Smoother Panning in GNOME Shell Magnifier
alanbell at ubuntu.com
Thu Jan 26 09:11:41 UTC 2012
I guess there must be a performance penalty from polling the mouse so
often (can't imagine why that setting exists if there isn't one) and
that value is in milliseconds, so 1/1000 of a second. Assuming a screen
refresh rate of 60Hz each screen refresh takes 16ms so I think if the
setting is put at 15ms then a mouse poll will happen during every screen
refresh cycle. From my testing I can't tell the difference between a
setting of 15 and a setting of 1. Whatever the performance hit is (I
couldn't detect one but a low performance netbook might struggle) I
would imagine that a setting of 15 would be easier to argue to move to
than 1 because its only a change of about a factor of 3 rather than a
factor of 50.
Is 15 as good as 1 for you?
On 26/01/12 02:01, Robert cole wrote:
> Hello, everyone.
> Well, I did a slight bit of tinkering with the GNOME Shell Magnifier
> settings today (I love that I can tinker in Linux!).
> I am not trying to complain by any means, so I hope that this does not
> sound as such. I have been trying out Unity2D in Ubuntu 11.10, which I
> recently installed onto my desktop system to replace Linux Mint 12. I
> love how the GNOME Shell Magnifier is coming along, but at the present
> time it does not pan as smoothly as I am used to, which makes it
> slightly more difficult to read and to navigate my system. The same
> can be said for panning using Compiz's eZoom plugin on a fresh install
> of Ubuntu--it does not pan so smoothly either.
> Well...I learned through experience that I could change the value for
> Compiz's Mouse position polling plugin to smoothen things out. (Just
> for the record, the GNOME Shell Magnifier pans much more smoothly by
> default as compared to Compiz's default settings under Unity.) Anyway,
> I learned that if I decrease the Mouse Poll Interval from 40 to 1
> panning was very smooth...well...just beautiful to me.
> So today, rather than bother the list by asking where I could find the
> settings files for the Zoom feature, I figured I'd do some
> exploration. I ran the basic command:
> locate magnifier
> and this file stood out to me:
> I am not a professional programmer, but I figured I'd take a look at
> this file. I fired up nano (after making a backup of the file to my
> /home directory) and began reading. I found the following line under
> the first set of functions at the top of the file (section comment
> // Keep enums in sync with GSettings schemas
> const MOUSE_POLL_FREQUENCY = 50;
> So I contemplated whether I should change this value from 50 to 1. I
> gave in and did it!
> I made the changes from within Unity2D, so I logged out and then
> logged into GNOME Shell. I crossed my fingers and then hit CTRL+ALT+M,
> the keyboard shortcut I set to activate the magnifier...and...VOILA!
> Super smooth panning! This made me love GNOME Shell even more than I
> already do!
> My questions as concerning this thread, though, is this: How likely is
> it that decreasing this value from 50 to 1 will cause possible
> instabilities? Is it set to 50 for any given reason (I am sure there
> has to be a reason)? I ask this because it is the same way with
> Compiz, but it seems (in either case) that the lower the Poll Interval
> (Compiz) or Poll Frequency (GNOME shell Magnifier) the more smoothly
> panning is in fullscreen magnification mode.
> In any case, I just wanted to put this on the list to get some input.
> As I mentioned earlier, I am definitely not a professional programmer.
> I took classes in C++, Visual Basic, and Python throughout the years,
> but I the class content was quite basic.
> thanks for any input regarding this subject. I'm really looking
> forward to GNOME 3.4!
> Take care.
> gnome-accessibility-list mailing list
> gnome-accessibility-list at gnome.org
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