215 lines
8.2 KiB
Lua
215 lines
8.2 KiB
Lua
--[[ Lua Image save
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/***************************************************************************
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* __________ __ ___.
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* Open \______ \ ____ ____ | | _\_ |__ _______ ___
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* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
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* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
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* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
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* \/ \/ \/ \/ \/
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* $Id$
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*
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* Copyright (C) 2017 William Wilgus
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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*
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* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
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* KIND, either express or implied.
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*
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****************************************************************************/
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]]
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-- save(img, path/name)
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-- bmp saving derived from rockbox - screendump.c
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-- bitdepth is limited by the device
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-- eg. device displays greyscale, rgb images are saved greyscale
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if not rb.lcd_framebuffer then rb.splash(rb.HZ, "No Support!") return nil end
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do
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local rocklib_image = getmetatable(rb.lcd_framebuffer())
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-- internal constants
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local _NIL = nil -- _NIL placeholder
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local _points = rocklib_image.points
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-- saves img to file: name
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return function(img, name)
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local file
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local bbuffer = {} -- concat buffer for s_bytes
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local fbuffer = {} -- concat buffer for file writes, reused
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local function s_bytesLE(bits, value)
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-- bits must be multiples of 8 (sizeof byte)
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local byte
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local nbytes = bit.rshift(bits, 3)
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for b = 1, nbytes do
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if value > 0 then
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byte = value % 256
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value = (value - byte) / 256
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else
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byte = 0
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end
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bbuffer[b] = string.char(byte)
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end
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return table.concat(bbuffer, _NIL, 1, nbytes)
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end
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local function s_bytesBE(bits, value)
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-- bits must be multiples of 8 (sizeof byte)
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local byte
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local nbytes = bit.rshift(bits, 3)
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for b = nbytes, 1, -1 do
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if value > 0 then
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byte = value % 256
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value = (value - byte) / 256
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else
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byte = 0
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end
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bbuffer[b] = string.char(byte)
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end
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return table.concat(bbuffer, _NIL, 1, nbytes)
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end
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local cmp = {["r"] = function(c) return bit.band(bit.rshift(c, 16), 0xFF) end,
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["g"] = function(c) return bit.band(bit.rshift(c, 08), 0xFF) end,
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["b"] = function(c) return bit.band(c, 0xFF) end}
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local function bmp_color(color)
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return s_bytesLE(8, cmp.b(color))..
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s_bytesLE(8, cmp.g(color))..
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s_bytesLE(8, cmp.r(color))..
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s_bytesLE(8, 0) .. ""
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end -- c_cmp(color, c.r))
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local function bmp_color_mix(c1, c2, num, den)
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-- mixes c1 and c2 as ratio of numerator / denominator
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-- used 2x each save results
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local bc1, gc1, rc1 = cmp.b(c1), cmp.g(c1), cmp.r(c1)
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return s_bytesLE(8, cmp.b(c2) - bc1 * num / den + bc1)..
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s_bytesLE(8, cmp.g(c2) - gc1 * num / den + gc1)..
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s_bytesLE(8, cmp.r(c2) - rc1 * num / den + rc1)..
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s_bytesLE(8, 0) .. ""
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end
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local w, h = img:width(), img:height()
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local depth = tonumber(img:__tostring(6)) -- RLI_INFO_DEPTH = 0x6
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local format = tonumber(img:__tostring(7)) -- RLI_INFO_FORMAT = 0x7
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local bpp, bypl -- bits per pixel, bytes per line
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-- bypl, pad rows to a multiple of 4 bytes
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if depth <= 4 then
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bpp = 8 -- 256 color image
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bypl = (w + 3)
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elseif depth <= 16 then
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bpp = 16
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bypl = (w * 2 + 3)
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elseif depth <= 24 then
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bpp = 24
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bypl = (w * 3 + 3)
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else
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bpp = 32
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bypl = (w * 4 + 3)
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end
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local linebytes = bit.band(bypl, bit.bnot(3))
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local bytesperpixel = bit.rshift(bpp, 3)
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local headersz = 54
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local imgszpad = h * linebytes
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local compression, n_colors = 0, 0
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local h_ppm, v_ppm = 0x00000EC4, 0x00000EC4 --Pixels Per Meter ~ 96 dpi
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if depth == 16 then
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compression = 3 -- BITFIELDS
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n_colors = 3
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elseif depth <= 8 then
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n_colors = bit.lshift(1, depth)
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end
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headersz = headersz + (4 * n_colors)
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file = io.open('/' .. name, "w+") -- overwrite, rb ignores the 'b' flag
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if not file then
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rb.splash(rb.HZ, "Error opening /" .. name)
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return
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end
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-- create a bitmap header 'rope' with image details -- concatenated at end
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local bmpheader = fbuffer
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bmpheader[01] = "BM"
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bmpheader[02] = s_bytesLE(32, headersz + imgszpad)
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bmpheader[03] = "\0\0\0\0" -- WORD reserved 1 & 2
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bmpheader[04] = s_bytesLE(32, headersz) -- BITMAPCOREHEADER size
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bmpheader[05] = s_bytesLE(32, 40) -- BITMAPINFOHEADER size
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bmpheader[06] = s_bytesLE(32, w)
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bmpheader[07] = s_bytesLE(32, h)
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bmpheader[08] = "\1\0" -- WORD color planes ALWAYS 1
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bmpheader[09] = s_bytesLE(16, bpp) -- bits/pixel
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bmpheader[10] = s_bytesLE(32, compression)
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bmpheader[11] = s_bytesLE(32, imgszpad)
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bmpheader[12] = s_bytesLE(32, h_ppm) -- biXPelsPerMeter
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bmpheader[13] = s_bytesLE(32, v_ppm) -- biYPelsPerMeter
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bmpheader[14] = s_bytesLE(32, n_colors)
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bmpheader[15] = s_bytesLE(32, n_colors)
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-- Color Table (#n_colors entries)
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if depth == 1 then -- assuming positive display
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bmpheader[#bmpheader + 1] = bmp_color(0xFFFFFF)
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bmpheader[#bmpheader + 1] = bmp_color(0x0)
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elseif depth == 2 then
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bmpheader[#bmpheader + 1] = bmp_color(0xFFFFFF)
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bmpheader[#bmpheader + 1] = bmp_color_mix(0xFFFFFF, 0, 1, 3)
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bmpheader[#bmpheader + 1] = bmp_color_mix(0xFFFFFF, 0, 2, 3)
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bmpheader[#bmpheader + 1] = bmp_color(0x0)
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elseif depth == 16 then
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if format == 555 then
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-- red bitfield mask
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bmpheader[#bmpheader + 1] = s_bytesLE(32, 0x00007C00)
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-- green bitfield mask
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bmpheader[#bmpheader + 1] = s_bytesLE(32, 0x000003E0)
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-- blue bitfield mask
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bmpheader[#bmpheader + 1] = s_bytesLE(32, 0x0000001F)
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else --565
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-- red bitfield mask
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bmpheader[#bmpheader + 1] = s_bytesLE(32, 0x0000F800)
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-- green bitfield mask
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bmpheader[#bmpheader + 1] = s_bytesLE(32, 0x000007E0)
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-- blue bitfield mask
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bmpheader[#bmpheader + 1] = s_bytesLE(32, 0x0000001F)
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end
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end
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file:write(table.concat(fbuffer))-- write the header to the file now
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for i=1, #fbuffer do fbuffer[i] = _NIL end -- reuse table
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local imgdata = fbuffer
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-- pad rows to a multiple of 4 bytes
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local bytesleft = linebytes - (bytesperpixel * w)
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local t_data = {}
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local fs_bytes_E = s_bytesLE -- default save in Little Endian
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if format == 3553 then -- RGB565SWAPPED
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fs_bytes_E = s_bytesBE -- Saves in Big Endian
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end
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-- Bitmap lines start at bottom unless biHeight is negative
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for point in _points(img, 1, h, w + bytesleft, 1) do
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imgdata[#imgdata + 1] = fs_bytes_E(bpp, point or 0)
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if #fbuffer >= 31 then -- buffered write, increase # for performance
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file:write(table.concat(fbuffer))
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for i=1, #fbuffer do fbuffer[i] = _NIL end -- reuse table
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end
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end
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file:write(table.concat(fbuffer)) --write leftovers to file
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fbuffer = _NIL
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file:close()
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end -- save(img, name)
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end
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