1DTK_PROCESS_EVENTS(3) Draw Toolkit manual DTK_PROCESS_EVENTS(3)
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6 dtk_process_events, dtk_set_event_handler - Events processing
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9 #include <dtk_event.h>
10 typedef int (*DTKEvtProc)(dtk_hwnd, int, const union dtk_event*);
12 void dtk_set_event_handler(dtk_hwnd wnd, DTKEvtProc handler);
14 int dtk_process_events(dtk_hwnd wnd);
15
17 dtk_set_event_handler() set handler as the current event handler for
18 the window wnd. handler is a function that has arguments in the follow‐
19 ing order:
20 * a reference of type dtk_hwnd to the window that has received the
22 event.
23 * the type ID of the event.
25 * a pointer to a union dtk_event holding event-specific data (if not
27 NULL) defined as follows:
28 union dtk_event {
30 struct dtk_keyevent key;
31 struct dtk_mouseevent mouse;
32 };
33 dtk_process_events() processes pending events in the event queues asso‐
35 ciated to the window referenced by wnd, i.e. for each event in the
36 queue, it calls the event handler that has been set by
37 dtk_set_event_handler(). dtk_process_events() returns if a event han‐
38 dler has returned 0 or if there is no more pending event in the queue.
39 If dtk_set_event_handler() has never been called or called with handle
41 as NULL, it use a minimalistic event handler that returns 0 (i.e. stop
42 the loop) when pressing the close button on the window.
43 The type ID of the event can be one of the following:
45 DTK_EVT_REDRAW
47 This event indicates that the whole window or parts of it must
48 be redrawn. This may be caused by another window has been over‐
49 lapped it or the window has been resized. If such an event is
50 received, the event pointer passed to the handler will be NULL.
51 DTK_EVT_QUIT
53 This event indicates that the close button of the window has
54 been clicked. The event pointer passed will be NULL.
55 DTK_EVT_KEYBOARD
57 Indicates that a key of the keyboard has been pressed or
58 released. If such an event is received, the meaningfull member
59 of the union dtk_event will be key which is defined as follows:
60 struct dtk_keyevent {
62 unsigned int state; /* pressed or released */
63 unsigned int sym; /* Symbolic code of the key */
64 unsigned int mod; /* modifiers key */
65 };
66 DTK_EVT_MOUSEBUTTON
68 This event indicates that one of the mouse buttons has been
69 pressed or released. If such an event is received, the meaning‐
70 full member of the union dtk_event will be mouse which is
71 defined as follows:
72 struct dtk_mouseevent {
74 unsigned int button; /* button identifier */
75 unsigned int state; /* pressed or realeased */
76 unsigned int x; /* x-coordinate of the mouse position */
77 unsigned int y; /* y-coordinate of the mouse position */
78 };
79 DTK_EVT_MOUSEMOTION
81 This is similar to the DTK_EVT_MOUSEBUTTON but indicates that
82 the mouse has moved. Event data should also be accessed through
83 mouse member but its button and state members will be meaning‐
84 less.
85
87 dtk_set_event_handler() does not return value.
88 dtk_process_events() returns 1 if there is no more pending event in the
90 queue. It returns 0 if the processing loop has been interrupted by an
91 event handler, i.e. the last event handler has returned 0.
92EPFL 2010 DTK_PROCESS_EVENTS(3)