feat(电子公文): 支持标引编辑与图元绑定

ofdgo_structure_object.go

@@ -0,0 +1,88 @@
+// 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
+
+// structureObjectVisitor 收集页面及复合图元标识，绑定校验不解码字体、图片或裁剪
+type structureObjectVisitor struct {
+	objects map[string]bool
+	targets []StructureTarget
+}
+
+// StructureObjects 列出指定页可绑定的图元及原文，包含模板、隐藏内容和复合图元成员
+// 不解码字体和图片，返回顺序遵循页面遍历顺序，同一标识仅列出一次
+// 入参: page 从0开始的页面索引
+// 返回: []StructureTarget 候选图元，不计算Bounds, error 页面或遍历错误
+func (r *Renderer) StructureObjects(page int) ([]StructureTarget, error) {
+	content, err := r.Reader.PageContentByIndex(page)
+	if err != nil {
+		return nil, err
+	}
+	visitor := &structureObjectVisitor{objects: make(map[string]bool)}
+	if err := r.WalkPage(content, visitor); err != nil {
+		return nil, err
+	}
+	for i := range visitor.targets {
+		visitor.targets[i].Page, visitor.targets[i].PageID = page+1, content.ID
+	}
+	return visitor.targets, nil
+}
+
+// BeginObject 登记图元标识，不创建分组状态
+// 入参: object 页面图元
+// 返回: bool 始终为false
+func (v *structureObjectVisitor) BeginObject(object *GraphicObject) bool {
+	id := editorResourceID(editorObjectID(*object))
+	if id != "" && !v.objects[id] {
+		v.objects[id] = true
+		target := StructureTarget{ID: id}
+		if object.Type == "TextObject" {
+			target.Text = object.TextObject.Text()
+		}
+		v.targets = append(v.targets, target)
+	}
+	return false
+}
+
+// EndObject 满足分组访问接口，不维护分组栈
+func (v *structureObjectVisitor) EndObject() {}
+
+// BeginAnnotation 不为注解容器分配正文图元标识
+// 入参: id 注解标识
+// 返回: bool 始终为false
+func (v *structureObjectVisitor) BeginAnnotation(id string) bool { return false }
+
+// SkipObjects 不依赖图元序号
+// 入参: count 跳过数量
+func (v *structureObjectVisitor) SkipObjects(count int) {}
+
+// IncludeHidden 允许绑定隐藏图元
+// 返回: bool 始终为true
+func (v *structureObjectVisitor) IncludeHidden() bool { return true }
+
+// SkipClips 绑定校验不需要裁剪轮廓
+// 返回: bool 始终为true
+func (v *structureObjectVisitor) SkipClips() bool { return true }
+
+// DrawObject 不绘制图元，标识已由BeginObject登记
+// 入参: object 页面图元, state 继承状态
+// 返回: error 始终为nil
+func (v *structureObjectVisitor) DrawObject(object *GraphicObject, state RenderState) error {
+	return nil
+}
+
+// DrawStamp 不将签章外观作为正文绑定目标
+// 入参: stamp 签章外观
+// 返回: error 始终为nil
+func (v *structureObjectVisitor) DrawStamp(stamp Stamp) error { return nil }