--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/libui/ui/button.c	Thu Oct 15 10:32:18 2020 +0200
@@ -0,0 +1,79 @@
+/*
+ * button.c -- GUI button
+ *
+ * Copyright (c) 2020 David Demelier <markand@malikania.fr>
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
+ * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
+ * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <assert.h>
+
+#include <core/event.h>
+#include <core/maths.h>
+
+#include "button.h"
+#include "theme.h"
+
+static bool
+is_boxed(const struct button *button, const struct event_click *click)
+{
+	assert(button);
+	assert(click);
+	assert(click->type == EVENT_CLICKDOWN || click->type == EVENT_CLICKUP);
+
+	return maths_is_boxed(button->x, button->y, button->w, button->h,
+	    click->x, click->y);
+}
+
+void
+button_handle(struct button *button, const union event *ev)
+{
+	assert(button);
+	assert(ev);
+
+	switch (ev->type) {
+	case EVENT_CLICKDOWN:
+		if (is_boxed(button, &ev->click))
+			button->state = BUTTON_STATE_PRESSED;
+		break;
+	case EVENT_CLICKUP:
+		/*
+		 * If the button was pressed, indicate that the button is
+		 * finally activated. This let the user to move the cursor
+		 * outside the button to "forget" the press.
+		 */
+		if (!is_boxed(button, &ev->click))
+			button->state = BUTTON_STATE_NONE;
+		else if (button->state == BUTTON_STATE_PRESSED)
+			button->state = BUTTON_STATE_ACTIVATED;
+		break;
+	default:
+		break;
+	}
+}
+
+void
+button_reset(struct button *button)
+{
+	assert(button);
+
+	button->state = BUTTON_STATE_NONE;
+}
+
+void
+button_draw(struct button *button)
+{
+	assert(button);
+
+	theme_draw_button(button->theme, button);
+}