scrcpy/app/src/hid_keyboard.h
Romain Vimont c96874b257 Synchronize HID keyboard state on first event
When an AOA HID keyboard is registered, CAPSLOCK and NUMLOCK are both
disabled, regardless of the state of the computer keyboard.

To synchronize the state, on first key event, inject CAPSLOCK and/or
NUMLOCK if necessary.
2021-10-26 21:30:04 +02:00

44 lines
1.4 KiB
C

#ifndef SC_HID_KEYBOARD_H
#define SC_HID_KEYBOARD_H
#include "common.h"
#include <stdbool.h>
#include "aoa_hid.h"
#include "trait/key_processor.h"
// See "SDL2/SDL_scancode.h".
// Maybe SDL_Keycode is used by most people, but SDL_Scancode is taken from USB
// HID protocol.
// 0x65 is Application, typically AT-101 Keyboard ends here.
#define SC_HID_KEYBOARD_KEYS 0x66
/**
* HID keyboard events are sequence-based, every time keyboard state changes
* it sends an array of currently pressed keys, the host is responsible for
* compare events and determine which key becomes pressed and which key becomes
* released. In order to convert SDL_KeyboardEvent to HID events, we first use
* an array of keys to save each keys' state. And when a SDL_KeyboardEvent was
* emitted, we updated our state, and then we use a loop to generate HID
* events. The sequence of array elements is unimportant and when too much keys
* pressed at the same time (more than report count), we should generate
* phantom state. Don't forget that modifiers should be updated too, even for
* phantom state.
*/
struct sc_hid_keyboard {
struct sc_key_processor key_processor; // key processor trait
struct sc_aoa *aoa;
bool keys[SC_HID_KEYBOARD_KEYS];
bool mod_lock_synchronized;
};
bool
sc_hid_keyboard_init(struct sc_hid_keyboard *kb, struct sc_aoa *aoa);
void
sc_hid_keyboard_destroy(struct sc_hid_keyboard *kb);
#endif