path: root/src/evdev-mt-touchpad-gestures.c

/*
 * Copyright © 2015 Red Hat, Inc.
 *
 * Permission to use, copy, modify, distribute, and sell this software and
 * its documentation for any purpose is hereby granted without fee, provided
 * that the above copyright notice appear in all copies and that both that
 * copyright notice and this permission notice appear in supporting
 * documentation, and that the name of the copyright holders not be used in
 * advertising or publicity pertaining to distribution of the software
 * without specific, written prior permission.  The copyright holders make
 * no representations about the suitability of this software for any
 * purpose.  It is provided "as is" without express or implied warranty.
 *
 * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS
 * SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
 * FITNESS, IN NO EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY
 * SPECIAL, 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 "config.h"

#include <math.h>
#include <stdbool.h>
#include <limits.h>

#include "evdev-mt-touchpad.h"

#define DEFAULT_GESTURE_SWITCH_TIMEOUT 100 /* ms */
#define DEFAULT_GESTURE_2FG_SCROLL_TIMEOUT 1000 /* ms */

static struct normalized_coords
tp_get_touches_delta(struct tp_dispatch *tp, bool average)
{
	struct tp_touch *t;
	unsigned int i, nchanged = 0;
	struct normalized_coords normalized;
	struct normalized_coords delta = {0.0, 0.0};

	for (i = 0; i < tp->real_touches; i++) {
		t = &tp->touches[i];

		if (tp_touch_active(tp, t) && t->dirty) {
			nchanged++;
			normalized = tp_get_delta(t);

			delta.x += normalized.x;
			delta.y += normalized.y;
		}
	}

	if (!average || nchanged == 0)
		return delta;

	delta.x /= nchanged;
	delta.y /= nchanged;

	return delta;
}

static inline struct normalized_coords
tp_get_combined_touches_delta(struct tp_dispatch *tp)
{
	return tp_get_touches_delta(tp, false);
}

static inline struct normalized_coords
tp_get_average_touches_delta(struct tp_dispatch *tp)
{
	return tp_get_touches_delta(tp, true);
}

static void
tp_gesture_start(struct tp_dispatch *tp, uint64_t time)
{
	struct libinput *libinput = tp->device->base.seat->libinput;

	if (tp->gesture.started)
		return;

	switch (tp->gesture.finger_count) {
	case 2:
		switch (tp->gesture.twofinger_state) {
		case GESTURE_2FG_STATE_NONE:
		case GESTURE_2FG_STATE_UNKNOWN:
			log_bug_libinput(libinput,
				 "%s in unknown gesture mode\n", __func__);
			break;
		case GESTURE_2FG_STATE_SCROLL:
			/* NOP */
			break;
		case GESTURE_2FG_STATE_PINCH:
			gesture_notify_pinch(&tp->device->base, time,
					    LIBINPUT_EVENT_GESTURE_PINCH_START,
					    0, 0, 0, 0, 0, 0);
			break;
		}
		break;
	case 3:
	case 4:
		gesture_notify_swipe(&tp->device->base, time,
				     LIBINPUT_EVENT_GESTURE_SWIPE_START,
				     tp->gesture.finger_count,
				     0, 0, 0, 0);
		break;
	}
	tp->gesture.started = true;
}

static void
tp_gesture_post_pointer_motion(struct tp_dispatch *tp, uint64_t time)
{
	struct normalized_coords delta, unaccel;

	/* When a clickpad is clicked, combine motion of all active touches */
	if (tp->buttons.is_clickpad && tp->buttons.state)
		delta = tp_get_combined_touches_delta(tp);
	else
		delta = tp_get_average_touches_delta(tp);

	tp_filter_motion(tp, &delta.x, &delta.y, &unaccel.x, &unaccel.y, time);

	if (delta.x != 0.0 || delta.y != 0.0 ||
	    unaccel.x != 0.0 || unaccel.y != 0.0) {
		pointer_notify_motion(&tp->device->base, time,
				      &delta, &unaccel);
	}
}

static unsigned int
tp_gesture_get_active_touches(struct tp_dispatch *tp,
			      struct tp_touch **touches,
			      unsigned int count)
{
	unsigned int i, n = 0;
	struct tp_touch *t;

	memset(touches, 0, count * sizeof(struct tp_touch *));

	for (i = 0; i < tp->real_touches; i++) {
		t = &tp->touches[i];
		if (tp_touch_active(tp, t)) {
			touches[n++] = t;
			if (n == count)
				return count;
		}
	}

	/*
	 * This can happen when the user does .e.g:
	 * 1) Put down 1st finger in center (so active)
	 * 2) Put down 2nd finger in a button area (so inactive)
	 * 3) Put down 3th finger somewhere, gets reported as a fake finger,
	 *    so gets same coordinates as 1st -> active
	 *
	 * We could avoid this by looking at all touches, be we really only
	 * want to look at real touches.
	 */
	return n;
}

static int
tp_gesture_get_direction(struct tp_dispatch *tp, int touch)
{
	double dx, dy, move_threshold;

	/*
	 * Semi-mt touchpads have somewhat inaccurate coordinates when
	 * 2 fingers are down, so use a slightly larger threshold.
	 */
	if (tp->semi_mt)
		move_threshold = TP_MM_TO_DPI_NORMALIZED(4);
	else
		move_threshold = TP_MM_TO_DPI_NORMALIZED(3);

	dx = tp->gesture.touches[touch]->x -
		tp->gesture.touches[touch]->gesture.initial_x;
	dy = tp->gesture.touches[touch]->y -
		tp->gesture.touches[touch]->gesture.initial_y;
	tp_normalize_delta(tp, &dx, &dy);
	if (hypot(dx, dy) < move_threshold)
		return UNDEFINED_DIRECTION;

	return vector_get_direction(dx, dy);
}

static void
tp_gesture_get_pinch_info(struct tp_dispatch *tp,
			  double *distance,
			  double *angle,
			  double *center_x,
			  double *center_y)
{
	double dx, dy;

	dx = tp->gesture.touches[0]->x - tp->gesture.touches[1]->x;
	dy = tp->gesture.touches[0]->y - tp->gesture.touches[1]->y;
	tp_normalize_delta(tp, &dx, &dy);

	*distance = hypot(dx, dy);
	if (!tp->semi_mt)
		*angle = atan2(dy, dx) * 180.0 / M_PI;
	else
		*angle = 0.0;

	*center_x = (tp->gesture.touches[0]->x + tp->gesture.touches[1]->x) / 2;
	*center_y = (tp->gesture.touches[0]->y + tp->gesture.touches[1]->y) / 2;
}

static void
tp_gesture_set_scroll_buildup(struct tp_dispatch *tp)
{
	double dx, dy;

	dx = tp->gesture.touches[0]->x -
		tp->gesture.touches[0]->gesture.initial_x;
	dy = tp->gesture.touches[0]->y -
		tp->gesture.touches[0]->gesture.initial_y;
	dx += tp->gesture.touches[1]->x -
		tp->gesture.touches[1]->gesture.initial_x;
	dy += tp->gesture.touches[1]->y -
		tp->gesture.touches[1]->gesture.initial_y;

	tp->device->scroll.buildup_horizontal = dx / 2.0;
	tp->device->scroll.buildup_vertical = dy / 2.0;
}

static void
tp_gesture_twofinger_state_none(struct tp_dispatch *tp, uint64_t time)
{
	if (tp_gesture_get_active_touches(tp, tp->gesture.touches, 2) != 2)
		return;

	tp->gesture.initial_time = time;
	tp->gesture.touches[0]->gesture.initial_x =
		tp->gesture.touches[0]->x;
	tp->gesture.touches[0]->gesture.initial_y =
		tp->gesture.touches[0]->y;
	tp->gesture.touches[1]->gesture.initial_x =
		tp->gesture.touches[1]->x;
	tp->gesture.touches[1]->gesture.initial_y =
		tp->gesture.touches[1]->y;

	tp->gesture.twofinger_state = GESTURE_2FG_STATE_UNKNOWN;
}

static void
tp_gesture_twofinger_state_unknown(struct tp_dispatch *tp, uint64_t time)
{
	double dx, dy;
	int dir0, dir1;

	dx = tp->gesture.touches[0]->x - tp->gesture.touches[1]->x;
	dy = tp->gesture.touches[0]->y - tp->gesture.touches[1]->y;
	tp_normalize_delta(tp, &dx, &dy);

	/* If fingers are further than 3 cm apart assume pinch */
	if (hypot(dx, dy) > TP_MM_TO_DPI_NORMALIZED(30)) {
		tp->gesture.twofinger_state = GESTURE_2FG_STATE_PINCH;
		tp_gesture_get_pinch_info(tp,
					  &tp->gesture.distance,
					  &tp->gesture.angle,
					  &tp->gesture.center_x,
					  &tp->gesture.center_y);
		return;
	}

	/* Elif fingers have been close together for a while, scroll */
	if (time > (tp->gesture.initial_time + DEFAULT_GESTURE_2FG_SCROLL_TIMEOUT)) {
		tp->gesture.twofinger_state = GESTURE_2FG_STATE_SCROLL;
		tp_gesture_set_scroll_buildup(tp);
		return;
	}

	/* Else wait for both fingers to have moved */
	dir0 = tp_gesture_get_direction(tp, 0);
	dir1 = tp_gesture_get_direction(tp, 1);
	if (dir0 == UNDEFINED_DIRECTION || dir1 == UNDEFINED_DIRECTION)
		return;

	/*
	 * If both touches are moving in the same direction assume scroll.
	 *
	 * In some cases (semi-mt touchpads) We may seen one finger move
	 * e.g. N/NE and the other W/NW so we not only check for overlapping
	 * directions, but also for neighboring bits being set.
	 * The ((dira & 0x80) && (dirb & 0x01)) checks are to check for bit 0
	 * and 7 being set as they also represent neighboring directions.
	 */
	if (((dir0 | (dir0 >> 1)) & dir1) ||
	    ((dir1 | (dir1 >> 1)) & dir0) ||
	    ((dir0 & 0x80) && (dir1 & 0x01)) ||
	    ((dir1 & 0x80) && (dir0 & 0x01))) {
		tp->gesture.twofinger_state = GESTURE_2FG_STATE_SCROLL;
		tp_gesture_set_scroll_buildup(tp);
	} else {
		tp->gesture.twofinger_state = GESTURE_2FG_STATE_PINCH;
		tp_gesture_get_pinch_info(tp,
					  &tp->gesture.distance,
					  &tp->gesture.angle,
					  &tp->gesture.center_x,
					  &tp->gesture.center_y);
	}
}

static void
tp_gesture_twofinger_state_scroll(struct tp_dispatch *tp, uint64_t time)
{
	struct normalized_coords delta;

	delta = tp_get_average_touches_delta(tp);
	tp_filter_motion(tp, &delta.x, &delta.y, NULL, NULL, time);

	if (delta.x == 0.0 && delta.y == 0.0)
		return;

	tp_gesture_start(tp, time);
	evdev_post_scroll(tp->device,
			  time,
			  LIBINPUT_POINTER_AXIS_SOURCE_FINGER,
			  &delta);
}

static void
tp_gesture_twofinger_state_pinch(struct tp_dispatch *tp, uint64_t time)
{
	double dx, dy, distance, angle, center_x, center_y, delta;
	double dx_unaccel, dy_unaccel;

	tp_gesture_get_pinch_info(tp, &distance, &angle,
				  &center_x, &center_y);

	delta = distance - tp->gesture.distance;
	tp->gesture.distance = distance;
	distance = delta;

	delta = angle - tp->gesture.angle;
	if (delta > 180.0)
		delta -= 360.0;
	else if (delta < -180.0)
		delta += 360.0;
	tp->gesture.angle = angle;
	angle = delta;

	dx = center_x - tp->gesture.center_x;
	dy = center_y - tp->gesture.center_y;
	tp->gesture.center_x = center_x;
	tp->gesture.center_y = center_y;
	tp_normalize_delta(tp, &dx, &dy);
	tp_filter_motion(tp, &dx, &dy, &dx_unaccel, &dy_unaccel, time);

	if (dx == 0.0 && dy == 0.0 &&
	    dx_unaccel == 0.0 && dy_unaccel == 0.0 && 
	    distance == 0.0 && angle == 0.0)
		return;

	tp_gesture_start(tp, time);
	gesture_notify_pinch(&tp->device->base, time,
			     LIBINPUT_EVENT_GESTURE_PINCH_UPDATE,
			     dx, dy, dx_unaccel, dy_unaccel,
			     distance, angle);
}

static void
tp_gesture_post_twofinger(struct tp_dispatch *tp, uint64_t time)
{
	switch (tp->gesture.twofinger_state) {
	case GESTURE_2FG_STATE_NONE:
		tp_gesture_twofinger_state_none(tp, time);
		if (tp->gesture.twofinger_state != GESTURE_2FG_STATE_UNKNOWN)
			break;
		/* fall through */
	case GESTURE_2FG_STATE_UNKNOWN:
		tp_gesture_twofinger_state_unknown(tp, time);
		if (tp->gesture.twofinger_state != GESTURE_2FG_STATE_SCROLL)
			break;
		/* fall through */
	case GESTURE_2FG_STATE_SCROLL:
		tp_gesture_twofinger_state_scroll(tp, time);
		break;
	case GESTURE_2FG_STATE_PINCH:
		tp_gesture_twofinger_state_pinch(tp, time);
		break;
	}
}

static void
tp_gesture_post_swipe(struct tp_dispatch *tp, uint64_t time)
{
	double dx, dy, dx_unaccel, dy_unaccel;

	tp_get_average_touches_delta(tp, &dx, &dy);
	tp_filter_motion(tp, &dx, &dy, &dx_unaccel, &dy_unaccel, time);

	if (dx != 0.0 || dy != 0.0 || dx_unaccel != 0.0 || dy_unaccel != 0.0) {
		tp_gesture_start(tp, time);
		gesture_notify_swipe(&tp->device->base, time,
				     LIBINPUT_EVENT_GESTURE_SWIPE_UPDATE,
				     tp->gesture.finger_count,
				     dx, dy, dx_unaccel, dy_unaccel);
	}
}

void
tp_gesture_post_events(struct tp_dispatch *tp, uint64_t time)
{
	if (tp->gesture.finger_count == 0)
		return;

	/* When tap-and-dragging, or a clickpad is clicked force 1fg mode */
	if (tp_tap_dragging(tp) || (tp->buttons.is_clickpad && tp->buttons.state)) {
		tp_gesture_stop(tp, time);
		tp->gesture.finger_count = 1;
		tp->gesture.finger_count_pending = 0;
	}

	/* Don't send events when we're unsure in which mode we are */
	if (tp->gesture.finger_count_pending)
		return;

	switch (tp->gesture.finger_count) {
	case 1:
		tp_gesture_post_pointer_motion(tp, time);
		break;
	case 2:
		tp_gesture_post_twofinger(tp, time);
		break;
	case 3:
	case 4:
		tp_gesture_post_swipe(tp, time);
		break;
	}
}

void
tp_gesture_stop_twofinger_scroll(struct tp_dispatch *tp, uint64_t time)
{
	evdev_stop_scroll(tp->device,
			  time,
			  LIBINPUT_POINTER_AXIS_SOURCE_FINGER);
}

void
tp_gesture_stop(struct tp_dispatch *tp, uint64_t time)
{
	struct libinput *libinput = tp->device->base.seat->libinput;
	enum tp_gesture_2fg_state twofinger_state = tp->gesture.twofinger_state;

	tp->gesture.twofinger_state = GESTURE_2FG_STATE_NONE;

	if (!tp->gesture.started)
		return;

	switch (tp->gesture.finger_count) {
	case 2:
		switch (twofinger_state) {
		case GESTURE_2FG_STATE_NONE:
		case GESTURE_2FG_STATE_UNKNOWN:
			log_bug_libinput(libinput,
				 "%s in unknown gesture mode\n", __func__);
			break;
		case GESTURE_2FG_STATE_SCROLL:
			tp_gesture_stop_twofinger_scroll(tp, time);
			break;
		case GESTURE_2FG_STATE_PINCH:
			gesture_notify_pinch(&tp->device->base, time,
					    LIBINPUT_EVENT_GESTURE_PINCH_END,
					    0, 0, 0, 0, 0, 0);
			break;
		}
		break;
	case 3:
	case 4:
		gesture_notify_swipe(&tp->device->base, time,
				     LIBINPUT_EVENT_GESTURE_SWIPE_END,
				     tp->gesture.finger_count,
				     0, 0, 0, 0);
		break;
	}
	tp->gesture.started = false;
}

static void
tp_gesture_finger_count_switch_timeout(uint64_t now, void *data)
{
	struct tp_dispatch *tp = data;

	if (!tp->gesture.finger_count_pending)
		return;

	tp_gesture_stop(tp, now); /* End current gesture */
	tp->gesture.finger_count = tp->gesture.finger_count_pending;
	tp->gesture.finger_count_pending = 0;
}

void
tp_gesture_handle_state(struct tp_dispatch *tp, uint64_t time)
{
	unsigned int active_touches = 0;
	struct tp_touch *t;

	tp_for_each_touch(tp, t)
		if (tp_touch_active(tp, t))
			active_touches++;

	if (active_touches != tp->gesture.finger_count) {
		/* If all fingers are lifted immediately end the gesture */
		if (active_touches == 0) {
			tp_gesture_stop(tp, time);
			tp->gesture.finger_count = 0;
			tp->gesture.finger_count_pending = 0;
		/* Immediately switch to new mode to avoid initial latency */
		} else if (!tp->gesture.started) {
			tp->gesture.finger_count = active_touches;
			tp->gesture.finger_count_pending = 0;
		/* Else debounce finger changes */
		} else if (active_touches != tp->gesture.finger_count_pending) {
			tp->gesture.finger_count_pending = active_touches;
			libinput_timer_set(&tp->gesture.finger_count_switch_timer,
				time + DEFAULT_GESTURE_SWITCH_TIMEOUT);
		}
	} else {
		 tp->gesture.finger_count_pending = 0;
	}
}

int
tp_init_gesture(struct tp_dispatch *tp)
{
	tp->gesture.twofinger_state = GESTURE_2FG_STATE_NONE;

	libinput_timer_init(&tp->gesture.finger_count_switch_timer,
			    tp->device->base.seat->libinput,
			    tp_gesture_finger_count_switch_timeout, tp);
	return 0;
}

void
tp_remove_gesture(struct tp_dispatch *tp)
{
	libinput_timer_cancel(&tp->gesture.finger_count_switch_timer);
}