feat(后端架构): 完善后端解耦

ofdgo_render_svg.go

@@ -0,0 +1,73 @@
+// 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"
+	"io"
+)
+
+// SVGFont SVG引用的字体资源，Name为CSS字体族标识，Data为只读字体数据
+type SVGFont struct {
+	Name   string
+	Weight int
+	Style  string
+	Data   []byte
+}
+
+// SVGImage SVG引用的图片资源，Name为图片地址，Data为只读图片数据
+type SVGImage struct {
+	Name string
+	MIME string
+	Data []byte
+}
+
+// SVGResources SVG引用的字体和图片资源
+type SVGResources struct {
+	Fonts  []SVGFont
+	Images []SVGImage
+}
+
+// RenderToSVGWithFonts 渲染为SVG并返回页面引用的字体资源，不在SVG中嵌入字体
+// 入参: page 页面内容, writer 输出流
+// 返回: []SVGFont 字体资源，可按Name复用并按Weight、Style注册，error 错误信息
+func (r *Renderer) RenderToSVGWithFonts(page *PageContent, writer io.Writer) ([]SVGFont, error) {
+	resources, err := r.renderSVG(page, writer, SVGExternalFonts)
+	return resources.Fonts, err
+}
+
+// RenderToSVGWithResources 渲染为SVG并分离字体和图片，调用方需注册字体并将图片Name映射为可访问地址
+// 入参: page 页面内容, writer 输出流
+// 返回: SVGResources 可跨页面复用的资源, error 错误信息
+func (r *Renderer) RenderToSVGWithResources(page *PageContent, writer io.Writer) (SVGResources, error) {
+	return r.renderSVG(page, writer, SVGExternalResources)
+}
+
+// RenderToSVGWithObjects 渲染SVG并为页面对象和注解添加data-ofd-object分组，注解标识使用annotation:前缀
+// 入参: page 页面内容, writer 输出流
+// 返回: SVGResources 字体和图片资源, error 错误信息
+func (r *Renderer) RenderToSVGWithObjects(page *PageContent, writer io.Writer) (SVGResources, error) {
+	return r.renderSVG(page, writer, SVGObjects)
+}
+
+// renderSVG 将SVG输出及对象分组交给指定后端
+// 入参: page 页面内容, writer 输出流, mode 资源封装方式
+// 返回: SVGResources 字体和图片资源, error 输出错误
+func (r *Renderer) renderSVG(page *PageContent, writer io.Writer, mode SVGMode) (SVGResources, error) {
+	if r.backends.SVG == nil {
+		return SVGResources{}, fmt.Errorf("svg: %w", ErrBackendUnavailable)
+	}
+	return r.backends.SVG.RenderSVG(r, page, writer, mode)
+}