292 lines
8.3 KiB
Markdown
292 lines
8.3 KiB
Markdown
# The declarative layout system
|
|
|
|
This system provide an alternative to the system used in Awesome 3.5 and is
|
|
inspired by the one once used by Awesome 3.2-3.4 and Qt QML system.
|
|
|
|
## The default widgets
|
|
|
|
### Widgets
|
|
|
|
Awesome provide 2 collections of widgets:
|
|
|
|
* `wibox.widget`: Generic widgets, containers and layouts
|
|
* `awful.widget`: The Awesome specific widgets
|
|
|
|
|
|
@DOC_widget_WIDGET_LIST@
|
|
|
|
### Containers
|
|
|
|
Containers are widget wrapping another widget. It can be used to add decorations
|
|
or to modify the content of the child widget.
|
|
|
|
@DOC_container_WIDGET_LIST@
|
|
|
|
### Layouts
|
|
|
|
Layouts are collection of children widgets. They place them according to rules
|
|
and usually provide some options.
|
|
|
|
@DOC_layout_WIDGET_LIST@
|
|
|
|
## Placing widgets
|
|
|
|
### A simple layout
|
|
|
|
* Display `my_first_widget` only on screen one
|
|
* Add a background color to `my_third_widget`
|
|
* Dispose in a `wibox.layout.fixed.horizontal` layout
|
|
|
|
Code:
|
|
|
|
s.mywibox : setup {
|
|
s == 1 and my_first_widget, -- Only display on screen 1
|
|
my_second_widget,
|
|
{ -- Add a background color/pattern for my_third_widget
|
|
my_third_widget,
|
|
bg = beautiful.bg_focus,
|
|
widget = wibox.container.background,
|
|
},
|
|
layout = wibox.layout.fixed.horizontal,
|
|
}
|
|
|
|
|
|
In this example `s == 1` is an inline expression. In the default `rc.lua`,
|
|
there is an `s` variable represent to define the current screen. Any lua
|
|
logic expression can be used as long as it return a valid widget, or a
|
|
declarative layout, or `nil`.
|
|
|
|
|
|
### Define widgets inline and place them
|
|
|
|
* Create a `wibox.widget.textbox` with various properties
|
|
* Force the textbox size using `wibox.layout.constraint`
|
|
* Add a margin around another textbox
|
|
* Add a `wibox.container.background` (for visualization)
|
|
|
|
Code:
|
|
|
|
s.mywibox : setup {
|
|
{
|
|
-- Force the textbox to always be 300 pixel long
|
|
{
|
|
{
|
|
markup = "<b>Hello World!</b>",
|
|
align = "center",
|
|
widget = wibox.widget.textbox
|
|
},
|
|
bg = "#ff0000",
|
|
widget = wibox.container.background,
|
|
},
|
|
width = 300,
|
|
strategy = "min",
|
|
layout = wibox.layout.constraint
|
|
},
|
|
{
|
|
-- Add a border around the background
|
|
{
|
|
{
|
|
markup = "Foobar",
|
|
widget = wibox.widget.textbox
|
|
},
|
|
bg = "#0000ff",
|
|
widget = wibox.container.background
|
|
},
|
|
left = 10,
|
|
right = 10,
|
|
top = 1,
|
|
bottom = 2,
|
|
layout = wibox.container.margin
|
|
},
|
|
layout = wibox.layout.fixed.horizontal,
|
|
}
|
|
|
|
|
|
Result:
|
|
|
|
|
|
|
|
### Use an `wibox.layout.align` layout
|
|
The `wibox.layout.align` is a little different. While most layouts will
|
|
ignore any `nil` lines, the `align` layout rely on them so `left`, `middle`
|
|
and `right` can be defined
|
|
|
|
Code:
|
|
|
|
s.mywibox : setup {
|
|
my_textbox1, -- Left
|
|
nil, -- Nothing in the middle
|
|
my_textbox2, -- Right
|
|
layout = wibox.layout.fixed.horizontal,
|
|
}
|
|
|
|
|
|
|
|
### Define new widgets
|
|
|
|
New trivial widgets can be created directly in the layout declaration. Here
|
|
is a simple circle widget:
|
|
|
|
Code:
|
|
|
|
s.mywibox : setup {
|
|
fit = function(self, context, width, height)
|
|
return height, height -- A square taking the full height
|
|
end,
|
|
draw = function(self, context, cr, width, height)
|
|
cr:set_source_rgb(1, 0, 0) -- Red
|
|
cr:arc(height/2, height/2, height/2, 0, math.pi*2)
|
|
cr:fill()
|
|
end,
|
|
layout = wibox.widget.base.make_widget,
|
|
}
|
|
|
|
Result:
|
|
|
|
|
|
For more information about how to draw widgets, refer to the `Cairo` api:
|
|
|
|
* [Path](http://cairographics.org/manual/cairo-Paths.html)
|
|
* [Context](http://cairographics.org/manual/cairo-cairo-t.html)
|
|
* [Pattern](http://cairographics.org/manual/cairo-cairo-pattern-t.html)
|
|
* [transformation](http://cairographics.org/manual/cairo-Transformations.html)
|
|
* [Operator](http://cairographics.org/operators/)
|
|
* [Pango text](https://developer.gnome.org/pango/stable/)
|
|
|
|
|
|
### Externally defined widgets and layouts
|
|
|
|
This is useful when the widget is provided by an external module or when it
|
|
requires complex manipulations which would make the declaration unreadable.
|
|
|
|
Code:
|
|
|
|
local tb = wibox.widget.textbox()
|
|
tb:set_markup("Hello world! ")
|
|
|
|
-- Repeat "tb" 3 times
|
|
s.mywibox : setup {
|
|
tb,
|
|
tb,
|
|
tb,
|
|
layout = wibox.layout.fixed.horizontal,
|
|
}
|
|
|
|
|
|
|
|
### Accessing widgets
|
|
|
|
For each widget or container, it is possible to add an `identifier` attribute
|
|
so the widget can be accessed later.
|
|
|
|
Widgets defined using `setup` can be access by 3 means:
|
|
|
|
* Avoid the issue by using externally created widgets
|
|
* Use `my_wibox.my_first_widget.my_second_widget` style access
|
|
* Use JavaScript like `my_wibox:get_children_by_id("my_second_widget")[1]`
|
|
|
|
The first method mixes the imperative and declarative syntax, but makes the code
|
|
less readable. The second is a little verbose and only works if every node in
|
|
the chain have a valid identifier. The last one doesn't require long paths,
|
|
but it is not easy to get a specific instance if multiple widgets have the
|
|
same identifier.
|
|
|
|
WARNING: The widget identifier must not use reseved name. This include all
|
|
method names, existing widget attributes, `layout` and `widget`. Names should
|
|
also respect the lua variable name policies (case sensitive, alphanumeric and
|
|
underscore characters and non-numeric first character)
|
|
|
|
Code:
|
|
|
|
s.mywibox : setup {
|
|
{
|
|
id = "second",
|
|
widget = wibox.widget.textbox
|
|
},
|
|
{
|
|
id = "third",
|
|
widget = wibox.widget.textbox
|
|
},
|
|
id = "first",
|
|
layout = wibox.layout.fixed.horizontal,
|
|
}
|
|
|
|
s.mywibox.first.second:set_markup("changed!")
|
|
s.mywibox:get_children_by_id("third")[1]:set_markup("Also changed!")
|
|
|
|
|
|
|
|
### Extending the system
|
|
|
|
This system is very flexible. Each section attribute (the entries with string
|
|
keys) is directly linked to the layout or widget API. When setting the
|
|
imaginary `myproperty`, it will first check if `set_myproperty` exist. If it
|
|
doesn't, it will check if there is a `myproperty` method. Finally, it will
|
|
just set the `mywidget.myproperty` directly in case it is used later or
|
|
catched by a lua `metatable` (operator overload).
|
|
|
|
Code:
|
|
|
|
-- "Monkeypatch" a new function to wibox.widget.textbox to add vicious
|
|
-- extension support
|
|
function wibox.widget.textbox:vicious(args)
|
|
local f = unpack or table.unpack -- Lua 5.1 compat
|
|
vicious.register(w, f(args))
|
|
end
|
|
|
|
s.mywibox : setup {
|
|
{
|
|
vicious = {vicious.widgets.cpu, "CPU: $1%", 3},
|
|
widget = wibox.widget.textbox
|
|
},
|
|
layout = wibox.layout.fixed.horizontal,
|
|
}
|
|
|
|
|
|
In this example, the system is extended to that the popular
|
|
[Vicious](http://awesome.naquadah.org/wiki/Vicious) extension module can be
|
|
used directly in the layout declaration. This example will update the textbox
|
|
every 3 seconds to show the CPU usage.
|
|
|
|
|
|
### Handling sections
|
|
|
|
The system allows sections to be defined externally, then composed into
|
|
the final layout declaration. Here is an example re-using one of the above
|
|
example:
|
|
|
|
Code:
|
|
|
|
local circle = {
|
|
fit = function(self, context, width, height)
|
|
return height, height -- A square taking the full height
|
|
end,
|
|
draw = function(self, context, cr, width, height)
|
|
cr:set_source_rgb(1, 0, 0) -- Red
|
|
cr:arc(height/2, height/2, height/2, 0, math.pi*2)
|
|
cr:fill()
|
|
end,
|
|
layout = wibox.widget.base.make_widget,
|
|
}
|
|
|
|
-- Define a layout with the imperative syntax
|
|
local l = wibox.widget.align()
|
|
|
|
-- 3 circle
|
|
s.mywibox : setup {
|
|
circle,
|
|
circle,
|
|
circle,
|
|
l,
|
|
layout = wibox.layout.align.horizontal
|
|
}
|
|
|
|
-- This can be done instead
|
|
local three_circle = {layout = wibox.layout.align.horizontal}
|
|
for i=1, 3 do
|
|
table.insert(three_circle, circle)
|
|
end
|
|
|
|
s.mywibox : setup (three_circle)
|
|
|