wibox: Support screen objects

This commit documents that a textbox already accepts a screen object where a
screen index is expected. Also, this changes the widget API in that a widget's
context.screen is now a screen object instead of a screen index.

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

lib/wibox/drawable.lua

@@ -10,7 +10,8 @@
 local drawable = {}
 local capi = {
     awesome = awesome,
-    root = root
+    root = root,
+    screen = screen
 }
 local beautiful = require("beautiful")
 local cairo = require("lgi").cairo
@@ -32,10 +33,10 @@ local function screen_getbycoord(x, y)
         local geometry = screen[i].geometry
         if x >= geometry.x and x < geometry.x + geometry.width
            and y >= geometry.y and y < geometry.y + geometry.height then
-            return i
+            return capi.screen[i]
         end
     end
-    return 1
+    return capi.screen[1]
 end
 
 -- Get the widget context. This should always return the same table (if

lib/wibox/widget/textbox.lua

@@ -66,7 +66,7 @@ end
 --- Get the preferred size of a textbox.
 -- This returns the size that the textbox would use if infinite space were
 -- available.
--- @tparam integer s The screen number on which the textbox will be displayed.
+-- @tparam integer|screen s The screen on which the textbox will be displayed.
 -- @treturn number The preferred width.
 -- @treturn number The preferred height.
 function textbox:get_preferred_size(s)
@@ -77,7 +77,7 @@ end
 -- This returns the height that the textbox would use when it is limited to the
 -- given width.
 -- @tparam number width The available width.
--- @tparam integer s The screen number on which the textbox will be displayed.
+-- @tparam integer|screen s The screen on which the textbox will be displayed.
 -- @treturn number The needed height.
 function textbox:get_height_for_width(width, s)
     return self:get_height_for_width_at_dpi(width, beautiful.xresources.get_dpi(s))