feat(后端架构): 优化多后端渲染，修复描边与字形校验

ofdgo_text_xml.go

@@ -0,0 +1,72 @@
+// 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/xml"
+
+// textObjectTokens 记录字形变换所属TextCode，供解码后转换为对象内索引
+type textObjectTokens struct {
+	decoder     *xml.Decoder
+	start       *xml.StartElement
+	depth, code int
+	transforms  []int
+}
+
+// Token 转发XML令牌并记录直接子节点顺序
+// 返回: xml.Token XML令牌, error 解码错误
+func (s *textObjectTokens) Token() (xml.Token, error) {
+	if s.start != nil {
+		start := *s.start
+		s.start = nil
+		return start, nil
+	}
+	token, err := s.decoder.Token()
+	switch value := token.(type) {
+	case xml.StartElement:
+		if s.depth == 0 && value.Name.Local == "CGTransform" {
+			s.transforms = append(s.transforms, s.code)
+		}
+		s.depth++
+	case xml.EndElement:
+		s.depth--
+		if s.depth == 0 && value.Name.Local == "TextCode" {
+			s.code++
+		}
+	}
+	return token, err
+}
+
+// UnmarshalXML 将各TextCode前的局部字形位置统一为对象内索引
+// 入参: decoder XML解码器, start 对象起始节点
+// 返回: error 解码错误
+func (obj *TextObject) UnmarshalXML(decoder *xml.Decoder, start xml.StartElement) error {
+	type plain TextObject
+	stream := &textObjectTokens{decoder: decoder, start: &start}
+	var value plain
+	if err := xml.NewTokenDecoder(stream).Decode(&value); err != nil {
+		return err
+	}
+	offsets := make([]int, len(value.TextCode))
+	for i := 1; i < len(offsets); i++ {
+		offsets[i] = offsets[i-1] + len(textCodeRunes(value.TextCode[i-1].Value))
+	}
+	for i, code := range stream.transforms {
+		if code < len(offsets) {
+			value.CGTransform[i].CodePosition += offsets[code]
+		}
+	}
+	*obj = TextObject(value)
+	return nil
+}