Tuesday, March 24, 2009

Proposal for Tiling support in KWin

*Note to my normal blog readers, this post may not be of interest to you

This project will add a tiling layout mode to KWin. Tiling window managers displays all windows on the desktop at once, side by side. This allows easy navigation and allows tasks shared across applications to be carried out effortlessly. Unfortunately it is usually presented as a power user option. This will be an attempt to make it more accessible to new users.

Name: Nikhil Marathe

Email Address: nsm.nikhil@gmail.com

Freenode IRC Nick: nsm

Location (City, Country and/or Time Zone): Mumbai, India ( GMT + 5:30 )

Proposal Name:
Implement support for tiling in KWin

Motivation for Proposal / Goal:

Tiling is a very good way to view multiple tasks/windows together. This is well
suited for tasks like writing reports where you can keep looking at references, or watching multiple pictures/videos and even programming. Fast window
switching via the keyboard also improves productivity and decreases needless
Alt+Tabbing. Although tiling window managers have existed for a long time, KWin
does not have this feature. It has been requested for a long time now too ( https://bugs.kde.org/show_bug.cgi?id=59338 ), and
will be useful for those who want to use KDE yet still want a tiling WM.
In addition tiling WMs have always tried to appeal to power users, leaving a gap for the new user to jump. They eschew the mouse and more often the configurability, while available in abundance, often requires scripting. My belief is that the tiling mode should be an intuitive and friendly user experience and should be offered to the new user as a must-have feature.

* Provide an intuitive tiling mode, with different layouts ( like Awesome ) and
support for certain floating windows.
* Expose a D-BUS API for tiling so other applications, including Plasma can hook into it.
* Use compositing and the mouse wherever possible for a fluid experience.
* A feature where windows dragged to the edges will automatically resize themselves to half the screen size as suggested here http://lists.kde.org/?l=kwin&m=122749581132588&w=2 . Of course this could be extended and made more powerful.
* Marking/Selection - Move/tile only certain windows.
* Tiling Stacks - An entire set of
windows could be pushed back, brought in front or moved, each preserving there tiled layout. This could easily be extended to work across multiple monitors.
* Another UI feature that I would like to bring in from 'Present Windows'. The user should be able to select windows by typing a certain filter for the window titles. So a search for Dolphin followed by a keystroke would only tile dolphin instances, leaving xchat floating in the centre.

Implementation Details:

My goal would be to implement a complete tiling solution for KWin. This would

* Communicate with KWin team and community feedback, along with some help from the KDE Usability team to decide how best it can be made user friendly.

* Add tiling code to the core, including new Placement modes, support for Stacks, session management and screen edge gestures. ( Currently when a window is being moved, edge gestures are still passed on to KWin which rotates the desktop or something else. I'd like to intercept these if the user says so to enable tiling )

* Tiling architecture would be somewhat based on Awesome. Awesome is well engineered and well commented, and some of its principles can be adopted into KWin's tiling mode.

* Ensure tiling plays well with layout commands like Cascade or Unclutter or Present Windows.

* Add marking/selection and relevant key bindings.
Marking would be light weight, relevant only for the current window motion, while a Stack would be more permanent. This would use something like the resize geometry display box or if compositing is enabled, tinting or some similar effect.

* Add D-BUS API.
* Is tiling enabled?
* Available layouts, current layout.
* Switching layouts
* Stack awareness.

* Add configuration options for movement, shortcuts to layouts.
This would be intuitive. The shortcuts would only be active in tiling mode and not clash with application shortcuts. For example. in a multimedia keyboard Next would go to next track in Amarok, but Meta + Next would go to next layout or next stack.
Mouse (especially the scroll wheel) would be used extensively to do almost anything the keyboard can.

* Implement panel applet and plasma grouping by editing relevant taskbar code and leveraging the D-BUS API.

* Allow certain windows/applications to preserve their tiling by using KWin's Special Window/Application settings.

* Write user documentation, fix up bugs.

Tentative Timeline:

now - May 23rd : Understand relevant KWin code. Use KWin less, use a tiling WM more. Read KDE documentation, interact with the mentor and
community. Investigate entry points into code. Design the project and plan how the user interface should behave in
tiling mode.

May 23rd - June end: Attempt to implement the core completely. This includes the main tiling
components, the D-BUS API, working well with Plasma and so on. This will include
testing and bug squashing. Have a working tiling mode by the evaluation period.

July : Implement configuration dialogs/options, write user documentation, make the UI
sensible. Implement non critical features such as compositing support, bells and whistles.

August 1-10th: Fix remaining bugs, wrap loose ends, test test test.

Do you have other obligations from late May to early August (school, work,

My 3rd semester begins in the last week of July, which means I'll have
a bit less time ( around 25 hours a week ) towards the last two weeks of coding. Therefore I will attempt to finish almost all
of my proposal by the end of July.

About Me (let us know who you are!):

I'm 18 years old. I study in Gandhinagar, India. I'm pursuing
a B. Tech. in Information and Communication Technology at DA-IICT where I'm in
the first year.

I've been programming and using Linux for about 6 years now. I'm fascinated by
all the areas of computing, including compilers, operating systems, graphics and
web design+development. Python is the coolest language for me, although C/++

comes pretty close. I have significant experience in Qt ( including the new MVC
architecture ) - having developed a local network instant messaging client using

A complete list of my projects can be found at

KDE has been a really great piece of software for me ever since I first used
version 3.2. I've always been a fan of its configurability and the momentum and
innovation in the KDE community, and KDE 4 totally took it to the next level.
Okular and Amarok are the killer applications for me. It has been a kind of
dream to work on KDE someday. Unfortunately I could never participate in GSoC due to age restrictions. I also didn't have the experience to enter such a huge project until last year, but now I'm ready to become a full time contributor to KDE.

When not in front of the computer I also love playing football ( soccer ).
Otherwise I can be found reading or listening to music.

1 comment:

  1. Fantastic idea! Tiling window managers
    like awesome, xmonad, dwm, evilwm, wmii and ratpoison rock! They make a huge difference to
    productivity. I know kwin
    can be replaced by xmonad for example,
    but it would be brilliant if tiling features could be included in kwin
    by so everyone can use them easily on
    a default KDE system (perhaps with
    a normal/tiling checkbox setting).

    Have you seen the
    Google Summer of Code Project: Window Tiling proposal ?
    Perhaps you could join in?