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colour: Don't depend on bit library.

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Miku AuahDark 2022-05-09 10:16:43 +08:00
parent be48dd9115
commit fabbd3f702
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1 changed files with 33 additions and 63 deletions
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66
colour.lua
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@ -13,79 +13,49 @@ local colour = {}
-- hex handling routines -- hex handling routines
-- pack and unpack into 24 or 32 bit hex numbers -- pack and unpack into 24 or 32 bit hex numbers
local ok, bit = pcall(require, "bit") local floor = math.floor
if not ok then
for _, v in ipairs{
"pack_rgb",
"unpack_rgb",
"pack_argb",
"unpack_argb",
"pack_rgba",
"unpack_rgba",
} do
colour[v] = function()
error(
"batteries.colour requires the bit operations module for pack/unpack functionality.\n"
.."\tsee https://bitop.luajit.org/\n\n"
.."error from require(\"bit\"):\n\n"..bit)
end
end
else
local band, bor = bit.band, bit.bor
local lshift, rshift = bit.lshift, bit.rshift
--rgb only (no alpha) --rgb only (no alpha)
function colour.pack_rgb(r, g, b) function colour.pack_rgb(r, g, b)
local br = lshift(band(0xff, r * 255), 16) local br = floor(0xff * r) % 0x100 * 0x10000
local bg = lshift(band(0xff, g * 255), 8) local bg = floor(0xff * g) % 0x100 * 0x100
local bb = lshift(band(0xff, b * 255), 0) local bb = floor(0xff * b) % 0x100
return bor( br, bg, bb ) return br + bg + bb
end end
function colour.unpack_rgb(rgb) function colour.unpack_rgb(rgb)
local r = rshift(band(rgb, 0x00ff0000), 16) / 255 local r = floor(rgb / 0x10000) % 0x100
local g = rshift(band(rgb, 0x0000ff00), 8) / 255 local g = floor(rgb / 0x100) % 0x100
local b = rshift(band(rgb, 0x000000ff), 0) / 255 local b = floor(rgb) % 0x100
return r, g, b return r / 255, g / 255, b / 255
end end
--argb format (common for shared hex) --argb format (common for shared hex)
function colour.pack_argb(r, g, b, a) function colour.pack_argb(r, g, b, a)
local ba = lshift(band(0xff, a * 255), 24) local ba = floor(0xff * a) % 0x100 * 0x1000000
local br = lshift(band(0xff, r * 255), 16) return colour.pack_rgb(r, g, b) + ba
local bg = lshift(band(0xff, g * 255), 8)
local bb = lshift(band(0xff, b * 255), 0)
return bor( br, bg, bb, ba )
end end
function colour.unpack_argb(argb) function colour.unpack_argb(argb)
local r = rshift(band(argb, 0x00ff0000), 16) / 255 local r, g, b = colour.unpack_rgb(argb)
local g = rshift(band(argb, 0x0000ff00), 8) / 255 local a = floor(argb / 0x1000000) % 0x100
local b = rshift(band(argb, 0x000000ff), 0) / 255 return r, g, b, a / 255
local a = rshift(band(argb, 0xff000000), 24) / 255
return r, g, b, a
end end
--rgba format --rgba format
function colour.pack_rgba(r, g, b, a) function colour.pack_rgba(r, g, b, a)
local br = lshift(band(0xff, r * 255), 24) local ba = floor(0xff * a) % 0x100
local bg = lshift(band(0xff, g * 255), 16) return colour.pack_rgb(r, g, b) * 0x100 + ba
local bb = lshift(band(0xff, b * 255), 8)
local ba = lshift(band(0xff, a * 255), 0)
return bor( br, bg, bb, ba )
end end
function colour.unpack_rgba(rgba) function colour.unpack_rgba(rgba)
local r = rshift(band(rgba, 0xff000000), 24) / 255 local r, g, b = colour.unpack_rgb(floor(rgba / 0x100))
local g = rshift(band(rgba, 0x00ff0000), 16) / 255 local a = floor(rgba) % 0x100
local b = rshift(band(rgba, 0x0000ff00), 8) / 255
local a = rshift(band(rgba, 0x000000ff), 0) / 255
return r, g, b, a return r, g, b, a
end end
end
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