# Ftf libs

Here are some longer code (classes) from the Gideros forum and some other places :-)
All samples are ready to use. Enjoy!

## GFX

### Hex to Number / Number to Hex

```--[[
Lua Hex v0.4
-------------------
Hex conversion lib for Lua.

How to use:
lhex.to_hex(n) -- convert a number to a hex string
lhex.to_dec(hex) -- convert a hex "string" (prefix with "0x..." or "0X...") to number

Part of LuaBit(http://luaforge.net/projects/bit/).

--]]

local function to_bits(n)
-- checking not float
if(n - (n//1) > 0) then error("trying to apply bitwise operation on non-integer!") end
-- to bits table
local tbl = {}
local cnt = 1
while (n > 0) do
local last = n%2
if(last == 1) then tbl[cnt] = 1
else tbl[cnt] = 0
end
n = (n-last)/2
cnt += 1
end
return tbl
end

local function tbl_to_number(tbl)
local n = #tbl
local rslt = 0
local power = 1
for i = 1, n do
rslt += tbl[i]*power
power *= 2
end
return rslt
end

local function to_hex(n)
if(type(n) ~= "number") then error("non-number type passed in.") end
-- checking not float
if(n - (n//1) > 0) then error("trying to apply bitwise operation on non-integer!") end
if(n < 0) then -- negative
n = to_bits(~(-n<>n) + 1)
n = tbl_to_number(n)
end
local hex_tbl = { "A", "B", "C", "D", "E", "F" }
local hex_str = ""
while(n ~= 0) do
local last = n%16
if(last < 10) then hex_str = tostring(last) .. hex_str
else hex_str = hex_tbl[last-10+1] .. hex_str
end
n = (n/16)//1 -- floor
end
if(hex_str == "") then hex_str = "0" end
return "0x"..hex_str
end

local function to_dec(hexstring)
if(type(hexstring) ~= "string") then error("non-string type passed in.") end
local head = string.sub(hexstring, 1, 2)
if(head ~= "0x" and head ~= "0X") then error("wrong hex format, should lead by 0x or 0X.") end
end

--------------------
-- lua hex lib interface
lhex = {
to_hex=to_hex,
to_dec=to_dec,
}

--------------------
-- examples
local dec = 4341688
local hex = lhex.to_hex(dec) -- number to hex
print(hex) -- 0x423FB8
local revdec = lhex.to_dec(hex) -- hex string (prefix with "0x" or "0X") to number
print(revdec) -- 4341688

print(lhex.to_dec("0x0")) -- 0, hex string (prefix with "0x" or "0X") to number
print(lhex.to_dec("0x00ff00")) -- 65280, hex string (prefix with "0x" or "0X") to number
print(lhex.to_hex(16777215)) -- 0xFFFFFF, number to hex

local pix = Pixel.new(lhex.to_hex(56816), 1, 32, 32)