Added Container widget.

examples/containers.lua

@@ -0,0 +1,101 @@
+--- Conky config script
+
+-- Conky does not add our config directory to lua's PATH, so we do it manually
+local script_dir = debug.getinfo(1, 'S').source:match("^@(.*/)") or "./"
+package.path = script_dir .. "../?.lua;" .. package.path
+
+local util = require('src/util')
+local data = require('src/data')
+local widget = require('src/widget')
+local polycore = require('src/polycore')
+
+local width = 200
+local height = 400
+
+local dark_box_bg = {0.70, 0.70, 0.70, 1}
+local light_box_bg = {0.83, 0.83, 0.83, 1}
+local black = {0, 0, 0, 1}
+local blackish = {0.2, 0.2, 0.2, 1}
+local dark_grey = {0.5, 0.5, 0.5, 1}
+local white = {1, 1, 1, 1}
+local yellow = {1, 1, 0, 1}
+
+local dark_box = {white, dark_box_bg}
+local light_box = {dark_grey, light_box_bg}
+
+local BoxStat = util.class(widget.Frame)
+
+function BoxStat:init(box_color, title, stat)
+    local title_color = box_color[1]
+    local title_w = widget.StaticText(title, {font_size=32, font_weight=CAIRO_FONT_WEIGHT_BOLD, color=title_color})
+
+    local stat_widget = widget.TextLine{align="right", font_size=30, color=blackish, margin={0, 0, 8, 0}}
+    function stat_widget:update()
+        self:set_text(data.conky_loader:get(stat))
+    end
+
+    local grp = {title_w, widget.Filler{height=12}, stat_widget}
+    widget.Frame.init(self, widget.Rows(grp), {padding={10,12,18,6}, background_color=box_color[2]})
+end
+
+--- Called once on startup to initialize widgets.
+-- @treturn widget.Renderer
+function polycore.setup()
+
+    local rambox = BoxStat(dark_box, "RAM", "$mem")
+    local swapbox = BoxStat(light_box, "Swap", "$swap")
+
+    -- Alternate between showing RAM usage and Swap usage
+    local memory_container = widget.Container(rambox)
+    function memory_container:update(count)
+        if (count % 8) < 4 then
+            self:set_content(rambox)
+        else
+            self:set_content(swapbox)
+        end
+        return widget.Container.update(self, count)
+    end
+
+    local warn_text = widget.StaticText("CPU load\nis high!!", {align="center", font_size=26, font_weight=CAIRO_FONT_WEIGHT_BOLD, color=black})
+    local warn_frame = widget.Frame(widget.Rows{warn_text}, {})
+
+    -- Show a message if the load average is over 4.
+    -- Otherwise, hide it.
+    local cpu_container = widget.Container(warn_frame, {})
+    function cpu_container:update()
+        if tonumber(data.conky_loader:get("${loadavg 1}")) < 4 then
+            self:set_content(nil)
+        else
+            self:set_content(warn_frame)
+        end
+        return widget.Container.update(self, count)
+    end
+
+    local loadavg = BoxStat(dark_box, "CPU Load", "${loadavg 1}")
+
+    local root = widget.Rows({memory_container, cpu_container, loadavg})
+    return widget.Renderer{root=root, width=width, height=height}
+end
+
+local conkyrc = conky or {}
+conkyrc.config = {
+    lua_load = script_dir .. "containers.lua",
+    lua_startup_hook = "conky_setup",
+    lua_draw_hook_pre = "conky_paint_background",
+    lua_draw_hook_post = "conky_update",
+    alignment = "middle_right",
+    background = false,
+    double_buffer = true,
+    use_xft = false,
+    gap_x = -6,
+    gap_y = -40,
+    maximum_width = width,
+    minimum_height = height,
+    minimum_width = width,
+    own_window = true,
+    own_window_class = 'Conky',
+    own_window_type = 'panel',
+    own_window_transparent = true,
+    times_in_seconds = true,
+}
+conkyrc.text = ""

src/widget.lua

@@ -446,6 +446,69 @@ function Frame:render_background(cr)
     end
 end
 
+--- A container that holds a widget, but can have that widget dynamically changed.
+-- @type Container
+local Container = util.class(Widget)
+w.Container = Container
+
+--- @tparam Widget content Initial widget to be wrapped, or nil for no widget
+function Container:init(content)
+    self:set_content(content, true)
+end
+
+--- @tparam Widget content New widget to be wrapped, or nil for no widget
+-- @tparam boolean init Should only be set to true when initialising
+function Container:set_content(content, init)
+    if not (init or self._content ~= content) then
+        return
+    end
+
+    self._content = content
+    self.height = 0
+    self.width = 0
+
+    self._switched = not init
+
+    if content and content.height then
+        self.height = content.height
+    end
+    if content and content.width then
+        self.width = content.width
+    end
+end
+
+function Container:layout(width, height)
+    if self._content and self._content.layout then
+        local children = self._content:layout(width, height)
+        table.insert(children, 1, {self, 0, 0, width, height})
+        return children
+    end
+    return {{self, 0, 0, width, height}}
+end
+
+function Container:render(cr)
+    if self._content and self._content.render then
+        return self._content:render(cr)
+    end
+end
+
+function Container:render_background(cr)
+    if self._content and self._content.render_background then
+        return self._content:render_background(cr)
+    end
+end
+
+function Container:update()
+    local updated = false
+    if self._content and self._content.update then
+        updated = self._content:update()
+    end
+
+    local switched = self._switched
+    self._switched = false
+    return switched or updated
+end
+
 --- Common (abstract) base class for `StaticText` and `TextLine`.
 -- @type Text
 local Text = util.class(Widget)