piano

Interfaces

PianoLayout

Defined in: piano.ts:24

The geometry of a drawn keyboard.

One description is shared by the drawing and the hit testing, so a key cannot be drawn somewhere other than where it responds.

Properties

blackKeyHeightRatio?

optional blackKeyHeightRatio?: number;

Defined in: piano.ts:50

Height of a black key, as a fraction of the height of the keyboard.

Default

0.6

blackKeyWidthRatio?

optional blackKeyWidthRatio?: number;

Defined in: piano.ts:43

Width of a black key, as a fraction of PianoLayout.whiteKeyWidth.

Default

0.65

keyGap?

optional keyGap?: number;

Defined in: piano.ts:36

Space between two white keys. Part of the slot a white key occupies, so it still belongs to one of the keys for the purpose of hit testing.

Default

1

noteRange

noteRange: NoteRange;

Defined in: piano.ts:25

whiteKeyWidth

whiteKeyWidth: number;

Defined in: piano.ts:28

Width of a white key, excluding PianoLayout.keyGap.

Type Aliases

NoteRange

type NoteRange = object;

Defined in: piano.ts:3

Properties

first

first: number;

Defined in: piano.ts:4

last

last: number;

Defined in: piano.ts:5

Functions

blackKeyWidth()

function blackKeyWidth(layout): number;

Defined in: piano.ts:80

Width of a black key in pixels.

Parameters

Parameter	Type
layout	PianoLayout

Returns

number

---

getNoteRangeArray()

function getNoteRangeArray(noteRange): number[];

Defined in: piano.ts:11

[noteRange.first, noteRange.first + 1, ..., noteRange.last]

Parameters

Parameter	Type
noteRange	NoteRange

Returns

number[]

---

noteAt()

function noteAt(
   x, 
   y, 
   height, 
   layout
): number | null;

Defined in: piano.ts:135

The note drawn at a point, or null where there is none.

Black keys are tested first, so they win where they overlap a white one. A white key covers its gap as well as its width, so the whole width of the keyboard belongs to some key and a click cannot fall between two.

Parameters

Parameter	Type	Description
x	number	offset from the left edge of the keyboard, in pixels
y	number	offset from its top edge, in pixels
height	number	height of the keyboard, in pixels
layout	PianoLayout	-

Returns

number | null

---

notePosition()

function notePosition(note, layout): number;

Defined in: piano.ts:103

Offset of the left edge of a key from the left edge of the keyboard, in pixels.

Notes outside noteRange are placed too, so the value is negative below noteRange.first.

Parameters

Parameter	Type
note	number
layout	PianoLayout

Returns

number

---

pianoWidth()

function pianoWidth(layout): number;

Defined in: piano.ts:88

Width of the whole keyboard in pixels.

Parameters

Parameter	Type
layout	PianoLayout

Returns

number