Loading Bitmap images. (BMP)

colorRGB = {
{r = 221, g = 221, b = 221, code = "0"},
{r = 219, g = 125, b = 62, code = "1"},
{r = 179, g = 80, b = 188, code = "2"},
{r = 107, g = 138, b = 201, code = "3"},
{r = 177, g = 166, b = 39, code = "4"},
{r = 65, g = 174, b = 56, code = "5"},
{r = 208, g = 132, b = 153, code = "6"},
{r = 64, g = 64, b = 64, code = "7"},
{r = 154, g = 161, b = 161, code = "8"},
{r = 46, g = 110, b = 137, code = "9"},
{r = 126, g = 61, b = 181, code = "a"},
{r = 46, g = 56, b = 141, code = "b"},
{r = 79, g = 50, b = 31, code = "c"},
{r = 53, g = 70, b = 27, code = "d"},
{r = 150, g = 52, b = 48, code = "e"},
{r = 25, g = 22, b = 22, code = "f"}
}

function readWORD(str, offset)
local loByte = str:byte(offset)
local hiByte = str:byte(offset + 1)
return hiByte * 256 + loByte
end

function readDWORD(str, offset)
local loWord = readWORD(str, offset)
local hiWord = readWORD(str, offset + 2)
return hiWord * 65536 + loWord
end

function get4BitColor(r, g, B)/>
for k, v in ipairs(colorRGB) do
-- print(r .. "/" .. v.r .. " " .. g .. "/" .. v.g .. " " .. b .. "/" .. v.B)/>

local lookVel = 10

if r > v.r - lookVel and r < v.r + lookVel and g > v.g - lookVel and g < v.g + lookVel and b > v.b - lookVel and b < v.b + lookVel then
return v.code
end
end

return " "
end

function loadBitmap(path)
local pixels = {}

local f = assert(io.open(path, "rb"))
local bytecode = ""
local byte = f:read()

while byte ~= nil do
bytecode = bytecode .. string.char(byte)
byte = f:read()
end

f:close()

-- Parse BITMAPFILEHEADER
local offset = 1
local bfType = readWORD(bytecode, offset)
if(bfType ~= 0x4D42) then
print("Not a bitmap file (Invalid BMP magic value)")
error()
end
local offBits = readWORD(bytecode, offset + 10)

-- Parse BITMAPINFOHEADER
offset = 15; -- BITMAPFILEHEADER is 14 bytes long
local width = readDWORD(bytecode, offset + 4)
local height = readDWORD(bytecode, offset + 8)
local bitCount = readWORD(bytecode, offset + 14)
local compression = readDWORD(bytecode, offset + 16)

if(bitCount ~= 24) then
print("Only 24-bit bitmaps supported (Is " .. bitCount .. "bpp)")
error()
end

if(compression ~= 0) then
print("Only uncompressed bitmaps supported (Compression type is " .. compression .. ")")
error()
end

print("Found width " .. width .. "*" .. height)

-- Parse image
for y = height - 1, 0, -1 do
offset = offBits + (width * bitCount / 8) * y + 1

for x = 1, width do
if type(pixels[x]) ~= "table" then
pixels[x] = {}
end

local b = bytecode:byte(offset)
local g = bytecode:byte(offset + 1)
local r = bytecode:byte(offset + 2)
offset = offset + 3

-- print("RGB: " .. r .. " " .. g .. " " .. B)/>

pixels[x][height - y] = get4BitColor(r, g, B)/>
end
end

-- Generate the image
local tmpF = io.open("_tmp.temp", "w")

for y = 1, height do
for x = 1, width do
tmpF:write(pixels[x][y])
end

tmpF:write("\n")
end

tmpF:close()

if paintutils then
local img = paintutils.loadImage("_tmp.temp")
fs.delete("_tmp.temp")

return img
end
end