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mirror of https://github.com/20kdc/OC-KittenOS.git synced 2024-11-15 06:58:05 +11:00
OC-KittenOS/code/libs/bmp.lua
20kdc dcd7154ec2 License 'change' (Please see #5)
This license change should only increase the amount of stuff people can do in countries where the public domain is not a valid concept.
If this license somehow restricts you as opposed to the previous one, please file an issue.
2021-01-12 12:16:50 +00:00

255 lines
7.6 KiB
Lua

-- Copyright (C) 2018-2021 by KittenOS NEO contributors
--
-- Permission to use, copy, modify, and/or distribute this software for any purpose with or without fee is hereby granted.
--
-- THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF
-- THIS SOFTWARE.
-- bmp: Portable OC BMP/DIB library
-- Flexible: Reading can be set to
-- ignore first 14 bytes,
-- allowing reuse of the library on
-- ICO/CUR data. Yes, really.
-- handle(i, valDiv, valMod)
local function bitsCore(i, fieldOfs, fieldWidth, handle)
local adv = math.floor(fieldOfs / 8)
i = i + adv
fieldOfs = fieldOfs - (adv * 8)
-- above 3 lines are a removable optimization
while fieldWidth > 0 do
local bitsHere = math.min(fieldWidth, math.max(0, 8 - fieldOfs))
if bitsHere > 0 then
local pow1 = math.floor(2 ^ bitsHere)
-- offset
-- pixels are "left to right" in the MostSigBitFirst stream
local aFieldOfs = 8 - (fieldOfs + bitsHere)
local pow2 = math.floor(2 ^ aFieldOfs)
handle(i, pow2, pow1)
fieldWidth = fieldWidth - bitsHere
fieldOfs = 0
else
-- in case the 'adv' opt. gets removed
fieldOfs = fieldOfs - 8
end
i = i + 1
end
end
local function encode16(t)
return string.char(t % 0x100) .. string.char(math.floor(t / 0x100))
end
local function encode32(t)
return encode16(t % 0x10000) .. encode16(math.floor(t / 0x10000))
end
-- This & the BMP equivalent return a header,
-- a buffer size, and a 1-based data pointer,
-- and are used to initially create the image.
-- Notably, for bpp <= 8, a paletteSize of 0 is illegal.
-- topDown adjusts the order of scanlines.
-- cMode adjusts some values.
-- IT IS RECOMMENDED YOU PROPERLY SET THE MASK UP.
local function prepareDIB(w, h, p, bpp, paletteSize, topDown, cMode)
if bpp <= 8 then
if paletteSize == 0 then
error("A palette size of 0 is invalid for <= 8-bit images. Use 16-bit or 32-bit for no palette, or specify the amount of palette entries.")
end
end
local scanWB = math.ceil((bpp * w) / 32) * 4
local palSize = paletteSize * 4
local bufSize = scanWB * h * p
local aH = h
if cMode then
-- O.o why change format? who knows!
aH = aH * 2
bufSize = bufSize + ((math.ceil(w / 32) * 4) * h * p)
end
if topDown then
aH = 0x100000000 - aH
end
return
"\x28\x00\x00\x00" .. -- 0x0E
encode32(w) .. -- 0x12
encode32(aH) .. -- 0x16
encode16(p) .. -- 0x1A
encode16(bpp) .. -- 0x1C
"\x00\x00\x00\x00" .. -- 0x1E
encode32(bufSize) .. -- 0x22
"\x00\x00\x00\x00" .. -- 0x26
"\x00\x00\x00\x00" .. -- 0x2A
encode32(paletteSize) .. -- 0x2E
encode32(paletteSize), -- 0x32 then EOH
-- -14 here to move back into headless units
0x36 + palSize + bufSize - 14,
0x36 + palSize + 1 - 14 -- 1-based data pointer
end
return {
headerMinSzBMP = 0x36,
headerMinSzDIB = 0x36 - 14,
-- get/set are (index) and (index, value) respectively
-- they are 1-based
-- If "packed" is used, two things happen:
-- 1. The +1 offeset for 1-based is replaced
-- with packed (so -13 is pure packed-DIB)
-- 2. We don't try to use the BMP header
connect = function (get, set, cMode, packed)
-- NOTE: Internally, BMP addresses are used,
-- so that the Wikipedia page can be used
-- as a valid reference for header fields.
-- verify cMode
if cMode ~= nil and cMode ~= "mask" and cMode ~= "colour" then
error("Unknown cMode " .. cMode)
end
-- NOTE: 0-base is used
local function get8(i)
return get(i + (packed or 1))
end
local function get16(i)
return get8(i) + (256 * get8(i + 1))
end
local function get32(i)
return get16(i) + (65536 * get16(i + 2))
end
local function set8(i, v)
set(i + (packed or 1), v)
end
local function set32(i, v)
local st = encode32(v)
set8(i, st:byte(1))
set8(i + 1, st:byte(2))
set8(i + 2, st:byte(3))
set8(i + 3, st:byte(4))
end
local function getBits(i, fieldOfs, fieldWidth)
local v = 0
local vp = 1
bitsCore(i, fieldOfs, fieldWidth, function (i, valDiv, valMod)
local data = math.floor(get8(i) / valDiv) % valMod
v = v + (data * vp)
vp = vp * valMod
end)
return v
end
local function setBits(i, fieldOfs, fieldWidth, v)
return bitsCore(i, fieldOfs, fieldWidth, function (i, valDiv, valMod)
local data = get8(i)
-- Firstly need to eliminate the old data
data = data - ((math.floor(data / valDiv) % valMod) * valDiv)
-- Now to insert the new data
data = data + ((v % valMod) * valDiv)
set8(i, data)
-- Advance
v = math.floor(v / valMod)
end)
end
-- direct header reads (all of them)
local hdrSize = get32(0x0E)
if hdrSize < 0x28 then
error("OS/2 Bitmaps Incompatible")
end
local width = get32(0x12)
local height = get32(0x16)
local planes = get16(0x1A)
local bpp = get16(0x1C)
local compression = get32(0x1E)
local paletteCol = get32(0x2E)
-- negative height means sane coords
local upDown = true
if height >= 0x80000000 then
height = height - 0x100000000
height = -height
upDown = false
end
-- postprocess
-- The actual values used for addressing, for cMode to mess with
local basePtr = 14 + hdrSize + (paletteCol * 4)
local scanWB = math.ceil((bpp * width) / 32) * 4
local monoWB = math.ceil(width / 32) * 4
local planeWB = scanWB * height
if not packed then
basePtr = get32(0x0A) -- 'BM' header
end
-- Cursor/Icon
if cMode then
height = math.floor(height / 2)
assert(planes == 1, "planes ~= 1 for cursor")
planeWB = planeWB + (monoWB * height)
end
if cMode == "mask" then
if upDown then
basePtr = basePtr + (scanWB * height)
end
bpp = 1
scanWB = monoWB
paletteCol = 0
compression = 3
elseif cMode == "colour" then
if not upDown then
basePtr = basePtr + (monoWB * height)
end
end
-- Check compression
if (compression ~= 0) and (compression ~= 3) and (compression ~= 6) then
error("compression " .. compression .. " unavailable")
end
-- paletteSize correction for comp == 0
if (bpp <= 8) and (paletteCol == 0) and (compression == 0) then
paletteCol = math.floor(2 ^ bpp)
end
return {
width = width,
height = height,
planes = planes,
bpp = bpp,
ignoresPalette = (compression ~= 0) or (paletteCol == 0) or (cMode == "mask"),
paletteCol = paletteCol,
paletteAddress = 14 + hdrSize + (packed or 1),
dataAddress = basePtr + (packed or 1),
dsFull = get32(0x22),
dsSpan = scanWB,
dsPlane = planeWB,
getPalette = function (i)
return get32(14 + hdrSize + (i * 4))
end,
setPalette = function (i, xrgb)
set32(14 + hdrSize + (i * 4), xrgb)
end,
-- Coordinates are 0-based for sanity. Returns raw colour value.
getPixel = function (x, y, p)
if upDown then
y = height - (1 + y)
end
local i = basePtr + (y * scanWB) + (p * planeWB)
return getBits(i, x * bpp, bpp)
end,
-- Uses raw colour value.
setPixel = function (x, y, p, v)
if upDown then
y = height - (1 + y)
end
local i = basePtr + (y * scanWB) + (p * planeWB)
setBits(i, x * bpp, bpp, v)
end
}
end,
-- See prepareDIB above for format.
prepareBMP = function (...)
local head, tLen, dtPtr = prepareDIB(...)
tLen = tLen + 14 -- add BM header
dtPtr = dtPtr + 14
head = "BM" .. encode32(tLen) .. "mRWH" .. encode32(dtPtr - 1) .. head
return head, tLen, dtPtr
end,
prepareDIB = prepareDIB
}