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/*
* SPDX-FileCopyrightText: 2014 Nikita Skovoroda <chalkerx@gmail.com>
*
* SPDX-License-Identifier: GPL-2.0-or-later
*/
#include "powerdevilscreenbrightnesslogic.h"
#include "powerdevil_debug.h"
#include <QDebug>
namespace PowerDevil
{
int ScreenBrightnessLogic::calculateSteps(int maxValue) const
{
// We assume that the preferred number of steps for screen brightness is 20, but we don't want more.
if (maxValue <= 20) {
// Too few steps, return the number of actual steps.
// Those would be uniform, but not round in some cases.
return maxValue;
}
if (maxValue >= 100 || maxValue % 20 == 0 || (maxValue >= 80 && maxValue % 4 == 0)) {
// In this case all 20 steps are perfect.
return 20;
}
// At this point we have maxValue in the range 21-79 which probably is a rare case.
if (maxValue >= 34 || maxValue == 32 || maxValue == 28) {
// In this case all 20 steps are matched +-1%, which is fine.
return 20;
}
// At this point we have maxValue in the range 21-33.
// Trying to make 20 steps from here will make them not uniform.
if (maxValue % 5 == 0) {
// For maxValue == 30 there are 10 even and round steps.
// For maxValue == 25 steps are shown as
// 0% 12% 20% 32% 40% 52% 60% 72% 80% 92% 100%, which is also fine.
return 10;
}
// Trying hard to find an uniform steps set
for (int steps = 9; steps <= 14; steps++) {
if (maxValue % steps == 0) {
return steps;
}
}
// 4 different maxValue values left: 21, 23, 29, 31.
// Those produce +-2% on 10 steps, there is nothing better we can do here.
return 10;
}
};
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