103 lines
2.3 KiB
Lua
103 lines
2.3 KiB
Lua
--- Utility functions to manipulate colors.
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--
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-- Colors are represented as RGB or RGBA, each channel
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-- with values in range [0, 1].
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--
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-- @module gear.color
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-- @copyright 2023 The DoubleFourteen Code Forge
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-- @author Lorenzo Cogotti
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local Color = {}
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--- Darken RGB color by the specified amount.
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--
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-- @number r red channel
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-- @number g green channel
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-- @number b blue channel
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-- @number amount darken factor, must be in [0,1] range.
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function Color.darken(r, g, b, amount)
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r = r * (1 - amount)
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g = g * (1 - amount)
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b = b * (1 - amount)
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return r, g, b
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end
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--- Lighten RGB color by the specified amount.
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--
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-- @number r red channel
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-- @number g green channel
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-- @number b blue channel
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-- @number amount lightening factor, must be in [0,1] range.
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function Color.lighten(r, g, b, amount)
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r = r + (1 - r) * amount
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g = g + (1 - g) * amount
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b = b + (1 - b) * amount
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return r, g, b
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end
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function Color.hsl(h, s, l, a)
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a = a or 1
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if s <= 0 then return 1, 1, 1, a end
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h = h * 6
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local abs = math.abs
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local c = (1 - abs(l*2 - 1))*s
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local x = (1 - abs(h%2 - 1))*c
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local m = l - c*0.5
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local r, g, b
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if h < 1 then r, g, b = c, x, 0
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elseif h < 2 then r, g, b = x, c, 0
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elseif h < 3 then r, g, b = 0, c, x
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elseif h < 4 then r, g, b = 0, x, c
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elseif h < 5 then r, g, b = x, 0, c
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else r, g, b = c, 0, x
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end
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return r+m, g+m, b+m, a
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end
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function Color.hsv(h, s, v, a)
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a = a or 1
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if s <= 0 then return v, v, v, a end
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h = h * 6
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local c = v * s
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local x = (1 - math.abs(h%2 - 1))*c
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local m = v - c
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local r, g, b
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if h < 1 then r, g, b = c, x, 0
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elseif h < 2 then r, g, b = x, c, 0
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elseif h < 3 then r, g, b = 0, c, x
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elseif h < 4 then r, g, b = 0, x, c
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elseif h < 5 then r, g, b = x, 0, c
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else r, g, b = c, 0, x
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end
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return r+m, g+m, b+m, a
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end
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--- Given two RGB colors, calculate fade by the specified amount.
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--
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-- @number cr first color, red channel
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-- @number cg first color, green channel
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-- @number cb first color, blue channel
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-- @number ar second color, red channel
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-- @number ag second color, green channel
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-- @number ab second color, blue channel
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-- @number amount fading factor, must be in [0,1] range.
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function Color.fade(cr, cg, cb, ar, ag, ab, amount)
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cr = cr + (ar - cr) * amount
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cg = cg + (ag - cg) * amount
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cb = cb + (ab - cb) * amount
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return cr, cg, cb
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end
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return Color
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