use rotate gesture to set screen mode

frontend/ui/reader/readerrotation.lua

@@ -1,12 +1,42 @@
 ReaderRotation = InputContainer:new{
-	key_events = {
-		-- these will all generate the same event, just with different arguments
-		RotateLeft = { {"J"}, doc = "rotate left by 90 degrees", event = "Rotate", args = -90 },
-		RotateRight = { {"K"}, doc = "rotate right by 90 degrees", event = "Rotate", args = 90 },
-	},
+	ROTATE_ANGLE_THRESHOLD = 15,
 	current_rotation = 0
 }
 
+function ReaderRotation:init()
+	if Device:hasKeyboard() then
+		self.key_events = {
+			-- these will all generate the same event, just with different arguments
+			RotateLeft = { {"J"}, doc = "rotate left by 90 degrees", event = "Rotate", args = -90 },
+			RotateRight = { {"K"}, doc = "rotate right by 90 degrees", event = "Rotate", args = 90 },
+		}
+	end
+	if Device:isTouchDevice() then
+		self.ges_events = {
+			RotateGes = {
+				GestureRange:new{
+					ges = "rotate",
+					range = Geom:new{
+						x = 0, y = 0,
+						w = Screen:getWidth(),
+						h = Screen:getHeight(),
+					}
+				}
+			},
+			TwoFingerPanRelease = {
+				GestureRange:new{
+					ges = "two_finger_pan_release",
+					range = Geom:new{
+						x = 0, y = 0,
+						w = Screen:getWidth(),
+						h = Screen:getHeight(),
+					}
+				}
+			}
+		}
+	end
+end
+
 -- TODO: reset rotation on new document, maybe on new page?
 
 function ReaderRotation:onRotate(rotate_by)
@@ -14,3 +44,19 @@ function ReaderRotation:onRotate(rotate_by)
 	self.ui:handleEvent(Event:new("RotationUpdate", self.current_rotation))
 	return true
 end
+
+function ReaderRotation:onRotateGes(arg, ges)
+	self.ratate_angle = ges.angle
+	return true
+end
+
+function ReaderRotation:onTwoFingerPanRelease(arg, ges)
+	if self.ratate_angle and self.ratate_angle > self.ROTATE_ANGLE_THRESHOLD then
+		if Screen:getScreenMode() == "portrait" then
+			self.ui:handleEvent(Event:new("SetScreenMode", "landscape"))
+		else
+			self.ui:handleEvent(Event:new("SetScreenMode", "portrait"))
+		end
+		self.ratate_angle = nil
+	end
+end