated and will probably print
a warning in future versions. Any code comparing number and screen objects is
now broken. Use screen objects instead of numbers.

### Awesome no longer restarts when a new screen is added

By default, `rc.lua` now handles screen changes without restarting.
It allows to preserve the tag and layout state across changes. Old `rc.lua` can
either be ported to handle this by taking clues from the new `rc.lua` or
restore the old behavior by adding the following at the end:

```
screen.connect("list", awesome.restart)
```

### Widgets' `:fit()` and `:draw()` methods signature changed and `:layout()` is mandatory for layouts and containers

All custom widgets need to change their function signature.

### The "align" layout default behavior changes

There is a new "strategy" property to define how the space is distributed.

### Many APIs are deprecated, fix them before they turn into errors

For example, instead of `awful.tag.viewonly(t)`, the recommended API is now
`t:view_only()`. The whole API has been standardized around this object
oriented notation. The warnings will be printed on stderr.

### Most widgets' private APIs have changed

You should not use undocumented APIs. Those can change at any time, and this
is no exception. The private API of all widgets has been broken.

### Spawn changes

- It has been moved into its own module (`awful.spawn`).
- Some methods have been deprecated. It is not recommended to use blocking
  methods in Awesome. We made sure to make your life harder if you wish to
  ignore this warning.
  Really, using blocking calls in rc.lua has very nasty side effects.

### Prompt changes

Most arguments have been deprecated, they are now taken from the `args`
argument-by-name table. This was done because the number of optional arguments
was getting out of control.

### Timers are no longer part of the C API

Use `gears.timer`.

### Deprecated functions

The previous Awesome API mixed different conventions. There was a major
undertaking in 4.0 to make the API coherent and well documented.

Those functions have been renamed or converted to methods:

- `awful.client.jumpto`
- `awful.client.visible`
- `awful.client.tiled`
- `awful.client.moveresize`
- `awful.client.movetotag`
- `awful.client.toggletag`
- `awful.client.movetoscreen`
- `awful.client.mark`
- `awful.client.unmark`
- `awful.client.ismarked`
- `awful.client.togglemarked`
- `awful.client.floating.set`
- `awful.client.isfixed`
- `awful.client.floating.get`
- `awful.client.floating.toggle`
- `awful.client.dockable.get`
- `awful.client.dockable.set`
- `awful.client.property.get`
- `awful.client.property.set`
- `awful.client.get_transient_for_matching`
- `awful.client.is_transient_for`
- `awful.mouse.client_under_pointer`
- `awful.mouse.client.dragtotag.border`
- `awful.mouse.client.corner`
- `awful.screen.getdistance_sq`
- `awful.screen.padding`
- `awful.tag.move`
- `awful.tag.swap`
- `awful.tag.delete`
- `awful.tag.gettags`
- `awful.tag.setscreen`
- `awful.tag.getscreen`
- `awful.tag.selectedlist`
- `awful.tag.selected`
- `awful.tag.setmwfact`
- `awful.tag.getmwfact`
- `awful.tag.setlayout`
- `awful.tag.setvolatile`
- `awful.tag.getvolatile`
- `awful.tag.setgap`
- `awful.tag.getgap`
- `awful.tag.setmfpol`
- `awful.tag.getmfpol`
- `awful.tag.setnmaster`
- `awful.tag.getnmaster`
- `awful.tag.seticon`
- `awful.tag.geticon`
- `awful.tag.setncol`
- `awful.tag.getncol`
- `awful.tag.getidx`
- `awful.tag.viewonly`
- `awful.tag.getdata`
- `awful.tag.getproperty`
- `awful.tag.setproperty`
- `awful.tag.withcurrent`
- `awful.util.get_rectangle_in_direction`
- `awful.wibox.get_position`
- `awful.wibox.set_position`
- `awful.wibox.attach`
- `awful.wibox.align`
- `awful.wibox.stretch`
- `awful.widget.progressbar.set_vertical`
- `awful.widget.progressbar.set_height`
- `awful.widget.progressbar.set_width`

Note that for 4.0, only a warning will be printed if these functions are used.
They will eventually be removed.

### Increased use of asynchronous programming

Many operations, such as re-draw, re-layout, geometry changes and various C API
calls are now delayed to the end of the event loop iteration to avoid multiple
changes per iteration (to not waste CPU time).
The downside of this is that it is no longer reliable to assume the result of
the previous line of code being applied in the next already.

### Startup handling

There is no longer a "startup" argument to the client "manage" signal. If
Awesome is currently starting up, then `awesome.startup` is set to `true`.

### Renamed modules

Just as the functions above, many modules have been moved to follow a naming
convention.
Using the old name will print a warning and will alias into the new module.
Note that theses aliases are temporary and will be removed.

- `awful.wibox`
- `awful.widget.graph`
- `awful.widget.progressbar`
- `awful.widget.textclock`
- `wibox.layout.constraint`
- `wibox.layout.margin`
- `wibox.layout.mirror`
- `wibox.layout.rotate`
- `wibox.layout.scroll`
- `wibox.widget.background`

### The mouse finder module is gone

It has been broken for ages, so we concluded nobody cared.

### Menubar changes

`menubar.menu_gen.generate` is now asynchronous and needs a callback as an
argument.

### Rules execution order changes

The order in which rules are executed changed.
It has been manually curated to avoid known race conditions between the rules
execution. For example, adding a titlebar after setting the position resulted
in an unwanted shift proportional to the titlebar size.

This is regarded as a breaking changes since it impacts the behavior of
existing code, hopefully for the better.

## Other

### New dependencies

Awesome now depends on Gio and a few other new packages since 3.5.
See the README for an extensive list.

### A new documentation

Awesome 4.0 now uses LDoc and MarkDown based documentation. We also introduced
official guides into our documentation such as

http://new.awesomewm.org/apidoc/documentation/03-declarative-layout.md.html

The new documentation is vastly superior to the previous one and includes
previously missing elements such as:

- a hundred images (from zero)
- more than a hundred new code examples, most of them unit tested (from very,
  very few)
- all signals (previously partially documented in the wiki)
- all theme variables
- the object properties
- references throughout the documentation
- variable types (previously mostly undocumented)
- many auto-generated pages instead of manually curated (and out of date) ones

### The old wiki is closing down

We are moving to a 2 tier solution based on official (and curated)
documentation, and a Git based wiki solution.
The old wiki has been partially closed down for years due to spam issues and
given the API breakage in the past, a non-negligible percentage of the content
and tips were no longer working properly.

### New website address

The official website is now `http://awesomewm.org/` and is now hosted by
GitHub. This will allow to retire the former server.

### Awesome is now developed on GitHub

This isn't technically part of the release and has been true for years, but as
the first major releases since the move, it is a good time to point out that we
retired the old infrastructure. This includes the bug tracker, download, wiki,
website, repository and continuous integration system.

This move increased our development velocity, number of contributor,
visibility count and reduced our infrastructure maintenance cost.

### Test driven development

Awesome went from 0% to 75% unit test coverage. We now have 4 testing systems:

- Linting (checks the code quality and consistency)
- Unit testing
- Documentation examples, documentation images and user interface appearance
  tests
- Integration tests

We also have a test matrix for:

- Different Lua versions
- Different screen resolutions
- Installation paths
- Dependencies versions

### Packaging support

Apart from the existing packages in distributions, Awesome users can now use
"make package" to generate .deb or .rpm instead of using `make install`.

TODO: Get rid of links to new.awesomewm.org