add front light intensity adjustment by vertical two_finger_pan

frontend/ui/reader/readerfrontlight.lua

@@ -0,0 +1,60 @@
+package.cpath = package.cpath..";/usr/lib/lua/?.so"
+require "ui/device"
+
+ReaderFrontLight = InputContainer:new{
+	steps = {0,1,2,3,4,5,6,7,8,9,10},
+	intensity = nil,
+}
+
+function ReaderFrontLight:init()
+	local dev_mod = Device:getModel()
+	if dev_mod == "KindlePaperWhite" then
+		require "liblipclua"
+		self.lipc_handle = lipc.init("com.github.koreader")
+		self.intensity = self.lipc_handle:get_int_property("com.lab126.powerd", "flIntensity")
+	end
+	self.ges_events = {
+		Adjust = {
+			GestureRange:new{
+				ges = "two_finger_pan",
+				range = Geom:new{
+					x = 0, y = 0,
+					w = Screen:getWidth(),
+					h = Screen:getHeight(),
+				},
+				rate = 2.0,
+			}
+		},
+	}
+end
+
+function ReaderFrontLight:onAdjust(arg, ges)
+	if self.lipc_handle then
+		local rel_proportion = ges.distance / Screen:getWidth()
+		local delta_int = self.steps[math.floor(#self.steps*rel_proportion)]
+		local msg = ""
+		if ges.direction == "north" then
+			msg = _("Increase front light intensity to ")
+			self.intensity = self.intensity + delta_int
+			self:setIntensity(self.intensity, msg)
+		elseif ges.direction == "south" then
+			msg = _("Decrease front light intensity to ")
+			self.intensity = self.intensity - delta_int
+			self:setIntensity(self.intensity, msg)
+		end
+	end
+	return true
+end
+
+function ReaderFrontLight:setIntensity(intensity, msg)
+	if self.lipc_handle then 
+		intensity = intensity < 0 and 0 or intensity
+		intensity = intensity > 24 and 24 or intensity
+		self.lipc_handle:set_int_property("com.lab126.powerd", "flIntensity", intensity)
+		UIManager:show(Notification:new{
+			text = msg..intensity,
+			timeout = 1
+		})
+	end
+	return true
+end

frontend/ui/readerui.lua

@@ -13,8 +13,9 @@ require "ui/reader/readerconfig"
 require "ui/reader/readercropping"
 require "ui/reader/readerkopt"
 require "ui/reader/readercopt"
-require "ui/reader/readerscreenshot"
 require "ui/reader/readerhinting"
+require "ui/reader/readerscreenshot"
+require "ui/reader/readerfrontlight"
 
 --[[
 This is an abstraction for a reader interface
@@ -99,7 +100,14 @@ function ReaderUI:init()
 		view = self[1],
 		ui = self
 	}
+	-- frontlight controller
+	local reader_fl = ReaderFrontLight:new{
+		dialog = self.dialog,
+		view = self[1],
+		ui = self
+	}
 	table.insert(self.active_widgets, reader_ss)
+	table.insert(self.active_widgets, reader_fl)
 
 	if self.document.info.has_pages then
 		-- for page specific controller