Converts a color from RGB to HSL

rgb_to_hsl_converter

def converte_hex_para_hsl(hexstring : str):

    import colorsys

    # especificacao do formato retirada de
    # https://en.wikipedia.org/wiki/Web_colors

    # tamanho da string
    CONST_FULLSIZE  = 7
    CONST_MINSIZE  = 4
    CONST_STARTS = '#'

    # verifica que temos uma string
    # dentro do formato esperado
    if (len(hexstring) != CONST_FULLSIZE and len(hexstring) != CONST_MINSIZE):
        raise ValueError("String HEX fora de formato 1 " + hexstring)

    if (hexstring[0] != CONST_STARTS):
        raise ValueError("String HEX fora de formato 3 " + hexstring)

    # remove o simbolo inicial
    hexstring = hexstring[1:]

    # verifica se eh shorthand
    # se eh curto faz um padding
    if(len(hexstring) == CONST_MINSIZE - 1):
        hexstring = hexstring[0] * 2 + hexstring[1] * 2 + hexstring[2] * 2
  
    # separamos os tres canais
    # e convertemos para rgb
    # EM FLOAT DE 0 a 1
    try:

        r = int(hexstring[0:2], 16) / 255.0
        g = int(hexstring[2:4], 16) / 255.0
        b = int(hexstring[4:6], 16) / 255.0
    
    except ValueError as e:
        raise ValueError("String HEX fora de formato 4 " + hexstring)

    # convertemos usando a lib        
    hls = colorsys.rgb_to_hls(r, g, b)

    # separamos os canais
    # atentar a ordem aqui
    hue = hls[0]
    saturation = hls[2]
    luminosity = hls[1]

    # corrigimos a formatacao vinda
    # da biblioteca padrao

    # convertemos de float para graus
    # no disco de cores
    hue = round(hue * 360)

    #convertemos de float para porcento
    saturation = round(saturation * 100)
    luminosity = round(luminosity * 100)

    # string e sinais de porcento
    hue = str(hue) 
    saturation = f'{str(saturation)}%'
    luminosity = f'{str(luminosity)}%'
    
    return f'hsl({hue}, {saturation}, {luminosity})'

def main():

    print("Testes...")
    
    # ValueError exceptions
    valuerrors = []
    valuerrors.append("asdasdadads")
    valuerrors.append("asd")
    valuerrors.append("abc")
    valuerrors.append("aabbcc")
    valuerrors.append("#f00c")
    valuerrors.append("#zzzzzz")
    valuerrors.append("#zzz")
    valuerrors.append("#zfc")
    valuerrors.append("#fzc")
    valuerrors.append("#fcz")
    valuerrors.append("#ffcczz")
    valuerrors.append("#ffzzcc")
    valuerrors.append("#ffcczz")

    # assertivos
    asserts = []
    asserts.append(["#aabbcc", "hsl(210, 25%, 73%)"])
    asserts.append(["#abc", "hsl(210, 25%, 73%)"])
    asserts.append(["#000", "hsl(0, 0%, 0%)"])
    asserts.append(["#000000", "hsl(0, 0%, 0%)"])
    asserts.append(["#ffffff", "hsl(0, 0%, 100%)"])
    asserts.append(["#fff", "hsl(0, 0%, 100%)"])


    for caso in valuerrors:
        try:
            c = converte_hex_para_hsl(caso)
        except ValueError as e:            
            print("caso " + caso + " OK")
            pass
        else:
            print("erro no caso " + caso)
            exit
   
    for caso in asserts:

        c = converte_hex_para_hsl(caso[0])
        print("caso " + caso[0] + " OK")
        assert(c == caso[1]), "Erro no caso " + caso[0]


    print("Testes OK")


if __name__ == '__main__':
    main()