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/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright (C) 2009-2010 by Thomas Martitz
*
* 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 "config.h"
#include "button.h"
#include "kernel.h"
#include "backlight.h"
void scrollwheel(unsigned int wheel_value)
{
#ifndef BOOTLOADER
/* current wheel values, parsed from dbop and the resulting button */
unsigned btn = BUTTON_NONE;
/* old wheel values */
static unsigned old_wheel_value = 0;
static unsigned old_btn = BUTTON_NONE;
/*
* Getting BUTTON_REPEAT works like this: Remember when the btn value was
* posted to the button_queue last, and if it was recent enough, generate
* BUTTON_REPEAT
*/
static long last_wheel_post = 0;
/*
* Providing wheel acceleration works as follows: We increment accel
* by 2 if the wheel was turned, and decrement it by 1 each tick
* (no matter if it was turned), that means: the longer and faster you turn,
* the higher accel will be. accel>>2 will actually posted to the button_queue
*/
static int accel = 0;
/* We only post every 4th action, as this matches better with the physical
* clicks of the wheel */
static int counter = 0;
/* Read wheel
* Bits 13 and 14 of DBOP_DIN change as follows (Gray Code):
* Clockwise rotation 00 -> 01 -> 11 -> 10 -> 00
* Counter-clockwise 00 -> 10 -> 11 -> 01 -> 00
*
* For easy look-up, actual wheel values act as indicies also,
* which is why the table seems to be not ordered correctly
*/
static const unsigned char wheel_tbl[2][4] =
{
{ 2, 0, 3, 1 }, /* Clockwise rotation */
{ 1, 3, 0, 2 }, /* Counter-clockwise */
};
if(button_hold())
{
accel = counter = 0;
return;
}
if (old_wheel_value == wheel_tbl[0][wheel_value])
btn = BUTTON_SCROLL_FWD;
else if (old_wheel_value == wheel_tbl[1][wheel_value])
btn = BUTTON_SCROLL_BACK;
else if (old_wheel_value != wheel_value && accel > ACCEL_INCREMENT)
{ /* if no button is read and wheel_value changed, assume old_btn */
btn = old_btn;
}
/* else btn = BUTTON_NONE */
if (btn != BUTTON_NONE)
{
if (btn != old_btn)
{
/* direction reversals nullify acceleration and counters */
old_btn = btn;
accel = counter = 0;
}
/* wheel_delta will cause lists to jump over items,
* we want this for fast scrolling, but we must keep it accurate
* for slow scrolling */
int wheel_delta = 0;
/* generate BUTTON_REPEAT if quick enough, scroll slightly faster too*/
if (TIME_BEFORE(current_tick, last_wheel_post + WHEEL_REPEAT_INTERVAL))
{
btn |= BUTTON_REPEAT;
wheel_delta = accel>>ACCEL_SHIFT;
}
accel += ACCEL_INCREMENT;
/* the wheel is more reliable if we don't send every change,
* every WHEEL_COUNTER_DIVth is basically one "physical click"
* which should make up 1 item in lists */
if (++counter >= WHEEL_COUNTER_DIV && queue_empty(&button_queue))
{
buttonlight_on();
backlight_on();
queue_post(&button_queue, btn, ((wheel_delta+1)<<24));
/* message posted - reset count and remember post */
counter = 0;
last_wheel_post = current_tick;
}
}
if (accel > 0)
accel--;
old_wheel_value = wheel_value;
#else
(void)wheel_value;
#endif
}
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