196 lines
7.7 KiB
Dart
196 lines
7.7 KiB
Dart
import 'dart:io';
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import 'dart:typed_data';
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import 'package:flutter/material.dart';
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import 'package:path_provider/path_provider.dart';
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import 'package:path/path.dart' as path;
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import 'package:image/image.dart' as img; // CR-005: 画像圧縮・リサイズ用
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/// 画像圧縮サービス
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/// Gemini APIのトークン消費を削減するため、画像を最適化します
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class ImageCompressionService {
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/// 最大画像サイズ(長辺): 1024px
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/// Geminiは高解像度でなくても十分な認識精度があります
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static const int maxDimension = 1024;
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/// JPEG品質: 85% (品質と容量のバランス)
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static const int jpegQuality = 85;
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/// 画像を圧縮してGemini API用に最適化
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///
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/// [sourcePath] 元画像のパス
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/// [targetPath] 圧縮後の保存先パス(nullの場合は自動生成)
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///
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/// 戻り値: 圧縮後の画像パス
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static Future<String> compressForGemini(String sourcePath, {String? targetPath}) async {
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try {
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final File sourceFile = File(sourcePath);
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if (!await sourceFile.exists()) {
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throw Exception('Source image not found: $sourcePath');
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}
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// CR-005: 画像をデコード（image packageを使用）
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final Uint8List imageBytes = await sourceFile.readAsBytes();
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final img.Image? originalImage = img.decodeImage(imageBytes);
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if (originalImage == null) {
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debugPrint('Failed to decode image, returning original');
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return sourcePath;
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}
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final int originalWidth = originalImage.width;
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final int originalHeight = originalImage.height;
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// リサイズが不要な場合は、圧縮のみ実施
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if (originalWidth <= maxDimension && originalHeight <= maxDimension) {
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debugPrint('Image dimensions OK: ${originalWidth}x$originalHeight, applying JPEG compression');
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// 保存先パス決定
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final String outputPath = targetPath ?? await _generateCompressedPath(sourcePath);
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// JPEG圧縮のみ適用
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final compressedBytes = img.encodeJpg(originalImage, quality: jpegQuality);
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await File(outputPath).writeAsBytes(compressedBytes);
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final originalSize = imageBytes.length;
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final compressedSize = compressedBytes.length;
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debugPrint('Compression result: ${(originalSize / 1024).toStringAsFixed(1)}KB -> ${(compressedSize / 1024).toStringAsFixed(1)}KB');
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return outputPath;
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}
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// CR-005: リサイズが必要な場合
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debugPrint('Resizing image: ${originalWidth}x$originalHeight -> max $maxDimension');
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// アスペクト比を保ったままリサイズ
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final img.Image resized = img.copyResize(
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originalImage,
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width: originalWidth > originalHeight ? maxDimension : null,
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height: originalHeight > originalWidth ? maxDimension : null,
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interpolation: img.Interpolation.linear, // 高品質な補間
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);
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// 保存先パス決定
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final String outputPath = targetPath ?? await _generateCompressedPath(sourcePath);
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// JPEG形式で保存
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final compressedBytes = img.encodeJpg(resized, quality: jpegQuality);
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await File(outputPath).writeAsBytes(compressedBytes);
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final originalSize = imageBytes.length;
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final compressedSize = compressedBytes.length;
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debugPrint('Resize & Compression result: ${originalWidth}x$originalHeight (${(originalSize / 1024).toStringAsFixed(1)}KB) -> ${resized.width}x${resized.height} (${(compressedSize / 1024).toStringAsFixed(1)}KB)');
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return outputPath;
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} catch (e) {
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debugPrint('Image compression error: $e');
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// エラー時は元のパスを返す(フォールバック)
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return sourcePath;
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}
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}
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/// 圧縮画像の保存先パスを生成（一時ディレクトリ）
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///
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/// 🔒 一時ファイルは getTemporaryDirectory() に保存
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static Future<String> _generateCompressedPath(String sourcePath) async {
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final directory = await getTemporaryDirectory();
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final fileName = path.basenameWithoutExtension(sourcePath);
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final extension = path.extension(sourcePath);
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return path.join(directory.path, '${fileName}_compressed$extension');
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}
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/// ファイルサイズを取得(デバッグ用)
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static Future<int> getFileSize(String filePath) async {
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final file = File(filePath);
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return await file.length();
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}
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/// ファイルサイズを人間が読みやすい形式で取得
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static Future<String> getFileSizeString(String filePath) async {
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final size = await getFileSize(filePath);
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if (size < 1024) {
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return '$size B';
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} else if (size < 1024 * 1024) {
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return '${(size / 1024).toStringAsFixed(1)} KB';
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} else {
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return '${(size / (1024 * 1024)).toStringAsFixed(1)} MB';
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}
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}
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/// ギャラリー保存用に画像を圧縮（高品質版）
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///
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/// [sourcePath] 元画像のパス
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/// [targetPath] 圧縮後の保存先パス(nullの場合は自動生成)
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/// [maxDimension] 最大画像サイズ(デフォルト: 2000px)
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/// [quality] JPEG品質(デフォルト: 90%)
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///
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/// 戻り値: 圧縮後の画像パス
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static Future<String> compressForGallery(
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String sourcePath, {
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String? targetPath,
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int maxDimension = 2000,
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int quality = 90,
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}) async {
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try {
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final File sourceFile = File(sourcePath);
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if (!await sourceFile.exists()) {
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throw Exception('Source image not found: $sourcePath');
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}
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final Uint8List imageBytes = await sourceFile.readAsBytes();
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final img.Image? originalImage = img.decodeImage(imageBytes);
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if (originalImage == null) {
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debugPrint('Failed to decode image, returning original');
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return sourcePath;
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}
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final int originalWidth = originalImage.width;
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final int originalHeight = originalImage.height;
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// リサイズが不要な場合は、圧縮のみ実施
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if (originalWidth <= maxDimension && originalHeight <= maxDimension) {
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debugPrint('Gallery: Image dimensions OK: ${originalWidth}x$originalHeight, applying JPEG compression');
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final String outputPath = targetPath ?? await _generateCompressedPath(sourcePath);
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final compressedBytes = img.encodeJpg(originalImage, quality: quality);
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await File(outputPath).writeAsBytes(compressedBytes);
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final originalSize = imageBytes.length;
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final compressedSize = compressedBytes.length;
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debugPrint('Gallery compression: ${(originalSize / 1024).toStringAsFixed(1)}KB -> ${(compressedSize / 1024).toStringAsFixed(1)}KB');
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return outputPath;
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}
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// リサイズが必要な場合
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debugPrint('Gallery: Resizing image: ${originalWidth}x$originalHeight -> max $maxDimension');
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final img.Image resized = img.copyResize(
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originalImage,
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width: originalWidth > originalHeight ? maxDimension : null,
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height: originalHeight > originalWidth ? maxDimension : null,
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interpolation: img.Interpolation.cubic, // ギャラリー用は最高品質
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);
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final String outputPath = targetPath ?? await _generateCompressedPath(sourcePath);
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final compressedBytes = img.encodeJpg(resized, quality: quality);
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await File(outputPath).writeAsBytes(compressedBytes);
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final originalSize = imageBytes.length;
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final compressedSize = compressedBytes.length;
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debugPrint('Gallery resize & compression: ${originalWidth}x$originalHeight (${(originalSize / 1024).toStringAsFixed(1)}KB) -> ${resized.width}x${resized.height} (${(compressedSize / 1024).toStringAsFixed(1)}KB)');
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return outputPath;
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} catch (e) {
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debugPrint('Gallery image compression error: $e');
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return sourcePath;
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}
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}
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}
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