WebKit on the new Raspberry Pi 2

Today the Raspberry Pi Foundation announced a new model of the Raspberry Pi!
While the new Raspberry Pi looks almost identical to the previous one, it’s much more powerful (and with four cores instead of one) and costs just $35.

Here at Collabora we have worked together with the Raspberry Pi Foundation on optimising WebKit for the first Raspberry Pi, achieving a good browsing experience (notwithstanding hardware limitations) with smooth 720 videos, good responsivity, etc.
Despite this work, a lot of web sites are just incredibly heavy and don’t run too well on the RPi1, so the extra CPU power is very useful. Just look at this video to see the difference in performances between the two Pis.


Comparison between the RPi1 and RPi2 (mp4 video file)

Our optimised WebKit-based web browser (i.e. GNOME Web, AKA Epiphany) is already available in Raspbian images, so you will get this out of the box.

A web browser for the Raspberry Pi

As I previously mentioned, Collabora has been working with the Raspberry Pi Foundation on various projects including a web browser optimised for the Raspberry Pi.
Since the first beta release we have made huge improvements; now the browser is more responsive, it’s faster, and videos work much better (the first beta could play 640×360 videos at 0.5fps, now we can play 25fps 1280×720 videos smoothly). Some web sites are still a bit slow (if they are heavy on the JavaScript side), but there’s not much we can do for web sites that, even on my laptop with an Intel Core i7, use 100% of one of the cores for more than ten seconds!

The browser is based on Gnome Web (Epiphany) using WebKit 1 (i.e. the non-multi-process version of WebKit).

Our main achievements are:

  • More responsive UI and scrolling, even under heavy load (like when loading a page)
  • Progressive tiled rendering for smoother scrolling (as mobile browsers do)
  • Startup is three times faster
  • Avoid useless image format conversions
  • Better YouTube support, including on-demand load of embedded YouTube videos to make page load much faster
  • Hardware decoding of videos (through gst-omx)
  • Hardware scaling of videos (again, through gst-omx)
  • Reduction of the number of memory copies to play videos
  • Faster fullscreen playback using dispmanx directly (a bit buggy at the moment, we are working on it)
  • Memory and CPU friendly tab management
  • JavaScript JIT fixes for ARMv6
  • Disk image cache (decoded images are kept in memory mapped files in a cache, saving CPU)
  • Memory pressure handler support


The Raspberry Pi web browser (mp4 video file)

To install the browser, just update your Raspbian and install the “epiphany-browser” package:

sudo apt-get update
sudo apt-get upgrade
sudo apt-get install epiphany-browser

Thanks to all the people at Collabora that, at some point or another, helped on this project: Julien Isorce, Emanuele Aina, ChangSeok Oh, Tomeu Vizoso, Pekka Paalanen, André Moreira Magalhaes, Derek Foreman, Gustavo Noronha, Danilo Cesar, Emilio Pozuelo Monfort and Jonny Lamb (I hope I haven’t forgotten anybody!).
Also thanks to the Raspberry Pi Foundation, and in particular to Eben Upton, for their commitment to making browsing on the Pi better, and to Ben Avison for his work on optimising pixman and libav for ARMv6.

Update: people have reported a few bugs since the release, in particular a problem with Raspbian configured to use 24-bit or 32-bit mode for graphics. We should be able to fix this in a week or so.
Another problem is that Vimeo videos stopped working. This seems to be due to a change made by Vimeo that broke playback also on other browsers and on Android.

Empathy chat accounts and GOA

Two years ago the first version of GNOME Online Accounts (GOA) was released and Empathy got the ability to use the GOA accounts that supported chat. This feature was a bit incomplete as you could configure Google and Facebook accounts in the control center (through GOA), but the other accounts could only be configured directly in Empathy. Similarly, you could use, but not modify, GOA accounts in Empathy. This problem was not fixed before as it required a lot of work, even if (from a user point of view) it was just a matter of moving some UI around.

In the last month at Collabora I worked hard on fixing this issue (and it took more than 160 patches in several components) and now you can configure every type of IM account in the control center.
All of this was done without breaking compatibility. If your program uses the Telepathy API nothing will change; if your program uses the GOA API then it will also able to handle Telepathy accounts.
This was also a good chance to fix several UI issues (mainly misaligned widgets and too much/too little spacing between widgets), see what the old UI looked like.

Adding a new account in GNOME Control Center
Adding a new account in GNOME Control Center (click for a bigger version)

Personal Details dialog
Personal Details dialog (click for a bigger version)

The task is not 100% finished yet as Empathy still opens its own accounts dialog instead of the control center and there are also a few other UI improvements to make.

Thanks to Emanuele for starting the job, Rishi and Guillaume for the help and the reviews, Allan for the designs, and Intel for sponsoring the bulk of the work.

Why is g_hash_table_insert used?

Yesterday I was discussing a bug in some code using a GHashTable with Will and we both started to wonder if there is any reason to use g_hash_table_insert instead of g_hash_table_replace.

First of all an example, look at this code and try to find the bug.

#include <glib.h>

static void
add_entry (GHashTable *ht, const gchar *config)
{
  gchar **split_config = g_strsplit (config, "=", 2);

  if (g_strv_length (split_config) == 2) {
      gchar *key = g_utf8_strdown (split_config[0], -1);
      gchar *value = g_strdup (split_config[1]);

      g_hash_table_insert (ht, key, value);

      g_print ("Set %s to %sn", key, value);
  }

  g_strfreev (split_config);
}

int
main (int argc, char **argv)
{
  GHashTable *ht = g_hash_table_new_full (g_str_hash,
      g_str_equal, g_free, g_free);
  gint i;

  for (i = 1; i < argc; i++)
    add_entry (ht, argv[i]);

  g_hash_table_unref (ht);

  return 0;
}

If it’s not clear where the bug is, try invoking the program with “apples=42 Pears=12 APPLES=10” on the command line.

If a key already exists in the hash table, the key passed to g_hash_table_insert is destroyed and you cannot use it afterwards. This behaviour is documented, but it’s easy to find code affected by this bug. g_hash_table_replace behaves like g_hash_table_insert, but without this problem.
Is there any good reason for using g_hash_table_insert instead of g_hash_table_replace? Can you come up with a non-contrived example where you want the behaviour of the former?

Boss Mode extension

Gnome-shell’s popup notifications and integrated chat are great, but sometimes I’m annoyed when the content of a chat is displayed on screen at the wrong moment (for instance if a colleague sends you a work-related message while you are sitting at a conference next to other people).
The Boss Mode extension allows you to quickly disable notifications, without any UI feedback, by just pressing Win+B. Press Win+N to enable notifications again.

The default keybindings can be modified by clicking the preferences button on the extension page (next to the switch to enable/disable the extension).