show battery icon in crereader page header

frontend/document/credocument.lua

@@ -297,6 +297,11 @@ function CreDocument:setVisiblePageCount(new_count)
 	self._document:setVisiblePageCount(new_count)
 end
 
+function CreDocument:setBatteryState(state)
+	DEBUG("CreDocument: set battery state", state)
+	self._document:setBatteryState(state)
+end
+
 function CreDocument:register(registry)
 	registry:addProvider("txt", "application/txt", self)
 	registry:addProvider("epub", "application/epub", self)

frontend/ui/reader/readerrolling.lua

@@ -204,10 +204,12 @@ end
 
 function ReaderRolling:onPosUpdate(new_pos)
 	self.current_pos = new_pos
+	self:updateBatteryState()
 end
 
 function ReaderRolling:onPageUpdate(new_page)
 	self.current_page = new_page
+	self:updateBatteryState()
 end
 
 function ReaderRolling:onGotoPercent(percent)
@@ -345,4 +347,15 @@ function ReaderRolling:onGotoPage(number)
 	return true
 end
 
+function ReaderRolling:updateBatteryState()
+	DEBUG("update battery state")
+	if self.view.view_mode == "page" then
+		local powerd = Device:getPowerDevice()
+		local state = powerd:isCharging() and -1 or powerd:getCapacity()
+		if state then
+			self.ui.document:setBatteryState(state)
+		end
+	end
+end
+
 return ReaderRolling

koreader-base

@@ -1 +1 @@
-Subproject commit bf3ef2a6c9002a665b8c224632eba744e6147fe0
+Subproject commit 5c2afc4f9f40b51ebe0ee86c9ba200859559e5f9