add DHINTCOUNT in defaults.lua

It controls how many number of pages will be hinted in background
after one page has been drawn. Default DHINTCOUNT is 2.

defaults.lua

@@ -1,7 +1,11 @@
 -- number of page turns between full screen refresh
--- default to full refresh on every page turn
+-- default to do a full refresh on every 6 page turns
 DRCOUNTMAX = 6
 
+-- number of pages for hinting
+-- default to pre-rendering 2 pages
+DHINTCOUNT = 2
+
 -- full screen mode, 1 for true, 0 for false
 DFULL_SCREEN = 1
 

frontend/ui/reader/readerhinting.lua

@@ -3,6 +3,21 @@ ReaderHinting = EventListener:new{
 	hinting_states = {}
 }
 
+function ReaderHinting:onHintPage()
+	if not self.view.hinting then return true end
+	for i=1, DHINTCOUNT do
+		if self.zoom.current_page + i <= self.ui.document.info.number_of_pages then
+			self.ui.document:hintPage(
+				self.view.state.page + i,
+				self.zoom:getZoom(self.view.state.page + i),
+				self.view.state.rotation,
+				self.view.state.gamma,
+				self.view.render_mode)
+		end
+	end
+	return true
+end
+
 function ReaderHinting:onSetHinting(hinting)
 	self.view.hinting = hinting
 end
@@ -16,4 +31,4 @@ end
 function ReaderHinting:onRestoreHinting()
 	self.view.hinting = table.remove(self.hinting_states)
 	return true
-end
+end

frontend/ui/reader/readerzooming.lua

@@ -161,19 +161,6 @@ function ReaderZooming:onReZoom()
 	return true
 end
 
-function ReaderZooming:onHintPage()
-	if not self.view.hinting then return true end
-	if self.current_page < self.ui.document.info.number_of_pages then
-		self.ui.document:hintPage(
-			self.view.state.page + 1,
-			self:getZoom(self.view.state.page + 1),
-			self.view.state.rotation,
-			self.view.state.gamma,
-			self.view.render_mode)
-	end
-	return true
-end
-
 function ReaderZooming:getZoom(pageno)
 	-- check if we're in bbox mode and work on bbox if that's the case
 	local zoom = nil

frontend/ui/readerui.lua

@@ -173,6 +173,7 @@ function ReaderUI:init()
 		-- hinting controller
 		local hinter = ReaderHinting:new{
 			dialog = self.dialog,
+			zoom = zoomer,
 			view = self[1],
 			ui = self,
 			document = self.document,

koreader-base

@@ -1 +1 @@
-Subproject commit 1940f8bd8b7c3c7c855d4fc7e1e86ea3f148c015
+Subproject commit 88c26d984c3232cdd6d03b19a0da5f6c49351810