feat(正式发布): 实现了OFD渲染和导出为PDF、图片、矢量图等

ofdgo_reader.go

@@ -0,0 +1,299 @@
+// Copyright 2025 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 首款原生、全平台兼容的纯 Go 语言 OFD 渲染库
+package ofdgo
+
+import (
+	"archive/zip"
+	"encoding/xml"
+	"fmt"
+	"io"
+	"path"
+	"strings"
+)
+
+// Reader OFD文件阅读器
+type Reader struct {
+	Path           string
+	Zip            *zip.Reader
+	Closer         io.Closer
+	OFD            *OFD
+	RootDir        string
+	ResMap         map[string]string
+	fontCache      map[string]*Font
+	drawParamCache map[string]*DrawParam
+	doc            *Document
+}
+
+// Close 关闭阅读器
+// 返回: error 错误信息
+func (r *Reader) Close() error {
+	if r.Closer != nil {
+		return r.Closer.Close()
+	}
+	return nil
+}
+
+// initRoot 读取根节点信息
+// 返回: error 错误信息
+func (r *Reader) initRoot() error {
+	data, err := r.readFile("OFD.xml")
+	if err != nil {
+		return fmt.Errorf("failed to read ofd.xml: %w", err)
+	}
+	var ofd OFD
+	if err := xml.Unmarshal(data, &ofd); err != nil {
+		return fmt.Errorf("failed to unmarshal ofd.xml: %w", err)
+	}
+	r.OFD = &ofd
+	return nil
+}
+
+// readFile 读取压缩包内的文件
+// 入参: name 文件名
+// 返回: []byte 文件内容, error 错误信息
+func (r *Reader) readFile(name string) ([]byte, error) {
+	name = strings.ReplaceAll(name, "\\", "/")
+	for _, f := range r.Zip.File {
+		if f.Name == name {
+			return readZipFile(f)
+		}
+	}
+	return nil, fmt.Errorf("file not found: %s", name)
+}
+
+// readZipFile 读取zip文件内容
+// 入参: f zip文件对象
+// 返回: []byte 文件内容, error 错误信息
+func readZipFile(f *zip.File) ([]byte, error) {
+	rc, err := f.Open()
+	if err != nil {
+		return nil, err
+	}
+	defer rc.Close()
+	return io.ReadAll(rc)
+}
+
+// Doc 获取主文档结构
+// 返回: *Document 文档结构, error 错误信息
+func (r *Reader) Doc() (*Document, error) {
+	if r.doc != nil {
+		return r.doc, nil
+	}
+	if r.OFD == nil || len(r.OFD.DocBody) == 0 {
+		return nil, fmt.Errorf("no docbody found")
+	}
+	docAttr := r.OFD.DocBody[0]
+	docRootPath := docAttr.DocRoot
+	r.RootDir = path.Dir(docRootPath)
+	data, err := r.readFile(docRootPath)
+	if err != nil {
+		return nil, err
+	}
+	var doc Document
+	if err := xml.Unmarshal(data, &doc); err != nil {
+		return nil, fmt.Errorf("failed to unmarshal document.xml: %w", err)
+	}
+	r.OFD.DocBody[0].DocInfo.DocID = "loaded"
+	r.ResMap = make(map[string]string)
+	r.fontCache = make(map[string]*Font)
+	r.drawParamCache = make(map[string]*DrawParam)
+	if doc.CommonData.DocumentRes != "" {
+		r.loadRes(doc.CommonData.DocumentRes)
+	}
+	if doc.CommonData.PublicRes != "" {
+		r.loadRes(doc.CommonData.PublicRes)
+	}
+	r.doc = &doc
+	return &doc, nil
+}
+
+// loadRes 加载资源文件
+// 入参: resPath 资源路径
+func (r *Reader) loadRes(resPath string) {
+	if resPath == "" {
+		return
+	}
+	fullPath := path.Join(r.RootDir, resPath)
+	data, err := r.readFile(fullPath)
+	if err != nil {
+		return
+	}
+	var res Res
+	if err := xml.Unmarshal(data, &res); err != nil {
+		return
+	}
+	baseLoc := res.BaseLoc
+	for _, mm := range res.MultiMedias.MultiMedia {
+		if mm.MediaFile != "" {
+			p := strings.TrimSpace(mm.MediaFile)
+			if p == "" {
+				continue
+			}
+			dir := path.Dir(resPath)
+			if baseLoc != "" {
+				if dir != baseLoc {
+					dir = path.Join(dir, baseLoc)
+				}
+			}
+			finalPath := path.Join(dir, p)
+			r.ResMap[mm.ID] = finalPath
+		}
+	}
+	for i := range res.Fonts.Font {
+		f := &res.Fonts.Font[i]
+		if f.FontFile != "" {
+			dir := path.Dir(resPath)
+			if baseLoc != "" {
+				if dir != baseLoc {
+					dir = path.Join(dir, baseLoc)
+				}
+			}
+			f.FontFile = path.Join(dir, f.FontFile)
+		}
+		r.fontCache[f.ID] = f
+	}
+	for i := range res.DrawParams.DrawParam {
+		dp := &res.DrawParams.DrawParam[i]
+		r.drawParamCache[dp.ID] = dp
+	}
+}
+
+// PageContent 获取页面内容
+// 入参: page 页面对象
+// 返回: *PageContent 页面内容, error 错误信息
+func (r *Reader) PageContent(page Page) (*PageContent, error) {
+	fullPath := path.Join(r.RootDir, page.BaseLoc)
+	data, err := r.readFile(fullPath)
+	if err != nil {
+		return nil, err
+	}
+	var content PageContent
+	if err := xml.Unmarshal(data, &content); err != nil {
+		return nil, fmt.Errorf("failed to unmarshal page content: %w", err)
+	}
+	return &content, nil
+}
+
+// ResPath 获取资源的完整路径
+// 入参: resLink 资源链接
+// 返回: string 完整路径
+func (r *Reader) ResPath(resLink string) string {
+	if resLink == "" {
+		return ""
+	}
+	return path.Join(r.RootDir, resLink)
+}
+
+// ResData 获取资源文件数据
+// 入参: resLink 资源链接
+// 返回: []byte 资源数据, error 错误信息
+func (r *Reader) ResData(resLink string) ([]byte, error) {
+	fullPath := r.ResPath(resLink)
+	return r.readFile(fullPath)
+}
+
+// DocRoots 获取所有文档根路径
+// 返回: []string 路径列表
+func (r *Reader) DocRoots() []string {
+	var roots []string
+	if r.OFD == nil {
+		return roots
+	}
+	for _, body := range r.OFD.DocBody {
+		roots = append(roots, body.DocRoot)
+	}
+	return roots
+}
+
+// Version 获取OFD版本号
+// 返回: string 版本号
+func (r *Reader) Version() string {
+	if r.OFD == nil {
+		return ""
+	}
+	return r.OFD.Version
+}
+
+// DocType 获取文档类型
+// 返回: string 文档类型
+func (r *Reader) DocType() string {
+	if r.OFD == nil {
+		return ""
+	}
+	return r.OFD.DocType
+}
+
+// DocInfo 获取文档元数据
+// 返回: *DocInfo 元数据, error 错误信息
+func (r *Reader) DocInfo() (*DocInfo, error) {
+	if r.OFD == nil || len(r.OFD.DocBody) == 0 {
+		return nil, fmt.Errorf("no docbody found")
+	}
+	return &r.OFD.DocBody[0].DocInfo, nil
+}
+
+// Permissions 获取文档权限信息
+// 返回: *Permissions 权限信息, error 错误信息
+func (r *Reader) Permissions() (*Permissions, error) {
+	doc, err := r.Doc()
+	if err != nil {
+		return nil, err
+	}
+	return &doc.Permissions, nil
+}
+
+// Outlines 获取文档大纲
+// 返回: []OutlineElem 大纲列表, error 错误信息
+func (r *Reader) Outlines() ([]OutlineElem, error) {
+	doc, err := r.Doc()
+	if err != nil {
+		return nil, err
+	}
+	return doc.Outlines.OutlineElem, nil
+}
+
+// Attachments 获取附件列表
+// 返回: []Attachment 附件列表, error 错误信息
+func (r *Reader) Attachments() ([]Attachment, error) {
+	doc, err := r.Doc()
+	if err != nil {
+		return nil, err
+	}
+	return doc.Attachments.Attachment, nil
+}
+
+// CustomDatas 获取自定义数据
+// 返回: []CustomData 自定义数据列表, error 错误信息
+func (r *Reader) CustomDatas() ([]CustomData, error) {
+	info, err := r.DocInfo()
+	if err != nil {
+		return nil, err
+	}
+	if info.CustomDatas == nil {
+		return nil, nil
+	}
+	return info.CustomDatas.CustomData, nil
+}
+
+// Extensions 获取分列扩展项
+// 返回: []Extension 扩展项列表, error 错误信息
+func (r *Reader) Extensions() ([]Extension, error) {
+	doc, err := r.Doc()
+	if err != nil {
+		return nil, err
+	}
+	return doc.Extensions.Extension, nil
+}