gears.wallpaper: Import

This is a lua module for managing the wallpaper.

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

lib/gears/init.lua.in

@@ -13,6 +13,7 @@ return
     object = require("gears.object");
     sort = require("gears.sort");
     surface = require("gears.surface");
+    wallpaper = require("gears.wallpaper");
 }
 
 -- vim: filetype=lua:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:textwidth=80

lib/gears/wallpaper.lua.in

@@ -0,0 +1,160 @@
+---------------------------------------------------------------------------
+-- @author Uli Schlachter
+-- @copyright 2012 Uli Schlachter
+-- @release @AWESOME_VERSION@
+---------------------------------------------------------------------------
+
+local cairo = require("lgi").cairo
+local color = require("gears.color")
+local surface = require("gears.surface")
+
+-- gears.wallpaper
+local wallpaper = { mt = {} }
+
+-- The size of the root window
+local root_geom
+do
+    local geom = screen[1].geometry
+    root_geom = {
+        x = 0, y = 0,
+        width = geom.x + geom.width,
+        height = geom.y + geom.height
+    }
+    for s = 1, screen.count() do
+        local g = screen[s].geometry
+        root_geom.width = math.max(root_geom.width, g.x + g.width)
+        root_geom.height = math.max(root_geom.height, g.y + g.height)
+    end
+end
+
+--- Prepare the needed state for setting a wallpaper
+-- @param s The screen to set the wallpaper on or nil for all screens
+-- @return The available geometry (table with entries width and height), a
+--         that should be used for setting the wallpaper and a cairo context
+--         for drawing to this surface
+local function prepare_wallpaper(s)
+    local geom = s and screen[s].geometry or root_geom
+    local img = surface(root.wallpaper())
+
+    if not img then
+        -- No wallpaper yet
+        img = cairo.ImageSurface(cairo.Format.RGB24, root_geom.width, root_geom.height)
+    end
+
+    local cr = cairo.Context(img)
+
+    -- Only draw to the selected area
+    cr:translate(geom.x, geom.y)
+    cr:rectangle(0, 0, geom.width, geom.height)
+    cr:clip()
+
+    return geom, img, cr
+end
+
+--- Get the size of a cairo surface
+-- @param surf The surface you are interested in
+-- @returns The surface's width and height
+local function surface_size(surf)
+    local cr = cairo.Context(surf)
+    local x, y, w, h = cr:clip_extents()
+    return w, h
+end
+
+--- Set the current wallpaper.
+-- @param pattern The wallpaper that should be set. This can be a cairo surface,
+--                a description for gears.color or a cairo pattern.
+function wallpaper.set(pattern)
+    if cairo.Surface:is_type_of(pattern) then
+        pattern = cairo.Pattern.create_for_surface(pattern)
+    end
+    if type(pattern) == "string" or type(pattern) == "table" then
+        pattern = color(pattern)
+    end
+    if not cairo.Pattern:is_type_of(pattern) then
+        error("wallpaper.set() called with an invalid argument")
+    end
+    root.wallpaper(pattern._native)
+end
+
+--- Set a centered wallpaper.
+-- @param surf The wallpaper to center. Either a cairo surface or a file name.
+-- @param s The screen whose wallpaper should be set. Can be nil, in which case
+--          all screens are set.
+-- @param background The background color that should be used. Gets handled via
+--                   gears.color. The default is black.
+function wallpaper.centered(surf, s, background)
+    local geom, img, cr = prepare_wallpaper(s)
+    local surf = surface(surf)
+    local background = color(background)
+
+    -- Fill the area with the background
+    cr.operator = cairo.Operator.SOURCE
+    cr.source = background
+    cr:paint()
+
+    -- Now center the surface
+    local w, h = surface_size(surf)
+    cr:translate((geom.width - w) / 2, (geom.height - h) / 2)
+    cr:rectangle(0, 0, w, h)
+    cr:clip()
+    cr:set_source_surface(surf, 0, 0)
+    cr:paint()
+
+    wallpaper.set(img)
+end
+
+--- Set a tiled wallpaper.
+-- @param surf The wallpaper to tile. Either a cairo surface or a file name.
+-- @param s The screen whose wallpaper should be set. Can be nil, in which case
+--          all screens are set.
+-- @param offset This can be set to a table with entries x and y.
+function wallpaper.tiled(surf, s, offset)
+    local geom, img, cr = prepare_wallpaper(s)
+
+    if offset then
+        cr:translate(offset.x, offset.y)
+    end
+
+    local pattern = cairo.Pattern.create_for_surface(surface(surf))
+    pattern.extend = cairo.Extend.REPEAT
+    cr.source = pattern
+    cr.operator = cairo.Operator.SOURCE
+    cr:paint()
+
+    wallpaper.set(img)
+end
+
+--- Set a maximized wallpaper.
+-- @param surf The wallpaper to set. Either a cairo surface or a file name.
+-- @param s The screen whose wallpaper should be set. Can be nil, in which case
+--          all screens are set.
+-- @param ignore_aspect If this is true, the image's aspect ratio is ignored.
+--                      The default is to honor the aspect ratio.
+-- @param offset This can be set to a table with entries x and y.
+function wallpaper.maximized(surf, s, ignore_aspect, offset)
+    local geom, img, cr = prepare_wallpaper(s)
+    local surf = surface(surf)
+    local w, h = surface_size(surf)
+    local aspect_w = geom.width / w
+    local aspect_h = geom.height / h
+
+    if not ignore_aspect then
+        aspect_h = math.max(aspect_w, aspect_h)
+        aspect_w = math.max(aspect_w, aspect_h)
+    end
+    cr:scale(aspect_w, aspect_h)
+
+    if offset then
+        cr:translate(offset.x, offset.y)
+    end
+
+    cr:set_source_surface(surf, 0, 0)
+    cr.operator = cairo.Operator.SOURCE
+    cr:paint()
+
+    wallpaper.set(img)
+end
+
+return wallpaper
+
+-- vim: filetype=lua:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:textwidth=80