cesnimda
39 lines
2.5 KiB
C#
39 lines
2.5 KiB
C#
using SkiaSharp;
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namespace JobTrackerApi.Services;
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public static class AvatarImageProcessor
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{
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public static byte[]? Normalize(byte[] source)
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{
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if (source.Length is 0 or > 1_000_000) return null;
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using var data = SKData.CreateCopy(source);
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using var codec = SKCodec.Create(data);
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if (codec is null || codec.EncodedFormat is not (SKEncodedImageFormat.Png or SKEncodedImageFormat.Jpeg or SKEncodedImageFormat.Webp)) return null;
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var info = codec.Info;
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if (info.Width is < 1 or > 2048 || info.Height is < 1 or > 2048 || (long)info.Width * info.Height > 4_000_000 || codec.FrameCount > 1) return null;
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using var pixels = new SKBitmap(info.Width, info.Height, SKColorType.Rgba8888, SKAlphaType.Premul);
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if (codec.GetPixels(pixels.Info, pixels.GetPixels()) != SKCodecResult.Success) return null;
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var rotated = codec.EncodedOrigin is SKEncodedOrigin.LeftTop or SKEncodedOrigin.RightTop or SKEncodedOrigin.RightBottom or SKEncodedOrigin.LeftBottom;
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using var oriented = new SKBitmap(rotated ? info.Height : info.Width, rotated ? info.Width : info.Height, SKColorType.Rgba8888, SKAlphaType.Premul);
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using (var canvas = new SKCanvas(oriented))
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{
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switch (codec.EncodedOrigin)
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{
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case SKEncodedOrigin.TopRight: canvas.Translate(info.Width, 0); canvas.Scale(-1, 1); break;
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case SKEncodedOrigin.BottomRight: canvas.Translate(info.Width, info.Height); canvas.RotateDegrees(180); break;
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case SKEncodedOrigin.BottomLeft: canvas.Translate(0, info.Height); canvas.Scale(1, -1); break;
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case SKEncodedOrigin.LeftTop: canvas.RotateDegrees(90); canvas.Scale(1, -1); break;
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case SKEncodedOrigin.RightTop: canvas.Translate(info.Height, 0); canvas.RotateDegrees(90); break;
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case SKEncodedOrigin.RightBottom: canvas.Translate(info.Height, info.Width); canvas.RotateDegrees(90); canvas.Scale(-1, 1); break;
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case SKEncodedOrigin.LeftBottom: canvas.Translate(0, info.Width); canvas.RotateDegrees(270); break;
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}
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canvas.DrawBitmap(pixels, 0, 0, new SKSamplingOptions(SKFilterMode.Nearest), null);
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}
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// Re-encoding decoded pixels drops source metadata and trailing payloads.
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using var image = SKImage.FromBitmap(oriented);
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using var encoded = image.Encode(SKEncodedImageFormat.Png, 100);
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return encoded is null || encoded.Size > 1_000_000 ? null : encoded.ToArray();
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}
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}
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