progressbar: Add shape support

The current progressbar code dates from a time when Awesome had
a very limited drawing API. This commit first re-write the
algorithm to remove the workaround used to draw the border using
full rectangles only. It then add support for outer and inner
shapes with their respective border settings.

This commit also add clip support. This is enabled by default, but
could be disabled to have the bar taller than the background.

lib/wibox/widget/progressbar.lua

@@ -19,6 +19,7 @@ local util =  require("awful.util")
 local base = require("wibox.widget.base")
 local color = require("gears.color")
 local beautiful = require("beautiful")
+local shape = require("gears.shape")
 
 local progressbar = { mt = {} }
 
@@ -28,6 +29,18 @@ local progressbar = { mt = {} }
 -- @property border_color
 -- @tparam gears.color color The border color to set.
 
+--- The progressbar border width.
+-- @property border_width
+
+--- The progressbar inner border color.
+-- If the value is nil, no border will be drawn.
+--
+-- @property bar_border_color
+-- @tparam gears.color color The border color to set.
+
+--- The progressbar inner border width.
+-- @property bar_border_width
+
 --- The progressbar foreground color.
 --
 -- @property color
@@ -38,11 +51,26 @@ local progressbar = { mt = {} }
 -- @property background_color
 -- @tparam gears.color color The progressbar background color.
 
+--- The progressbar inner shape.
+-- @property bar_shape
+-- @tparam[opt=gears.shape.rectangle] gears.shape shape
+-- @see gears.shape
+
+--- The progressbar shape.
+-- @property shape
+-- @tparam[opt=gears.shape.rectangle] gears.shape shape
+-- @see gears.shape
+
 --- Set the progressbar to draw vertically.
 -- This doesn't do anything anymore, use a `wibox.container.rotate` widget.
 -- @deprecated set_vertical
 -- @tparam boolean vertical
 
+--- Force the inner part (the bar) to fit in the background shape.
+--
+-- @property clip
+-- @tparam[opt=true] boolean clip
+
 --- The progressbar to draw ticks. Default is false.
 --
 -- @property ticks
@@ -69,12 +97,32 @@ local progressbar = { mt = {} }
 --- The progressbar foreground color.
 -- @beautiful beautiful.progressbar_fg
 
+--- The progressbar shape.
+-- @beautiful beautiful.progressbar_shape
+-- @see gears.shape
+
 --- The progressbar border color.
 -- @beautiful beautiful.progressbar_border_color
 
-local properties = { "border_color", "color"    , "background_color",
-                     "value"       , "max_value", "ticks",
-                     "ticks_gap"   , "ticks_size" }
+--- The progressbar outer border width.
+-- @beautiful beautiful.progressbar_border_width
+
+--- The progressbar inner shape.
+-- @beautiful beautiful.progressbar_bar_shape
+-- @see gears.shape
+
+--- The progressbar bar border width.
+-- @beautiful beautiful.progressbar_bar_border_width
+
+--- The progressbar bar border color.
+-- @beautiful beautiful.progressbar_bar_border_color
+
+local properties = { "border_color", "color"     , "background_color",
+                     "value"       , "max_value" , "ticks",
+                     "ticks_gap"   , "ticks_size", "border_width",
+                     "shape"       , "bar_shape" , "bar_border_width",
+                     "clip"        , "bar_border_color"
+                   }
 
 function progressbar.draw(pbar, _, cr, width, height)
     local ticks_gap = pbar._private.ticks_gap or 1
@@ -93,32 +141,92 @@ function progressbar.draw(pbar, _, cr, width, height)
 
     local over_drawn_width = width
     local over_drawn_height = height
-    local border_width = 0
-    local col = pbar._private.border_color or beautiful.progressbar_border_color
-    if col then
-        -- Draw border
-        cr:rectangle(0.5, 0.5, width - 1, height - 1)
-        cr:set_source(color(col))
-        cr:stroke()
+    local border_width = pbar._private.border_width
+        or beautiful.progressbar_border_width or 0
 
-        over_drawn_width = width - 2 -- remove 2 for borders
-        over_drawn_height = height - 2 -- remove 2 for borders
-        border_width = 1
+    local bcol = pbar._private.border_color or beautiful.progressbar_border_color
+
+    border_width = bcol and border_width or 0
+
+    local bg = pbar._private.background_color or
+        beautiful.progressbar_bg or "#ff0000aa"
+
+    local bg_width, bg_height = width, height
+
+    -- Draw the background shape
+    if border_width > 0 then
+        -- Cairo draw half of the border outside of the path area
+        cr:translate(border_width/2, border_width/2)
+        bg_width, bg_height = bg_width - border_width, bg_height - border_width
+        cr:set_line_width(border_width)
     end
 
-    cr:rectangle(border_width, border_width,
-                 over_drawn_width, over_drawn_height)
-    cr:set_source(color(pbar._private.color or beautiful.progressbar_fg or "#ff0000"))
-    cr:fill()
+    local background_shape = pbar._private.shape or
+        beautiful.progressbar_shape or shape.rectangle
+
+    background_shape(cr, bg_width, bg_height)
+
+    cr:set_source(color(bg))
+
+    if border_width > 0 then
+        cr:fill_preserve()
+
+        -- Draw the border
+        cr:set_source(color(bcol))
+
+        cr:stroke()
+
+        over_drawn_width  = width  - 2*border_width
+        over_drawn_height = height - 2*border_width
+    else
+        cr:fill()
+    end
+
+    -- Undo the translation
+    if border_width > 0 then
+        cr:translate(-border_width/2, -border_width/2)
+    end
 
-    -- Cover the part that is not set with a rectangle
     local rel_x = over_drawn_width * value
-    cr:rectangle(border_width + rel_x,
-                    border_width,
-                    over_drawn_width - rel_x,
-                    over_drawn_height)
-    cr:set_source(color(pbar._private.background_color or "#000000aa"))
-    cr:fill()
+
+    cr:translate(border_width, border_width)
+
+    -- Make sure the bar stay in the shape
+    if pbar._private.clip ~= false and beautiful.progressbar_clip ~= false then
+        background_shape(cr, over_drawn_width, over_drawn_height)
+        cr:clip()
+    end
+
+    -- Draw the progressbar shape
+
+    local bar_shape = pbar._private.bar_shape or
+        beautiful.progressbar_bar_shape or shape.rectangle
+
+    local bar_border_width = pbar._private.bar_border_width or
+        beautiful.progressbar_bar_border_width or pbar._private.border_width or
+        beautiful.progressbar_border_width or 0
+
+    local bar_border_color = pbar._private.bar_border_color or
+        beautiful.progressbar_bar_border_color
+
+    bar_border_width = bar_border_color and bar_border_width or 0
+
+    over_drawn_width  = over_drawn_width  - bar_border_width
+    over_drawn_height = over_drawn_height - bar_border_width
+    cr:translate(bar_border_width/2, bar_border_width/2)
+
+    bar_shape(cr, rel_x, over_drawn_height)
+
+    cr:set_source(color(pbar._private.color or beautiful.progressbar_fg or "#ff0000"))
+
+    if bar_border_width > 0 then
+        cr:fill_preserve()
+        cr:set_source(color(bar_border_color))
+        cr:set_line_width(bar_border_width)
+        cr:stroke()
+    else
+        cr:fill()
+    end
 
     if pbar._private.ticks then
         for i=0, width / (ticks_size+ticks_gap)-border_width do