Development/Tutorials/SuperKaramba

SuperKaramba

Intro

SuperKaramba is a tool that allows one to easily create functionality enhancement modules on a KDE desktop. Such modules are interactive programs written in Python or Ruby that are usually embedded directly into the background and do not disturb the normal view of the desktop.

Links

Examples

Clock with Ruby and Python

Let's take a look at one of them, the clock.rb theme written in Ruby. The theme just displays the current time in a RichText widget.

require 'karamba'

def initWidget(widget)
    Karamba.resizeWidget(widget, 300, 120)
    @richtext = Karamba.createRichText(widget, Time.now.to_s)
    Karamba.moveRichText(widget, @richtext, 10, 10)
    Karamba.setRichTextWidth(widget, @richtext, 280)
    Karamba.redrawWidget(widget)
end

def widgetUpdated(widget)
    puts  >> widgetUpdated"
    Karamba.changeRichText(widget, @richtext, Time.now.to_s)
    Karamba.redrawWidget(widget)
end

The initWidget method will be called once if the widget got initialized. Here we setup the RichText widget where we display the current time in. The widgetUpdated will be called each second once (the interval is defined in the clock.theme themefile) and just updates the text display in the RichText widget with the new time.

Let's take a look at another theme. The text.py theme written in Python just displays some text widgets. We take this is example to create our own script, that does the same as the clock.rb above, that is to display the current time within a text widget.

import karamba, time

text = None

def initWidget(widget):
    text = karamba.createText(widget, 0, 20, 200, 20, "Text meter")

def widgetUpdated(widget):
    t = time.strftime("%Y-%M-%d %H:%M.%S")
    karamba.changeText(widget, text, t)

In the initWidget method we create our text widget that is updated once per second (or per interval as defined in the matching theme file) at the widgetUpdated method to display the new current time.

Karamba with QtRuby/Kurundum

The following sample script written in Ruby demonstrates that you are able to use QtRuby/Kurundum within your Ruby scripts.

require 'karamba'

def widgetClicked(widget, x, y, button)
    require 'Qt'
    app = Qt::Application.new()
    hello = Qt:: PushButton.new('Hello World!', nil)
    hello.resize(100, 30)
    hello.show()
    app.exec()
end

The script does implement only the widgetClicked function that got called if the user clicks on the widget. What we do within that function is to just create a simple Qt4 Ruby 'Hello World' application and then display it.