Documentation
¶
Overview ¶
Package truetype provides a parser for the TTF and TTC file formats. Those formats are documented at http://developer.apple.com/fonts/TTRefMan/ and http://www.microsoft.com/typography/otspec/
Some of a font's methods provide lengths or co-ordinates, e.g. bounds, font metrics and control points. All these methods take a scale parameter, which is the number of pixels in 1 em, expressed as a 26.6 fixed point value. For example, if 1 em is 10 pixels then scale is fixed.I(10), which is equal to fixed.Int26_6(10 << 6).
To measure a TrueType font in ideal FUnit space, use scale equal to font.FUnitsPerEm().
Index ¶
- Constants
- func NewFace(f *Font, opts *Options) font.Face
- type Font
- func (f *Font) Bounds(scale fixed.Int26_6) fixed.Rectangle26_6
- func (f *Font) FUnitsPerEm() int32
- func (f *Font) HMetric(scale fixed.Int26_6, i Index) HMetric
- func (f *Font) Index(x rune) Index
- func (f *Font) Kern(scale fixed.Int26_6, i0, i1 Index) fixed.Int26_6
- func (f *Font) Name(id NameID) string
- func (f *Font) VMetric(scale fixed.Int26_6, i Index) VMetric
- type FormatError
- type GlyphBuf
- type HMetric
- type Index
- type NameID
- type Options
- type Point
- type UnsupportedError
- type VMetric
Constants ¶
const ( NameIDCopyright NameID = 0 NameIDFontFamily = 1 NameIDFontSubfamily = 2 NameIDUniqueSubfamilyID = 3 NameIDFontFullName = 4 NameIDNameTableVersion = 5 NameIDPostscriptName = 6 NameIDTrademarkNotice = 7 NameIDManufacturerName = 8 NameIDDesignerName = 9 NameIDFontDescription = 10 NameIDFontVendorURL = 11 NameIDFontDesignerURL = 12 NameIDFontLicense = 13 NameIDFontLicenseURL = 14 NameIDPreferredFamily = 16 NameIDPreferredSubfamily = 17 NameIDCompatibleName = 18 NameIDSampleText = 19 )
Variables ¶
This section is empty.
Functions ¶
Types ¶
type Font ¶
type Font struct {
// contains filtered or unexported fields
}
A Font represents a Truetype font.
func Parse ¶
Parse returns a new Font for the given TTF or TTC data.
For TrueType Collections, the first font in the collection is parsed.
func (*Font) Bounds ¶
func (f *Font) Bounds(scale fixed.Int26_6) fixed.Rectangle26_6
Bounds returns the union of a Font's glyphs' bounds.
func (*Font) FUnitsPerEm ¶
FUnitsPerEm returns the number of FUnits in a Font's em-square's side.
func (*Font) Kern ¶
Kern returns the horizontal adjustment for the given glyph pair. A positive kern means to move the glyphs further apart.
type FormatError ¶
type FormatError string
A FormatError reports that the input is not a valid TrueType font.
func (FormatError) Error ¶
func (e FormatError) Error() string
type GlyphBuf ¶
type GlyphBuf struct {
// AdvanceWidth is the glyph's advance width.
AdvanceWidth fixed.Int26_6
// Bounds is the glyph's bounding box.
Bounds fixed.Rectangle26_6
// Points contains all Points from all contours of the glyph. If hinting
// was used to load a glyph then Unhinted contains those Points before they
// were hinted, and InFontUnits contains those Points before they were
// hinted and scaled.
Points, Unhinted, InFontUnits []Point
// Ends is the point indexes of the end point of each contour. The length
// of Ends is the number of contours in the glyph. The i'th contour
// consists of points Points[Ends[i-1]:Ends[i]], where Ends[-1] is
// interpreted to mean zero.
Ends []int
// contains filtered or unexported fields
}
A GlyphBuf holds a glyph's contours. A GlyphBuf can be re-used to load a series of glyphs from a Font.
type NameID ¶
type NameID uint16
A NameID identifies a name table entry.
See https://developer.apple.com/fonts/TrueType-Reference-Manual/RM06/Chap6name.html
type Options ¶
type Options struct {
// Size is the font size in points, as in "a 10 point font size".
//
// A zero value means to use a 12 point font size.
Size float64
// DPI is the dots-per-inch resolution.
//
// A zero value means to use 72 DPI.
DPI float64
// Hinting is how to quantize the glyph nodes.
//
// A zero value means to use no hinting.
Hinting font.Hinting
// GlyphCacheEntries is the number of entries in the glyph mask image
// cache.
//
// If non-zero, it must be a power of 2.
//
// A zero value means to use 512 entries.
GlyphCacheEntries int
// SubPixelsX is the number of sub-pixel locations a glyph's dot is
// quantized to, in the horizontal direction. For example, a value of 8
// means that the dot is quantized to 1/8th of a pixel. This quantization
// only affects the glyph mask image, not its bounding box or advance
// width. A higher value gives a more faithful glyph image, but reduces the
// effectiveness of the glyph cache.
//
// If non-zero, it must be a power of 2, and be between 1 and 64 inclusive.
//
// A zero value means to use 4 sub-pixel locations.
SubPixelsX int
// SubPixelsY is the number of sub-pixel locations a glyph's dot is
// quantized to, in the vertical direction. For example, a value of 8
// means that the dot is quantized to 1/8th of a pixel. This quantization
// only affects the glyph mask image, not its bounding box or advance
// width. A higher value gives a more faithful glyph image, but reduces the
// effectiveness of the glyph cache.
//
// If non-zero, it must be a power of 2, and be between 1 and 64 inclusive.
//
// A zero value means to use 1 sub-pixel location.
SubPixelsY int
}
Options are optional arguments to NewFace.
type Point ¶
type Point struct {
X, Y fixed.Int26_6
// The Flags' LSB means whether or not this Point is 'on' the contour.
// Other bits are reserved for internal use.
Flags uint32
}
A Point is a co-ordinate pair plus whether it is 'on' a contour or an 'off' control point.
type UnsupportedError ¶
type UnsupportedError string
An UnsupportedError reports that the input uses a valid but unimplemented TrueType feature.
func (UnsupportedError) Error ¶
func (e UnsupportedError) Error() string
Source Files