File indexing completed on 2024-04-28 05:36:16

 /*
  *   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::toggled() const
 {
     // ignore, we won't toggle the display off
     return -1;
 }
 
 int ScreenBrightnessLogic::valueMin() const
 {
     // 0 can turn off the backlight with some drivers
     return 1;
 }
 
 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;
 }
 
 };