104 lines
2.6 KiB
Go
104 lines
2.6 KiB
Go
// Copyright 2017 The Go Authors. All rights reserved.
|
|
// Use of this source code is governed by a BSD-style
|
|
// license that can be found in the LICENSE file.
|
|
|
|
package opentype
|
|
|
|
import (
|
|
"image"
|
|
|
|
"git.fireandbrimst.one/aw/golang-image/font"
|
|
"git.fireandbrimst.one/aw/golang-image/font/sfnt"
|
|
"git.fireandbrimst.one/aw/golang-image/math/fixed"
|
|
)
|
|
|
|
// FaceOptions describes the possible options given to NewFace when
|
|
// creating a new font.Face from a sfnt.Font.
|
|
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
|
|
}
|
|
|
|
func defaultFaceOptions() *FaceOptions {
|
|
return &FaceOptions{
|
|
Size: 12,
|
|
DPI: 72,
|
|
Hinting: font.HintingNone,
|
|
}
|
|
}
|
|
|
|
// Face implements the font.Face interface for sfnt.Font values.
|
|
type Face struct {
|
|
f *sfnt.Font
|
|
hinting font.Hinting
|
|
scale fixed.Int26_6
|
|
|
|
buf sfnt.Buffer
|
|
}
|
|
|
|
// NewFace returns a new font.Face for the given sfnt.Font.
|
|
// if opts is nil, sensible defaults will be used.
|
|
func NewFace(f *sfnt.Font, opts *FaceOptions) (font.Face, error) {
|
|
if opts == nil {
|
|
opts = defaultFaceOptions()
|
|
}
|
|
face := &Face{
|
|
f: f,
|
|
hinting: opts.Hinting,
|
|
scale: fixed.Int26_6(0.5 + (opts.Size * opts.DPI * 64 / 72)),
|
|
}
|
|
return face, nil
|
|
}
|
|
|
|
// Close satisfies the font.Face interface.
|
|
func (f *Face) Close() error {
|
|
return nil
|
|
}
|
|
|
|
// Metrics satisfies the font.Face interface.
|
|
func (f *Face) Metrics() font.Metrics {
|
|
m, err := f.f.Metrics(&f.buf, f.scale, f.hinting)
|
|
if err != nil {
|
|
return font.Metrics{}
|
|
}
|
|
return m
|
|
}
|
|
|
|
// Kern satisfies the font.Face interface.
|
|
func (f *Face) Kern(r0, r1 rune) fixed.Int26_6 {
|
|
x0 := f.index(r0)
|
|
x1 := f.index(r1)
|
|
k, err := f.f.Kern(&f.buf, x0, x1, fixed.Int26_6(f.f.UnitsPerEm()), f.hinting)
|
|
if err != nil {
|
|
return 0
|
|
}
|
|
return k
|
|
}
|
|
|
|
// Glyph satisfies the font.Face interface.
|
|
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) {
|
|
panic("not implemented")
|
|
}
|
|
|
|
// GlyphBounds satisfies the font.Face interface.
|
|
func (f *Face) GlyphBounds(r rune) (bounds fixed.Rectangle26_6, advance fixed.Int26_6, ok bool) {
|
|
advance, ok = f.GlyphAdvance(r)
|
|
if !ok {
|
|
return bounds, advance, ok
|
|
}
|
|
panic("not implemented")
|
|
}
|
|
|
|
// GlyphAdvance satisfies the font.Face interface.
|
|
func (f *Face) GlyphAdvance(r rune) (advance fixed.Int26_6, ok bool) {
|
|
idx := f.index(r)
|
|
advance, err := f.f.GlyphAdvance(&f.buf, idx, f.scale, f.hinting)
|
|
return advance, err == nil
|
|
}
|
|
|
|
func (f *Face) index(r rune) sfnt.GlyphIndex {
|
|
x, _ := f.f.GlyphIndex(&f.buf, r)
|
|
return x
|
|
}
|