/*****************************************************************************
 *
 * grail - Gesture Recognition And Instantiation Library
 *
 * Copyright (C) 2010 Canonical Ltd.
 *
 * This program is free software: you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the
 * Free Software Foundation, either version 3 of the License, or (at your
 * option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 * Authors:
 *      Henrik Rydberg <rydberg@bitmath.org>
 *
 ****************************************************************************/

#include "grail-recognizer.h"
#include <math.h>

void gru_reset_scroll(struct grail *ge,
				 const struct touch_frame *frame)
{
	struct gesture_inserter *gin = ge->gin;
	struct gesture_recognizer *gru = ge->gru;
	struct scroll_model *state = &gru->scroll;
	struct move_model *move = &gru->move;
	gin_gesture_discard_type(gin, GRAIL_TYPE_SCROLL);
	state->x = move->x;
	state->y = move->y;
	state->active = 0;
	state->moving = 0;
}

int gru_scroll(struct grail *ge,
			  const struct touch_frame *frame)
{
	struct gesture_inserter *gin = ge->gin;
	struct gesture_recognizer *gru = ge->gru;
	struct scroll_model *state = &gru->scroll;
	struct move_model *move = &gru->move;
	grail_prop_t prop[DIM_GRAIL_PROP];
	float dx, dy;
	int i;
	dx = move->x - state->x;
	dy = move->y - state->y;
	if (fabs(dx) < 1 && fabs(dy) < 1)
		return 0;
	if (!state->active) {
		i = gin_gesture_begin(ge, GRAIL_TYPE_SCROLL, 1,
				      frame->touches, sizeof(frame->touches));
		state->geslot = i;
		state->active = 1;
	}
	if (!state->moving && fabs(dx) < move->xbar && fabs(dy) < move->ybar)
		return 0;
	state->moving = 1;
	prop[0] = dx;
	prop[1] = dy;
	gin_gesture_event(gin, state->geslot,
			  move->x, move->y, move->ntouch,
			  prop, 2);
	state->x = move->x;
	state->y = move->y;
	return 1;
}