Voyons comment gérer le pen avec la SDL3
Grâce à la SDL3, on peut dissocier un pen d'une souris. La façon de gérer un pen est identique à celle du joystick et tout se joue dans le switch des events.
Voici les évents du pen :
/* Pressure-sensitive pen events */
SDL_EVENT_PEN_PROXIMITY_IN = 0x1300, /**< Pressure-sensitive pen has become available */
SDL_EVENT_PEN_PROXIMITY_OUT, /**< Pressure-sensitive pen has become unavailable */
SDL_EVENT_PEN_DOWN, /**< Pressure-sensitive pen touched drawing surface */
SDL_EVENT_PEN_UP, /**< Pressure-sensitive pen stopped touching drawing surface */
SDL_EVENT_PEN_BUTTON_DOWN, /**< Pressure-sensitive pen button pressed */
SDL_EVENT_PEN_BUTTON_UP, /**< Pressure-sensitive pen button released */
SDL_EVENT_PEN_MOTION, /**< Pressure-sensitive pen is moving on the tablet */
SDL_EVENT_PEN_AXIS, /**< Pressure-sensitive pen angle/pressure/etc changed */
On peut donc accéder à PEN_UP et PEN_DOWN
while(SDL_PollEvent(&event)) {
switch (event.type) {
case SDL_EVENT_QUIT:
quit = true;
break;
case SDL_EVENT_PEN_UP:
std::cout << "Up" << std::endl;
break;
case SDL_EVENT_PEN_DOWN:
std::cout << "Down" << std::endl;
break;Mais aussi au déplacement du stylet grâce au PEN_MOTION
case SDL_EVENT_PEN_MOTION:
std::cout << "Motion" << std::endl;
event.pmotion.x;
event.pmotion.y;
break;On peut aussi gérer les éventuels boutons du stylet, en mode DOWN or UP:
case SDL_EVENT_PEN_BUTTON_DOWN:
std::cout << "SDL_EVENT_PEN_BUTTON_DOWN" <<std::endl;
switch (event.pbutton.button)
{
case SDL_PEN_INPUT_BUTTON_1:
std::cout << "SDL_PEN_INPUT_BUTTON_1" << std::endl;
break;
case SDL_PEN_INPUT_BUTTON_2:
std::cout << "SDL_PEN_INPUT_BUTTON_2" << std::endl;
break;
case SDL_PEN_INPUT_BUTTON_3:
std::cout << "SDL_PEN_INPUT_BUTTON_3" << std::endl;
break;
case SDL_PEN_INPUT_BUTTON_4:
std::cout << "SDL_PEN_INPUT_BUTTON_4" << std::endl;
break;
default:
break;
}
On peut aussi s'intéresser au PEN_AXIS:
typedef struct SDL_PenAxisEvent
{
SDL_EventType type; /**< SDL_EVENT_PEN_AXIS */
Uint32 reserved;
Uint64 timestamp; /**< In nanoseconds, populated using SDL_GetTicksNS() */
SDL_WindowID windowID; /**< The window with pen focus, if any */
SDL_PenID which; /**< The pen instance id */
SDL_PenInputFlags pen_state; /**< Complete pen input state at time of event */
float x; /**< X coordinate, relative to window */
float y; /**< Y coordinate, relative to window */
SDL_PenAxis axis; /**< Axis that has changed */
float value; /**< New value of axis */
} SDL_PenAxisEvent;Avec cette structure, on peut raffiner de très prêt les évènements du stylet !