property NSColor : a reference to current application’s NSColor
property NSString : a reference to current application’s NSString
property NSAttributedString : a reference to current application’s NSAttributedString
property NSUTF16StringEncoding : a reference to current application’s NSUTF16StringEncoding
property NSDeviceWhiteColorSpace : a reference to current application’s NSDeviceWhiteColorSpace

set aCol to "#412a23"
set wCol to calcBrightnessFromHTMLColorCodeStr(aCol) of me
–> 0.245871186256

set aCol to "#000000" –Black
set wCol to calcBrightnessFromHTMLColorCodeStr(aCol) of me
–> 0.0

set aCol to "#FFFFFF" –White
set wCol to calcBrightnessFromHTMLColorCodeStr(aCol) of me
–> 1.0

set aCol to "#EEA096"
set wCol to calcBrightnessFromHTMLColorCodeStr(aCol) of me
–> 0.759391903877

on calcBrightnessFromHTMLColorCodeStr(aStr as string)
　　set {rVal, gVal, bVal} to rgbHex2nunList(aStr) of me
　　–NSColorを作成
　　set aCol to makeNSColorFromRGBAval(rVal, gVal, bVal, 255, 255) of me
　　— グレースケール化
　　set gCol to aCol’s colorUsingColorSpaceName:(NSDeviceWhiteColorSpace)
　　set wComp to gCol’s whiteComponent() –whiteComponentを取得することで擬似的に明度情報を取得　　
　　return wComp
end calcBrightnessFromHTMLColorCodeStr

on makeNSColorFromRGBAval(redValue as integer, greenValue as integer, blueValue as integer, alphaValue as integer, aMaxVal as integer)
　　set aRedCocoa to (redValue / aMaxVal) as real
　　set aGreenCocoa to (greenValue / aMaxVal) as real
　　set aBlueCocoa to (blueValue / aMaxVal) as real
　　set aAlphaCocoa to (alphaValue / aMaxVal) as real
　　set aColor to NSColor’s colorWithCalibratedRed:aRedCocoa green:aGreenCocoa blue:aBlueCocoa alpha:aAlphaCocoa
　　return aColor
end makeNSColorFromRGBAval

on decodeCharacterReference(aStr)
　　set anNSString to NSString’s stringWithString:aStr
　　set theData to anNSString’s dataUsingEncoding:(NSUTF16StringEncoding)
　　set styledString to NSAttributedString’s alloc()’s initWithHTML:theData documentAttributes:(missing value)
　　set plainText to (styledString’s |string|()) as string
　　return plainText
end decodeCharacterReference

–HTMLコードのRGB 16進数コードを数値リストに変換
on rgbHex2nunList(aHexStr)
　　–エラーチェック
　　if aHexStr does not start with "#" then return false
　　if length of aHexStr is not equal to 7 then return false
　　set bHex to text 2 thru -1 of aHexStr
　　
　　set {rStr, gStr, bStr} to {text 1 thru 2 of bHex, text 3 thru 4 of bHex, text 5 thru 6 of bHex}
　　
　　set bList to {}
　　repeat with i in {rStr, gStr, bStr}
　　　　set j to contents of i
　　　　set the end of bList to aHexStrToNum(j) of me
　　end repeat
　　
　　return bList
end rgbHex2nunList

–16進数文字列を10進数数値に変換する
on aHexStrToNum(hexStr)
　　set hStr to "0123456789ABCDEF"
　　
　　set aNum to 0
　　set aLen to length of hexStr
　　
　　repeat with i from aLen to 1 by -1
　　　　
　　　　set aCon to contents of character i of hexStr
　　　　using terms from scripting additions
　　　　　　set aVal to (offset of aCon in hStr) – 1
　　　　end using terms from
　　　　set aNum to aNum + aVal * (16 ^ (aLen – i))
　　　　
　　end repeat
　　
　　return aNum as integer
end aHexStrToNum