add SetScreenViewMode event and related handler in ReaderView

frontend/ui/reader/readermenu.lua

@@ -37,17 +37,15 @@ function ReaderMenu:setUpdateItemTable()
 			{
 				text = "landscape",
 				callback = function()
-					Screen:setViewMode("landscape")
 					self.ui:handleEvent(
-						Event:new("SetDimensions", Screen:getSize()))
+						Event:new("SetScreenViewMode", "landscape"))
 				end
 			},
 			{
 				text = "portrait",
 				callback = function()
-					Screen:setViewMode("portrait")
 					self.ui:handleEvent(
-						Event:new("SetDimensions", Screen:getSize()))
+						Event:new("SetScreenViewMode", "portrait"))
 				end
 			},
 		}

frontend/ui/reader/readerview.lua

@@ -130,6 +130,14 @@ function ReaderView:PanningUpdate(dx, dy)
 	return true
 end
 
+function ReaderView:onSetScreenViewMode(new_mode)
+	if new_mode == "landscape" or new_mode == "portrait" then
+		Screen:setViewMode(new_mode)
+		self.ui:handleEvent(Event:new("SetDimensions", Screen:getSize()))
+	end
+	return true
+end
+
 function ReaderView:onSetDimensions(dimensions)
 	self.dimen = dimensions
 	-- recalculate view