Class Buffer

constructor

• new Buffer(existingPtr?: number): Buffer
  Internal

  Parameters

  • OptionalexistingPtr: number

    Wrap an existing buffer pointer.

  Returns Buffer

Readonlyptr

add

• add(codePoint: number, cluster: number): void

  Appends a character with the Unicode value of codePoint to the buffer, and gives it the initial cluster value of cluster. Clusters can be any thing the client wants, they are usually used to refer to the index of the character in the input text stream and are output in the cluster field of GlyphInfo.

  This function does not check the validity of codePoint, it is up to the caller to ensure it is a valid Unicode code point.

  Parameters

  • codePoint: number

    A Unicode code point.

  • cluster: number

    The cluster value of codePoint.

  Returns void

addCodePoints

• addCodePoints(
      codePoints: number[],
      itemOffset?: number,
      itemLength?: number,
  ): void

  Add code points to the buffer.

  Parameters

  • codePoints: number[]

    Array of code points to be added to the buffer.

  • itemOffset: number = 0

    The offset of the first code point to add to the buffer.

  • OptionalitemLength: number

    The number of code points to add to the buffer, or omit for the end of the array.

  Returns void

addText

• addText(text: string, itemOffset?: number, itemLength?: number): void

  Add text to the buffer.

  Parameters

  • text: string

    Text to be added to the buffer.

  • itemOffset: number = 0

    The offset of the first character to add to the buffer.

  • OptionalitemLength: number

    The number of characters to add to the buffer, or omit for the end of text.

  Returns void

clearContents

• clearContents(): void

  Similar to reset(), but does not clear the Unicode functions and the replacement code point.

  Returns void

getContentType

• getContentType(): BufferContentType

  Return the buffer content type.

  Returns BufferContentType

  The buffer content type as a BufferContentType value.

getGlyphInfos

• getGlyphInfos(): GlyphInfo[]

  Get the glyph information from the buffer.

  Returns GlyphInfo[]

  An array of GlyphInfo objects.

getGlyphInfosAndPositions

• getGlyphInfosAndPositions(): (GlyphInfo & Partial<GlyphPosition>)[]

  Get the glyph information and positions from the buffer.

  Returns (GlyphInfo & Partial<GlyphPosition>)[]

  The glyph information and positions.

  The glyph information is returned as an array of objects with the properties from getGlyphInfos and getGlyphPositions combined.

getGlyphPositions

• getGlyphPositions(): GlyphPosition[]

  Get the glyph positions from the buffer.

  Returns GlyphPosition[]

  An array of GlyphPosition objects.

getLength

• getLength(): number

  Get the the number of items in the buffer.

  Returns number

  The buffer length.

guessSegmentProperties

• guessSegmentProperties(): void

  Set buffer script, language and direction.

  This needs to be done before shaping.

  Returns void

reset

• reset(): void

  Reset the buffer to its initial status.

  Returns void

serialize

• serialize(
      options?: {
          end?: number;
          flags?: number;
          font?: Font;
          format?: number;
          start?: number;
      },
  ): string

  Serialize the buffer contents to a string.

  Parameters

  • options: { end?: number; flags?: number; font?: Font; format?: number; start?: number } = {}

    Serialization options:

    • font: the font to use for serialization;
    • start: the starting index of the glyphs (default 0);
    • end: the ending index of the glyphs (default end of buffer);
    • format: a BufferSerializeFormat value (default TEXT);
    • flags: a combination of BufferSerializeFlag values (default 0).

  Returns string

  The serialized buffer contents.

setClusterLevel

• setClusterLevel(level: ClusterLevel): void

  Set the HarfBuzz clustering level.

  Affects the cluster values returned from shaping.

  Parameters

  • level: ClusterLevel

    A ClusterLevel value. See the HarfBuzz manual chapter on Clusters.

  Returns void

setDirection

• setDirection(dir: Direction): void

  Set buffer direction explicitly.

  Parameters

  • dir: Direction

    A Direction value.

  Returns void

setFlags

• setFlags(flags: number): void

  Set buffer flags explicitly.

  Parameters

  • flags: number

    A combination of BufferFlag values (OR them together).

  Returns void

setLanguage

• setLanguage(language: string): void

  Set buffer language explicitly.

  Parameters

  • language: string

    The buffer language

  Returns void

setMessageFunc

• setMessageFunc(
      func: (buffer: Buffer, font: Font, message: string) => boolean,
  ): void

  Set message func.

  Parameters

  • func: (buffer: Buffer, font: Font, message: string) => boolean

    The function to set. It receives the buffer, font, and message string as arguments. Returning false will skip this shaping step and move to the next one.

  Returns void

setScript

• setScript(script: string): void

  Set buffer script explicitly.

  Parameters

  • script: string

    The buffer script

  Returns void

updateGlyphPositions

• updateGlyphPositions(positions: GlyphPosition[]): void

  Update the glyph positions in the buffer. WARNING: Do not use unless you know what you are doing.

  Parameters

  • positions: GlyphPosition[]

  Returns void