SDL Trackpad Click Test

Makefile

CFLAGS=-W -Wall -O2 -pedantic $(shell sdl2-config --cflags)
LIBS=-lm $(shell sdl2-config --libs)
OBJS=sdl-click.o
APP=sdl-click

.PHONY=all clean

all: $(APP)

$(APP): $(OBJS)
	$(CC) $(CFLAGS) -o $(APP) $(OBJS) $(LIBS)

%.o: %.c
	$(CC) $(CFLAGS) -c $<

clean:
	$(RM) -f $(APP) $(OBJS)

sdl-click.c

#include <stdbool.h> // bool
#include <stdlib.h> // EXIT_{FAILURE,SUCCESS}
#include <string.h> // strerror
#include <errno.h> // errno
#include <SDL.h>

#define UNUSED(a) ((void) (a))

#define die(...) do { \
  SDL_LogCritical(SDL_LOG_CATEGORY_APPLICATION, __VA_ARGS__); \
  exit(EXIT_FAILURE); \
} while (0)

static void
log_mouse_event(
  const SDL_Event * const ev
) {
  // populate which_buf
  char which_buf[512];
  if (ev->button.which == SDL_TOUCH_MOUSEID) {
    strncpy(which_buf, "SDL_TOUCH_MOUSEID", sizeof(which_buf));
  } else {
    snprintf(which_buf, sizeof(which_buf), "%u", ev->button.which);
  }

  fprintf(
    stderr,

    "{ "
    "type = %s, "
    "timestamp = %u, "
    "windowID = %u, "
    "which = %s, "
    "button = %u, "
    "state = %u, "
    "clicks = %u, "
    "x = %d, "
    "y = %d "
    "}\n",

    (ev->button.type == SDL_MOUSEBUTTONDOWN) ? "SDL_MOUSEBUTTONDOWN" : "SDL_MOUSEBUTTONUP",
    ev->button.timestamp,
    ev->button.windowID,
    which_buf,
    ev->button.button,
    ev->button.state,
    ev->button.clicks,
    ev->button.x,
    ev->button.y
  );
}

static void
log_touch_event(const SDL_Event * const ev) {
  fprintf(
    stderr,

    "{ "
    "type = %s, "
    "timestamp = %u, "
    "touchId = %ld, "
    "fingerId = %ld, "
    "x = %f, "
    "y = %f, "
    "dx = %f, "
    "dy = %f, "
    "pressure = %f "
    "}\n",

    (ev->tfinger.type == SDL_FINGERDOWN) ? "SDL_FINGERDOWN" : "SDL_FINGERUP",
    ev->tfinger.timestamp,
    ev->tfinger.touchId,
    ev->tfinger.fingerId,
    ev->tfinger.x,
    ev->tfinger.y,
    ev->tfinger.dx,
    ev->tfinger.dy,
    ev->tfinger.pressure
  );
}

static void
draw(SDL_Renderer * const renderer) {
  // set color
  if (SDL_SetRenderDrawColor(renderer, 0, 0, 0, 255)) {
    die("SDL_SetRenderDrawColor(): %s", SDL_GetError());
  }

  // clear background
  SDL_RenderClear(renderer);
}

int main(int argc, char *argv[]) {
  UNUSED(argc);
  UNUSED(argv);

  // init sdl
  if (SDL_Init(SDL_INIT_VIDEO)) {
    die("SDL_Init(): %s", SDL_GetError());
  }

  // register SDL exit handler
  if (atexit(SDL_Quit)) {
    die("atexit(SDL_Init): %s", strerror(errno));
    exit(EXIT_FAILURE);
  }

  // create window
  SDL_Window *win = SDL_CreateWindow("SDL Click Test", SDL_WINDOWPOS_UNDEFINED, SDL_WINDOWPOS_UNDEFINED, 800, 600, SDL_WINDOW_RESIZABLE
  );

  // check for error
  if (!win) {
    die("SDL_CreateWindow(): %s", SDL_GetError());
  }

  // create renderer
  SDL_Renderer *renderer = SDL_CreateRenderer(win, -1, SDL_RENDERER_ACCELERATED | SDL_RENDERER_PRESENTVSYNC);
  if (!renderer) {
    die("SDL_CreateRenderer(): %s", SDL_GetError());
  }

  // main loop
  bool done = false;
  while (!done) {
    SDL_Event ev;

    // read events
    while (SDL_PollEvent(&ev)) {
      switch (ev.type) {
      case SDL_QUIT:
        // exit
        done = true;

        break;
      case SDL_KEYUP:
        switch (ev.key.keysym.sym) {
        case SDLK_ESCAPE:
        case SDLK_q:
          // exit
          done = true;

          break;
        default:
          // ignore event
          break;
        }

        break;
      case SDL_MOUSEBUTTONDOWN:
      case SDL_MOUSEBUTTONUP:
        log_mouse_event(&ev);

        break;
      case SDL_FINGERDOWN:
      case SDL_FINGERUP:
        log_touch_event(&ev);

        break;
      }
    }

    // draw
    draw(renderer);
  }

  // fini renderer, window
  SDL_DestroyRenderer(renderer);
  SDL_DestroyWindow(win);

  // exit with success
  return EXIT_SUCCESS;
}

test-results.txt

sdl-click test results

actions:
  * three left taps (touchpad)
  * three right taps (touchpad)
  * three left clicks (hardware button)
  * three right clicks (hardware button)

# sdl version
> sdl2-config --version
2.0.9

# results of command
> ./sdl-click
// left tap
{ type = SDL_MOUSEBUTTONDOWN, timestamp = 17299, windowID = 2, which = 0, button = 1, state = 1, clicks = 1, x = 466, y = 163 }
{ type = SDL_MOUSEBUTTONUP, timestamp = 17477, windowID = 2, which = 0, button = 1, state = 0, clicks = 1, x = 466, y = 163 }

// left tap
{ type = SDL_MOUSEBUTTONDOWN, timestamp = 22686, windowID = 2, which = 0, button = 1, state = 1, clicks = 1, x = 484, y = 219 }
{ type = SDL_MOUSEBUTTONUP, timestamp = 22863, windowID = 2, which = 0, button = 1, state = 0, clicks = 1, x = 484, y = 219 }

// left tap
{ type = SDL_MOUSEBUTTONDOWN, timestamp = 27562, windowID = 2, which = 0, button = 1, state = 1, clicks = 1, x = 337, y = 207 }
{ type = SDL_MOUSEBUTTONUP, timestamp = 27740, windowID = 2, which = 0, button = 1, state = 0, clicks = 1, x = 337, y = 207 }


// right tap (two finger tap)
{ type = SDL_MOUSEBUTTONDOWN, timestamp = 34497, windowID = 2, which = 0, button = 3, state = 1, clicks = 1, x = 430, y = 295 }
{ type = SDL_MOUSEBUTTONUP, timestamp = 34497, windowID = 2, which = 0, button = 3, state = 0, clicks = 1, x = 430, y = 295 }

// right tap (two finger tap)
{ type = SDL_MOUSEBUTTONDOWN, timestamp = 38453, windowID = 2, which = 0, button = 3, state = 1, clicks = 1, x = 451, y = 299 }
{ type = SDL_MOUSEBUTTONUP, timestamp = 38453, windowID = 2, which = 0, button = 3, state = 0, clicks = 1, x = 451, y = 299 }

// right tap (two finger tap)
{ type = SDL_MOUSEBUTTONDOWN, timestamp = 41964, windowID = 2, which = 0, button = 3, state = 1, clicks = 1, x = 391, y = 306 }
{ type = SDL_MOUSEBUTTONUP, timestamp = 41965, windowID = 2, which = 0, button = 3, state = 0, clicks = 1, x = 391, y = 306 }


// left click (hardware button)
{ type = SDL_MOUSEBUTTONDOWN, timestamp = 49335, windowID = 2, which = 0, button = 1, state = 1, clicks = 1, x = 399, y = 289 }
{ type = SDL_MOUSEBUTTONUP, timestamp = 49414, windowID = 2, which = 0, button = 1, state = 0, clicks = 1, x = 399, y = 289 }

// left click (hardware button)
{ type = SDL_MOUSEBUTTONDOWN, timestamp = 53522, windowID = 2, which = 0, button = 1, state = 1, clicks = 1, x = 491, y = 286 }
{ type = SDL_MOUSEBUTTONUP, timestamp = 53613, windowID = 2, which = 0, button = 1, state = 0, clicks = 1, x = 491, y = 286 }

// left click (hardware button)
{ type = SDL_MOUSEBUTTONDOWN, timestamp = 56849, windowID = 2, which = 0, button = 1, state = 1, clicks = 1, x = 532, y = 317 }
{ type = SDL_MOUSEBUTTONUP, timestamp = 56955, windowID = 2, which = 0, button = 1, state = 0, clicks = 1, x = 532, y = 317 }


// right click (hardware button)
{ type = SDL_MOUSEBUTTONDOWN, timestamp = 61523, windowID = 2, which = 0, button = 3, state = 1, clicks = 1, x = 471, y = 297 }
{ type = SDL_MOUSEBUTTONUP, timestamp = 61661, windowID = 2, which = 0, button = 3, state = 0, clicks = 1, x = 471, y = 297 }

// right click (hardware button)
{ type = SDL_MOUSEBUTTONDOWN, timestamp = 65756, windowID = 2, which = 0, button = 3, state = 1, clicks = 1, x = 609, y = 320 }
{ type = SDL_MOUSEBUTTONUP, timestamp = 65896, windowID = 2, which = 0, button = 3, state = 0, clicks = 1, x = 609, y = 320 }

// right click (hardware button)
{ type = SDL_MOUSEBUTTONDOWN, timestamp = 69142, windowID = 2, which = 0, button = 3, state = 1, clicks = 1, x = 613, y = 274 }
{ type = SDL_MOUSEBUTTONUP, timestamp = 69247, windowID = 2, which = 0, button = 3, state = 0, clicks = 1, x = 613, y = 274 }