awful.client.shape: Import client shape handling (FS#1051)

This new awful module reacts to shapes that a client sets on itself and sets the
shape of awesome's frame window to match. This way, xeyes really gets
transparent parts again.

Signed-off-by: Uli Schlachter <psychon@znc.in>

lib/awful/client.lua.in

@@ -43,6 +43,7 @@ client.swap = {}
 client.floating = {}
 client.dockable = {}
 client.property = {}
+client.shape = require("awful.client.shape")
 
 ---
 -- Jump to the given client.  Takes care of focussing the screen, the right tag,

lib/awful/client/shape.lua.in

@@ -0,0 +1,89 @@
+---------------------------------------------------------------------------
+-- @author Uli Schlachter <psychon@znc.in>
+-- @copyright 2014 Uli Schlachter
+-- @release @AWESOME_VERSION@
+---------------------------------------------------------------------------
+
+-- Grab environment we need
+local surface = require("gears.surface")
+local cairo = require("lgi").cairo
+local capi =
+{
+    client = client,
+}
+
+--- Handle client shapes.
+-- awful.client.shape
+local shape = {}
+shape.update = {}
+
+--- Get one of a client's shapes and transform it to include window decorations
+-- @param c The client whose shape should be retrieved
+-- @param shape Either "bounding" or "clip"
+function shape.get_transformed(c, shape)
+    local border = shape == "bounding" and c.border_width or 0
+    local shape = surface(c["client_shape_" .. shape])
+    if not shape then return end
+
+    -- Get information about various sizes on the client
+    local geom = c:geometry()
+    local _, t = c:titlebar_top()
+    local _, b = c:titlebar_bottom()
+    local _, l = c:titlebar_left()
+    local _, r = c:titlebar_right()
+
+    -- Figure out the size of the shape that we need
+    local img_width = geom.width + 2*border
+    local img_height = geom.height + 2*border
+    local result = cairo.ImageSurface(cairo.Format.A1, img_width, img_height)
+    local cr = cairo.Context(result)
+
+    -- Fill everything (this paints the titlebars and border)
+    cr:paint()
+
+    -- Draw the client's shape in the middle
+    cr:set_operator(cairo.Operator.SOURCE)
+    cr:set_source_surface(shape, border + l, border + t)
+    cr:rectangle(border + l, border + t, geom.width - l - r, geom.height - t - b)
+    cr:fill()
+
+    return result
+end
+
+--- Update a client's bounding shape from the shape the client set itself
+-- @param c The client to act on
+function shape.update.bounding(c)
+    local res = shape.get_transformed(c, "bounding")
+    c.shape_bounding = res and res._native
+    -- Free memory
+    if res then
+        res:finish()
+    end
+end
+
+--- Update a client's clip shape from the shape the client set itself
+-- @param c The client to act on
+function shape.update.clip(c)
+    local res = shape.get_transformed(c, "clip")
+    c.shape_clip = res and res._native
+    -- Free memory
+    if res then
+        res:finish()
+    end
+end
+
+--- Update all of a client's shapes from the shapes the client set itself
+-- @param c The client to act on
+function shape.update.all(c)
+    shape.update.bounding(c)
+    shape.update.clip(c)
+end
+
+capi.client.connect_signal("property::shape_client_bounding", shape.update.bounding)
+capi.client.connect_signal("property::shape_client_clip", shape.update.clip)
+capi.client.connect_signal("property::width", shape.update.all)
+capi.client.connect_signal("property::height", shape.update.all)
+
+return shape
+
+-- vim: filetype=lua:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:textwidth=80