Lua for Conky Equalizer

--[[ Equalizer modified by plusdm 2012

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, possibles 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 colurs 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, parallelel, 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
                      calues 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",

--      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)

]]

require 'cairo'

----------------START OF PARAMETERS ----------
function conky_main_bars()
    local bars_settings={
        {
            name="cpu",
            arg="cpu1",
            max=100,
            alarm=80,
            bg_colour={0x4F5E63,0.20},
            fg_colour={0x56696F,1.00},
            alarm_colour={0xA0584A,0.80},
            x=5,y=45,
            blocks=6,
            height=4,width=25,
            angle=360,
            smooth=true,
            cap="r",
            skew_y=0,
                        space=4,
            mid_colour={{0.5,0x4F5E63,0.60}}
        },
        {
            name="cpu",
            arg="cpu2",
            max=100,
            alarm=80,
            bg_colour={0x4F5E63,0.20},
            fg_colour={0x56696F,1.00},
            alarm_colour={0xA0584A,0.80},
            x=40,y=45,
            blocks=6,
            height=4,width=25,
            angle=360,
            smooth=true,
            cap="r",
            skew_y=0,
                        space=4,
            mid_colour={{0.5,0x4F5E63,0.60}}
        },
        {
            name="memperc",
            arg="memperc",
            max=100,
            alarm=80,
            bg_colour={0x4F5E63,0.20},
            fg_colour={0x56696F,1.00},
            alarm_colour={0xA0584A,0.80},
            x=75,y=45,
            blocks=6,
            height=4,width=25,
            angle=360,
            smooth=true,
            cap="r",
            skew_y=0,
                        space=4,
            mid_colour={{0.5,0x4F5E63,0.60}}
        },
        {
            name="fs_used_perc",
            arg="swapperc",
            max=100,
            alarm=80,
            bg_colour={0x4F5E63,0.20},
            fg_colour={0x56696F,1.00},
            alarm_colour={0xA0584A,0.80},
            x=110,y=45,
            blocks=6,
            height=4,width=25,
            angle=360,
            smooth=true,
            cap="r",
            skew_y=0,
                        space=4,
            mid_colour={{0.5,0x4F5E63,0.60}}
        },
        {
            name="fs_used_perc",
            arg="/",
            max=100,
            alarm=80,
            bg_colour={0x4F5E63,0.20},
            fg_colour={0x56696F,1.00},
            alarm_colour={0xA0584A,0.80},
            x=145,y=45,
            blocks=6,
            height=4,width=25,
            angle=360,
            smooth=true,
            cap="r",
            skew_y=0,
                        space=4,
            mid_colour={{0.5,0x4F5E63,0.60}}
        },
        {
            name="fs_used_perc",
            arg="/home",
            max=100,
            alarm=80,
            bg_colour={0x4F5E63,0.20},
            fg_colour={0x56696F,1.00},
            alarm_colour={0xA0584A,0.80},
            x=180,y=45,
            blocks=6,
            height=4,width=25,
            angle=360,
            smooth=true,
            cap="r",
            skew_y=0,
                        space=4,
            mid_colour={{0.5,0x4F5E63,0.60}}
        },
        {
            name="upspeedf",
            arg="wlan0",
            max=140,
            alarm=100,
            bg_colour={0x4F5E63,0.20},
            fg_colour={0x56696F,1.00},
            alarm_colour={0xA0584A,0.80},
            x=215,y=45,
            blocks=6,
            height=4,width=25,
            angle=360,
            smooth=true,
            cap="r",
            skew_y=0,
                        space=4,
            mid_colour={{0.5,0x4F5E63,0.60}}
        },
        {
            name="downspeedf",
            arg="wlan0",
            max=700,
            alarm=600,
            bg_colour={0x4F5E63,0.20},
            fg_colour={0x56696F,1.00},
            alarm_colour={0xA0584A,0.80},
            x=250,y=45,
            blocks=6,
            height=4,width=25,
            angle=360,
            smooth=true,
            cap="r",
            skew_y=0,
                        space=4,
            mid_colour={{0.5,0x4F5E63,0.60}}
        },
        {
            name="wireless_link_qual_perc",
            arg="wlan0",
            max=100,
            alarm=80,
            bg_colour={0x4F5E63,0.20},
            fg_colour={0x56696F,1.00},
            alarm_colour={0xA0584A,0.80},
            x=285,y=45,
            blocks=6,
            height=4,width=25,
            angle=360,
            smooth=true,
            cap="r",
            skew_y=0,
                        space=4,
            mid_colour={{0.5,0x4F5E63,0.60}}
        },

        {
            name="battery_percent",
            arg="BAT1",
            max=100,
            alarm=20,
            bg_colour={0x4F5E63,0.20},
            fg_colour={0x56696F,1.00},
            alarm_colour={0xA0584A,0.80},
            x=320,y=45,
            blocks=6,
            height=4,width=25,
            angle=360,
            smooth=true,
            cap="r",
            skew_y=0,
                        space=4,
                        reflection=4,
            mid_colour={{0.5,0x4F5E63,0.60}}
        },
        {
            name="acpitemp",
            arg="",
            max=100,
            alarm=80,
            bg_colour={0x4F5E63,0.20},
            fg_colour={0x56696F,1.00},
            alarm_colour={0xA0584A,0.80},
            x=355,y=45,
            blocks=6,
            height=4,width=25,
            angle=360,
            smooth=true,
            cap="r",
            skew_y=0,
                        space=4,
                        reflection=4,
            mid_colour={{0.5,0x4F5E63,0.60}}
        },

    }

-----------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






    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