beautiful: Track the font for oopango

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

lib/beautiful.lua.in

@@ -17,7 +17,9 @@ local util = require("awful.util")
 local capi =
 {
     screen = screen,
-    awesome = awesome
+    awesome = awesome,
+    oocairo = oocairo,
+    oopango = oopango
 }
 
 --- Theme library.
@@ -25,6 +27,29 @@ module("beautiful")
 
 -- Local data
 local theme
+local font
+local font_height
+
+function get_font()
+    return font
+end
+
+function get_font_height()
+    return font_height
+end
+
+local function set_font(f)
+    font = capi.oopango.font_description_from_string(f)
+
+    -- Create a temporary surface that we need for computing the size :(
+    local surface = capi.oocairo.image_surface_create("argb32", 1, 1)
+    local cr = capi.oocairo.context_create(surface)
+    local layout = capi.oopango.cairo.layout_create(cr)
+    layout:set_font_description(font)
+
+    local width, height = layout:get_pixel_size()
+    font_height = height
+end
 
 --- Init function, should be runned at the beginning of configuration file.
 -- @param path The theme file path.
@@ -51,7 +76,7 @@ function init(path)
                     util.spawn(theme.wallpaper_cmd[util.cycle(#theme.wallpaper_cmd, s)], false, s)
                 end
             end
-            if theme.font then capi.awesome.font = theme.font end
+            if theme.font then set_font(theme.font) end
             if theme.fg_normal then capi.awesome.fg = theme.fg_normal end
             if theme.bg_normal then capi.awesome.bg = theme.bg_normal end
         else
@@ -68,6 +93,9 @@ function get()
     return theme
 end
 
+-- Set the default font
+set_font("sans 8")
+
 setmetatable(_M, { __index = function(t, k) return theme[k] end })
 
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