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https://github.com/Rockbox/rockbox.git
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bb1e0b48a0
Add a helper for computing the motion velocity during a touchscreen press. Change-Id: I1ef7452ba9815897fd3ec01f8980c89aeef5418f
137 lines
4.5 KiB
C
137 lines
4.5 KiB
C
/***************************************************************************
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* __________ __ ___.
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* Open \______ \ ____ ____ | | _\_ |__ _______ ___
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* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
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* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
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* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
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* \/ \/ \/ \/ \/
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* $Id$
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*
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* Copyright (C) 2022 Aidan MacDonald
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
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* KIND, either express or implied.
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*
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****************************************************************************/
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#ifndef _GESTURE_H_
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#define _GESTURE_H_
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#include <stddef.h>
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#include <stdbool.h>
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struct viewport;
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struct touchevent;
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/** Events which can be detected by the gesture API.
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*
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* The gesture state machine, informally, looks like this:
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*
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* NONE --+--> TAP ------------------------------------+
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* | |
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* +--> LONG_PRESS -----------------------------+
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* | | |
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* | +---> HOLD ---+ |
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* | | | |
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* +-------------+---> DRAG ---+--> RELEASE ----+--> NONE
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*
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* State transitions occur from gesture_process() in response to touch events.
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*
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* - The NONE "event" is returned prior to any other gesture being detected.
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* Although the graph above depicts a transition back to NONE at the end of
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* an event chain, that transition in fact happens on the TOUCHEVENT_PRESS
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* after the end of the last event.
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*
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* - TAP events are reported after getting a TOUCHEVENT_RELEASE event if no
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* other gestures were detected between the press and release.
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*
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* - LONG_PRESS events are reported on a TOUCHEVENT_CONTACT event if the long
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* press timeout has expired and the touch point hasn't moved too far from
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* its initial position.
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*
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* - HOLD events are reported on TOUCHEVENT_CONTACT events after a LONG_PRESS,
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* provided the touch point hasn't moved too far from its initial position.
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*
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* - DRAG events are reported on TOUCHEVENT_CONTACT events after the touch
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* point first moves a certain distance from its initial position. The first
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* time this happens, it is reported as DRAGSTART.
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*
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* - RELEASE events are reported on the TOUCHEVENT_RELEASE event following a
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* HOLD or DRAG gesture.
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*/
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enum gesture_id
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{
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GESTURE_NONE = 0, /** No gesture */
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GESTURE_TAP, /** Quick press & release */
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GESTURE_LONG_PRESS, /** Start of a long press */
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GESTURE_HOLD, /** Continuation of a long press */
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GESTURE_DRAGSTART, /** Start of a DRAG event */
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GESTURE_DRAG, /** Press and drag on the screen */
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GESTURE_RELEASE, /** End of a HOLD or DRAG event */
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};
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enum gesture_flags
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{
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GESTURE_F_VALID = 0x01,
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GESTURE_F_PRESSED = 0x02,
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};
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struct gesture
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{
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unsigned int flags;
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int id;
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short x, y;
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short ox, oy;
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long start_tick;
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long last_tick;
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};
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struct gesture_event
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{
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int id;
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short x, y;
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short ox, oy;
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long start_tick;
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long last_tick;
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};
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void gesture_reset(struct gesture *g);
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void gesture_process(struct gesture *g, const struct touchevent *ev);
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bool gesture_get_event_in_vp(struct gesture *g, struct gesture_event *gevt,
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const struct viewport *vp);
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static inline bool gesture_get_event(struct gesture *g,
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struct gesture_event *gevt)
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{
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return gesture_get_event_in_vp(g, gevt, NULL);
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}
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static inline bool gesture_is_valid(struct gesture *g)
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{
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return !!(g->flags & GESTURE_F_VALID);
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}
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static inline bool gesture_is_pressed(struct gesture *g)
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{
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return !!(g->flags & GESTURE_F_PRESSED);
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}
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/* Helper for computing velocity vectors */
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struct gesture_vel
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{
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size_t idx;
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size_t cnt;
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short xsamp[4];
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short ysamp[4];
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long tsamp[4];
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};
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void gesture_vel_reset(struct gesture_vel *gv);
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void gesture_vel_process(struct gesture_vel *gv, const struct touchevent *ev);
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bool gesture_vel_get(struct gesture_vel *gv, int *xvel, int *yvel);
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#endif /* _GESTURE_H_ */
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