feat(渲染压缩): 完善字体三维动作导航及压缩

ofdgo_compression_parallel.go

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+// 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 (
+	"crypto/sha256"
+	"image"
+	"runtime"
+	"sync"
+
+	"github.com/xiaoqidun/pdfgo"
+)
+
+// outputImageBatchLimit 限制并行批次持有的原始编码，超限图片单独处理
+const outputImageBatchLimit = 16 << 20
+
+// outputImageJob 保存独立图片任务，不访问编辑文档或调用进度回调
+type outputImageJob struct {
+	key       outputImageKey
+	data      []byte
+	candidate []byte
+	err       error
+}
+
+// outputImageOptions 统一资源压缩及像素需求，受保护图片只进行无损编码
+// 入参: key 资源路径
+// 返回: CompressionOptions 实际策略, image.Point 像素需求
+func (e *Editor) outputImageOptions(key string) (CompressionOptions, image.Point) {
+	options := e.output.options
+	if !e.output.images[key] {
+		options.Mode = CompressionLossless
+	}
+	demand := e.output.sizes[key]
+	if options.Mode != CompressionLossy {
+		options = CompressionOptions{Mode: options.Mode}
+		demand = image.Point{}
+	}
+	return options, demand
+}
+
+// prepareOutputImages 有界并行优化独立图片，读取、缓存及进度仍在调用线程处理
+// 入参: keys 资源路径, load 串行读取方法，空值表示跳过, results 本次写出的候选缓存
+// 返回: error 读取、进度或取消错误
+func (e *Editor) prepareOutputImages(keys []string, load func(string) ([]byte, error), results map[outputImageKey][]byte) error {
+	workers := min(2, runtime.GOMAXPROCS(0))
+	if workers < 2 || len(keys) < 2 {
+		return nil
+	}
+	batch := make([]outputImageJob, 0, workers)
+	size := 0
+	run := func() error {
+		if err := e.runOutputImages(batch, results); err != nil {
+			return err
+		}
+		clear(batch)
+		batch, size = batch[:0], 0
+		return nil
+	}
+	for _, key := range keys {
+		if err := e.output.ctx.Err(); err != nil {
+			return err
+		}
+		if err := editorProgress(e.OnWriteProgress).report("compress", e.output.completed, 0); err != nil {
+			return err
+		}
+		data, err := load(key)
+		if err != nil {
+			return err
+		}
+		if len(data) == 0 {
+			continue
+		}
+		options, demand := e.outputImageOptions(key)
+		cacheKey := outputImageKey{hash: sha256.Sum256(data), options: options, size: demand}
+		if _, cached := results[cacheKey]; cached {
+			continue
+		}
+		duplicate := false
+		for _, job := range batch {
+			duplicate = duplicate || job.key == cacheKey
+		}
+		if duplicate {
+			continue
+		}
+		if len(batch) != 0 && len(data) > outputImageBatchLimit-size {
+			if err := run(); err != nil {
+				return err
+			}
+		}
+		batch = append(batch, outputImageJob{key: cacheKey, data: data})
+		size += len(data)
+		if len(batch) == workers || size >= outputImageBatchLimit {
+			if err := run(); err != nil {
+				return err
+			}
+		}
+	}
+	return run()
+}
+
+// runOutputImages 等待整批结束后记录更小候选，失败图片保留原始编码
+// 入参: jobs 独占图片任务, results 本次写出的候选缓存
+// 返回: error 取消错误
+func (e *Editor) runOutputImages(jobs []outputImageJob, results map[outputImageKey][]byte) error {
+	ctx := e.output.ctx
+	optimize := func(job *outputImageJob) {
+		job.candidate, job.err = pdfgo.OptimizeImageResource(ctx, job.data, job.key.options, job.key.size)
+	}
+	if len(jobs) == 1 {
+		optimize(&jobs[0])
+	} else {
+		var group sync.WaitGroup
+		for i := range jobs {
+			group.Go(func() { optimize(&jobs[i]) })
+		}
+		group.Wait()
+	}
+	if err := ctx.Err(); err != nil {
+		return err
+	}
+	for _, job := range jobs {
+		results[job.key] = nil
+		if job.err == nil && len(job.candidate) < len(job.data) {
+			results[job.key] = job.candidate
+		}
+	}
+	return nil
+}