koreader/frontend/ui/device/screen.lua

local Geom = require("ui/geometry")
local DEBUG = require("dbg")

-- Blitbuffer
-- einkfb

--[[
Codes for rotation modes:

1 for no rotation,
2 for landscape with bottom on the right side of screen, etc.

           2
   +--------------+
   | +----------+ |
   | |          | |
   | | Freedom! | |
   | |          | |
   | |          | |
 3 | |          | | 1
   | |          | |
   | |          | |
   | +----------+ |
   |              |
   |              |
   +--------------+
          0
--]]


local Screen = {
	cur_rotation_mode = 0,
	native_rotation_mode = nil,

	bb = nil,
	saved_bb = nil,

	fb = einkfb.open("/dev/fb0"),
	-- will be set upon loading by Device class:
	device = nil,
}

function Screen:init()
	self.bb = self.fb.bb
	-- asking the framebuffer for orientation is error prone,
	-- so we do this simple heuristic (for now)
	if self:getWidth() > self:getHeight() then
		self.native_rotation_mode = 1
	else
		self.native_rotation_mode = 0
	end
	self.cur_rotation_mode = self.native_rotation_mode
end

function Screen:refresh(refresh_type, waveform_mode, x, y, w, h)
	self.fb:refresh(refresh_type, waveform_mode, x, y, w, h)
end

function Screen:getSize()
	return Geom:new{w = self.bb:getWidth(), h = self.bb:getHeight()}
end

function Screen:getWidth()
	return self.bb:getWidth()
end

function Screen:getHeight()
	return self.bb:getHeight()
end

function Screen:getDPI()
	if(self.device:getModel() == "KindlePaperWhite")
	or (self.device:getModel() == "Kobo_kraken")
	or (self.device:getModel() == "Kobo_phoenix") then
		return 212
	elseif self.device:getModel() == "Kobo_dragon" then
		return 265
	elseif self.device:getModel() == "Kobo_pixie" then
		return 200
	else
		return 167
	end
end

function Screen:scaleByDPI(px)
	return math.floor(px * self:getDPI()/167)
end

function Screen:rescaleByDPI(px)
	return math.ceil(px * 167/self:getDPI())
end

function Screen:getRotationMode()
	return self.cur_rotation_mode
end

function Screen:getScreenMode()
	if self:getWidth() > self:getHeight() then
		return "landscape"
	else
		return "portrait"
	end
end

function Screen:setRotationMode(mode)
	self.fb.bb:rotateAbsolute(-90 * (mode - self.native_rotation_mode))
	self.cur_rotation_mode = mode
end

function Screen:setScreenMode(mode)
	if mode == "portrait" then
		if self.cur_rotation_mode ~= 0 then
			self:setRotationMode(0)
		end
	elseif mode == "landscape" then
		if self.cur_rotation_mode == 0 or self.cur_rotation_mode == 2 then
			self:setRotationMode(1)
		elseif self.cur_rotation_mode == 1 or self.cur_rotation_mode == 3 then
			self:setRotationMode((self.cur_rotation_mode + 2) % 4)
		end
	end
end

function Screen:saveCurrentBB()
	local width, height = self:getWidth(), self:getHeight()

	if not self.saved_bb then
		self.saved_bb = Blitbuffer.new(width, height)
	end
	if self.saved_bb:getWidth() ~= width then
		self.saved_bb:free()
		self.saved_bb = Blitbuffer.new(width, height)
	end
	self.saved_bb:blitFullFrom(self.bb)
end

function Screen:restoreFromSavedBB()
	self:restoreFromBB(self.saved_bb)
	-- free data
	self.saved_bb = nil
end

function Screen:getCurrentScreenBB()
	local bb = Blitbuffer.new(self:getWidth(), self:getHeight())
	bb:blitFullFrom(self.bb)
	return bb
end

function Screen:restoreFromBB(bb)
	if bb then
		self.bb:blitFullFrom(bb)
	else
		DEBUG("Got nil bb in restoreFromSavedBB!")
	end
end

return Screen