Documentation
¶
Overview ¶
Package opentype implements a glyph rasterizer for TTF (TrueType Fonts) and OTF (OpenType Fonts).
This package provides a high-level API, centered on the NewFace function, implementing the golang.org/x/image/font.Face interface.
The sibling golang.org/x/image/font/sfnt package provides a low-level API.
Index ¶
- func NewFace(f *Font, opts *FaceOptions) (font.Face, error)
- type Collection
- type Face
- func (f *Face) Close() error
- func (f *Face) Glyph(dot fixed.Point26_6, r rune) (dr image.Rectangle, mask image.Image, maskp image.Point, advance fixed.Int26_6, ...)
- func (f *Face) GlyphAdvance(r rune) (advance fixed.Int26_6, ok bool)
- func (f *Face) GlyphBounds(r rune) (bounds fixed.Rectangle26_6, advance fixed.Int26_6, ok bool)
- func (f *Face) Kern(r0, r1 rune) fixed.Int26_6
- func (f *Face) Metrics() font.Metrics
- type FaceOptions
- type Font
Examples ¶
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
func NewFace ¶
func NewFace(f *Font, opts *FaceOptions) (font.Face, error)
NewFace returns a new font.Face for the given Font.
If opts is nil, sensible defaults will be used.
Example ¶
package main
import (
"fmt"
"image"
"image/color"
"log"
"os"
"golang.org/x/image/font"
"golang.org/x/image/font/gofont/goitalic"
"golang.org/x/image/font/opentype"
"golang.org/x/image/math/fixed"
)
func main() {
const (
width = 72
height = 36
startingDotX = 6
startingDotY = 28
)
f, err := opentype.Parse(goitalic.TTF)
if err != nil {
log.Fatalf("Parse: %v", err)
}
face, err := opentype.NewFace(f, &opentype.FaceOptions{
Size: 32,
DPI: 72,
Hinting: font.HintingNone,
})
if err != nil {
log.Fatalf("NewFace: %v", err)
}
dst := image.NewGray(image.Rect(0, 0, width, height))
d := font.Drawer{
Dst: dst,
Src: image.White,
Face: face,
Dot: fixed.P(startingDotX, startingDotY),
}
fmt.Printf("The dot is at %v\n", d.Dot)
d.DrawString("jel")
fmt.Printf("The dot is at %v\n", d.Dot)
d.Src = image.NewUniform(color.Gray{0x7F})
d.DrawString("ly")
fmt.Printf("The dot is at %v\n", d.Dot)
const asciiArt = ".++8"
buf := make([]byte, 0, height*(width+1))
for y := 0; y < height; y++ {
for x := 0; x < width; x++ {
c := asciiArt[dst.GrayAt(x, y).Y>>6]
if c != '.' {
// No-op.
} else if x == startingDotX-1 {
c = ']'
} else if y == startingDotY-1 {
c = '_'
}
buf = append(buf, c)
}
buf = append(buf, '\n')
}
os.Stdout.Write(buf)
}
Output: The dot is at {6:00 28:00} The dot is at {41:32 28:00} The dot is at {66:48 28:00} .....].................................................................. .....].................................................................. .....].................................................................. .....]..................................+++......+++.................... .....]........+++.......................888......+++.................... .....].......+88+......................+88+......+++.................... .....].......888+......................+88+.....+++..................... .....].......888+......................+88+.....+++..................... .....].................................888......+++..................... .....].................................888......+++..................... .....]....................++..........+88+......+++..................... .....]......+88+.......+888888+.......+88+.....+++....+++..........++... .....]......888......+888888888+......+88+.....+++....++++........+++... .....]......888.....+888+...+888......888......+++.....+++........++.... .....].....+888....+888......+88+.....888......+++.....+++.......+++.... .....].....+88+....888.......+88+....+88+......+++.....+++......+++..... .....].....+88+...+888.......+88+....+88+.....+++......+++......+++..... .....].....888....888+++++++++88+....+88+.....+++......+++.....+++...... .....].....888....88888888888888+....888......+++......++++....++....... .....]....+888...+88888888888888.....888......+++.......+++...+++....... .....]....+88+...+888...............+888......+++.......+++..+++........ .....]....+88+...+888...............+88+.....+++........+++..+++........ .....]....888....+888...............+88+.....+++........+++.+++......... .....]....888....+888...............888......+++........++++++.......... .....]...+888.....888+..............888......+++........++++++.......... .....]...+88+.....+8888+....++8.....888+.....++++........++++........... .....]...+88+......+8888888888+.....+8888....+++++.......++++........... _____]___888________+88888888++______+888_____++++_______+++____________ .....]...888...........+++.............++................+++............ .....]..+88+............................................+++............. .....]..+88+...........................................+++.............. .....].+888............................................+++.............. ....888888............................................+++............... ....88888............................................++++............... ....+++................................................................. .....]..................................................................
Types ¶
type Collection ¶
type Collection = sfnt.Collection
Collection is a collection of one or more fonts.
All of the Collection methods are safe to call concurrently.
func ParseCollection ¶
func ParseCollection(src []byte) (*Collection, error)
ParseCollection parses an OpenType font collection, such as TTC or OTC data, from a []byte data source.
If passed data for a single font, a TTF or OTF instead of a TTC or OTC, it will return a collection containing 1 font.
func ParseCollectionReaderAt ¶
func ParseCollectionReaderAt(src io.ReaderAt) (*Collection, error)
ParseCollectionReaderAt parses an OpenType collection, such as TTC or OTC data, from an io.ReaderAt data source.
If passed data for a single font, a TTF or OTF instead of a TTC or OTC, it will return a collection containing 1 font.
type Face ¶
type Face struct {
// contains filtered or unexported fields
}
Face implements the font.Face interface for Font values.
A Face is not safe to use concurrently.
func (*Face) Glyph ¶
func (f *Face) Glyph(dot fixed.Point26_6, r rune) (dr image.Rectangle, mask image.Image, maskp image.Point, advance fixed.Int26_6, ok bool)
Glyph satisfies the font.Face interface.
func (*Face) GlyphAdvance ¶
GlyphAdvance satisfies the font.Face interface.
func (*Face) GlyphBounds ¶
GlyphBounds satisfies the font.Face interface.
type FaceOptions ¶
type FaceOptions struct {
Size float64 // Size is the font size in points
DPI float64 // DPI is the dots per inch resolution
Hinting font.Hinting // Hinting selects how to quantize a vector font's glyph nodes
}
FaceOptions describes the possible options given to NewFace when creating a new font.Face from a Font.
type Font ¶
Font is an OpenType font, also known as an SFNT font.
All of the Font methods are safe to call concurrently, as long as each call has a different *sfnt.Buffer (or nil).
The Font methods that don't take a *sfnt.Buffer argument are always safe to call concurrently.
Source Files