feat(能力完善): 完善转换保真，修复交互缺陷

ofdgo_renderer_pdf_sound.go

@@ -0,0 +1,61 @@
+// 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 (
+	"context"
+	"fmt"
+
+	"github.com/xiaoqidun/pdfgo"
+)
+
+// soundAction 保留音量、循环及等待语义，PDF同步播放同时限制交互
+// 入参: action OFD音频动作
+// 返回: *pdfNavigationAction PDF音频动作, error 资源或参数错误
+func (n *pdfNavigation) soundAction(action Sound) (*pdfNavigationAction, error) {
+	volume := 100
+	if action.Volume != nil {
+		volume = *action.Volume
+	}
+	if volume < 0 || volume > 100 {
+		return nil, fmt.Errorf("invalid sound volume")
+	}
+	file := n.audio[action.ResourceID]
+	if file == nil {
+		media, err := n.source.Media(action.ResourceID)
+		if err != nil {
+			return nil, err
+		}
+		if media.Type != "Audio" {
+			return nil, fmt.Errorf("sound resource is not audio: %s", action.ResourceID)
+		}
+		if n.audio == nil {
+			n.audio = make(map[string]*pdfgo.FileSpecification)
+		}
+		file = n.mediaFile(media)
+		n.audio[action.ResourceID] = file
+	}
+	return &pdfNavigationAction{Sound: &pdfgo.SoundAction{
+		Sound: pdfgo.Sound{File: file}, Volume: float64(volume) / 100,
+		Repeat: action.Repeat, Synchronous: action.Synchronous && !action.Repeat,
+	}}, nil
+}
+
+// loadAudio 在绘制后读取自描述音频文件，原始内容不作采样转换
+// 入参: ctx 取消上下文
+// 返回: error 资源读取或取消错误
+func (n *pdfNavigation) loadAudio(ctx context.Context) error {
+	return n.loadMediaFiles(ctx, n.audio)
+}