1Prima::EventHook(3) User Contributed Perl Documentation Prima::EventHook(3)
2
6 Prima::EventHook - event filtering
7
9 use Prima::EventHook;
10 sub hook
12 {
13 my ( $my_param, $object, $event, @params) = @_;
14 ...
15 print "Object $object received event $event\n";
16 ...
17 return 1;
18 }
19 Prima::EventHook::install( \&hook,
21 param => $my_param,
22 object => $my_window,
23 event => [qw(Size Move Destroy)],
24 children => 1
25 );
26 Prima::EventHook::deinstall(\&hook);
28
30 Prima dispatches events by calling notifications registered on one or
31 more objects interested in the events. Also, one event hook can be
32 installed that would receive all events occurred on all objects.
33 "Prima::EventHook" provides multiplex access to the core event hook and
34 introduces set of dispatching rules so the user hook subs receive only
35 a defined subset of events.
36 The filtering criteria are event names and object hierarchy.
38
40 install SUB, %RULES
41 Installs SUB into hook list using hash of RULES.
42 The SUB is called with variable list of parameters, formed so first
44 passed parameters from 'param' key ( see below ), then event source
45 object, then event name, and finally parameters to the event. SUB must
46 return an integer, either 0 or 1, to block or pass the event,
47 respectively. If 1 is returned, other hook subs are called; if 0 is
48 returned, the event is efficiently blocked and no hooks are further
49 called.
50 Rules can contain the following keys:
52 event
54 Event is either a string, an array of strings, or "undef" value.
55 In the latter case it is equal to '*' string, which selects all
56 events to be passed in the SUB. A string is either name of an
57 event, or one of pre-defined event groups, declared in %groups
58 package hash. The group names are:
59 ability
61 focus
62 geometry
63 keyboard
64 menu
65 mouse
66 objects
67 visibility
68 These contain respective events. See source for detailed
70 description.
71 In case 'event' key is an array of strings, each of the strings is
73 also name of either an event or a group. In this case, if '*'
74 string or event duplicate names are present in the list, SUB is
75 called several times which is obviously inefficient.
76 object
78 A Prima object, or an array of Prima objects, or undef; the latter
79 case matches all objects. If an object is defined, the SUB is
80 called if event source is same as the object.
81 children
83 If 1, SUB is called using same rules as described in 'object', but
84 also if the event source is a child of the object. Thus, selecting
85 "undef" as a filter object and setting 'children' to 0 is almost
86 the same as selecting $::application, which is the root of Prima
87 object hierarchy, as filter object with 'children' set to 1.
88 Setting together object to "undef" and children to 1 is
90 inefficient.
91 param
93 A scalar or array of scalars passed as first parameters to SUB
94 whenever it is called.
95 deinstall SUB
97 Removes the hook sub for the hook list.
98
100 "Prima::EventHook" by default automatically starts and stops Prima
101 event hook mechanism when appropriate. If it is not desired, for
102 example for your own event hook management, set $auto_hook to 0.
103
105 Dmitry Karasik, <dmitry@karasik.eu.org>.
106
108 Prima, Prima::Object
109perl v5.28.0 2017-02-28 Prima::EventHook(3)