48 lines
1.6 KiB
Dart
48 lines
1.6 KiB
Dart
import 'package:flutter/foundation.dart';
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import 'package:image/image.dart' as img;
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const int _avatarMaxDimension = 1024;
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const int _avatarTargetBytes = 900 * 1024;
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/// Maximum accepted size for a user-picked avatar before compression.
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const int kMaxAvatarBytes = 8 * 1024 * 1024;
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Future<Uint8List?> compressAvatar(Uint8List input) => compute(_encodeAvatar, input);
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Future<Uint8List?> encodeRgbaToJpeg(Uint8List rgba, int width, int height) =>
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compute(_encodeRgba, (rgba, width, height));
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Uint8List? _encodeRgba((Uint8List, int, int) args) {
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final (rgba, width, height) = args;
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if (width <= 0 || height <= 0) return null;
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final image = img.Image.fromBytes(
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width: width,
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height: height,
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bytes: rgba.buffer,
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numChannels: 4,
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order: img.ChannelOrder.rgba,
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);
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return img.encodeJpg(image, quality: 90);
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}
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Uint8List? _encodeAvatar(Uint8List input) {
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final decoded = img.decodeImage(input);
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if (decoded == null) return null;
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final oriented = img.bakeOrientation(decoded);
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final image = oriented.width > _avatarMaxDimension || oriented.height > _avatarMaxDimension
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? img.copyResize(
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oriented,
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width: oriented.width >= oriented.height ? _avatarMaxDimension : null,
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height: oriented.height > oriented.width ? _avatarMaxDimension : null,
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interpolation: img.Interpolation.average,
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)
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: oriented;
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var quality = 88;
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var out = img.encodeJpg(image, quality: quality);
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while (out.lengthInBytes > _avatarTargetBytes && quality > 35) {
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quality -= 12;
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out = img.encodeJpg(image, quality: quality);
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}
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return out;
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}
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