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https://github.com/1bardesign/batteries.git
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Merge branch 'feature/nobit-colour'
This commit is contained in:
commit
662101ddae
70
colour.lua
70
colour.lua
@ -14,28 +14,12 @@ local colour = {}
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-- pack and unpack into 24 or 32 bit hex numbers
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local ok, bit = pcall(require, "bit")
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if not ok then
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for _, v in ipairs{
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"pack_rgb",
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"unpack_rgb",
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"pack_argb",
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"unpack_argb",
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"pack_rgba",
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"unpack_rgba",
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} do
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colour[v] = function()
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error(
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"batteries.colour requires the bit operations module for pack/unpack functionality.\n"
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.."\tsee https://bitop.luajit.org/\n\n"
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.."error from require(\"bit\"):\n\n"..bit)
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end
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end
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else
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if ok then
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--we have bit operations module, use the fast path
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local band, bor = bit.band, bit.bor
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local lshift, rshift = bit.lshift, bit.rshift
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--rgb only (no alpha)
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function colour.pack_rgb(r, g, b)
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local br = lshift(band(0xff, r * 255), 16)
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local bg = lshift(band(0xff, g * 255), 8)
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@ -69,7 +53,6 @@ else
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end
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--rgba format
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function colour.pack_rgba(r, g, b, a)
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local br = lshift(band(0xff, r * 255), 24)
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local bg = lshift(band(0xff, g * 255), 16)
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@ -85,13 +68,55 @@ else
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local a = rshift(band(rgba, 0x000000ff), 0) / 255
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return r, g, b, a
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end
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else
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--we don't have bitops, use a slower pure-float path
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local floor = math.floor
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--rgb only (no alpha)
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function colour.pack_rgb(r, g, b)
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local br = floor(0xff * r) % 0x100 * 0x10000
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local bg = floor(0xff * g) % 0x100 * 0x100
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local bb = floor(0xff * b) % 0x100
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return br + bg + bb
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end
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function colour.unpack_rgb(rgb)
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local r = floor(rgb / 0x10000) % 0x100
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local g = floor(rgb / 0x100) % 0x100
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local b = floor(rgb) % 0x100
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return r / 255, g / 255, b / 255
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end
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--argb format (common for shared hex)
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function colour.pack_argb(r, g, b, a)
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local ba = floor(0xff * a) % 0x100 * 0x1000000
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return colour.pack_rgb(r, g, b) + ba
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end
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function colour.unpack_argb(argb)
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local r, g, b = colour.unpack_rgb(argb)
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local a = floor(argb / 0x1000000) % 0x100
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return r, g, b, a / 255
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end
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--rgba format
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function colour.pack_rgba(r, g, b, a)
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local ba = floor(0xff * a) % 0x100
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return colour.pack_rgb(r, g, b) * 0x100 + ba
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end
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function colour.unpack_rgba(rgba)
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local r, g, b = colour.unpack_rgb(floor(rgba / 0x100))
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local a = floor(rgba) % 0x100
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return r, g, b, a
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end
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end
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-------------------------------------------------------------------------------
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-- colour space conversion
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-- rgb is the common language but it's useful to have other spaces to work in
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-- for us as humans :)
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-- rgb is the common language for computers
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-- but it's useful to have other spaces to work in for us as humans :)
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--convert hsl to rgb
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--all components are 0-1, hue is fraction of a turn rather than degrees or radians
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@ -145,11 +170,10 @@ function colour.rgb_to_hsl(r, g, b)
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else
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h = (r - g) / d + 4
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end
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assert(h)
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return h / 6, s, l
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end
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--todo: hsv, other colour spaces
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--todo: hsv
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--oklab https://bottosson.github.io/posts/oklab/
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function colour.oklab_to_rgb(l, a, b)
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