awful.widget.graph: don't draw bg color over fg color

behavior before: draw fg color everywhere and draw each value inverted as bg color.
if not enough values available "remove" the free area (draw a big rectangle with bg color over it).

behavior now: draw each value onto background as fg stroke.

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

lib/awful/widget/graph.lua.in

@@ -77,6 +77,13 @@ function draw(graph, wibox, cr, width, height)
 
     cr:set_line_width(1)
 
+    -- Draw the background first
+    cr:rectangle(border_width, border_width,
+                 width - (2 * border_width),
+                 height)
+    cr:set_source(color(data[graph].background_color or "#000000aa"))
+    cr:fill()
+
     -- Draw a stacked graph
     if data[graph].stack then
 
@@ -90,23 +97,15 @@ function draw(graph, wibox, cr, width, height)
             end
         end
 
-        -- Draw the background first
-        cr:rectangle(border_width, border_width,
-                     width - (2 * border_width),
-                     height)
-        cr:set_source(color(data[graph].background_color or "#000000aa"))
-        cr:fill()
-
         for i = 0, width - (2 * border_width) do
             local rel_i = 0
-            local rel_x = width - border_width - i - 0.5
+            local rel_x = border_width + i
 
             if data[graph].stack_colors then
                 for idx, col in ipairs(data[graph].stack_colors) do
                     local stack_values = values[idx]
                     if stack_values and i < #stack_values then
                         local value = stack_values[#stack_values - i] + rel_i
-
                         cr:move_to(rel_x, border_width - 0.5 +
                                           (height - 2 * border_width) * (1 - (rel_i / max_value)))
                         cr:line_to(rel_x, border_width - 0.5 +
@@ -127,12 +126,6 @@ function draw(graph, wibox, cr, width, height)
             end
         end
 
-        cr:rectangle(border_width, border_width,
-                     width - (2 * border_width),
-                     height - (2 * border_width))
-        cr:set_source(color(data[graph].color or "#ff0000"))
-        cr:fill()
-
         -- Draw the background on no value
         if #values ~= 0 then
             -- Draw reverse
@@ -140,26 +133,16 @@ function draw(graph, wibox, cr, width, height)
                 local value = values[#values - i]
                 if value >= 0 then
                     value = value / max_value
-                    cr:move_to(width - border_width - i - 0.5,
+                    cr:move_to(border_width + i - 0.5, border_width - 0.5 +
-                               border_width - 0.5 +
                                   (height - 2 * border_width) * (1 - value))
-                    cr:line_to(width - border_width - i - 0.5,
+                    cr:line_to(border_width + i - 0.5, border_width +
-                               border_width - 1)
+                                  (height - 2 * border_width))
                 end
             end
-            cr:set_source(color(data[graph].background_color or "#000000aa"))
+            cr:set_source(color(data[graph].color or "#ff0000"))
             cr:stroke()
         end
 
-        -- If we didn't draw values in full length, draw a square
-        -- over the last, left, part to reset everything to 0
-        if #values < width - (2 * border_width) then
-            cr:rectangle(border_width, border_width,
-                         width - (2 * border_width) - #values,
-                         height - (2 * border_width))
-            cr:set_source(color(data[graph].background_color or "#000000aa"))
-            cr:fill()
-        end
     end
 
     -- Draw the border last so that it overlaps already drawn values