comfortable-swipe/comfortable_swipe/gesture/keyboard_swipe_gesture.cpp

#ifndef __COMFORTABLE_SWIPE__gesture_keyboard_swipe_gesture__
#define __COMFORTABLE_SWIPE__gesture_keyboard_swipe_gesture__

/*
Comfortable Swipe
by Rico Tiongson

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/>.
*/

#include <iostream> // std::cout, std::endl
#include "keyboard_swipe_gesture.h"

extern "C"
{
    #include <xdo.h> // xdo, xdo_new, xdo_free,
                     // xdo_get_mouse_location
                     // CURRENT_WINDOW
}

namespace comfortable_swipe::gesture
{

    /* STATICS DEFINITIONS */
    const int keyboard_swipe_gesture::MSK_THREE_FINGERS = 0;
    const int keyboard_swipe_gesture::MSK_FOUR_FINGERS = 1;
    const int keyboard_swipe_gesture::MSK_NEGATIVE = 0;
    const int keyboard_swipe_gesture::MSK_POSITIVE = 2;
    const int keyboard_swipe_gesture::MSK_HORIZONTAL = 0;
    const int keyboard_swipe_gesture::MSK_VERTICAL = 4;
    const int keyboard_swipe_gesture::FRESH = -1;
    const char * const keyboard_swipe_gesture::command_map[8] = {
        "left3",
        "left4",
        "right3",
        "right4",
        "up3",
        "up4",
        "down3",
        "down4"
    };

    /**
     * Constructs a new keyboard-based swipe gesture, given configurations
     * for certain swipe events. Here, we construct our definition based on
     * the four directions (left, up, right, down) for 3-finger and 4-finger
     * swipes. Note that the direction is based on the Australian natural
     * scrolling direction (ie. left3 is natural movement of 3 fingers left).
     */
    keyboard_swipe_gesture::keyboard_swipe_gesture
    (
        const float threshold,
        const char* left3   /* 000 */,
        const char* left4   /* 001 */,
        const char* right3  /* 010 */,
        const char* right4  /* 011 */,
        const char* up3     /* 100 */,
        const char* up4     /* 101 */,
        const char* down3   /* 110 */,
        const char* down4   /* 111 */
    ):
        // construct superclass
        comfortable_swipe::gesture::swipe_gesture(),
        // compute square of threshold because we will use squared distances
        threshold_squared(threshold*threshold),
        // register our commands
        commands(new const char*[8]{
            left3, left4, right3, right4, up3, up4, down3, down4
        })
    { }

    /**
     * Destructs this keyboard swipe gesture.
     */
    keyboard_swipe_gesture::~keyboard_swipe_gesture()
    {
        delete[] commands;
    }

    /**
     * Hook on begin of swipe gesture.
     */
    void keyboard_swipe_gesture::begin()
    {
        // call superclass method
        swipe_gesture::begin();

        // assign previous gesture to FRESH
        this->previous_gesture = keyboard_swipe_gesture::FRESH;
    }

    /**
     * Hook on update of swipe gesture.
     */
    void keyboard_swipe_gesture::update()
    {
        // call superclass method
        swipe_gesture::update();

        // scale threshold to 1/10 when gesture is not fresh
        float scale =
            this->previous_gesture == keyboard_swipe_gesture::FRESH
            ? 1.00f
            : 0.01f; // square root of 1/10

        // we are working with floating points which are not exact
        // make sure we compare with a very small value (epsilon)
        static const float EPSILON = 1e-6f;
        const float distance_squared = this->x * this->x + this->y * this->y;
        const float beyond_threshold = this->threshold_squared * scale;

        // apply if strictly beyond threshold
        if (distance_squared > beyond_threshold + EPSILON)
        {
            // we parse our mask based on the values obtained from the regex
            int mask = 0;

            if (this->fingers == 3)
                mask |= keyboard_swipe_gesture::MSK_THREE_FINGERS;

            else if (this->fingers == 4)
                mask |= keyboard_swipe_gesture::MSK_FOUR_FINGERS;

            const float absx = x >= 0 ? x : -x;
            const float absy = y >= 0 ? y : -y;

            if (absx > absy)
            {
                // gesture is horizontal
                mask |= keyboard_swipe_gesture::MSK_HORIZONTAL;
                if (x < 0)
                    mask |= keyboard_swipe_gesture::MSK_NEGATIVE;
                else
                    mask |= keyboard_swipe_gesture::MSK_POSITIVE;
            }
            else /* std::abs(x) <= std::abs(y) */
            {
                // gesture is vertical
                mask |= keyboard_swipe_gesture::MSK_VERTICAL;
                if (y < 0)
                    mask |= keyboard_swipe_gesture::MSK_NEGATIVE;
                else
                    mask |= keyboard_swipe_gesture::MSK_POSITIVE;
            }

            // send command on fresh OR opposite gesture
            if (this->previous_gesture == keyboard_swipe_gesture::FRESH
             || this->previous_gesture == (mask ^ keyboard_swipe_gesture::MSK_POSITIVE))
            {
                this->do_keyboard_gesture(mask);
            }
        }
    }

    /**
     * Apply the update given a mask.
     */
    void keyboard_swipe_gesture::do_keyboard_gesture(int mask)
    {
        // perform our keyboard command with xdo_send_keysequence
        const char * command = keyboard_swipe_gesture::commands[mask];
        xdo_send_keysequence_window(this->xdo, CURRENTWINDOW, command, 0);

        // reset our location variables
        this->x = this->y = 0;
        this->previous_gesture = mask;

        // log our command name in stdout
        const char * command_name = keyboard_swipe_gesture::command_map[mask];
        std::cout << "SWIPE " << command_name << std::endl;
    }

    /**
     * Hook on end of swipe gesture.
     */
    void keyboard_swipe_gesture::end()
    {
        // call superclass method
        swipe_gesture::end();
    }

}

#endif /* __COMFORTABLE_SWIPE__gesture_keyboard_swipe_gesture__ */