Add support for key press and release events.

cpp/events/events_x11.cpp

@@ -0,0 +1,55 @@
+// Copyright (C) 2022 RozK
+//
+// This program is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Affero General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// This program is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU Affero General Public License for more details.
+//
+// You should have received a copy of the GNU Affero General Public License
+// along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+#include "../events.hpp"
+#include <X11/Xlib.h>
+
+unsigned rk_events_mask = KeyPressMask | KeyReleaseMask;
+extern Display * rk_display;
+extern Window rk_window;
+
+rk_uint rk_consume_events(
+    rk_event * events,
+    rk_uint max_events) {
+    if (!events || !max_events) {
+        return 0;
+    }
+    XEvent x11_event;
+    unsigned nevents = 0;
+    for ( ; nevents < max_events ; ++nevents) {
+        if (XCheckWindowEvent(rk_display, rk_window, rk_events_mask, &x11_event)) {
+            rk_event & event = events[nevents];
+            switch (x11_event.type) {
+                case KeyPress:
+                    event.type = RK_EVENT_KEY_PRESS;
+                    event.key.keycode = x11_event.xkey.keycode;
+                    break;
+                case KeyRelease:
+                    event.type = RK_EVENT_KEY_RELEASE;
+                    event.key.keycode = x11_event.xkey.keycode;
+                    break;
+            }
+        } else {
+            break;
+        }
+    }
+    return nevents;
+}
+
+void rk_flush_events() {
+    XEvent x11_event;
+    while (XCheckWindowEvent(rk_display, rk_window, rk_events_mask, &x11_event)) {
+    }
+}