package loader

import "github.com/go-text/typesetting/opentype/loader"

Package opentype provides the low level routines required to read Opentype font files, including collections.

This package is designed to provide an efficient, lazy, reading API.

For the parsing of the various tables, see package [tables].

Index ¶

• Variables
• func WriteTTF(tables []Table) []byte
• type Loader
• func NewLoader(file Resource) (*Loader, error)
• func NewLoaders(file Resource) ([]*Loader, error)
• func (pr *Loader) HasTable(table Tag) bool
• func (pr *Loader) RawTable(tag Tag) ([]byte, error)
• func (pr *Loader) RawTableTo(tag Tag, dst []byte) ([]byte, error)
• func (ld *Loader) Tables() []Tag
• type Resource
• type Table
• type Tag
• func MustNewTag(str string) Tag
• func NewTag(a, b, c, d byte) Tag
• func (t Tag) String() string

Variables ¶

var (
	// TrueType is the first four bytes of an OpenType file containing a TrueType font
	TrueType = Tag(0x00010000)
	// AppleTrueType is the first four bytes of an OpenType file containing a TrueType font
	// (specifically one designed for Apple products, it's recommended to use TrueType instead)
	AppleTrueType = MustNewTag("true")
	// PostScript1 is the first four bytes of an OpenType file containing a PostScript 1 font
	PostScript1 = MustNewTag("typ1")
	// OpenType is the first four bytes of an OpenType file containing a PostScript Type 2 font
	// as specified by OpenType
	OpenType = MustNewTag("OTTO")
)

Functions ¶

func WriteTTF ¶

func WriteTTF(tables []Table) []byte

WriteTTF creates a single Truetype font file (.ttf) from the given [tables] slice, which must be sorted by Tag

Types ¶

type Loader ¶

type Loader struct {

	// Type represents the kind of this font being loaded.
	// It is one of TrueType, TrueTypeApple, PostScript1, OpenType
	Type Tag
	// contains filtered or unexported fields
}

Loader is the low level font reader, providing full control over table loading.

func NewLoader ¶

func NewLoader(file Resource) (*Loader, error)

NewLoader reads the `file` header and returns a new lazy loader. `file` will be used to parse tables, and should not be close.

func NewLoaders ¶

func NewLoaders(file Resource) ([]*Loader, error)

NewLoaders is the same as `NewLoader`, but supports collections.

func (*Loader) HasTable ¶

func (pr *Loader) HasTable(table Tag) bool

HasTable returns true if [table] is present.

func (*Loader) RawTable ¶

func (pr *Loader) RawTable(tag Tag) ([]byte, error)

RawTable returns the binary content of the given table, or an error if not found.

func (*Loader) RawTableTo ¶

func (pr *Loader) RawTableTo(tag Tag, dst []byte) ([]byte, error)

RawTable writes the binary content of the given table to [dst], returning it, or an error if not found.

func (*Loader) Tables ¶

func (ld *Loader) Tables() []Tag

Tables returns all the tables found in the file, as a sorted slice.

type Resource ¶

type Resource interface {
	Read([]byte) (int, error)
	ReadAt([]byte, int64) (int, error)
	Seek(int64, int) (int64, error)
}

Resource is a combination of io.Reader, io.Seeker and io.ReaderAt. This interface is satisfied by most things that you'd want to parse, for example *os.File, io.SectionReader or *bytes.Reader.

type Table ¶

type Table struct {
	Content []byte
	Tag     Tag
}

Table is one opentype binary table and its tag.

type Tag ¶

type Tag uint32

Tag represents an open-type name. These are technically uint32's, but are usually displayed in ASCII as they are all acronyms. See https://developer.apple.com/fonts/TrueType-Reference-Manual/RM06/Chap6.html#Overview

func MustNewTag ¶

func MustNewTag(str string) Tag

MustNewTag gives you the Tag corresponding to the acronym. This function will panic if the string passed in is not 4 bytes long.

func NewTag ¶

func NewTag(a, b, c, d byte) Tag

NewTag returns the tag for <abcd>.

func (Tag) String ¶

func (t Tag) String() string

String return the ASCII form of the tag.

Source Files ¶

opentype.go reader.go reader_otf.go reader_woff.go writer.go