touchscreen: Add gesture recognition API

Add a basic gesture API which can detect taps, long presses,
and dragging gestures.

Change-Id: Id10bf8d46b9195330ce951f9f108c81e87a8dad4
This commit is contained in:
Aidan MacDonald 2022-04-23 16:15:15 +01:00 committed by Solomon Peachy
parent 0f4cc33d26
commit 7aa823215b
3 changed files with 247 additions and 0 deletions

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@ -11,6 +11,9 @@ core_keymap.c
debug_menu.c
filetypes.c
fileop.c
#ifdef HAVE_TOUCHSCREEN
gesture.c
#endif
language.c
main.c
menu.c

121
apps/gesture.c Normal file
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@ -0,0 +1,121 @@
/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright (C) 2022 by Aidan MacDonald
*
* 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 2
* of the License, or (at your option) any later version.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
****************************************************************************/
#include "gesture.h"
#include "button.h"
#include "viewport.h"
#include "system.h"
/* could be a setting */
#define TOUCH_LONG_PRESS_TIME (30 * HZ / 100)
void gesture_reset(struct gesture *g)
{
g->flags = 0;
}
void gesture_process(struct gesture *g, const struct touchevent *ev)
{
/* wait for the first press if we haven't seen it */
if (!gesture_is_pressed(g) && ev->type != TOUCHEVENT_PRESS)
return;
int dx, dy, dist_sqr;
switch (ev->type)
{
case TOUCHEVENT_PRESS:
g->flags |= GESTURE_F_PRESSED | GESTURE_F_VALID;
g->id = GESTURE_NONE;
g->ox = g->x = ev->x;
g->oy = g->y = ev->y;
g->start_tick = ev->tick;
g->last_tick = ev->tick;
break;
case TOUCHEVENT_CONTACT:
g->x = ev->x;
g->y = ev->y;
g->last_tick = ev->tick;
if (g->id == GESTURE_LONG_PRESS)
g->id = GESTURE_HOLD;
else if (g->id == GESTURE_DRAGSTART)
g->id = GESTURE_DRAG;
else if (g->id != GESTURE_DRAG)
{
dx = ev->x - g->ox;
dy = ev->y - g->oy;
dist_sqr = dx*dx + dy*dy;
/* if squared distance exceeds a threshold, report as a DRAG. */
const int thresh = touchscreen_get_scroll_threshold();
if (dist_sqr > thresh*thresh)
g->id = GESTURE_DRAGSTART;
/* report a LONG_PRESS if no motion occurs within a timeout */
if (g->id == GESTURE_NONE &&
TIME_AFTER(ev->tick, g->start_tick + TOUCH_LONG_PRESS_TIME))
g->id = GESTURE_LONG_PRESS;
}
break;
case TOUCHEVENT_RELEASE:
/* report a RELEASE event after a continuous HOLD or DRAG */
if (g->id == GESTURE_HOLD ||
g->id == GESTURE_DRAGSTART ||
g->id == GESTURE_DRAG)
g->id = GESTURE_RELEASE;
/* report a TAP event if we got a press & release without
* triggering any other gestures */
else if (g->id == GESTURE_NONE)
g->id = GESTURE_TAP;
g->flags &= ~GESTURE_F_PRESSED;
g->last_tick = ev->tick;
break;
}
}
bool gesture_get_event_in_vp(struct gesture *g, struct gesture_event *gevt,
const struct viewport *vp)
{
if (!gesture_is_valid(g))
return false;
gevt->id = g->id;
gevt->x = g->x;
gevt->y = g->y;
gevt->ox = g->ox;
gevt->oy = g->oy;
gevt->start_tick = g->start_tick;
gevt->last_tick = g->last_tick;
if (vp) {
gevt->x -= vp->x;
gevt->y -= vp->y;
gevt->ox -= vp->x;
gevt->oy -= vp->y;
}
return !vp || viewport_point_within_vp(vp, g->ox, g->oy);
}

123
apps/gesture.h Normal file
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@ -0,0 +1,123 @@
/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright (C) 2022 Aidan MacDonald
*
* 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 2
* of the License, or (at your option) any later version.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
****************************************************************************/
#ifndef _GESTURE_H_
#define _GESTURE_H_
#include <stddef.h>
#include <stdbool.h>
struct viewport;
struct touchevent;
/** Events which can be detected by the gesture API.
*
* The gesture state machine, informally, looks like this:
*
* NONE --+--> TAP ------------------------------------+
* | |
* +--> LONG_PRESS -----------------------------+
* | | |
* | +---> HOLD ---+ |
* | | | |
* +-------------+---> DRAG ---+--> RELEASE ----+--> NONE
*
* State transitions occur from gesture_process() in response to touch events.
*
* - The NONE "event" is returned prior to any other gesture being detected.
* Although the graph above depicts a transition back to NONE at the end of
* an event chain, that transition in fact happens on the TOUCHEVENT_PRESS
* after the end of the last event.
*
* - TAP events are reported after getting a TOUCHEVENT_RELEASE event if no
* other gestures were detected between the press and release.
*
* - LONG_PRESS events are reported on a TOUCHEVENT_CONTACT event if the long
* press timeout has expired and the touch point hasn't moved too far from
* its initial position.
*
* - HOLD events are reported on TOUCHEVENT_CONTACT events after a LONG_PRESS,
* provided the touch point hasn't moved too far from its initial position.
*
* - DRAG events are reported on TOUCHEVENT_CONTACT events after the touch
* point first moves a certain distance from its initial position. The first
* time this happens, it is reported as DRAGSTART.
*
* - RELEASE events are reported on the TOUCHEVENT_RELEASE event following a
* HOLD or DRAG gesture.
*/
enum gesture_id
{
GESTURE_NONE = 0, /** No gesture */
GESTURE_TAP, /** Quick press & release */
GESTURE_LONG_PRESS, /** Start of a long press */
GESTURE_HOLD, /** Continuation of a long press */
GESTURE_DRAGSTART, /** Start of a DRAG event */
GESTURE_DRAG, /** Press and drag on the screen */
GESTURE_RELEASE, /** End of a HOLD or DRAG event */
};
enum gesture_flags
{
GESTURE_F_VALID = 0x01,
GESTURE_F_PRESSED = 0x02,
};
struct gesture
{
unsigned int flags;
int id;
short x, y;
short ox, oy;
long start_tick;
long last_tick;
};
struct gesture_event
{
int id;
short x, y;
short ox, oy;
long start_tick;
long last_tick;
};
void gesture_reset(struct gesture *g);
void gesture_process(struct gesture *g, const struct touchevent *ev);
bool gesture_get_event_in_vp(struct gesture *g, struct gesture_event *gevt,
const struct viewport *vp);
static inline bool gesture_get_event(struct gesture *g,
struct gesture_event *gevt)
{
return gesture_get_event_in_vp(g, gevt, NULL);
}
static inline bool gesture_is_valid(struct gesture *g)
{
return !!(g->flags & GESTURE_F_VALID);
}
static inline bool gesture_is_pressed(struct gesture *g)
{
return !!(g->flags & GESTURE_F_PRESSED);
}
#endif /* _GESTURE_H_ */