mirror of
https://github.com/xiaoqidun/ofdgo.git
synced 2026-10-29 08:46:55 +08:00
276 lines
9.4 KiB
Go
276 lines
9.4 KiB
Go
// Copyright 2025-2026 肖其顿 (XIAO QI DUN)
|
|
//
|
|
// Licensed under the Apache License, Version 2.0 (the "License");
|
|
// you may not use this file except in compliance with the License.
|
|
// You may obtain a copy of the License at
|
|
//
|
|
// http://www.apache.org/licenses/LICENSE-2.0
|
|
//
|
|
// Unless required by applicable law or agreed to in writing, software
|
|
// distributed under the License is distributed on an "AS IS" BASIS,
|
|
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
// See the License for the specific language governing permissions and
|
|
// limitations under the License.
|
|
|
|
package ofdgo
|
|
|
|
import (
|
|
"encoding/binary"
|
|
"fmt"
|
|
"sync"
|
|
|
|
basefont "github.com/xiaoqidun/ofdgo/internal/base/font"
|
|
)
|
|
|
|
// sfntGlyphBoundsLimit 限制单个字体保留的字形与字号边界数量
|
|
const sfntGlyphBoundsLimit = 4096
|
|
|
|
// FontResource 保存独立字体数据、标准元信息与只读度量，不包含绘图库类型
|
|
type FontResource struct {
|
|
FontMetrics
|
|
Data []byte
|
|
Font Font
|
|
Extension string
|
|
CanSubset bool
|
|
}
|
|
|
|
// FontUsage 描述全包已确认的字体引用，Unsafe禁止裁剪
|
|
type FontUsage struct {
|
|
Characters []rune
|
|
Glyphs []uint16
|
|
Unsafe bool
|
|
}
|
|
|
|
// FontResourceBackend 解析和裁剪保存资源，独立于显示字体后端
|
|
// SubsetFont的preserve为true时不得改变字形编号，SubsetSourceFont无安全收益时返回nil
|
|
type FontResourceBackend interface {
|
|
Backend
|
|
OpenFontResource(file FontFile, index int) (*FontResource, error)
|
|
SubsetFont(data []byte, glyphs []uint16, preserve bool) ([]byte, error)
|
|
SubsetSourceFont(data []byte, usage FontUsage) ([]byte, error)
|
|
}
|
|
|
|
// SFNTBackend 提供独立的OpenType字体度量、轮廓和资源处理
|
|
type SFNTBackend struct{}
|
|
|
|
// sfntFontMetrics 保留默认字体度量，写出时不更新原始时间
|
|
type sfntFontMetrics struct {
|
|
*basefont.SFNT
|
|
*fontShaper
|
|
outlines *basefont.Outliner
|
|
bounds *sfntFontBounds
|
|
}
|
|
|
|
// sfntFontBounds 缓存已成功提取的字形边界，不保留轮廓或失败结果
|
|
type sfntFontBounds struct {
|
|
mu sync.Mutex
|
|
values map[sfntGlyphSize]Box
|
|
}
|
|
|
|
// sfntGlyphSize 区分字形编号及精确毫米字号
|
|
type sfntGlyphSize struct {
|
|
glyph uint16
|
|
size float64
|
|
}
|
|
|
|
// glyphGeometry 将字体轮廓转换为纵轴向下的几何路径
|
|
type glyphGeometry struct{ path GeometryPath }
|
|
|
|
// sfntResourceMetrics 隔离资源解析器的度量实现
|
|
type sfntResourceMetrics struct{ *basefont.SFNT }
|
|
|
|
// MoveTo 开始子路径
|
|
// 入参: x 横坐标, y 纵坐标
|
|
func (p *glyphGeometry) MoveTo(x, y float64) {
|
|
p.path = append(p.path, GeometrySegment{Verb: GeometryMove, End: Point{X: x, Y: -y}})
|
|
}
|
|
|
|
// LineTo 添加直线
|
|
// 入参: x 横坐标, y 纵坐标
|
|
func (p *glyphGeometry) LineTo(x, y float64) {
|
|
p.path = append(p.path, GeometrySegment{Verb: GeometryLine, End: Point{X: x, Y: -y}})
|
|
}
|
|
|
|
// QuadTo 添加二次贝塞尔曲线
|
|
// 入参: cx 控制点横坐标, cy 控制点纵坐标, x 终点横坐标, y 终点纵坐标
|
|
func (p *glyphGeometry) QuadTo(cx, cy, x, y float64) {
|
|
p.path = append(p.path, GeometrySegment{Verb: GeometryQuad, Control1: Point{X: cx, Y: -cy}, End: Point{X: x, Y: -y}})
|
|
}
|
|
|
|
// CubeTo 添加三次贝塞尔曲线
|
|
// 入参: ax 第一控制点横坐标, ay 第一控制点纵坐标, bx 第二控制点横坐标, by 第二控制点纵坐标, x 终点横坐标, y 终点纵坐标
|
|
func (p *glyphGeometry) CubeTo(ax, ay, bx, by, x, y float64) {
|
|
p.path = append(p.path, GeometrySegment{Verb: GeometryCubic, Control1: Point{X: ax, Y: -ay}, Control2: Point{X: bx, Y: -by}, End: Point{X: x, Y: -y}})
|
|
}
|
|
|
|
// Close 闭合当前子路径
|
|
func (p *glyphGeometry) Close() { p.path = append(p.path, GeometrySegment{Verb: GeometryClose}) }
|
|
|
|
// ResolveFont 按需加载字体资源，保留内嵌数据及外部字体的名称、样式和集合索引匹配
|
|
// 入参: r 渲染器, id 字体标识, exact 是否禁止无关回退
|
|
// 返回: ResolvedFont 字体与来源, error 字体不可用错误
|
|
func (b SFNTBackend) ResolveFont(r *Renderer, id string, exact bool) (ResolvedFont, error) {
|
|
return r.resolveFontSource(b, id, exact)
|
|
}
|
|
|
|
// OpenFont 解析独立SFNT数据，度量与原有编辑排版保持一致
|
|
// 入参: data 字体数据
|
|
// 返回: FontMetrics 字体度量, error 解析错误
|
|
func (SFNTBackend) OpenFont(data []byte) (FontMetrics, error) {
|
|
data, err := basefont.DefaultCFF2Font(data)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
sfnt, err := basefont.ParseSFNT(data)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
metrics := &sfntFontMetrics{SFNT: sfnt, outlines: &basefont.Outliner{Font: sfnt}, bounds: &sfntFontBounds{}}
|
|
metrics.fontShaper = &fontShaper{metrics: metrics}
|
|
return metrics, nil
|
|
}
|
|
|
|
// Write 返回字体数据，不修改字体元信息
|
|
// 返回: []byte 独立SFNT数据
|
|
func (f sfntFontMetrics) Write() []byte {
|
|
return f.SFNT.Write()
|
|
}
|
|
|
|
// GlyphOutline 返回基线原点、纵轴向下的字形轮廓
|
|
// 入参: glyph 字形编号, size 字号，单位为毫米
|
|
// 返回: GeometryPath 字形路径, error 字形解析错误
|
|
func (f sfntFontMetrics) GlyphOutline(glyph uint16, size float64) (GeometryPath, error) {
|
|
if !rasterPositive(size) || glyph >= f.NumGlyphs() {
|
|
return nil, fmt.Errorf("invalid glyph or size")
|
|
}
|
|
path := &glyphGeometry{}
|
|
if err := f.outlines.Path(path, glyph, size/float64(f.UnitsPerEm())); err != nil {
|
|
return nil, err
|
|
}
|
|
return path.path, nil
|
|
}
|
|
|
|
// GlyphBounds 返回字形轮廓的精确边界，重复编号及字号复用有限缓存
|
|
// 入参: glyph 字形编号, size 字号，单位为毫米
|
|
// 返回: Box 字形边界, error 字形解析错误
|
|
func (f sfntFontMetrics) GlyphBounds(glyph uint16, size float64) (Box, error) {
|
|
key := sfntGlyphSize{glyph: glyph, size: size}
|
|
if f.bounds != nil {
|
|
f.bounds.mu.Lock()
|
|
value, ok := f.bounds.values[key]
|
|
f.bounds.mu.Unlock()
|
|
if ok {
|
|
return value, nil
|
|
}
|
|
}
|
|
outline, err := f.GlyphOutline(glyph, size)
|
|
if err != nil {
|
|
return Box{}, err
|
|
}
|
|
value, err := outline.Bounds()
|
|
if err != nil {
|
|
return Box{}, err
|
|
}
|
|
if f.bounds != nil {
|
|
f.bounds.mu.Lock()
|
|
if f.bounds.values == nil || len(f.bounds.values) >= sfntGlyphBoundsLimit {
|
|
f.bounds.values = make(map[sfntGlyphSize]Box)
|
|
}
|
|
f.bounds.values[key] = value
|
|
f.bounds.mu.Unlock()
|
|
}
|
|
return value, nil
|
|
}
|
|
|
|
// GlyphWarning 返回无效字形指令后保留设计轮廓的提示，原始字体不变
|
|
// 入参: glyph 字形编号
|
|
// 返回: error 恢复原因，无恢复时为空
|
|
func (f sfntFontMetrics) GlyphWarning(glyph uint16) error {
|
|
return f.outlines.GlyphWarning(glyph)
|
|
}
|
|
|
|
// GlyphOutlines 批量提取字形轮廓，重复编号只解析一次
|
|
// 入参: glyphs 字形编号, size 毫米字号
|
|
// 返回: []GeometryPath 同序只读轮廓, error 轮廓错误
|
|
func (f sfntFontMetrics) GlyphOutlines(glyphs []uint16, size float64) ([]GeometryPath, error) {
|
|
if !rasterPositive(size) {
|
|
return nil, fmt.Errorf("invalid glyph size")
|
|
}
|
|
result := make([]GeometryPath, len(glyphs))
|
|
paths := make(map[uint16]GeometryPath, len(glyphs))
|
|
for i, glyph := range glyphs {
|
|
path, ok := paths[glyph]
|
|
if !ok {
|
|
var err error
|
|
path, err = f.GlyphOutline(glyph, size)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
paths[glyph] = path
|
|
}
|
|
result[i] = path
|
|
}
|
|
return result, nil
|
|
}
|
|
|
|
// Name 返回资源后端标识
|
|
// 返回: string 后端标识
|
|
func (SFNTBackend) Name() string { return "sfnt" }
|
|
|
|
// OpenFontResource 提取独立字体并读取名称、样式和裁剪能力
|
|
// CFF2使用默认实例的静态轮廓，不改变原字体文件
|
|
// 入参: file 字体文件, index 集合索引
|
|
// 返回: *FontResource 字体资源, error 解析错误
|
|
func (SFNTBackend) OpenFontResource(file FontFile, index int) (*FontResource, error) {
|
|
data, err := file.Face(index)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
data, err = basefont.DefaultCFF2Font(data)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
sfnt, err := basefont.ParseSFNT(data)
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
name := basefont.SFNTName(sfnt, 6, 4, 1)
|
|
if name == "" {
|
|
return nil, fmt.Errorf("font has no name")
|
|
}
|
|
extension := ".ttf"
|
|
if sfnt.IsCFF {
|
|
extension = ".otf"
|
|
}
|
|
return &FontResource{
|
|
FontMetrics: sfntResourceMetrics{sfnt}, Data: data, Extension: extension,
|
|
Font: Font{FontName: name, FamilyName: basefont.SFNTName(sfnt, 16, 1), Charset: "unicode", Bold: binary.BigEndian.Uint16(sfnt.Tables["head"][44:])&1 != 0, Italic: binary.BigEndian.Uint16(sfnt.Tables["head"][44:])&2 != 0, FixedWidth: len(sfnt.Tables["post"]) >= 16 && binary.BigEndian.Uint32(sfnt.Tables["post"][12:]) != 0},
|
|
CanSubset: basefont.Subsettable(sfnt),
|
|
}, nil
|
|
}
|
|
|
|
// SubsetFont 裁剪新建字体并按要求保留显式字形编号
|
|
// 入参: data 字体数据, glyphs 用字, preserve 是否保留编号
|
|
// 返回: []byte 子集, error 裁剪错误
|
|
func (SFNTBackend) SubsetFont(data []byte, glyphs []uint16, preserve bool) ([]byte, error) {
|
|
return basefont.SubsetSFNT(data, glyphs, preserve)
|
|
}
|
|
|
|
// SubsetSourceFont 按全包引用裁剪原字体，不确定时保留原资源
|
|
// 入参: data 字体数据, usage 用字信息
|
|
// 返回: []byte 子集, error 裁剪错误
|
|
func (SFNTBackend) SubsetSourceFont(data []byte, usage FontUsage) ([]byte, error) {
|
|
u := &basefont.Usage{Characters: make(map[rune]bool), Glyphs: make(map[uint16]bool), Unsafe: usage.Unsafe}
|
|
for _, char := range usage.Characters {
|
|
u.Characters[char] = true
|
|
}
|
|
for _, glyph := range usage.Glyphs {
|
|
u.Glyphs[glyph] = true
|
|
}
|
|
return basefont.SubsetSourceSFNT(data, u), nil
|
|
}
|
|
|
|
// Write 返回未改动元信息的字体数据
|
|
// 返回: []byte 字体数据
|
|
func (f sfntResourceMetrics) Write() []byte { return f.SFNT.Write() }
|