52 lines
1.8 KiB
C#
52 lines
1.8 KiB
C#
using SkiaSharp;
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namespace SteUp.Maui.Core.Services;
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public static class ImageThumb
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{
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public static async Task CreateThumbnailAsync(
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string inputPath,
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string outputPath,
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int maxSide = 320,
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int quality = 70,
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CancellationToken ct = default)
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{
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// Leggi bytes (meglio in async)
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var data = await File.ReadAllBytesAsync(inputPath, ct);
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using var codec = SKCodec.Create(new SKMemoryStream(data));
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if (codec is null)
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throw new InvalidOperationException("Formato immagine non supportato o file corrotto.");
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// Decodifica
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var info = codec.Info;
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using var bitmap = SKBitmap.Decode(codec);
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if (bitmap is null)
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throw new InvalidOperationException("Impossibile decodificare l'immagine.");
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// Calcola resize mantenendo aspect ratio
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var w = bitmap.Width;
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var h = bitmap.Height;
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if (w <= 0 || h <= 0) throw new InvalidOperationException("Dimensioni immagine non valide.");
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var scale = (float)maxSide / Math.Max(w, h);
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if (scale > 1f) scale = 1f; // non ingrandire
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var newW = Math.Max(1, (int)Math.Round(w * scale));
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var newH = Math.Max(1, (int)Math.Round(h * scale));
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using var resized = bitmap.Resize(new SKImageInfo(newW, newH), SKFilterQuality.Medium);
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if (resized is null)
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throw new InvalidOperationException("Resize fallito.");
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using var image = SKImage.FromBitmap(resized);
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using var encoded = image.Encode(SKEncodedImageFormat.Jpeg, quality);
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Directory.CreateDirectory(Path.GetDirectoryName(outputPath)!);
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await using var fs = File.Open(outputPath, FileMode.Create, FileAccess.Write, FileShare.None);
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encoded.SaveTo(fs);
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await fs.FlushAsync(ct);
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}
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} |