[Sugar-devel] slow animation performance when moving the mouse

[Erik Blankinship]

I have a simple performance question related to animation based on mouse
movement in an activity.

When you move the mouse, a colored rectangle follows the mouse around.  When
you click with the mouse, we change the way in which we get the mouse
coordinates to position the colored rectangle (and change the color too):

        if (self.opt2):
            #green ... fast
            on, xx, yy, mod = gtk.gdk.Display.get_pointer(
gtk.gdk.display_get_default() )
            self.fake_cursor.x = xx
            self.fake_cursor.y = yy
        else:
            #red ... slow
            #self.mouse_x and self.mouse_y are updated via
motion_notify_event callbacks.
            self.fake_cursor.x = self.mouse_x
            self.fake_cursor.y = self.mouse_y

Here is a video showing the performance hit in both f13 yummed sugar
(mistakenly called jhbuild in the video) and on an xo:
http://www.youtube.com/watch?v=dq9_k1vyrLA

Here is the sample activity source:
http://alumni.media.mit.edu/~erikb/tmp/Test.activity.xo<http://alumni.media.mit.edu/%7Eerikb/tmp/Test.activity.xo>

I don't understand the poor performance when using the self.mouse_x and
self.mouse_y variables.  Shouldn't these two ways of positioning the cursor
behave identically?
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