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to save screenshots as bmp (4bpp, 166dpi > fast) or pgm (8bpp, slow)

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NuPogodi
2012-07-05 15:31:44 +03:00
committed by Qingping Hou
parent 17585c2bf4
commit 333537dfd6
1 changed files with 32 additions and 36 deletions
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68
screen.lua
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@@ -107,43 +107,38 @@ function Screen:restoreFromBB(bb)
end
end
-- NuPogodi (02.07.2012): functions to save the fb-content as common graphic files - bmp & pgm.
-- ToDo: png, gif ?
function Screen:screenshot()
lfs.mkdir("./screenshots")
local start = os.clock()
--showInfoMsgWithDelay("making screenshot... ", 1000, 1)
self:BMP(lfs.currentdir().."/screenshots/"..os.date("%Y%m%d%H%M%S")..".bmp", "bzip2 ") -- fastest for 4bpp devices
--self:PGM(lfs.currentdir().."/screenshots/"..os.date("%Y%m%d%H%M%S")..".pgm", "bzip2 ",8) -- fastest for 8bpp devices
showInfoMsgWithDelay(string.format("Screenshot is ready in %.2f(s) ", os.clock()-start), 1000, 1)
end
-- NuPogodi (02.07.2012): added the functions to save the fb-content in common graphic files - bmp & pgm.
-- todo: to look for the arm-compiled bmp2png converter & to use it instead of the current bzip2-packer.
function Screen:LE(i) -- returns value in the little-endian binary sequence (4chars)
local j=i%256 -- lowest byte
return string.char(0,0,j,(i-j)/256)
function Screen:LE(x) -- converts positive upto 32bit-number to a little-endian for bmp-header
local s, n = "", 4
if x<0x10000 then
s = string.char(0,0)
n = 2
end
x = math.floor(x)
for i = 1,n do
s = s..string.char(x%256)
x = math.floor(x/256)
end
return s
end
--[[ This function saves the 4bpp framebuffer as 4bpp BMP and, if necessary, packes the output by command os.execute(pack..fn).
Since framebuffer enumerates the lines from top to bottom and the bmp-file does it in the inversed order, the process includes
a vertical flip that makes it a bit slower - ~0.15(s) @ Kindle3 & Kindle2.
a vertical flip that makes it a bit slower - ~0.16(s) @ Kindle3 & Kindle2.
NB: needs free memory of G_width*G_height/2 bytes to manupulate the fb-content! ]]
function Screen:BMP(fn, pack) -- for 4bpp framebuffers only
local inputf = assert(io.open("/dev/fb0","rb"))
function Screen:fb2bmp(fin, fout, pack) -- atm, for 4bpp framebuffers only
local inputf = assert(io.open(fin,"rb"))
if inputf then
local outputf, size = assert(io.open(fn,"wb"))
if math.max(G_width,G_height)>1000 then -- KDX(G)
size=string.char(0x98,0x8D,7,0) -- raw bytes in image 825*1200/2 = 0x00078D98 @ KDX(G)
else -- 600x800
size=string.char(0x80,0xA9,3,0) -- raw bytes in image 600*800/2 = 0x0003A980 @ K2&3
end
local outputf, size = assert(io.open(fout,"wb"))
-- writing bmp-header
outputf:write(string.char(0x42,0x4D,0xF6,0xA9,3,0,0,0,0,0,0x76,0,0,0,40,0),
self:LE(G_width), self:LE(G_height), -- width & height: 4 chars each
string.char(0,0,1,0,4,0,0,0,0,0), size,
string.char(0x87,0x19,0,0,0x87,0x19,0,0), -- 0x87,0x19,0x00,0x00 = 6536 pix/m = 166 dpi - resolution_x, res_y
string.char(0,0,1,0,4,0,0,0,0,0),
self:LE(G_width*G_height/2), -- raw bytes in image
string.char(0x87,0x19,0,0,0x87,0x19,0,0), -- 6536 pixel/m = 166 dpi for both x&y resolutions
string.char(16,0,0,0,0,0,0,0)) -- 16 colors
local line, i = G_width/2, 15
-- add palette to bmp-header
@@ -162,28 +157,28 @@ function Screen:BMP(fn, pack) -- for 4bpp framebuffers only
end
inputf:close()
outputf:close()
if pack then os.execute(pack..fn) end
if pack then os.execute(pack..fout) end
end
end
--[[ This function saves the fb-content (both 4bpp and 8bpp) as 8bpp PGM and pack it. It's relatively slow for 4bpp devices
(~2.5s on Kindle3, 600x800, 4bpp), but should be extremely fast (<0.1s) when no 4bbp to 8bpp is needed. ]]
(~2.5s on Kindle3, 600x800, 4bpp), but should be extremely fast (<0.1s) when no color conversion (4bpp>8bpp) is needed. ]]
function Screen:PGM(fn, pack, bpp)
local inputf = assert(io.open("/dev/fb0","rb"))
function Screen:fb2pgm(fin, fout, pack, bpp)
local inputf = assert(io.open(fin,"rb"))
if inputf then
local outputf = assert(io.open(fn,"wb"))
local outputf = assert(io.open(fout,"wb"))
outputf:write("P5\n\# Created by kindlepdfviewer\n"..G_width.." "..G_height.."\n255\n")
if bpp == 8 then -- needs free memory of G_width*G_height bytes!
if bpp == 8 then -- then needs free memory of G_width*G_height bytes, but extremely fast!
outputf:write(inputf:read("*all"))
else -- convert 4bpp to 8bpp; needs free memory to store a block = G_width/2 bytes (could be changed)
else -- convert 4bpp to 8bpp; needs free memory just to store a block = G_width/2 bytes
local bpp8, block, i, j, line = {}, G_width/2
-- to accelerate a process, let us first create the convertion table: char (0..255) > 2 chars
for j=0, 255 do
i = j%16
bpp8[#bpp8+1] = string.char(255-j+i)..string.char(255-i*16)
bpp8[#bpp8+1] = string.char(255-j+i, 255-i*16)
end
-- now read, convert & write the fb0-content by blocks
-- now read, convert & write the fb-content by blocks
for i=1, G_height do
line = inputf:read(block)
for j=1, block do
@@ -193,6 +188,7 @@ function Screen:PGM(fn, pack, bpp)
end
inputf:close()
outputf:close()
if pack then os.execute(pack..fn) end
if pack then os.execute(pack..fout) end
end
end