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Png - Preserve Pixel Format for Non-generic decode. #1861

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Merged
merged 15 commits into from
Dec 14, 2021
Merged

Png - Preserve Pixel Format for Non-generic decode. #1861

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61c30de
Stub out approach
JimBobSquarePants Nov 30, 2021
65bd0de
Update PngDecoder.cs
JimBobSquarePants Nov 30, 2021
ee4876b
Merge branch 'master' into js/png-decode-to-type
JimBobSquarePants Nov 30, 2021
d7032fe
Update src/ImageSharp/Formats/Png/PngDecoderCore.cs
JimBobSquarePants Dec 1, 2021
509f254
Merge branch 'master' into js/png-decode-to-type
JimBobSquarePants Dec 1, 2021
8fd9b72
Fix transparency chunk identification
JimBobSquarePants Dec 1, 2021
eb68bb2
Update PngDecoderTests.cs
JimBobSquarePants Dec 1, 2021
8a20f3f
Merge branch 'master' into js/png-decode-to-type
JimBobSquarePants Dec 2, 2021
c9f2c9e
Merge branch 'master' into js/png-decode-to-type
JimBobSquarePants Dec 7, 2021
c214af5
Optimize chunk reading to maximize performance
JimBobSquarePants Dec 7, 2021
7429547
Faster exit
JimBobSquarePants Dec 7, 2021
3a76e34
Merge branch 'master' into js/png-decode-to-type
JimBobSquarePants Dec 12, 2021
1157710
Merge branch 'master' into js/png-decode-to-type
JimBobSquarePants Dec 12, 2021
a63bf58
Merge branch 'master' into js/png-decode-to-type
JimBobSquarePants Dec 14, 2021
f6b8383
Update PngDecoderCore.cs
JimBobSquarePants Dec 14, 2021
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114 changes: 107 additions & 7 deletions src/ImageSharp/Formats/Png/PngDecoder.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -20,37 +20,137 @@ public sealed class PngDecoder : IImageDecoder, IPngDecoderOptions, IImageInfoDe
public Image<TPixel> Decode<TPixel>(Configuration configuration, Stream stream)
where TPixel : unmanaged, IPixel<TPixel>
{
var decoder = new PngDecoderCore(configuration, this);
PngDecoderCore decoder = new(configuration, this);
return decoder.Decode<TPixel>(configuration, stream);
}

/// <inheritdoc />
public Image Decode(Configuration configuration, Stream stream) => this.Decode<Rgba32>(configuration, stream);
public Image Decode(Configuration configuration, Stream stream)
{
PngDecoderCore decoder = new(configuration, true);
IImageInfo info = decoder.Identify(configuration, stream);
stream.Position = 0;

PngMetadata meta = info.Metadata.GetPngMetadata();
PngColorType color = meta.ColorType.GetValueOrDefault();
PngBitDepth bits = meta.BitDepth.GetValueOrDefault();
switch (color)
{
case PngColorType.Grayscale:
if (bits == PngBitDepth.Bit16)
{
return !meta.HasTransparency
? this.Decode<L16>(configuration, stream)
: this.Decode<La32>(configuration, stream);
}

return !meta.HasTransparency
? this.Decode<L8>(configuration, stream)
: this.Decode<La16>(configuration, stream);

case PngColorType.Rgb:
if (bits == PngBitDepth.Bit16)
{
return !meta.HasTransparency
? this.Decode<Rgb48>(configuration, stream)
: this.Decode<Rgba64>(configuration, stream);
}

return !meta.HasTransparency
? this.Decode<Rgb24>(configuration, stream)
: this.Decode<Rgba32>(configuration, stream);

case PngColorType.Palette:
return this.Decode<Rgba32>(configuration, stream);

case PngColorType.GrayscaleWithAlpha:
return (bits == PngBitDepth.Bit16)
? this.Decode<La32>(configuration, stream)
: this.Decode<La16>(configuration, stream);

case PngColorType.RgbWithAlpha:
return (bits == PngBitDepth.Bit16)
? this.Decode<Rgba64>(configuration, stream)
: this.Decode<Rgba32>(configuration, stream);

default:
return this.Decode<Rgba32>(configuration, stream);
}
}

/// <inheritdoc/>
public Task<Image<TPixel>> DecodeAsync<TPixel>(Configuration configuration, Stream stream, CancellationToken cancellationToken)
where TPixel : unmanaged, IPixel<TPixel>
{
var decoder = new PngDecoderCore(configuration, this);
PngDecoderCore decoder = new(configuration, this);
return decoder.DecodeAsync<TPixel>(configuration, stream, cancellationToken);
}

/// <inheritdoc />
public async Task<Image> DecodeAsync(Configuration configuration, Stream stream, CancellationToken cancellationToken)
=> await this.DecodeAsync<Rgba32>(configuration, stream, cancellationToken)
.ConfigureAwait(false);
{
PngDecoderCore decoder = new(configuration, true);
IImageInfo info = await decoder.IdentifyAsync(configuration, stream, cancellationToken).ConfigureAwait(false);
stream.Position = 0;

PngMetadata meta = info.Metadata.GetPngMetadata();
PngColorType color = meta.ColorType.GetValueOrDefault();
PngBitDepth bits = meta.BitDepth.GetValueOrDefault();
switch (color)
{
case PngColorType.Grayscale:
if (bits == PngBitDepth.Bit16)
{
return !meta.HasTransparency
? await this.DecodeAsync<L16>(configuration, stream, cancellationToken).ConfigureAwait(false)
: await this.DecodeAsync<La32>(configuration, stream, cancellationToken).ConfigureAwait(false);
}

return !meta.HasTransparency
? await this.DecodeAsync<L8>(configuration, stream, cancellationToken).ConfigureAwait(false)
: await this.DecodeAsync<La16>(configuration, stream, cancellationToken).ConfigureAwait(false);

case PngColorType.Rgb:
if (bits == PngBitDepth.Bit16)
{
return !meta.HasTransparency
? await this.DecodeAsync<Rgb48>(configuration, stream, cancellationToken).ConfigureAwait(false)
: await this.DecodeAsync<Rgba64>(configuration, stream, cancellationToken).ConfigureAwait(false);
}

return !meta.HasTransparency
? await this.DecodeAsync<Rgb24>(configuration, stream, cancellationToken).ConfigureAwait(false)
: await this.DecodeAsync<Rgba32>(configuration, stream, cancellationToken).ConfigureAwait(false);

case PngColorType.Palette:
return await this.DecodeAsync<Rgba32>(configuration, stream, cancellationToken).ConfigureAwait(false);

case PngColorType.GrayscaleWithAlpha:
return (bits == PngBitDepth.Bit16)
? await this.DecodeAsync<La32>(configuration, stream, cancellationToken).ConfigureAwait(false)
: await this.DecodeAsync<La16>(configuration, stream, cancellationToken).ConfigureAwait(false);

case PngColorType.RgbWithAlpha:
return (bits == PngBitDepth.Bit16)
? await this.DecodeAsync<Rgba64>(configuration, stream, cancellationToken).ConfigureAwait(false)
: await this.DecodeAsync<Rgba32>(configuration, stream, cancellationToken).ConfigureAwait(false);

default:
return await this.DecodeAsync<Rgba32>(configuration, stream, cancellationToken).ConfigureAwait(false);
}
}

/// <inheritdoc/>
public IImageInfo Identify(Configuration configuration, Stream stream)
{
var decoder = new PngDecoderCore(configuration, this);
PngDecoderCore decoder = new(configuration, this);
return decoder.Identify(configuration, stream);
}

/// <inheritdoc/>
public Task<IImageInfo> IdentifyAsync(Configuration configuration, Stream stream, CancellationToken cancellationToken)
{
var decoder = new PngDecoderCore(configuration, this);
PngDecoderCore decoder = new(configuration, this);
return decoder.IdentifyAsync(configuration, stream, cancellationToken);
}
}
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