revelation: import

Signed-off-by: Julien Danjou <julien@danjou.info>

lib/revelation.lua.in

@@ -0,0 +1,134 @@
+---------------------------------------------------------------------------
+-- @author Espen Wiborg <espenhw@grumblesmurf.org>
+-- @author Julien Danjou <julien@danjou.info>
+-- @copyright 2008 Espen Wiborg, Julien Danjou
+-- @release @AWESOME_VERSION@
+---------------------------------------------------------------------------
+
+local math = math
+local table = table
+local pairs = pairs
+local button = button
+local otable = otable
+local awful =
+{
+    tag = require("awful.tag"),
+    client = require("awful.client")
+}
+local capi =
+{
+    tag = tag,
+    client = client,
+    keygrabber = keygrabber,
+    mouse = mouse
+}
+
+--- Exposé implementation
+module("revelation")
+
+-- Layout functions
+layout = {}
+
+--- The default layout function for revelation
+-- Tries to arrange clients in an approximated square grid, by
+-- calculating c = floor(sqrt(n)) and arranging for c columns in a
+-- tile layout.
+-- @param t The tag to do revelation on.
+-- @param n The number of clients to reveal.
+function layout.default (t, n)
+    t.layout = "tile"
+    local columns = math.floor(math.sqrt(n))
+
+    if columns > 1 then
+        t.mwfact = 1 / columns
+        t.ncol = columns - 1
+    end
+    t.nmaster = n / columns
+end
+
+function clients(class, s)
+    local clients
+    if class then
+        clients = {}
+        for k, c in pairs(capi.client.get(s)) do
+            if c.class == class then
+                table.insert(clients, c)
+            end
+        end
+   else
+        clients = capi.client.get(s)
+   end
+   return clients
+end
+
+function selectfn(restore)
+    return function(c)
+               restore()
+               -- Pop to client tag
+               awful.tag.viewonly(c:tags()[1])
+               -- Focus and raise
+               capi.client.focus = c
+               c:raise()
+           end
+end
+
+--- Returns keyboardhandler.
+-- Arrow keys move focus, Return selects, Escape cancels.
+-- Ignores modifiers.
+function keyboardhandler (restore)
+    return function (mod, key)
+                if key == "Escape" then
+                    restore()
+                    awful.tag.history.restore()
+                    return false
+                elseif key == "Return" then
+                    selectfn(restore)(capi.client.focus)
+                    return false
+                end
+                return true
+           end
+end
+
+--- Implement Exposé (from Mac OS X).
+-- @param class The class of clients to expose, or nil for all clients.
+-- @param fn A binary function f(t, n) to set the layout for tag t for n clients, or nil for the default layout.
+-- @param s The screen to consider clients of, or nil for "current screen".
+function revelation(class, fn, s)
+    local screen = s or capi.mouse.screen
+    local layout_fn = fn or layout.default
+    local data = otable()
+
+    local clients = clients(class, screen)
+    if #clients == 0 then
+        return
+    end
+
+    local tag = capi.tag({ name = "Revelation" })
+    tag.screen = screen
+
+    layout_fn(tag, #clients)
+
+    local function restore()
+        for k, cl in pairs(tag:clients()) do
+            -- Clear revelation tag
+            local tags = cl:tags()
+            if tags[tag] then
+                tags[tags[tag]] = nil
+            end
+            cl:tags(tags)
+            -- Restore client mouse bindings
+            cl:buttons(data[cl])
+            data[cl] = nil
+        end
+        tag.screen = nil
+        capi.keygrabber.stop()
+    end
+
+    for k, c in pairs(clients) do
+        data[c] = c:buttons()
+        c:buttons({ button({}, 1, selectfn(restore)) })
+    end
+    tag:clients(clients)
+    awful.tag.viewonly(tag)
+    capi.keygrabber.run(keyboardhandler(restore))
+end