--[[
BARGRAPH WIDGET
v2.1 by wlourf (07 Jan. 2011)
this widget draws a bargraph with different effects
http://u-scripts.blogspot.com/2010/07/bargraph-widget.html

To call the script in a conky, use, before TEXT
 lua_load /path/to/the/script/bargraph.lua
 lua_draw_hook_pre main_rings
and add one line (blank or not) after TEXT

Parameters are :
3 parameters are mandatory
name - the name of the conky variable to display, for example for {$cpu cpu0}, just write name="cpu"
arg  - the argument of the above variable, for example for {$cpu cpu0}, just write arg="cpu0"
       arg can be a numerical value if name=""
max  - the maximum value the above variable can reach, for example, for {$cpu cpu0}, just write max=100

Optional parameters:
x,y   - coordinates of the starting point of the bar, default = middle of the conky window
cap   - end of cap line, ossibles values are r,b,s (for round, butt, square), default="b"
     http://www.cairographics.org/samples/set_line_cap/
angle   - angle of rotation of the bar in degress, default = 0 (i.e. a vertical bar)
     set to 90 for an horizontal bar
skew_x   - skew bar around x axis, default = 0
skew_y   - skew bar around y axis, default = 0
blocks    - number of blocks to display for a bar (values >0) , default= 10
height   - height of a block, default=10 pixels
width   - width of a block, default=20 pixels
space   - space between 2 blocks, default=2 pixels
angle_bar - this angle is used to draw a bar on a circular way (ok, this is no more a bar !) default=0
radius   - for cicular bars, internal radius, default=0
     with radius, parameter width has no more effect.

Colours below are defined into braces {colour in hexadecimal, alpha}
fg_colour    - colour of a block ON, default= {0x00FF00,1}
bg_colour    - colour of a block OFF, default = {0x00FF00,0.5}
alarm      - threshold, values after this threshold will use alarm_colour colour , default=max
alarm_colour - colour of a block greater than alarm, default=fg_colour
smooth      - (true or false), create a gradient from fg_colour to bg_colour, default=false
mid_colour   - colours to add to gradient, with this syntax {position into the gradient (0 to1), colour hexa, alpha}
        for example, this table {{0.25,0xff0000,1},{0.5,0x00ff00,1},{0.75,0x0000ff,1}} will add
        3 colours to gradient created by fg_colour and alarm_colour, default=no mid_colour
led_effect   - add LED effects to each block, default=no led_effect
        if smooth=true, led_effect is not used
        possibles values : "r","a","e" for radial, parallel, perdendicular to the bar (just try!)
        led_effect has to be used with theses colours :
fg_led      - middle colour of a block ON, default = fg_colour
bg_led      - middle colour of a block OFF, default = bg_colour
alarm_led    - middle colour of a block > ALARM,  default = alarm_colour

reflection parameters, not available for circular bars
reflection_alpha  - add a reflection effect (values from 0 to 1) default = 0 = no reflection
      other values = starting opacity
reflection_scale  - scale of the reflection (default = 1 = height of text)
reflection_length - length of reflection, define where the opacity will be set to zero
      values from 0 to 1, default =1
reflection   - position of reflection, relative to a vertical bar, default="b"
      possibles values are : "b","t","l","r" for bottom, top, left, right
draw_me        - if set to false, text is not drawn (default = true or 1)
      it can be used with a conky string, if the string returns 1, the text is drawn :
      example : "${if_empty ${wireless_essid wlan0}}${else}1$endif",

v1.0 (10 Feb. 2010) original release
v1.1 (13 Feb. 2010) numeric values can be passed instead conky stats with parameters name="", arg = numeric_value
v1.2 (28 Feb. 2010) just renamed the widget to bargraph
v1.3 (03 Mar. 2010) added parameters radius & angle_bar to draw the bar in a circular way
v2.0 (12 Jul. 2010) rewrite script + add reflection effects and parameters are now set into tables
v2.1 (07 Jan. 2011) Add draw_me parameter and correct memory leaks, thanks to "Creamy Goodness"

--      This program is free software; you can redistribute it and/or modify
--      it under the terms of the GNU General Public License as published by
--      the Free Software Foundation version 3 (GPLv3)
--
--      This program is distributed in the hope that it will be useful,
--      but WITHOUT ANY WARRANTY; without even the implied warranty of
--      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
--      GNU General Public License for more details.
--
--      You should have received a copy of the GNU General Public License
--      along with this program; if not, write to the Free Software
--      Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
--      MA 02110-1301, USA.

]]

local corner_r = 50
local bg_colour = 0x34486D
local bg_alpha = 0.4


require 'cairo'

----------------START OF PARAMETERS ----------


function conky_main_bars()
 local bars_settings={
  { --[ Graph for CPU1 ]--
   name="cpu",
   arg="cpu1",
   max=100,
   alarm=50,
   alarm_colour={0xFF0000,0.72},
   bg_colour={0xFFFFFF,0.25},
   fg_colour={0x00FF00,0.55},
   mid_colour={{0.45,0xFFFF00,0.70}},
   x=115,y=185,
   blocks=70,
   space=0,
   height=2,width=5,
   angle=90,
   smooth=true
   },
  { --[ Graph for CPU2 ]--
   name="cpu",
   arg="cpu2",
   max=100,
   alarm=50,
   alarm_colour={0xFF0000,0.72},
   bg_colour={0xFFFFFF,0.25},
   fg_colour={0x00FF00,0.55},
   mid_colour={{0.45,0xFFFF00,0.70}},
   x=115,y=198,
   blocks=70,
   space=0,
   height=2,width=5,
   angle=90,
   smooth=true
   },
  { --[ Graph for CPU3 ]--
   name="cpu",
   arg="cpu3",
   max=100,
   alarm=50,
   alarm_colour={0xFF0000,0.72},
   bg_colour={0xFFFFFF,0.25},
   fg_colour={0x00FF00,0.55},
   mid_colour={{0.45,0xFFFF00,0.70}},
   x=115,y=212,
   blocks=70,
   space=0,
   height=2,width=5,
   angle=90,
   smooth=true
   },
  { --[ Graph for CPU4 ]--
   name="cpu",
   arg="cpu4",
   max=100,
   alarm=50,
   alarm_colour={0xFF0000,0.72},
   bg_colour={0xFFFFFF,0.25},
   fg_colour={0x00FF00,0.55},
   mid_colour={{0.45,0xFFFF00,0.70}},
   x=115,y=225,
   blocks=70,
   space=0,
   height=2,width=5,
   angle=90,
   smooth=true
   },
  { --[ Graph for Memory ]--
   name="memperc",
   arg="",
   max=100,
   alarm=50,
   alarm_colour={0xFF0000,0.72},
   bg_colour={0xFFFFFF,0.25},
   fg_colour={0x00FF00,0.55},
   mid_colour={{0.45,0xFFFF00,0.70}},
   x=7,y=395,
   blocks=83,
   space=1,
   height=2,width=5,
   angle=90,
   smooth=true
   },
   }
-----------END OF PARAMETERS--------------



 if conky_window == nil then return end

 local cs = cairo_xlib_surface_create(conky_window.display, conky_window.drawable, conky_window.visual, conky_window.width, conky_window.height)

 cr = cairo_create(cs)
 --prevent segmentation error when reading cpu state
    if tonumber(conky_parse('${updates}'))>3 then
        for i in pairs(bars_settings) do

         draw_multi_bar_graph(bars_settings[i])

        end
    end
 cairo_destroy(cr)
 cairo_surface_destroy(cs)
 cr=nil

end



function draw_multi_bar_graph(t)
 cairo_save(cr)
 --check values
 if t.draw_me == true then t.draw_me = nil end
 if t.draw_me ~= nil and conky_parse(tostring(t.draw_me)) ~= "1" then return end
 if t.name==nil and t.arg==nil then
  print ("No input values ... use parameters 'name' with 'arg' or only parameter 'arg' ")
  return
 end
 if t.max==nil then
  print ("No maximum value defined, use 'max'")
  return
 end
 if t.name==nil then t.name="" end
 if t.arg==nil then t.arg="" end

 --set default values
 if t.x == nil  then t.x = conky_window.width/2 end
 if t.y == nil  then t.y = conky_window.height/2 end
 if t.blocks == nil then t.blocks=10 end
 if t.height == nil then t.height=10 end
 if t.angle == nil  then t.angle=0 end
 t.angle = t.angle*math.pi/180
 --line cap style
 if t.cap==nil  then t.cap = "b" end
 local cap="b"
 for i,v in ipairs({"s","r","b"}) do
  if v==t.cap then cap=v end
 end
 local delta=0
 if t.cap=="r" or t.cap=="s" then delta = t.height end
 if cap=="s" then  cap = CAIRO_LINE_CAP_SQUARE
 elseif cap=="r" then
  cap = CAIRO_LINE_CAP_ROUND
 elseif cap=="b" then
  cap = CAIRO_LINE_CAP_BUTT
 end
 --end line cap style
 --if t.led_effect == nil then t.led_effect="r" end
 if t.width == nil then t.width=20 end
 if t.space == nil then t.space=2 end
 if t.radius == nil then t.radius=0 end
 if t.angle_bar == nil then t.angle_bar=0 end
 t.angle_bar = t.angle_bar*math.pi/360 --halt angle

 --colours
 if t.bg_colour == nil  then t.bg_colour = {0x00FF00,0.5} end
 if #t.bg_colour~=2   then t.bg_colour = {0x00FF00,0.5} end
 if t.fg_colour == nil  then t.fg_colour = {0x00FF00,1} end
 if #t.fg_colour~=2   then t.fg_colour = {0x00FF00,1} end
 if t.alarm_colour == nil  then t.alarm_colour = t.fg_colour end
 if #t.alarm_colour~=2   then t.alarm_colour = t.fg_colour end

 if t.mid_colour ~= nil then
  for i=1, #t.mid_colour do
      if #t.mid_colour[i]~=3 then
       print ("error in mid_color table")
       t.mid_colour[i]={1,0xFFFFFF,1}
      end
  end
    end

 if t.bg_led ~= nil and #t.bg_led~=2 then t.bg_led = t.bg_colour end
 if t.fg_led ~= nil and #t.fg_led~=2 then t.fg_led = t.fg_colour end
 if t.alarm_led~= nil and #t.alarm_led~=2 then t.alarm_led = t.fg_led end

 if t.led_effect~=nil then
  if t.bg_led == nil then t.bg_led = t.bg_colour end
  if t.fg_led == nil  then t.fg_led = t.fg_colour end
  if t.alarm_led == nil  then t.alarm_led = t.fg_led end
 end


 if t.alarm==nil then t.alarm = t.max end --0.8*t.max end
 if t.smooth == nil then t.smooth = false end

 if t.skew_x == nil then
  t.skew_x=0
 else
  t.skew_x = math.pi*t.skew_x/180
 end
 if t.skew_y == nil then
  t.skew_y=0
 else
  t.skew_y = math.pi*t.skew_y/180
 end

 if t.reflection_alpha==nil then t.reflection_alpha=0 end
 if t.reflection_length==nil then t.reflection_length=1 end
 if t.reflection_scale==nil then t.reflection_scale=1 end

 --end of default values


 local function rgb_to_r_g_b(col_a)
  return ((col_a[1] / 0x10000) % 0x100) / 255., ((col_a[1] / 0x100) % 0x100) / 255., (col_a[1] % 0x100) / 255., col_a[2]
 end


 --functions used to create patterns

 local function create_smooth_linear_gradient(x0,y0,x1,y1)
  local pat = cairo_pattern_create_linear (x0,y0,x1,y1)
  cairo_pattern_add_color_stop_rgba (pat, 0, rgb_to_r_g_b(t.fg_colour))
  cairo_pattern_add_color_stop_rgba (pat, 1, rgb_to_r_g_b(t.alarm_colour))
  if t.mid_colour ~=nil then
   for i=1, #t.mid_colour do
    cairo_pattern_add_color_stop_rgba (pat, t.mid_colour[i][1], rgb_to_r_g_b({t.mid_colour[i][2],t.mid_colour[i][3]}))
   end
  end
  return pat
 end

 local function create_smooth_radial_gradient(x0,y0,r0,x1,y1,r1)
  local pat =  cairo_pattern_create_radial (x0,y0,r0,x1,y1,r1)
  cairo_pattern_add_color_stop_rgba (pat, 0, rgb_to_r_g_b(t.fg_colour))
  cairo_pattern_add_color_stop_rgba (pat, 1, rgb_to_r_g_b(t.alarm_colour))
  if t.mid_colour ~=nil then
   for i=1, #t.mid_colour do
    cairo_pattern_add_color_stop_rgba (pat, t.mid_colour[i][1], rgb_to_r_g_b({t.mid_colour[i][2],t.mid_colour[i][3]}))
   end
  end
  return pat
 end

 local function create_led_linear_gradient(x0,y0,x1,y1,col_alp,col_led)
  local pat = cairo_pattern_create_linear (x0,y0,x1,y1) ---delta, 0,delta+ t.width,0)
  cairo_pattern_add_color_stop_rgba (pat, 0.0, rgb_to_r_g_b(col_alp))
  cairo_pattern_add_color_stop_rgba (pat, 0.5, rgb_to_r_g_b(col_led))
  cairo_pattern_add_color_stop_rgba (pat, 1.0, rgb_to_r_g_b(col_alp))
  return pat
 end

 local function create_led_radial_gradient(x0,y0,r0,x1,y1,r1,col_alp,col_led,mode)
  local pat = cairo_pattern_create_radial (x0,y0,r0,x1,y1,r1)
  if mode==3 then
   cairo_pattern_add_color_stop_rgba (pat, 0, rgb_to_r_g_b(col_alp))
   cairo_pattern_add_color_stop_rgba (pat, 0.5, rgb_to_r_g_b(col_led))
   cairo_pattern_add_color_stop_rgba (pat, 1, rgb_to_r_g_b(col_alp))
  else
   cairo_pattern_add_color_stop_rgba (pat, 0, rgb_to_r_g_b(col_led))
   cairo_pattern_add_color_stop_rgba (pat, 1, rgb_to_r_g_b(col_alp))
  end
  return pat
 end

 function rgb_to_r_g_b2(colour,alpha)
   return ((colour / 0x10000) % 0x100) / 255., ((colour / 0x100) % 0x100) / 255., (colour % 0x100) / 255., alpha
 end

 function conky_draw_bg()
  if conky_window == nil then return end

    local w=conky_window.width
    local h=conky_window.height
    local cs=cairo_xlib_surface_create(conky_window.display, conky_window.drawable, conky_window.visual, w, h)
    cr=cairo_create(cs)

    cairo_move_to(cr,corner_r,0)
    cairo_line_to(cr,w-corner_r,0)
    cairo_curve_to(cr,w,0,w,0,w,corner_r)
    cairo_line_to(cr,w,h-corner_r)
    cairo_curve_to(cr,w,h,w,h,w-corner_r,h)
    cairo_line_to(cr,corner_r,h)
    cairo_curve_to(cr,0,h,0,h,0,h-corner_r)
    cairo_line_to(cr,0,corner_r)
    cairo_curve_to(cr,0,0,0,0,corner_r,0)
    cairo_close_path(cr)

    cairo_set_source_rgba(cr,rgb_to_r_g_b2(bg_colour,bg_alpha))
    cairo_fill(cr)
 end

 local function draw_single_bar()
  --this fucntion is used for bars with a single block (blocks=1) but
  --the drawing is cut in 3 blocks : value/alarm/background
  --not zvzimzblr for circular bar
 local function create_pattern(col_alp,col_led,bg)
   local pat

   if not t.smooth then
    if t.led_effect=="e" then
     pat = create_led_linear_gradient (-delta, 0,delta+ t.width,0,col_alp,col_led)
    elseif t.led_effect=="a" then
     pat = create_led_linear_gradient (t.width/2, 0,t.width/2,-t.height,col_alp,col_led)
    elseif  t.led_effect=="r" then
     pat = create_led_radial_gradient (t.width/2, -t.height/2, 0, t.width/2,-t.height/2,t.height/1.5,col_alp,col_led,2)
    else
     pat = cairo_pattern_create_rgba  (rgb_to_r_g_b(col_alp))
    end
   else
    if bg then
     pat = cairo_pattern_create_rgba  (rgb_to_r_g_b(t.bg_colour))
    else
     pat = create_smooth_linear_gradient(t.width/2, 0, t.width/2,-t.height)
    end
   end
   return pat
  end

  local y1=-t.height*pct/100
  local y2,y3
  if pct>(100*t.alarm/t.max) then
   y1 = -t.height*t.alarm/100
   y2 = -t.height*pct/100
   if t.smooth then y1=y2 end
  end

  if t.angle_bar==0 then

   --block for fg value
   local pat = create_pattern(t.fg_colour,t.fg_led,false)
   cairo_set_source(cr,pat)
   cairo_rectangle(cr,0,0,t.width,y1)
   cairo_fill(cr)
   cairo_pattern_destroy(pat)

   -- block for alarm value
   if not t.smooth and y2 ~=nil then
    pat = create_pattern(t.alarm_colour,t.alarm_led,false)
    cairo_set_source(cr,pat)
    cairo_rectangle(cr,0,y1,t.width,y2-y1)
    cairo_fill(cr)
    y3=y2
    cairo_pattern_destroy(pat)
   else
    y2,y3=y1,y1
   end
   -- block for bg value
   cairo_rectangle(cr,0,y2,t.width,-t.height-y3)
   pat = create_pattern(t.bg_colour,t.bg_led,true)
   cairo_set_source(cr,pat)
   cairo_pattern_destroy(pat)
   cairo_fill(cr)
  end
 end  --end single bar

local function draw_multi_bar()
  --function used for bars with 2 or more blocks
  for pt = 1,t.blocks do
   --set block y
   local y1 = -(pt-1)*(t.height+t.space)
   local light_on=false

   --set colors
   local col_alp = t.bg_colour
   local col_led = t.bg_led
   if pct>=(100/t.blocks) or pct>0 then --ligth on or not the block
    if pct>=(pcb*(pt-1))  then
     light_on = true
     col_alp = t.fg_colour
     col_led = t.fg_led
     if pct>=(100*t.alarm/t.max) and (pcb*pt)>(100*t.alarm/t.max) then
      col_alp = t.alarm_colour
      col_led = t.alarm_led
     end
    end
   end

   --set colors
   --have to try to create gradients outside the loop ?
   local pat

   if not t.smooth then
    if t.angle_bar==0 then
     if t.led_effect=="e" then
      pat = create_led_linear_gradient (-delta, 0,delta+ t.width,0,col_alp,col_led)
     elseif t.led_effect=="a" then
      pat = create_led_linear_gradient (t.width/2, -t.height/2+y1,t.width/2,0+t.height/2+y1,col_alp,col_led)
     elseif  t.led_effect=="r" then
      pat = create_led_radial_gradient (t.width/2, y1, 0, t.width/2,y1,t.width/1.5,col_alp,col_led,2)
     else
      pat = cairo_pattern_create_rgba  (rgb_to_r_g_b(col_alp))
     end
    else
      if t.led_effect=="a"  then
       pat = create_led_radial_gradient (0, 0, t.radius+(t.height+t.space)*(pt-1),
               0, 0, t.radius+(t.height+t.space)*(pt),
            col_alp,col_led,3)
     else
      pat = cairo_pattern_create_rgba  (rgb_to_r_g_b(col_alp))
     end

    end
   else

    if light_on then
     if t.angle_bar==0 then
      pat = create_smooth_linear_gradient(t.width/2, t.height/2, t.width/2,-(t.blocks-0.5)*(t.height+t.space))
     else
      pat = create_smooth_radial_gradient(0, 0, (t.height+t.space),  0,0,(t.blocks+1)*(t.height+t.space),2)
     end
    else
     pat = cairo_pattern_create_rgba  (rgb_to_r_g_b(t.bg_colour))
    end
   end
   cairo_set_source (cr, pat)
   cairo_pattern_destroy(pat)

   --draw a block
   if t.angle_bar==0 then
    cairo_move_to(cr,0,y1)
    cairo_line_to(cr,t.width,y1)
   else
    cairo_arc( cr,0,0,
     t.radius+(t.height+t.space)*(pt)-t.height/2,
      -t.angle_bar -math.pi/2 ,
      t.angle_bar -math.pi/2)
   end
   cairo_stroke(cr)
  end
 end

 local function setup_bar_graph()
  --function used to retrieve the value to display and to set the cairo structure
  if t.blocks ~=1 then t.y=t.y-t.height/2 end

  local value = 0
  if t.name ~="" then
   value = tonumber(conky_parse(string.format('${%s %s}', t.name, t.arg)))
   --$to_bytes doesn't work when value has a decimal point,
   --https://garage.maemo.org/plugins/ggit/browse.php/?p=monky;a=commitdiff;h=174c256c81a027a2ea406f5f37dc036fac0a524b;hp=d75e2db5ed3fc788fb8514121f67316ac3e5f29f
   --http://sourceforge.net/tracker/index.php?func=detail&aid=3000865&group_id=143975&atid=757310
   --conky bug?
   --value = (conky_parse(string.format('${%s %s}', t.name, t.arg)))
   --if string.match(value,"%w") then
   -- value = conky_parse(string.format('${to_bytes %s}',value))
   --end
  else
   value = tonumber(t.arg)
  end

  if value == nil then value = 0 end

  pct = 100*value/t.max
  pcb = 100/t.blocks

  cairo_set_line_width (cr, t.height)
  cairo_set_line_cap  (cr, cap)
  cairo_translate(cr,t.x,t.y)
  cairo_rotate(cr,t.angle)

  local matrix0 = cairo_matrix_t:create()
  tolua.takeownership(matrix0)
  cairo_matrix_init (matrix0, 1,t.skew_y,t.skew_x,1,0,0)
  cairo_transform(cr,matrix0)



  --call the drawing function for blocks
  if t.blocks==1 and t.angle_bar==0 then
   draw_single_bar()
   if t.reflection=="t" or t.reflection=="b" then cairo_translate(cr,0,-t.height) end
  else
   draw_multi_bar()
  end

  --dot for reminder
  --[[
  if t.blocks ~=1 then
   cairo_set_source_rgba(cr,1,0,0,1)
   cairo_arc(cr,0,t.height/2,3,0,2*math.pi)
   cairo_fill(cr)
  else
   cairo_set_source_rgba(cr,1,0,0,1)
   cairo_arc(cr,0,0,3,0,2*math.pi)
   cairo_fill(cr)
  end]]

  --call the drawing function for reflection and prepare the mask used
  if t.reflection_alpha>0 and t.angle_bar==0 then
   local pat2
   local matrix1 = cairo_matrix_t:create()
   tolua.takeownership(matrix1)
   if t.angle_bar==0 then
    pts={-delta/2,(t.height+t.space)/2,t.width+delta,-(t.height+t.space)*(t.blocks)}
    if t.reflection=="t" then
     cairo_matrix_init (matrix1,1,0,0,-t.reflection_scale,0,-(t.height+t.space)*(t.blocks-0.5)*2*(t.reflection_scale+1)/2)
     pat2 = cairo_pattern_create_linear (t.width/2,-(t.height+t.space)*(t.blocks),t.width/2,(t.height+t.space)/2)
    elseif t.reflection=="r" then
     cairo_matrix_init (matrix1,-t.reflection_scale,0,0,1,delta+2*t.width,0)
     pat2 = cairo_pattern_create_linear (delta/2+t.width,0,-delta/2,0)
    elseif t.reflection=="l" then
     cairo_matrix_init (matrix1,-t.reflection_scale,0,0,1,-delta,0)
     pat2 = cairo_pattern_create_linear (-delta/2,0,delta/2+t.width,-0)
    else --bottom
     cairo_matrix_init (matrix1,1,0,0,-1*t.reflection_scale,0,(t.height+t.space)*(t.reflection_scale+1)/2)
     pat2 = cairo_pattern_create_linear (t.width/2,(t.height+t.space)/2,t.width/2,-(t.height+t.space)*(t.blocks))
    end
   end
   cairo_transform(cr,matrix1)

   if t.blocks==1 and t.angle_bar==0 then
    draw_single_bar()
    cairo_translate(cr,0,-t.height/2)
   else
    draw_multi_bar()
   end


   cairo_set_line_width(cr,0.01)
   cairo_pattern_add_color_stop_rgba (pat2, 0,0,0,0,1-t.reflection_alpha)
   cairo_pattern_add_color_stop_rgba (pat2, t.reflection_length,0,0,0,1)
   if t.angle_bar==0 then
    cairo_rectangle(cr,pts[1],pts[2],pts[3],pts[4])
   end
   cairo_clip_preserve(cr)
   cairo_set_operator(cr,CAIRO_OPERATOR_CLEAR)
   cairo_stroke(cr)
   cairo_mask(cr,pat2)
   cairo_pattern_destroy(pat2)
   cairo_set_operator(cr,CAIRO_OPERATOR_OVER)

  end --reflection
  pct,pcb=nil
 end --setup_bar_graph()

 --start here !
 setup_bar_graph()
 cairo_restore(cr)
end