Files
ofdgo/ofdgo_renderer_font_canvas.go
T
2026-10-14 00:12:00 +08:00

61 lines
1.9 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 (
"fmt"
"sync"
"github.com/tdewolff/canvas"
basefont "github.com/xiaoqidun/ofdgo/internal/base/font"
)
// canvasFontLoadMu 保护绘图后端加载无名称字体时使用的共享状态
var canvasFontLoadMu sync.Mutex
// loadCanvasFont 串行加载绘图字体,不改动原始字体数据
// 入参: data 字体数据, index 集合索引, style 字体样式
// 返回: *canvas.Font 绘图字体, error 加载错误
func loadCanvasFont(data []byte, index int, style canvas.FontStyle) (*canvas.Font, error) {
canvasFontLoadMu.Lock()
defer canvasFontLoadMu.Unlock()
return canvas.LoadFont(data, index, style)
}
// decodeFontContainer 展开字体封装,保留原始OpenType表及CFF2轮廓
// 入参: data 字体文件
// 返回: []byte OpenType数据, error 格式错误
func decodeFontContainer(data []byte) ([]byte, error) {
if len(data) < 12 {
return nil, fmt.Errorf("invalid font header")
}
switch string(data[:4]) {
case "\x00\x01\x00\x00", "OTTO", "true", "ttcf":
return data, nil
case "wOFF":
return basefont.DecodeWOFF(data)
case "wOF2":
decoded, handled, err := basefont.DecodeWOFF2(data)
if handled {
return decoded, err
}
}
loaded, err := loadCanvasFont(data, 0, canvas.FontRegular)
if err != nil {
return nil, err
}
return basefont.SerializeOTF(loaded.Tables)
}