159 lines
4.5 KiB
Lua
159 lines
4.5 KiB
Lua
local tonumber = tonumber
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local string = string
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local math = math
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local floor = math.floor
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local max = math.max
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local min = math.min
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local abs = math.abs
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local format = string.format
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local _color = {}
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--- Try to guess if a color is dark or light.
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--
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-- @string color The color with hexadecimal HTML format `"#RRGGBB"`.
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-- @treturn bool `true` if the color is dark, `false` if it is light.
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function _color.is_dark(color)
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-- Try to determine if the color is dark or light
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local numeric_value = 0
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for s in color:gmatch("[a-fA-F0-9][a-fA-F0-9]") do
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numeric_value = numeric_value + tonumber("0x" .. s)
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end
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return (numeric_value < 383)
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end
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function _color.is_opaque(color)
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if type(color) == "string" then
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color = _color.hex_to_rgba(color)
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end
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return color.a < 0.01
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end
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--- Lighten a color.
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--
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-- @string color The color to lighten with hexadecimal HTML format `"#RRGGBB"`.
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-- @int[opt=26] amount How much light from 0 to 255. Default is around 10%.
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-- @treturn string The lighter color
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function _color.lighten(color, amount)
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amount = amount or 26
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local c = {
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r = tonumber("0x" .. color:sub(2, 3)),
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g = tonumber("0x" .. color:sub(4, 5)),
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b = tonumber("0x" .. color:sub(6, 7)),
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}
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c.r = c.r + amount
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c.r = c.r < 0 and 0 or c.r
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c.r = c.r > 255 and 255 or c.r
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c.g = c.g + amount
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c.g = c.g < 0 and 0 or c.g
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c.g = c.g > 255 and 255 or c.g
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c.b = c.b + amount
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c.b = c.b < 0 and 0 or c.b
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c.b = c.b > 255 and 255 or c.b
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return string.format("#%02x%02x%02x", c.r, c.g, c.b)
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end
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--- Darken a color.
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--
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-- @string color The color to darken with hexadecimal HTML format `"#RRGGBB"`.
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-- @int[opt=26] amount How much dark from 0 to 255. Default is around 10%.
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-- @treturn string The darker color
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function _color.darken(color, amount)
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amount = amount or 26
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return _color.lighten(color, -amount)
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end
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-- Returns a value that is clipped to interval edges if it falls outside the interval
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function _color.clip(num, min_num, max_num)
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return max(min(num, max_num), min_num)
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end
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-- Converts the given hex color to rgba
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function _color.hex_to_rgba(color)
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color = color:gsub("#", "")
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return { r = tonumber("0x" .. color:sub(1, 2)),
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g = tonumber("0x" .. color:sub(3, 4)),
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b = tonumber("0x" .. color:sub(5, 6)),
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a = #color == 8 and tonumber("0x" .. color:sub(7, 8)) or 255 }
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end
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-- Converts the given rgba color to hex
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function _color.rgba_to_hex(color)
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local r = _color.clip(color.r or color[1], 0, 255)
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local g = _color.clip(color.g or color[2], 0, 255)
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local b = _color.clip(color.b or color[3], 0, 255)
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local a = _color.clip(color.a or color[4] or 255, 0, 255)
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return "#" .. format("%02x%02x%02x%02x",
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floor(r),
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floor(g),
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floor(b),
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floor(a))
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end
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-- Converts the given hex color to hsv
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function _color.hex_to_hsv(color)
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local color = _color.hex2rgb(color)
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local C_max = max(color.r, color.g, color.b)
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local C_min = min(color.r, color.g, color.b)
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local delta = C_max - C_min
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local H, S, V
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if delta == 0 then
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H = 0
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elseif C_max == color.r then
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H = 60 * (((color.g - color.b) / delta) % 6)
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elseif C_max == color.g then
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H = 60 * (((color.b - color.r) / delta) + 2)
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elseif C_max == color.b then
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H = 60 * (((color.r - color.g) / delta) + 4)
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end
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if C_max == 0 then
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S = 0
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else
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S = delta / C_max
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end
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V = C_max
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return { h = H,
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s = S * 100,
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v = V * 100 }
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end
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-- Converts the given hsv color to hex
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function _color.hsv_to_hex(H, S, V)
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S = S / 100
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V = V / 100
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if H > 360 then H = 360 end
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if H < 0 then H = 0 end
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local C = V * S
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local X = C * (1 - abs(((H / 60) % 2) - 1))
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local m = V - C
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local r_, g_, b_ = 0, 0, 0
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if H >= 0 and H < 60 then
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r_, g_, b_ = C, X, 0
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elseif H >= 60 and H < 120 then
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r_, g_, b_ = X, C, 0
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elseif H >= 120 and H < 180 then
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r_, g_, b_ = 0, C, X
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elseif H >= 180 and H < 240 then
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r_, g_, b_ = 0, X, C
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elseif H >= 240 and H < 300 then
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r_, g_, b_ = X, 0, C
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elseif H >= 300 and H < 360 then
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r_, g_, b_ = C, 0, X
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end
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local r, g, b = (r_ + m) * 255, (g_ + m) * 255, (b_ + m) * 255
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return ("#%02x%02x%02x"):format(floor(r), floor(g), floor(b))
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end
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function _color.multiply(color, amount)
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return { _color.clip(color.r * amount, 0, 255),
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_color.clip(color.g * amount, 0, 255),
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_color.clip(color.b * amount, 0, 255),
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255 }
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end
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return _color
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