|
1
|
|
|
<?php |
|
2
|
|
|
|
|
3
|
|
|
declare(strict_types = 1); |
|
4
|
|
|
|
|
5
|
|
|
namespace ExtendedStrings\Strings; |
|
6
|
|
|
|
|
7
|
|
|
class Stop |
|
8
|
|
|
{ |
|
9
|
|
|
private $stringLength; |
|
10
|
|
|
|
|
11
|
|
|
/** |
|
12
|
|
|
* Stop constructor. |
|
13
|
|
|
* |
|
14
|
|
|
* @param float $stringLength A "string length": the length of string |
|
15
|
|
|
* between the stop and the bridge, as a fraction |
|
16
|
|
|
* of the whole string. A string length of 1.0 |
|
17
|
|
|
* indicates an open string. |
|
18
|
|
|
*/ |
|
19
|
|
|
public function __construct(float $stringLength) |
|
20
|
|
|
{ |
|
21
|
|
|
if ($stringLength <= 0 || $stringLength > 1) { |
|
22
|
|
|
throw new \InvalidArgumentException(sprintf('Invalid string length: %f', $stringLength)); |
|
23
|
|
|
} |
|
24
|
|
|
|
|
25
|
|
|
$this->stringLength = $stringLength; |
|
26
|
|
|
} |
|
27
|
|
|
|
|
28
|
|
|
/** |
|
29
|
|
|
* Create a Stop instance from a frequency over a string. |
|
30
|
|
|
* |
|
31
|
|
|
* @param float $frequency |
|
32
|
|
|
* @param \ExtendedStrings\Strings\VibratingStringInterface $string |
|
33
|
|
|
* |
|
34
|
|
|
* @return \ExtendedStrings\Strings\Stop |
|
35
|
|
|
*/ |
|
36
|
|
|
public static function fromFrequency(float $frequency, VibratingStringInterface $string): self |
|
37
|
|
|
{ |
|
38
|
|
|
if (Math::isZero($frequency)) { |
|
39
|
|
|
throw new \InvalidArgumentException(sprintf('Invalid frequency: %f', $frequency)); |
|
40
|
|
|
} |
|
41
|
|
|
$centsOverString = Cent::frequenciesToCents($string->getFrequency(), $frequency); |
|
42
|
|
|
|
|
43
|
|
|
return new self(self::centsToStringLength($centsOverString)); |
|
44
|
|
|
} |
|
45
|
|
|
|
|
46
|
|
|
/** |
|
47
|
|
|
* Returns the frequency of the stop (assuming normal stop pressure). |
|
48
|
|
|
* |
|
49
|
|
|
* @param VibratingStringInterface $string |
|
50
|
|
|
* |
|
51
|
|
|
* @return float |
|
52
|
|
|
*/ |
|
53
|
|
|
public function getFrequency(VibratingStringInterface $string): float |
|
54
|
|
|
{ |
|
55
|
|
|
$centsOverString = Cent::frequenciesToCents($this->stringLength, 1); |
|
56
|
|
|
|
|
57
|
|
|
return Cent::centsToFrequency($centsOverString, $string->getFrequency()); |
|
58
|
|
|
} |
|
59
|
|
|
|
|
60
|
|
|
/** |
|
61
|
|
|
* Returns the string length for the stop. |
|
62
|
|
|
* |
|
63
|
|
|
* @see Stop::__construct() for a definition of "string length" |
|
64
|
|
|
* |
|
65
|
|
|
* @return float |
|
66
|
|
|
*/ |
|
67
|
|
|
public function getStringLength(): float |
|
68
|
|
|
{ |
|
69
|
|
|
return $this->stringLength; |
|
70
|
|
|
} |
|
71
|
|
|
|
|
72
|
|
|
/** |
|
73
|
|
|
* Convert a number of cents over a string to a string length. |
|
74
|
|
|
* |
|
75
|
|
|
* @see Stop::__construct() for a definition of "string length" |
|
76
|
|
|
* |
|
77
|
|
|
* @param float $cents The number of cents between the open string's pitch |
|
78
|
|
|
* and the stopped pitch. |
|
79
|
|
|
* |
|
80
|
|
|
* @return float |
|
81
|
|
|
*/ |
|
82
|
|
|
private static function centsToStringLength(float $cents): float |
|
83
|
|
|
{ |
|
84
|
|
|
return 1 / pow(2, $cents / 1200); |
|
85
|
|
|
} |
|
86
|
|
|
} |
|
87
|
|
|
|
extended-strings /
strings
