Add the most useless widget of them all, the PieChart

widgets/init.lua

@@ -5,4 +5,5 @@ return {
     fkey     = require( "radical.widgets.fkey"     ),
     table    = require( "radical.widgets.table"    ),
     header   = require( "radical.widgets.header"   ),
+    piechart = require( "radical.widgets.piechart" ),
 }

widgets/piechart.lua

@@ -0,0 +1,66 @@
+local setmetatable = setmetatable
+local math,pairs   = math,pairs
+local color        = require( "gears.color" )
+local cairo        = require( "lgi"         ).cairo
+local wibox        = require( "wibox"       )
+local beautiful    = require( "beautiful"   )
+
+local module,colors = {},nil
+
+local function draw_label(cr,angle,radius,center_x,center_y,text)
+  cr:set_source_rgba(1,1,1,1)
+  cr:move_to(center_x+(radius/2)*math.cos(angle),center_y+(radius/2)*math.sin(angle))
+  cr:line_to(center_x+(1.5*radius)*math.cos(angle),center_y+(1.5*radius)*math.sin(angle))
+  local x,y = cr:get_current_point()
+  cr:line_to(x+(x>center_x and radius/2 or -radius/2),y)
+  cr:move_to(x+(x>center_x and radius/2 + 5 or (-radius/2 - cr:text_extents(text).width - 5)),y+(cr:font_extents().height/4))
+  cr:show_text(text)
+  cr:stroke()
+  cr:arc(center_x+(radius/2)*math.cos(angle),center_y+(radius/2)*math.sin(angle),2,0,2*math.pi)
+  cr:arc(x+(x>center_x and radius/2 or -radius/2),y,2,0,2*math.pi)
+  cr:fill()
+end
+
+local function draw_pie(cr,start_rad,end_rad,radius,col,center_x,center_y)
+  cr:arc(center_x,center_y,radius,start_rad,end_rad)
+  cr:line_to(center_x,center_y)
+  cr:line_to(center_x+radius*math.cos(start_rad),center_y+radius*math.sin(start_rad))
+  cr:close_path()
+  cr:set_source_rgba(1,1,1,1)
+  cr:stroke_preserve()
+  cr:set_source(col)
+  cr:fill()
+end
+
+local function compute_sum(data)
+  local ret = 0
+  for k,v in pairs(data) do ret = ret + v end
+  return ret
+end
+
+local function draw(self, w, cr, width, height)
+  if not self._data then return end
+  local radius = (height > width and width or height) / 4
+  local sum,start,count = compute_sum(self._data),0,0
+  for k,v in pairs(self._data) do
+    local end_angle = start + 2*math.pi*(v/sum)
+    draw_pie(cr,start,end_angle,radius,colors[math.mod(count,4)+1],width/2,height/2)
+    draw_label(cr,start+(end_angle-start)/2,radius,width/2,height/2,k)
+    start,count = end_angle,count+1
+  end
+end
+
+local function set_data(self,data)
+  self._data = data
+  self:emit_signal("widget::changed")
+end
+
+local function new(data)
+  if not colors then colors = {color(beautiful.fg_normal),color(beautiful.bg_alternate),color(beautiful.fg_focus),color(beautiful.bg_highlight)} end
+  local im = wibox.widget.imagebox()
+  im._data,im.draw,im.set_data = dummy_dataset,draw,set_data
+  return im
+end
+
+return setmetatable(module, { __call = function(_, ...) return new(...) end })
+-- kate: space-indent on; indent-width 2; replace-tabs on;