[Sugar-devel] prevent screen rotation in a sugar activity?

[James Simmons]

Erik,

Here is how you can be notified when the screen is rotated:

First, listen for the "expose" event in PyGTK:

        self.connect("expose_event", self.area_expose_cb)

Here is the method that gets invoked:

    def area_expose_cb(self, area, event):
        screen_width = gtk.gdk.screen_width()
        screen_height = gtk.gdk.screen_height()
        if self.saved_screen_width != screen_width and
self.saved_screen_width != 0:
            self.show_page(self.page)
        self.saved_screen_width = screen_width
        return False

Now if you write a PyGTK Activity the layouts usually make this
unnecessary.  In this case I was displaying an image which needed to
be resized to make the best use of the new screen dimensions, so I
invoke the method that shows the image when the dimensions change.

Every new Activity developer seems to want to do something that Sugar
won't allow.  In time you'll come to terms with what Sugar is and make
your Activities accordingly.

Your iPhone and Android examples are not good.  If I had paid money
for an app for either platform and it refused to rotate when I rotated
my phone I would not think highly of that app.  Supporting screen
rotation in a PyGTK Activity is trivial.  With PyGame it's more work,
but it's work you should be doing anyway.  With Sugar on a Stick your
Activity will need to support a variety of screen dimensions.  A good
example of the wrong thing to do is the commercial game "Super Vampire
Ninja Zero".  It ONLY works on the XO screen dimensions, without
rotation.  Don't be that guy!

James Simmons


On Fri, Dec 10, 2010 at 4:14 PM, James Cameron <quozl at laptop.org> wrote:
> On Fri, Dec 10, 2010 at 04:29:31PM -0500, Erik Blankinship wrote:
>> It is sometimes a designer's prerogative to present their work in one format.
>>  Numerous examples are available on the iPhone and android markets.
>
> It is sometimes a platform designer's perogative to enforce human
> interface guidelines and require applications to support certain
> behaviours.
>
>> Is it possible to override or be notified of a rotation signal?
>
> No, not without taking control of components outside the scope of a
> Sugar activity.  You're welcome to try that, but the problems that occur
> are:
>
> 0.  installation will require root access, which is not available to
> some users due to deployment team policy,
>
> 1.  the API will keep changing, instead of remaining relatively static
> in the case of the Sugar Activity API,
>
> 2.  there are multiple build versions to test against,
>
> 3.  there is a higher risk of breaking something later.
>
> --
> James Cameron
> http://quozl.linux.org.au/
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