Wayland开发入门教程16：键盘输入

系列索引地址：Wayland开发入门教程索引

上一篇：Wayland开发入门教程15：窗口背景

上一篇介绍了鼠标的相关操作，本文介绍键盘的相关操作。

使用的是标准的键盘库xkb，官网为：xkb。

先把上一篇的鼠标操作的部分复制过来。

注册并绑定键盘相关的内容

static void seat_capabilities(void *data, struct wl_seat *seat, uint32_t capabilities)
{
	if ((capabilities & WL_SEAT_CAPABILITY_POINTER) && !pointer)
	{
		pointer = wl_seat_get_pointer(seat);
		wl_pointer_add_listener(pointer, &pointer_listener, NULL);
	}
	if (capabilities & WL_SEAT_CAPABILITY_KEYBOARD)
	{
		keyboard = wl_seat_get_keyboard(seat);
		wl_keyboard_add_listener(keyboard, &keyboard_listener, NULL);
	}
}

然后添加键盘的回调函数：字符映射、进入、离开、字符、修饰符（Ctrl/Shift之类的）

static void keyboard_keymap(void *data, struct wl_keyboard *keyboard, uint32_t format, int32_t fd, uint32_t size)
{
	char *keymap_string = mmap(NULL, size, PROT_READ, MAP_SHARED, fd, 0);
	xkb_keymap_unref(keymap);
	keymap = xkb_keymap_new_from_string(xkb_context, keymap_string, XKB_KEYMAP_FORMAT_TEXT_V1, XKB_KEYMAP_COMPILE_NO_FLAGS);
	munmap(keymap_string, size);
	close(fd);
	xkb_state_unref(xkb_state);
	xkb_state = xkb_state_new(keymap);
}

static void keyboard_enter(void *data, struct wl_keyboard *keyboard, uint32_t serial, struct wl_surface *surface, struct wl_array *keys)
{
}

static void keyboard_leave(void *data, struct wl_keyboard *keyboard, uint32_t serial, struct wl_surface *surface)
{
}

static void keyboard_key(void *data, struct wl_keyboard *keyboard, uint32_t serial, uint32_t time, uint32_t key, uint32_t state)
{
	if (state == WL_KEYBOARD_KEY_STATE_PRESSED)
	{
		xkb_keysym_t keysym = xkb_state_key_get_one_sym(xkb_state, key + 8);
		uint32_t utf32 = xkb_keysym_to_utf32(keysym);
		if (utf32)
		{
			if (utf32 >= 0x21 && utf32 <= 0x7E)
			{
				printf("the key %c was pressed\n", (char)utf32);
				if (utf32 == 'q')
					running = 0;
			}
			else
			{
				printf("the key U+%04X was pressed\n", utf32);
			}
		}
		else
		{
			char name[64];
			xkb_keysym_get_name(keysym, name, 64);
			printf("the key %s was pressed\n", name);
		}
	}
}

static void keyboard_modifiers(void *data, struct wl_keyboard *keyboard, uint32_t serial, uint32_t mods_depressed, uint32_t mods_latched, uint32_t mods_locked, uint32_t group)
{
	xkb_state_update_mask(xkb_state, mods_depressed, mods_latched, mods_locked, 0, 0, group);
}

static struct wl_keyboard_listener keyboard_listener = {
	keyboard_keymap, 
	keyboard_enter, 
	keyboard_leave, 
	keyboard_key, 
	keyboard_modifiers
};

wl_keyboard_listener是一个结构体，每个函数的功能都对应好了，就算不实现也要有个空函数占位。

在创建窗口之前，创建键盘上下文

xkb_context = xkb_context_new(XKB_CONTEXT_NO_FLAGS);

然后编译执行。效果为：

EGL版本只是替换了窗口显示部分，其他的代码一样。

完整代码在Wayland_Freshman下的16.keyboard中。

到此为止，基本功能介绍完毕，接下来我们正式进入wayland开发。

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