Conky Lua & Cairo Troubleshooting

[londonali1010]

Hi guys...It seems as though there are several of you out there having trouble getting started with Conky's Cairo bindings for Lua. In case you don't know what I'm on about, Cairo bindings for Lua mean that you can draw nifty things directly to the Conky window, like this:
2009-09-27--1254084788_1024x600_scrot.png
The first thing you'll need to do to get this up and running is to get a copy of Conky 1.7.2, either from source, or from a PPA. If you compile from source, ensure that you enable Cairo and Lua (and you may as well enable imlib2 while you're there). If you download the .deb, make sure you choose the "all" version.

I have made some scripts already that you can try out; you can download them from Conky Hardcore. I've also written a blog post over on the Conky Blog to get you started writing your own.

If you have any more trouble, please post here, with your script, and the output of

conky -v

[mobilediesel]

Hi guys...It seems as though there are several of you out there having trouble getting started with Conky's Cairo bindings for Lua. In case you don't know what I'm on about, Cairo bindings for Lua mean that you can draw nifty things directly to the Conky window, like this:
2009-09-27--1254084788_1024x600_scrot.png
The first thing you'll need to do to get this up and running is to get a copy of Conky 1.7.2, either from source, or from a PPA. If you compile from source, ensure that you enable Cairo and Lua (and you may as well enable imlib2 while you're there). If you download the .deb, make sure you choose the "all" version.

I have made some scripts already that you can try out; you can download them from Conky Hardcore. I've also written a blog post over on the Conky Blog to get you started writing your own.

If you have any more trouble, please post here, with your script, and the output of

conky -v

I'm going to end up upgrading from Hardy to Jaunty or Karmic just to get Conky 1.7.2! It looks like the tolua++ it what's giving me the problem. Conky wont compile without tolua++ and I can't get tolua++ installed.

The PPA linked above tells me there's a dependency that cannot be met. I imagine that's because there's no .deb for Hardy.

After seeing your rings script, my CPU, MEM and DRIVE bars are looking uglier by the day!

[BornTwisted]

Hi Ali, a couple of things have crossed my mind about the display of the rings, is there an easy way to get the rings to work anti-clockwise and is it possible to make them ovals?

[dk75]

OK. So I'm doing "parachute drop" here.

Heres 3 helepers LUA script to make Clock ( at the moment ).
It needs to be unpacked and copied to "/usr/share/lua51" to work properly.

Then theres clock script:

-- Conky Lua Cairo clock
--
do
	require 'ubuntuforums-conky-main'
	require 'ubuntuforums-conky-cairo'

	function conky_draw_clock(radius,thick,alpha)
		if (radius == 0) or (thick == 0) then return end
		cr, w, h = conky_cairo_window_hook()
		if ((radius+thick)*2 > w) then radius = (w/2)-thick; end
		if ((radius+thick)*2 > h) then radius = (h/2)-thick; end
		local x, y = radius+thick, radius+thick
		cairo_set_line_width(cr, thick)
		cairo_set_source_rgba(cr, conky_cairo_rgb2rgba(0xFFFFFF,1))
		cairo_arc(cr, x, y, radius, 0/180*math.pi, 360/180*math.pi)
		cairo_stroke(cr)
		cairo_set_line_width(cr, thick/2)
		for pins = 0, 330, 30 do
			cairo_move_to(cr, conky_main_pointATcircle(x,y,pins,radius*0.95))
			cairo_line_to(cr, conky_main_pointATcircle(x,y,pins,radius*0.85))
		end
		cairo_stroke(cr)
		cairo_set_line_width(cr, thick)
		cairo_set_source_rgba(cr, conky_cairo_rgb2rgba(0xFFFFFF,0.5))
		cairo_arc(cr, x, y, thick, 0, 2*math.pi)
		cairo_stroke(cr)
		
		local h_alpha, m_alpha, s_alpha = conky_main_time2angle()
		
		cairo_set_line_width(cr, thick*1.5)
		cairo_set_source_rgba(cr, conky_cairo_rgb2rgba(0x606060,0.5))
		cairo_move_to(cr, conky_main_pointATcircle(x,y,h_alpha,thick*2))
		cairo_line_to(cr, conky_main_pointATcircle(x,y,h_alpha,radius*0.5))
		cairo_stroke(cr)
		
		cairo_set_line_width(cr, thick*0.8)
		cairo_set_source_rgba(cr, conky_cairo_rgb2rgba(0xFFFFFF,0.5))
		cairo_move_to(cr, conky_main_pointATcircle(x,y,m_alpha,thick*2.5))
		cairo_line_to(cr, conky_main_pointATcircle(x,y,m_alpha,radius*0.8))
		cairo_stroke(cr)
		
		cairo_set_line_width(cr, thick*0.2)
		cairo_set_source_rgba(cr, conky_cairo_rgb2rgba(0xff0000,1))
		cairo_move_to(cr, conky_main_pointATcircle(x,y,s_alpha,thick*4))
		cairo_line_to(cr, conky_main_pointATcircle(x,y,s_alpha,radius*0.9))
		cairo_stroke(cr)
	end
end

and theres corresponding conkyrc:

background no
use_xft yes
xftfont Bitstream Vera Sans Mono:size=13.5
xftalpha 0.8
update_interval 1.0
total_run_times 0
own_window yes
own_window_type override
own_window_transparent yes
own_window_colour hotpink
#own_window_hints undecorated,below,sticky,skip_taskbar,skip_pager
double_buffer yes
minimum_size 200 200
maximum_width 500
draw_shades no
draw_outline no
draw_borders no
draw_graph_borders yes
stippled_borders 0
border_inner_margin 16
border_width 1
default_color white
default_shade_color black
default_outline_color black
alignment top_left
gap_x 100
gap_y 500
no_buffers yes
uppercase no
cpu_avg_samples 2
net_avg_samples 2
override_utf8_locale yes
use_spacer right
max_port_monitor_connections 80
max_specials 256
max_user_text 256
#text_buffer_size 16384
imlib_cache_size 16777216
color0 ffffff
lua_load ~/.conky/lua/analog-clock.lua
lua_draw_hook_post conky_draw_clock 200 10

TEXT














${execp ps u -p $(pidof conky) |awk '/conky/ {sub(".*-","",$NF); print $NF,"${goto 80}CPU:",$3"%","${goto 190}MEM:",$4"%"}'}

PS: test9 is the Conky with Cairo-Clock

[londonali1010]

I'm going to end up upgrading from Hardy to Jaunty or Karmic just to get Conky 1.7.2! It looks like the tolua++ it what's giving me the problem. Conky wont compile without tolua++ and I can't get tolua++ installed.

The PPA linked above tells me there's a dependency that cannot be met. I imagine that's because there's no .deb for Hardy.

After seeing your rings script, my CPU, MEM and DRIVE bars are looking uglier by the day!

How come you haven't upgraded already?! Just kidding, that's your decision!

You can probably write a script in Python to use Cairo, rather than Lua/Cairo, and then use ${exec} to run it, but it would be harder...

Hi Ali, a couple of things have crossed my mind about the display of the rings, is there an easy way to get the rings to work anti-clockwise and is it possible to make them ovals?

Probably!
There's a cairo_arc_negative() function, which is the same as the cairo_arc function, just counterclockwise. I'm not sure about drawing an oval/ellipse...

[dk75]

"cairo_curve_to" draws Bezier - it might be usable, but we need some mathematical function to compute needed Bezier subpoints to draw oval/elipse with.

[londonali1010]

Okay, then, use this, from the Cairo documentation:

The arc is circular in user space. To achieve an elliptical arc, you can scale the current transformation matrix by different amounts in the X and Y directions. For example, to draw an ellipse in the box given by x, y, width, height:

cairo_save (cr);
cairo_translate (cr, x + width / 2., y + height / 2.);
cairo_scale (cr, width / 2., height / 2.);
cairo_arc (cr, 0., 0., 1., 0., 2 * M_PI);
cairo_restore (cr);

[BornTwisted]

There's a cairo_arc_negative() function, which is the same as the cairo_arc function, just counterclockwise.

Thanks Ali, not sure if i did it correctly but it's working And no errors showing in the terminal.

Changed cairo_arc to cairo_arc_negative in the -- Draw background ring and -- Draw indicator ring sections (working from your rings.lua script).

EDIT:
D'oh, just noticed that the background alpha doesn't show if i only edit those two parts.

[mobilediesel]

How come you haven't upgraded already?! Just kidding, that's your decision!

Only because it's the "Long Term Support" version. I'm really re-thinking the need for that since there's newer versions of most software in the newer versions of Ubuntu.

You can probably write a script in Python to use Cairo, rather than Lua/Cairo, and then use ${exec} to run it, but it would be harder...

I have been looking at Python tutorials already. I even found one aimed at cairo with Python. http://www.tortall.net/mu/wiki/CairoTutorial

I like to think I'm good with Bash scripting but it's not great for anything beyond simple text manipulation.

[srbharadwaj]

ok i hav started playing around with lua scripts....one question from my side....how do i place the graphical object within the conky window.......in other words if i write a lua script for clock or rings wat parameter determines the position of the clock or rings within the conky window?