2004.04_Superkaramba-Add Tools and Functionality to Your Kde Desktop.pdf

KNOW HOW

SuperKaramba

Karamba on the Desktop

The desktop background – is it simply a place to display pretty pictures? No way! SuperKaramba allows you to re-vamp

your KDE root window to provide a multifunctional tool. BY HAGEN HÖPFNER

occupy a major part of the screen,

there would be no need to worry

about the amount of space wasted. For-

tunately, there are some tools, such as

superkaramba [12], that help remedy

this unbalance.

This small K Desktop tool is based on

an application called karamba [11],

which it leverages to display system

information on the desktop, and to

remotely control media players such as

XMMS [8] or noatun [6]. Karamba uses

well-known pseudo-

transparency

effects in a similar way to applications

like konsole . But you can use Python

scripts to control SuperKaramba, in con-

trast to its predecessor.

Acting directly on the desktop,

SuperKaramba addons do not hide any

windows – if you have a screen full of

applications running, you will need to

move them aside to see the addons.

does not exist, create it by typing mkdir

~/.superkaramba ):

tar -C ~/.superkaramba/ -xvjf U

archivename .tar.bz2

tar -C ~/.superkaramba/ -xvzf U

archivename gz

You can then select the Open… link in

the main menu to open the definition file

from the unpacked theme folder. The file

will have a .theme suffix.

Figure 2 shows the “glassmachine”

theme from [2], which includes a clock,

the Kmenu, some application and system

icons, and an XMMS control panel.

More cautious users might like to opt

for the “Liquid Weather Plus” theme (see

Figure 3) to display weather information

on the background. Although this does

require Python to be first installed. The

dropdown menu available by right-click-

ing the display takes you to the Configure

Theme / Find location on weather.com

menu item, where you can enter your

own location (such as Liverpool, UK ).

You can then click on Reload Theme , and

a quick glance at the desktop will tell

you if you need your umbrella today.

Curious?

The current version of the tool has

binary packages for Suse, Mandrake, Red

Hat, Debian and Slackware, and is avail-

able from [1]; Gentoo users can run the

emerge command.

At this time of writing, users

wanting to install the very latest

version (0.33) had to download

the sources, and run the usual three

card trick: ./configure && make && make

install to compile and install. As this

assumes pre-installed Qt and KDE header

files, and a Qt 3.x binary compiled with

thread support, you might prefer to use a

ready-made binary. It was for this

reason that we decided to base

this article on version 0.32b.

When issued in a KDE com-

mand line window ( konsole ), the

superkaramba & command will

call a functional, but unspectac-

ular, main menu (see Figure 1).

The Download… item suggests

that you might be able to down-

load addons for the K Desktop

background just by clicking. Unfor-

tunately, the Web page that

Konqueror opened when we did so

failed to provide any themes at time of

writing.

There are some themes available at

[2], however. Our recommendation is to

use the following two commands to

unpack any themes archives that you

download from this address in the hid-

den ~/.superkaramba directory (if it

Figure 1: Any color if you want black – the

SuperKaramba main menu.

April 2004

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Liven up your KDE wallpaper with SuperKaramba

I f the desktop background didn’t

SuperKaramba

KNOW HOW

Creating Your

Own Theme

If you intend to create

your own theme, ready-

made themes are an

endless source of ideas and information.

Each of them has its own top-level direc-

tory with a control file (which ends in

.theme ). You can refer to [3,4,5] for

details of what this directory should con-

tain.

“Glassmachine” merely has the con-

trol file and a few icons.

In contrast, “Liquid

Weather Plus” adds

another program file. As

this theme needs to

download weather data

off the Internet, it needs

more than just the .theme

file. A Python script

provides the added func-

tionality. Don’t worry,

you can do without program-

ming skills for your initial steps

as SuperKaramba offers such a

wide range of options for dis-

playing system information and

the like.

The .theme file content can be divided

into two categories; the first category

being commands that influence the gen-

eral appearance of the theme. The other

thing SuperKaramba can do is evaluate

monitoring parameters.

Our first theme (see Listing 1) will dis-

play a simple digital clock, the current

date, and the CPU load (see Figure 4).

This theme is based on the glassmachine

(see Figure 2).

The first thing we need is a main win-

dow – this is indicated by the KARAMBA

keyword. The X and Y co-ordinates spec-

ify the number of points from the top left

corner of the screen the top left corner of

the window will be. W specifies the

width, and H the height of the window.

To allow users to move or scale the win-

dow on the desktop, you need to

stipulate LOCKED=FALSE . The final

option, INTERVAL , specifies the interval

Figure 2: The glassmachine is simply another toolbox on the desktop background.

layout of the date and

time display. In our

example, “ddd MM.dd.

yyyy” , means that the

abbreviated weekday (e.

g. Mon for Monday) will be displayed,

followed by the date in month.day.year

format. If you stipulate dddd for the

weekday, the full name of the weekday is

displayed.

In the last line of the clock group,

CLICKAREA defines an interactive area,

where the parameters X and Y define the

top left corner of the group relative to the

main window, or to the parent group. W

and H again specify the width and

height, while the ONCLICK=”…” para-

meter specifies the command line (in

double quotes) that a mouse click in this

area will launch. In LOCKED=FALSE

mode, this can be a simple left click; as

we are using LOCKED=TRUE in this

case (see line 1), we need to double-click

to call the KDE module and configure the

date, time and timezone.

Figure 3: The weather, straight

from your desktop.

between window updates in millisec-

onds. As our clock has a seconds display,

1000 milliseconds seems like a sensible

choice of update interval. Incidentally,

capitalization is not significant for

.theme files.

The second line in our example uses

the DEFAULTFONT key-

word to specify which

font the theme should

normally use. It is up to

you to decide which of

the optional parameters

you will use here. In List-

ing 1, we opted for a

Sans Serif type font

( FONT=“Sans” ) in white

( COLOR ) with a two-

pixel shadow width

( SHADOW=2 ). You can

overwrite any font parame-

ters that you define here at a

later stage.

SuperKaramba uses RGB

values to define colors. The first value is

red, the second green, and the third the

blue channel of the desired color. If you

set all three values to the maximum

value, 255 , you end up with white. At

the opposite end of the scale,

COLOR=0,0,0 specifies black.

Now let’s divide the display up into

groups. The first group will display the

time and date, and the second the CPU

load. The format parameter specifies the

Figure 4: Time, date

and CPU load.

Accessing System Parameters

We need two kinds of sensor to query

the time, date, and CPU load: SEN-

SOR=TIME provides the first two values,

and SENSOR=CPU the CPU load.

SuperKaramba has more parameters:

• DISK shows details of mounted drives,

including NFS and Samba mounts.

• MEMORY displays the status of the

main memory and swap partition .

• NETWORK provide details of network

traffic.

• NOATUN tells us the audio track

noatun [6] is currently playing.

Listing 1: Code for Figure 4

01 KARAMBA x=0 y=0 w=140 h=65 locked=false interval=1000

02 DEFAULTFONT font="Sans" shadow=2 color=255,255,255

04 <GROUP> x=10 y=10

TEXT x=12 y=0 sensor=time fontsize=22 format="hh:mm:ss"

interval=500

TEXT x=12 y=25 sensor=time fontsize=10 format="ddd

MM.dd.yyyy"

CLICKAREA x=0 y=0 w=120 h=35 onclick=" kdesu kcmshell clock"

GLOSSARY

08 </GROUP>

10 <GROUP> x=10 y=50

kdesu: A KDE dialog box that prompts for the

root password, and then runs the program

specified in the argument passed to it (in this

case: kcmshell clock) with superuser privi-

leges.

TEXT x=12 y=0 value="CPU"

TEXT x=42 y=0 sensor=cpu

13 </GROUP>

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April 2004

KNOW HOW

SuperKaramba

• PROGRAM displays the standard out-

put of a program. For example

Table 1: General commands in .theme files

Command

Meaning

important parameters

TEXT ... sensor=program program U

=" who | cut -d\ -f 1 | U

sort | uniq "

KARAMBA

defines the main window

X : horizontal position (default: x=0 )

Y :vertical position (default: y=0 )

W : width (default: w=300 )

H : height (default: h=300 )

LOCKED : Disable ( true ) or enable ( false ) scaling/moving (default:

locked=false )

INTERVAL :Refresh interval in milliseconds (default: interval=5000 )

would display logged on users.

• SENSOR uses the external sensors [7]

tool to collect statistics.

• TEXTFILE continually reads a text file

and outputs its content. For example:

CLICKAREA

defines an area which laun-

X : horizontal position (relative to main window or parent group)

ches a program when clicked

Y :vertical position (relative to main window or parent group)

W : width

H : height

PREVIEW : Should the user see the boundaries of the click area? If

so, preview=true will draw a frame round it.

ONCLICK : the program to launch

TEXT ... sensor=textfile path U

="/proc/acpi/thermal_zone/THRM U

/temperature"

would display the current system tem-

perature – assuming that the computer

can provide this information.

• UPTIME displays the time since the

machine was last booted.

• XMMS displays the audio track cur-

rently being played by xmms [8].

A full overview of these parameters is

available from [4].

DEFAULTFONT

specifies the default font

FONT :Font family (example: font=“times” ). Use the xfontsel in fmly

menu to discover the fonts installed on your system.

COLOR :RGB color values for font (example: color=255,0,0 for red)

SHADOW : shadow width in points (example: shadow=2 )

<GROUP> , </GROUP> groups multiple elements

BAR x=42 y=0 sensor=CPU U

path="bar.png"

changes to a running theme, you can

right-click the display and select Reload

theme in the dropdown.

If we now replace the line we just

changed with the following:

Eye-Candy

Displaying statistics in text-only formats

will not win you any prizes for elegance.

A level indicator would be useful for the

CPU load. To enable this display, let’s

replace the last line for the second group

in Listing 1 with the following code:

We can use The Gimp [9], or another

graphics package to create the bar.png

graphic – in Figure 5 this is a white rec-

tangle that measures 70x12 pixels.

SuperKaramba displays a section of the

graphic to reflect the current load status.

The display starts in the top left corner of

the image, and one pixel corresponds to

one point on the level indicator.

If the graphic is bigger than the main

window, or if you restricted the display

with regard to width w or height h ,

SuperKaramba will automatically crop

the graphic. The image file can use for-

mat-specific transparency effects.

If you do not specify a specific folder

for path , SuperKaramba will assume the

folder that contains the .theme file.

Instead of an image file on disk, you can

supply a http URL as the image path.

To allow SuperKaramba to apply the

GRAPH x=42 y=0 w=70 h=12 color U

=255,255,255 points=100 U

sensor=cpu

SuperKaramba will draw a line graph of

the CPU load as shown in Figure 6. x , y ,

w and h define the relative position of

the display, and its width and height.

You can use the COLOR keyword to

define the color. The new POINTS para-

meter specifies the number of measuring

points; this is 100 in our case. The tool

will normalize this against the width of

the graphic ( 70 in our example).

It can interpret the return values as an

image file, and display this file at a

specified position, along the following

lines:

Figure 5: CPU load

as a bar graphic…

Figure 6: … and as a

line graph.

Figure 7: XMMS

remote control.

Figure 8: The com-

plete example.

GLOSSARY

Samba: A software package that provides

compatibility to Microsoft file and printer

sharing functions, and allows Linux to access

resources of this type. Linux with Samba can

also provide file and/or print server function-

ality for Windows based network clients.

Swap-Partition: An area on the hard disk, that

(particularly) computers with little physical

memory (RAM) use as an additional, virtual

memory area to handle memory intensive

applications. Swapping main memory out to

disk, is a slow process.

who | cut -d\ -f 1 | sort | uniq: Shows use of the

traditional Unix pipeline (|). The who com-

mand tells you who is logged on. The cut

command cuts the first field with the user-

name out of this output (-f 1), using the space

character to delimit the columns (-d). The

space character needs to be escaped with a

backslash \. The sort command sorts the out-

put alphabetically, and uniq removes any

duplicates, ensuring that each user appears

only once.

NFS: The “Network File System” allows trans-

parent mounting of directories on remote

Unix/Linux servers within the local filesystem

tree.

April 2004

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SuperKaramba

KNOW HOW

Table 2: Important parameters

for the BAR level display

window specified in the

KARAMBA line of Listing 1

( H=100 ).

A click on the < button

jumps back to the previous

track in the playlist, as

specified by the ONCLICK

=“xmms --rew” command.

W will start to play ( xmms -

-play ), > will fast forward

to the next track ( --fwd ),

and the pause button, P ,

will temporarily pause the

current track ( --play-pause ).

S stops the player ( --stop ), and M

launches the KDE mixer kmix to allow

you to adjust the volume control. This

uses the dcop kmix kmix-mainwindow#1

show [13,14] command.

If you take a closer look at the

“glassmachine” theme, you will note

that the position within the current track

is indicated by a status bar. Also, the title

and artist are read and displayed. We can

do that, too, as Figure 8 shows! Let’s cre-

ate an image file called bar1.png for the

status display. The file will contain a

gray rectangle that measures 96x12

pixels. We also need to add the following

line to extend the group defined in

Listing 2:

The %ms format parameter, which

unfortunately is not officially docu-

mented, causes the bar display for the

XMMS sensor to grow while the track is

playing, thus indicating the current posi-

tion within the track.

So, now we are just missing the title

and artist display. Again, we only need

to add a single line to retrieve the appro-

priate data from the XMMS sensor:

Parameter

Meaning

horizontal position of top left corner (relative to main

window or parent group)

vertical position of bottom left corner (relative to main

window or parent group)

width (optional; if not supplied, SuperKaramba will default

to the width of the image)

height (optional; height of image by default)

PATH

path to image file

VERTICAL

display bottom/up instead of left/right (default:

vertical=false )

TEXT x=13 y=16 w=94 H=10 SENSOR U

=XMMS fontsize=8 font="Sans" co U

lor=255,255,255 format="%title"

IMAGE x= numeric y= numeric U

w= width h= height path=" path/to U

/or/URL/of/imagefile "

format=”%title” returns both the artist

and the title in this case. The complete

theme, small_text_xmms.theme is avail-

able as a packed tar archive, small_text_

xmms.tar.bz2 , from [10].

If you are raring to flaunt your Python

skills to define addons for themes, don’t

worry. I’ll be back soon.

This function is useful for adding web-

cam images to a theme. Refer to [5] for

more good ideas.

More Interaction

As previously mentioned, SuperKaramba

is not only capable of displaying system

information, but can also remotely con-

trol your applications – for example

XMMS [8], as shown in Figure 7. To

allow this to happen, let’s add the code

from Listing 2 to Listing 1.

In addition to adding the new group,

which will contain buttons for remotely

controlling XMMS that use labels and

highlighted areas ( preview=true ), we

need to adjust the height of the main

■

INFO

[1] SuperKaramba binary packages:

http://netdragon.sourceforge.net/?page=

Download+SuperKaramba

[2] SuperKaramba themes:

http://www.kde-look.org/index.php?

xcontentmode=karamba

[3] General .theme parameters:

http://netdragon.sourceforge.net/

?page=General+Commands

[4] .theme sensors: http://netdragon.

sourceforge.net/?page=Sensors

[5] .theme meters: http://netdragon.

sourceforge.net/?page=Meters

[6] The KDE media player, noatun:

http://noatun.kde.org/

[7] Linux system hardware monitoring:

http://secure.netroedge.com/~lm78/

[8] X Multimedia System:

http://www.xmms.org/

[9] The GIMP: http://www.gimp.org/

[10] Sample theme:

http://wwwiti.cs.uni-magdeburg.de/

~hoepfner/download.html

[11] Karamba, the original:

http://www.efd.lth.se/~d98hk/karamba/

[12] SuperKaramba:

http://netdragon.sourceforge.net/

[13] Patricia Jung:“Hidden but sooo useful!”,

Linux Magazine 9/2003, Issue 34 p40,

http://www.linux-magazine.com/issue/

34/KDETricks.pdf

[14] Scott Wheeler:“Boost your efficiency”,

Linux Magazine 11/2003, Issue 36 p46,

http://www.linux-magazine.com/issue/

36/KDE_Scripting_DCOP.pdf

BAR X=12 Y=15 SENSOR=XMMS U

format="%ms" path="bar1.png" U

interval=500

Listing 2: Adding XMMS controls

01 <GROUP> X=10 Y=65

text x=12 y=0 value="XMMS"

text x=50 y=0 value="<"

text x=60 y=0 value="W"

text x=70 y=0 value=">"

text x=80 y=0 value="P"

text x=90 y=0 value="S"

text x=100 y=0 value="M"

10 CLICKAREA x=50 y=0 w=9 h=12 preview=true SENSOR=PROGRAM

ONCLICK="xmms --rew"

11 CLICKAREA x=60 y=0 w=9 h=12 preview=true SENSOR=PROGRAM

ONCLICK="xmms --play"

12 CLICKAREA x=70 y=0 w=9 H=12 preview=true SENSOR=PROGRAM

ONCLICK="xmms --fwd"

13 CLICKAREA x=80 y=0 w=9 H=12 preview=true SENSOR=PROGRAM

ONCLICK="xmms --play-pause"

14 CLICKAREA x=90 y=0 w=9 H=12 preview=true SENSOR=PROGRAM

ONCLICK="xmms --stop"

15 CLICKAREA x=100 y=0 w=9 H=12 preview=true SENSOR=PROGRAM

ONCLICK="dcop kmix kmix-mainwindow#1 show"

16 </GROUP>

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