mousegesturerecognizer.cpp

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/*
 * This file is part of the mouse gesture package.
 * Copyright (C) 2006 Johan Thelin <e8johan@gmail.com>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or
 * without modification, are permitted provided that the
 * following conditions are met:
 *
 *   - Redistributions of source code must retain the above
 *     copyright notice, this list of conditions and the
 *     following disclaimer.
 *   - Redistributions in binary form must reproduce the
 *     above copyright notice, this list of conditions and
 *     the following disclaimer in the documentation and/or
 *     other materials provided with the distribution.
 *   - The names of its contributors may be used to endorse
 *     or promote products derived from this software without
 *     specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
 * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
 * GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
 * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 *
 */
 
#include "mousegesturerecognizer.h"
 
using namespace Gesture;
 
// Private data structure
struct MouseGestureRecognizer::Private {
    PosList positions;
    GestureList gestures;
 
    int minimumMovement2;
    double minimumMatch;
 
    bool allowDiagonals;
};
 
// Class implementation
 
MouseGestureRecognizer::MouseGestureRecognizer(int minimumMovement, double minimumMatch, bool allowDiagonals)
{
    d = new Private;
    d->minimumMovement2 = minimumMovement * minimumMovement;
    d->minimumMatch = minimumMatch;
 
    d->allowDiagonals = allowDiagonals;
}
 
MouseGestureRecognizer::~MouseGestureRecognizer()
{
    delete d;
}
 
void MouseGestureRecognizer::addGestureDefinition(const GestureDefinition &gesture)
{
    d->gestures.push_back(gesture);
}
 
void MouseGestureRecognizer::clearGestureDefinitions()
{
    d->gestures.clear();
}
 
void MouseGestureRecognizer::startGesture(int x, int y)
{
    d->positions.clear();
    d->positions.push_back(Pos(x, y));
}
 
bool MouseGestureRecognizer::endGesture(int x, int y)
{
    bool matched = false;
 
    if (x != d->positions.back().x || y != d->positions.back().y) {
        d->positions.push_back(Pos(x, y));
    }
 
    int dx = x - d->positions.at(0).x;
    int dy = y - d->positions.at(0).y;
 
    if (dx * dx + dy * dy < d->minimumMovement2) {
        return false;
    }
 
    if (d->positions.size() > 1) {
        matched = recognizeGesture();
    }
 
    d->positions.clear();
 
    return matched;
}
 
void MouseGestureRecognizer::abortGesture()
{
    d->positions.clear();
}
 
void MouseGestureRecognizer::addPoint(int x, int y)
{
    int dx, dy;
 
    dx = x - d->positions.back().x;
    dy = y - d->positions.back().y;
 
    if (dx * dx + dy * dy >= d->minimumMovement2) {
        d->positions.push_back(Pos(x, y));
    }
}
 
PosList MouseGestureRecognizer::currentPath() const
{
    return d->positions;
}
 
bool MouseGestureRecognizer::recognizeGesture()
{
    PosList directions = simplify(limitDirections(d->positions, d->allowDiagonals));
    double minLength = calcLength(directions) * d->minimumMatch;
 
    while (directions.size() > 0 && calcLength(directions) > minLength) {
        for (GestureList::const_iterator gi = d->gestures.begin(); gi != d->gestures.end(); ++gi) {
            if (gi->directions.size() == directions.size()) {
                bool match = true;
                PosList::const_iterator pi = directions.begin();
                for (DirectionList::const_iterator di = gi->directions.begin(); di != gi->directions.end() && match; ++di, ++pi) {
                    switch (*di) {
                    case UpLeft:
                        if (!(pi->y < 0 && pi->x < 0)) {
                            match = false;
                        }
 
                        break;
                    case UpRight:
                        if (!(pi->y < 0 && pi->x > 0)) {
                            match = false;
                        }
 
                        break;
                    case DownLeft:
                        if (!(pi->y > 0 && pi->x < 0)) {
                            match = false;
                        }
 
                        break;
                    case DownRight:
                        if (!(pi->y > 0 && pi->x > 0)) {
                            match = false;
                        }
 
                        break;
                    case Up:
                        if (pi->y >= 0 || pi->x != 0) {
                            match = false;
                        }
 
                        break;
                    case Down:
                        if (pi->y <= 0 || pi->x != 0) {
                            match = false;
                        }
 
                        break;
                    case Left:
                        if (pi->x >= 0 || pi->y != 0) {
                            match = false;
                        }
 
                        break;
                    case Right:
                        if (pi->x <= 0 || pi->y != 0) {
                            match = false;
                        }
 
                        break;
                    case AnyHorizontal:
                        if (pi->x == 0 || pi->y != 0) {
                            match = false;
                        }
 
                        break;
                    case AnyVertical:
                        if (pi->y == 0 || pi->x != 0) {
                            match = false;
                        }
 
                        break;
                    case NoMatch:
                        match = false;
 
                        break;
                    }
                }
 
                if (match) {
                    gi->callbackClass->callback();
                    return true;
                }
            }
        }
 
        directions = simplify(removeShortest(directions));
    }
 
    for (GestureList::const_iterator gi = d->gestures.begin(); gi != d->gestures.end(); ++gi) {
        if (gi->directions.size() == 1) {
            if (gi->directions.back() == NoMatch) {
                gi->callbackClass->callback();
                return true;
            }
        }
    }
 
    return false;
}
 
// Support functions implementation
 
/*
 *  limitDirections - limits the directions of a list to up, down, left or right.
 *
 *  Notice! This function converts the list to a set of relative moves instead of a set of screen coordinates.
 */
PosList MouseGestureRecognizer::limitDirections(const PosList &positions, bool allowDiagonals)
{
    PosList res;
    int lastx, lasty;
    bool firstTime = true;
 
    for (PosList::const_iterator ii = positions.begin(); ii != positions.end(); ++ii) {
        if (firstTime) {
            lastx = ii->x;
            lasty = ii->y;
 
            firstTime = false;
        }
        else {
            int dx, dy;
 
            dx = ii->x - lastx;
            dy = ii->y - lasty;
 
            const int directions[8][2] = { {0, 15}, {0, -15}, {15, 0}, { -15, 0}, {10, 10}, { -10, 10}, { -10, -10}, {10, -10} };
            int maxValue = 0;
            int maxIndex = -1;
 
            for (int i = 0; i < (allowDiagonals ? 8 : 4); i++) {
                int value = dx * directions[i][0] + dy * directions[i][1];
                if (value > maxValue) {
                    maxValue = value;
                    maxIndex = i;
                }
            }
 
            if (maxIndex == -1) {
                dx = dy = 0;
            }
            else {
                dx = directions[maxIndex][0]; // * abs(sqrt(maxValue))
                dy = directions[maxIndex][1]; // * abs(sqrt(maxValue))
            }
 
            res.push_back(Pos(dx, dy));
 
            lastx = ii->x;
            lasty = ii->y;
        }
    }
 
    return res;
}
 
/*
 *  simplify - joins together continuous movements in the same direction.
 *
 *  Notice! This function expects a list of limited directions.
 */
PosList MouseGestureRecognizer::simplify(const PosList &positions)
{
    PosList res;
    int lastdx = 0, lastdy = 0;
    bool firstTime = true;
 
    for (PosList::const_iterator ii = positions.begin(); ii != positions.end(); ++ii) {
        if (firstTime) {
            lastdx = ii->x;
            lastdy = ii->y;
 
            firstTime = false;
        }
        else {
            bool joined = false;
 
            //horizontal lines
            if (((lastdx > 0 && ii->x > 0) || (lastdx < 0 && ii->x < 0)) && (lastdy == 0 && ii->y == 0)) {
                lastdx += ii->x;
                joined = true;
            }
            //vertical
            if (((lastdy > 0 && ii->y > 0) || (lastdy < 0 && ii->y < 0)) && (lastdx == 0 && ii->x == 0)) {
                lastdy += ii->y;
                joined = true;
            }
            //down right/left
            if (((lastdx > 0 && ii->x > 0) || (lastdx < 0 && ii->x < 0)) && (lastdy > 0 && ii->y > 0)) {
                lastdx += ii->x;
                lastdy += ii->y;
                joined = true;
            }
            //up left/right
            if (((lastdx > 0 && ii->x > 0) || (lastdx < 0 && ii->x < 0)) && (lastdy < 0 && ii->y < 0)) {
                lastdx += ii->x;
                lastdy += ii->y;
                joined = true;
            }
 
            if (!joined) {
                res.push_back(Pos(lastdx, lastdy));
 
                lastdx = ii->x;
                lastdy = ii->y;
            }
        }
    }
 
    if (lastdx != 0 || lastdy != 0) {
        res.push_back(Pos(lastdx, lastdy));
    }
 
    return res;
}
 
/*
 *  removeShortest - removes the shortest segment from a list of movements.
 *
 *  If there are several equally short segments, the first one is removed.
 */
PosList MouseGestureRecognizer::removeShortest(const PosList &positions)
{
    PosList res;
 
    int shortestSoFar;
    PosList::const_iterator shortest;
    bool firstTime = true;
 
    for (PosList::const_iterator ii = positions.begin(); ii != positions.end(); ++ii) {
        if (firstTime) {
            shortestSoFar = ii->x * ii->x + ii->y * ii->y;
            shortest = ii;
 
            firstTime = false;
        }
        else {
            if ((ii->x * ii->x + ii->y * ii->y) < shortestSoFar) {
                shortestSoFar = ii->x * ii->x + ii->y * ii->y;
                shortest = ii;
            }
        }
    }
 
    for (PosList::const_iterator ii = positions.begin(); ii != positions.end(); ++ii) {
        if (ii != shortest) {
            res.push_back(*ii);
        }
    }
 
    return res;
}
 
/*
 *  calcLength - calculates the total length of the movements from a list of relative movements.
 */
int MouseGestureRecognizer::calcLength(const PosList &positions)
{
    int res = 0;
 
    for (PosList::const_iterator ii = positions.begin(); ii != positions.end(); ++ii) {
        if (ii->x > 0) {
            res += ii->x;
        }
        else if (ii->x < 0) {
            res -= ii->x;
        }
        else if (ii->y > 0) {
            res += ii->y;
        }
        else {
            res -= ii->y;
        }
    }
 
    return res;
}