Geis

How to use regions?

Asked by H. Guijt

Could someone please be kind enough to explain how to use regions?

I would like to receive gesture events on some of my (sub)windows, so I try to create a subscription somewhat like this:

      mywindowid = XCreateWindow (....);
       Subscription = geis_subscription_new (Geis, "subscription", GEIS_SUBSCRIPTION_CONT);
        Filter = geis_filter_new (Geis, "filter");
        Region = geis_region_new (Geis, "region", GEIS_REGION_X11_WINDOWID, mywindowid, nullptr);

        geis_filter_add_term (Filter, GEIS_FILTER_CLASS,
            GEIS_CLASS_ATTRIBUTE_NAME, GEIS_FILTER_OP_EQ, GEIS_GESTURE_DRAG,
            GEIS_REGION_ATTRIBUTE_WINDOWID, GEIS_FILTER_OP_EQ, Region, // (*)
            GEIS_GESTURE_ATTRIBUTE_TOUCHES, GEIS_FILTER_OP_LE, 2,
            nullptr);

      geis_filter_add_term (Filter, GEIS_FILTER_CLASS,
            GEIS_CLASS_ATTRIBUTE_NAME, GEIS_FILTER_OP_EQ, GEIS_GESTURE_PINCH,
            GEIS_REGION_ATTRIBUTE_WINDOWID, GEIS_FILTER_OP_EQ, Region, // (*)
            GEIS_GESTURE_ATTRIBUTE_TOUCHES, GEIS_FILTER_OP_EQ, 2,
            nullptr);

        geis_subscription_add_filter (Subscription, Filter);
        geis_subscription_activate (Subscription);

This works, as long as I leave out the lines marked (*). Of course in that case I have not restricted my gestures to one region, instead catching them system wide (and exclusively, apparently - other applications no longer seem to receive gestures once my application is running).

What is the appropriate way for doing this?

Once I delete the subscription, will the filter and region automatically be deleted as well, or do I need to clean them up manually?

Is there any significance to the names for the various items like "subscription", "filter", and "region"?

Thanks in advance!

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H. Guijt (hg-p) said : 		#1

Anyone, please?

If the problem is that I'm somehow not following the proper procedure, please be kind enough to help me with that, at least...

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Stephen M. Webb (bregma) said : 		#2

(1) Try passing "(GeisInteger*)&mywindowid" instead of "Region" to the geis_filter_add_term() call and see what happens.

(2) The names are not significant but should be unique.

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H. Guijt (hg-p) said : 		#3

I've tried that. I get the exact same error messages as before (-100). After studying the library source itself for a bit I've come to believe that your solution is incorrect; the window ID should be passed directly, not as a pointer.

After some more experimentation and reading of library code, I've come to believe that Geis cannot set subscriptions on both gesture classes and individual windows simultaneously; it is either on specific classes (but always full screen), or on specific windows (but always all classes). Moreover, Geis cannot set subscriptions on anything that is not a top-level window. Only top-level windows can be subscribed as a region.

Is it possible I'm simply using the wrong library? I want to capture gesture events for specific controls - I have a set of graphs on screen that I want to zoom in and out, and move around, using gestures, but each graph is a control, not a top-level window. I originally thought Geis would be able to handle this for me, but maybe that was never its intended purpose?

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H. Guijt (hg-p) said : 		#4

As a follow-on question: is it correct that windows that have a gesture subscription (with the region limited to the window) no longer receive emulated mouse pointer events from non-gesture touches? Or is this a sign of me doing something wrong? If so, what?

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Amit Nayar (amit-nyr) said : 		#5

I am also struggling to use regions. I would like to restrict the gesture filters to a specific window and allow for multiple gesture regions within the window.

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Amit Nayar (amit-nyr) said : 		#6

Is this a case where we use GEIS_FILTER_REGION instead of GEIS_FILTER_CLASS on the filter?

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H. Guijt (hg-p) said : 		#7

I've managed to get a little bit further... The main problem I was running into is that GEIS does not allow filtering on non-toplevel windows. So setting a filter on a toplevel window is fine, and can be combined with further filters in the same subscription on specific gesture classes, but I have not found a way to specify a filter down to childwindow level. For me this is fine: once I receive the event for a toplevel window I can forward it to the relevant child window myself. I would suggest you do the same.

Actually, scratch that earlier remark: the main problem I ran into is that the documentation for this library is such a pile of shit - turned what should have been a few hours effort into more than a week of trial and error.

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H. Guijt (hg-p) said : 		#8

Anyway, try something like this:

Window SomeTopLevelWindow = ...;

geis_filter_add_term (MyFilter, GEIS_FILTER_REGION,
GEIS_REGION_ATTRIBUTE_WINDOWID, GEIS_FILTER_OP_EQ, SomeTopLevelWindow,
nullptr);

geis_filter_add_term (MyFilter, GEIS_FILTER_CLASS,
GEIS_CLASS_ATTRIBUTE_NAME, GEIS_FILTER_OP_EQ, GEIS_GESTURE_TAP,
GEIS_GESTURE_ATTRIBUTE_TOUCHES, GEIS_FILTER_OP_EQ, 2,
nullptr);

Revision history for this message
Amit Nayar (amit-nyr) said : 		#9

Thanks a lot. Yes I've been battling with the documentation for the past week and not getting very far. It's pretty shocking!

So that seems to work. I was getting confused with how to create a filter with both a region and a class - It didn't help that I was using the GEIS_REGION_X11_WINDOWID instead of GEIS_REGION_ATTRIBUTE_WINDOWID.
Anyway thanks for your help.

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