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device/kobo/sysfs_light: Make used exponent in formulas a variable

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This commit is contained in:
David Engster
2018-03-09 23:15:32 +01:00
committed by Frans de Jonge
parent effc7135a1
commit a912e00aa3
1 changed files with 7 additions and 6 deletions
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13
frontend/device/kobo/sysfs_light.lua
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@@ -17,6 +17,7 @@ local KoboSysfsLight = {
white_offset = -25,
red_offset = 0,
green_offset = -65,
exponent = 0.25,
}
function KoboSysfsLight:new(o)
@@ -61,14 +62,14 @@ function KoboSysfsLight:setNaturalBrightness(brightness, warmth)
if brightness > 0 then
-- On Nickel, the values for white/red/green are roughly linearly dependent
-- on the 4th root of brightness and warmth.
white = math.min(self.white_gain * math.pow(brightness, 0.25) *
math.pow(100 - warmth, 0.25) + self.white_offset, 255)
white = math.min(self.white_gain * math.pow(brightness, self.exponent) *
math.pow(100 - warmth, self.exponent) + self.white_offset, 255)
end
if warmth > 0 then
red = math.min(self.red_gain * math.pow(brightness, 0.25) *
math.pow(warmth, 0.25) + self.red_offset, 255)
green = math.min(self.green_gain * math.pow(brightness, 0.25) *
math.pow(warmth, 0.25) + self.green_offset, 255)
red = math.min(self.red_gain * math.pow(brightness, self.exponent) *
math.pow(warmth, self.exponent) + self.red_offset, 255)
green = math.min(self.green_gain * math.pow(brightness, self.exponent) *
math.pow(warmth, self.exponent) + self.green_offset, 255)
end
white = math.max(white, 0)