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Pixel – a new desktop for the Raspberry Pi

Making the Pi desktop easier on the eyes

In 2012 the Raspberry Pi was launched, aimed at improving and promoting the teaching of computer science within schools. Fast forward to 2016, the Pi is being used for all manner of purposes. Over 10 million units have been sold and several revisions released, with the most powerful model, the Pi 3 equipped with a 1.2GHz ARM processor and 1 GB RAM.

This processing power means that the Pi is better than ever at functioning as a desktop computer, with a GUI based upon LXDE (Lightweight X11 Desktop Environment), an internet browser and suite of office applications amongst the pre-installed software.

Many Pi enthusiasts come to the platform with little or no prior knowledge of Linux, and find the LXDE-based desktop the most comfortable and convenient way of using the single board computer. Whilst familiar, this desktop has come to look somewhat dated and basic, especially for those who have grown up in a world of OSX, modern Windows and touchscreen devices.

Enter PIXEL: a beautification of LXDE that makes the Pi's GUI prettier, as well as incorporating several updates to enhance the user experience. In this post we take a quick look at upgrading to PIXEL on the Pi 3, before checking out some of the new features.

Upgrade a go-go

We will upgrade an existing install rather than starting from afresh, booting the Pi into the desktop, opening a Terminal window and double checking the version of the Raspbian installed using the command:

$ cat /etc/os-release

Next, again from the Terminal window and following the instructions issued by the Pi Foundation, I executed the following commands:

$ sudo apt-get update

$ sudo apt-get dist-upgrade

$ sudo apt-get install -y rpi-chromium-mods

$ sudo apt-get install -y python-sense-emu python3-sense-emu

$ sudo apt-get install -y python-sense-emu-doc realvncviewer realvnc-vnc-server

The first two commands being the ones that upgrade the disctribution and make the difference to the GUI, the latter three adding new packages, such as an optimised Chromium browser, Sense HAT emulator and documentation, and RealVNC. This took a fair while to do on a system that was last updated a couple of months ago. Downloading and writing the new image to a new SD card may have taken less time, but this was not tested.

Improvements

After installing the update, I rebooted the Pi and was greeted by the splash screen – a somewhat controversial feature of PIXEL that hides the scrolling bootup messages (more on this later).

After this, a brief period of black screen gave way to the new PIXEL desktop, with a nice photograph background and new icons. Web browsing is passable with the Chromium browser on the Pi 3, but I wouldn't want many tabs open, a habit I am certainly guilty of on my desktop.

Other touches include the ability to turn Bluetooth and WiFi on and off from the top panel, and larger drag handles on windows, contributing to a nicer user experience. Remember, this is not a brand new operating system, rather a polish and refresh of what we already had with Jessie.

This can be confirmed by checking the operating system version as we did earlier:

$ cat /etc/os-release

Gives us the same output as before the update.

More subtle graphical tweaks, like the rounded corners on windows, and different standard typeface are not immediately obvious, but contiribute to a more 'modern' feeling desktop. There are also improved warning icons for over-voltage and over-temperature indicators, replacing the previous, somewhat-cryptic coloured squares that appeared in the top corner of the display when the system was under duress.

Getting back boot messages

For many Pi users, including myself, seeing the boot messages upon startup is not a problem at all – in fact it is useful and reassuring, showing that the system is booting and what errors, if any, have occurred. The Raspberry Pi was designed as an educational tool; an inexpensive sandbox for people to experiment with Linux without worrying about breaking their 'main computer'. In my opinion, the scrolling boot up messages are part of that, particularly with a hackable Linux platform such as the Pi.

So, how do we get the messages back? Well, if you are used to booting into CLI (command line interface) mode and you don't want to lose the messages, fret not: the splash screen is automatically disabled if you have selected 'boot to CLI' in raspi-config, or the Menu->Preferences->Raspberry Pi Configuration tool.

If, however you prefer to use the desktop, but still want to see the bootup messages, you can edit /boot/cmdline.txt, removing 'quiet splash':

$ sudo nano /boot/cmdline.txt

Lastly, if you are feeling in the mood for customisation, you can modify the splash screen with your own image, by replacing /usr/share/plymouth/themes/pix/splash.png with a file of the same name. This could be useful for situations where you may be building a system for use as a emulation platform, media centre or similar, though it is worth bearing in mind that you will still see some messages before and when the splash screen appears, though with much less verbosity than before.

Making Sense

One cool thing that comes bundled with the new PIXEL Raspbian is the Sense HAT emulator (note that we installed it with a separate command, since we were upgrading from an older version of Jessie). Though this has been available for a short period as an online tool in the web browser, the Pi Foundation have developed a version that will run natively on the Pi. This looks to be super-useful for a classroom environment, or people that do not have access to a Sense HAT, but would like to start developing and testing their code before deploying on the real thing.

A number of code examples are provided, and can be modified and executed from within IDLE, the IDE (Integrated Development Environment) that many users will be familiar with. Programs can interface with emulated sensors on the board, as well as control the virtual RGB LED matrix. Once tested, simply changing the line:

from sense_emu import SenseHat

to

from sense_hat import SenseHat

Will allow the code to work with a physical Sense HAT connected to the Pi, rather than the emulation. This tool will undoubtedly prove handy for teachers and shows the Foundation's commitment to educational use of the Pi.

In short

Love it or hate it, the Pi is becoming more user friendly, as expectations are raised and rough edges are polished out. Notable plus points of this latest update are:

  •  It is now easy to have your own splash screen on boot should you wish
  • Improved user interface with clearer icons
  • Improved control over WiFi and Bluetooth from within GUI
  • Integrated Sense HAT emulator
  • Chromium browser bundled by default, with hardware acceleration for better video playback performance

However, those who prefer the familiar environment that is the command line can rest assured that it hasn't gone away, or been configured with a Raspberry pink background by default, at least not yet!

 

 

maker, hacker, doer

13 Jan 2015, 10:57