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Merged
Zeejfps merged 2 commits into from
Apr 10, 2026
Merged

feat: added sbit, iccp, and exif chunks #12

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36ba8ff
added sbit, iccp, exif chunks
Zeejfps Apr 10, 2026
0e300cb
added concept of IccpChunkContent for a better API
Zeejfps Apr 10, 2026
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72 changes: 72 additions & 0 deletions PngSharp.Tests/ExifChunkTests.cs
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using PngSharp.Api;
using PngSharp.Spec.Chunks.IHDR;
using PngSharp.Spec.Chunks.eXIf;
using Xunit;
using static PngSharp.Tests.PngTestHelpers;

namespace PngSharp.Tests;

public class ExifChunkTests
{
[Fact]
public void RoundTrip_Exif_BigEndian_Preserved()
{
byte[] exifData = [0x4D, 0x4D, 0x00, 0x2A, 0x00, 0x00, 0x00, 0x08];
var png = Png.Builder()
.WithIhdr(CreateIhdr(ColorType.TrueColorWithAlpha))
.WithExif(new ExifChunkData { Data = exifData })
.WithPixelData(new byte[2 * 2 * 4])
.Build();

var decoded = RoundTrip(png);

Assert.NotNull(decoded.Exif);
Assert.Equal(exifData, decoded.Exif.Value.Data);
}

[Fact]
public void RoundTrip_Exif_LittleEndian_Preserved()
{
byte[] exifData = [0x49, 0x49, 0x2A, 0x00, 0x08, 0x00, 0x00, 0x00];
var png = Png.Builder()
.WithIhdr(CreateIhdr(ColorType.TrueColorWithAlpha))
.WithExif(new ExifChunkData { Data = exifData })
.WithPixelData(new byte[2 * 2 * 4])
.Build();

var decoded = RoundTrip(png);

Assert.NotNull(decoded.Exif);
Assert.Equal(exifData, decoded.Exif.Value.Data);
}

[Fact]
public void Builder_Exif_TooShort_Throws()
{
Assert.Throws<InvalidOperationException>(() =>
Png.Builder()
.WithIhdr(CreateIhdr(ColorType.TrueColorWithAlpha))
.WithExif(new ExifChunkData { Data = [0x4D, 0x4D, 0x00] }) // 3 bytes, min is 4
.WithPixelData(new byte[2 * 2 * 4])
.Build());
}

[Fact]
public void Builder_Exif_InvalidByteOrderMark_Throws()
{
Assert.Throws<InvalidOperationException>(() =>
Png.Builder()
.WithIhdr(CreateIhdr(ColorType.TrueColorWithAlpha))
.WithExif(new ExifChunkData { Data = [0x00, 0x00, 0x00, 0x00] })
.WithPixelData(new byte[2 * 2 * 4])
.Build());
}

[Fact]
public void RoundTrip_NoExif_ReturnsNull()
{
var png = Png.CreateRgba(2, 2, new byte[2 * 2 * 4]);
var decoded = RoundTrip(png);
Assert.Null(decoded.Exif);
}
}
102 changes: 102 additions & 0 deletions PngSharp.Tests/IccpChunkTests.cs
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using PngSharp.Api;
using PngSharp.Spec.Chunks.IHDR;
using PngSharp.Spec.Chunks.iCCP;
using PngSharp.Spec.Chunks.sRGB;
using Xunit;
using static PngSharp.Tests.PngTestHelpers;

namespace PngSharp.Tests;

public class IccpChunkTests
{
private static readonly byte[] SampleProfile = [0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08];

[Fact]
public void RoundTrip_Iccp_Preserved()
{
var content = new IccpChunkContent { ProfileName = "TestProfile", RawProfile = SampleProfile };
var iccp = IccpChunkData.Encode(content);
var png = Png.Builder()
.WithIhdr(CreateIhdr(ColorType.TrueColorWithAlpha))
.WithIccp(iccp)
.WithPixelData(new byte[2 * 2 * 4])
.Build();

var decoded = RoundTrip(png);

Assert.NotNull(decoded.Iccp);
var decodedContent = decoded.Iccp.Value.Decode();
Assert.Equal("TestProfile", decodedContent.ProfileName);
Assert.Equal(SampleProfile, decodedContent.RawProfile);
}

[Fact]
public void RoundTrip_Iccp_CompressedDataPreserved()
{
var iccp = IccpChunkData.Encode(new IccpChunkContent { ProfileName = "MyProfile", RawProfile = SampleProfile });
var png = Png.Builder()
.WithIhdr(CreateIhdr(ColorType.TrueColor))
.WithIccp(iccp)
.WithPixelData(new byte[2 * 2 * 3])
.Build();

var decoded = RoundTrip(png);

Assert.NotNull(decoded.Iccp);
Assert.Equal(iccp.CompressedProfile, decoded.Iccp.Value.CompressedProfile);
}

[Fact]
public void Builder_Iccp_WithSrgb_Throws()
{
var iccp = IccpChunkData.Encode(new IccpChunkContent { ProfileName = "Test", RawProfile = SampleProfile });
Assert.Throws<InvalidOperationException>(() =>
Png.Builder()
.WithIhdr(CreateIhdr(ColorType.TrueColorWithAlpha))
.WithIccp(iccp)
.WithSrgb(new SrgbChunkData { RenderingIntent = RenderingIntent.Perceptual })
.WithPixelData(new byte[2 * 2 * 4])
.Build());
}

[Fact]
public void Builder_Iccp_EmptyProfileName_Throws()
{
Assert.Throws<InvalidOperationException>(() =>
Png.Builder()
.WithIhdr(CreateIhdr(ColorType.TrueColorWithAlpha))
.WithIccp(new IccpChunkData { ProfileName = "", CompressedProfile = [1, 2, 3] })
.WithPixelData(new byte[2 * 2 * 4])
.Build());
}

[Fact]
public void Builder_Iccp_ProfileNameTooLong_Throws()
{
Assert.Throws<InvalidOperationException>(() =>
Png.Builder()
.WithIhdr(CreateIhdr(ColorType.TrueColorWithAlpha))
.WithIccp(new IccpChunkData { ProfileName = new string('A', 80), CompressedProfile = [1, 2, 3] })
.WithPixelData(new byte[2 * 2 * 4])
.Build());
}

[Fact]
public void Builder_Iccp_EmptyCompressedData_Throws()
{
Assert.Throws<InvalidOperationException>(() =>
Png.Builder()
.WithIhdr(CreateIhdr(ColorType.TrueColorWithAlpha))
.WithIccp(new IccpChunkData { ProfileName = "Test", CompressedProfile = [] })
.WithPixelData(new byte[2 * 2 * 4])
.Build());
}

[Fact]
public void RoundTrip_NoIccp_ReturnsNull()
{
var png = Png.CreateRgba(2, 2, new byte[2 * 2 * 4]);
var decoded = RoundTrip(png);
Assert.Null(decoded.Iccp);
}
}
133 changes: 133 additions & 0 deletions PngSharp.Tests/SbitChunkTests.cs
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using PngSharp.Api;
using PngSharp.Spec.Chunks.IHDR;
using PngSharp.Spec.Chunks.PLTE;
using PngSharp.Spec.Chunks.sBIT;
using Xunit;
using static PngSharp.Tests.PngTestHelpers;

namespace PngSharp.Tests;

public class SbitChunkTests
{
[Fact]
public void RoundTrip_Sbit_TrueColorWithAlpha_Preserved()
{
byte[] sbitData = [8, 8, 8, 8];
var png = Png.Builder()
.WithIhdr(CreateIhdr(ColorType.TrueColorWithAlpha))
.WithSbit(new SbitChunkData { Data = sbitData })
.WithPixelData(new byte[2 * 2 * 4])
.Build();

var decoded = RoundTrip(png);

Assert.NotNull(decoded.Sbit);
Assert.Equal(sbitData, decoded.Sbit.Value.Data);
}

[Fact]
public void RoundTrip_Sbit_TrueColor_Preserved()
{
byte[] sbitData = [5, 6, 5];
var png = Png.Builder()
.WithIhdr(CreateIhdr(ColorType.TrueColor))
.WithSbit(new SbitChunkData { Data = sbitData })
.WithPixelData(new byte[2 * 2 * 3])
.Build();

var decoded = RoundTrip(png);

Assert.NotNull(decoded.Sbit);
Assert.Equal(sbitData, decoded.Sbit.Value.Data);
}

[Fact]
public void RoundTrip_Sbit_Grayscale_Preserved()
{
byte[] sbitData = [5];
var png = Png.Builder()
.WithIhdr(CreateIhdr(ColorType.Grayscale))
.WithSbit(new SbitChunkData { Data = sbitData })
.WithPixelData(new byte[2 * 2])
.Build();

var decoded = RoundTrip(png);

Assert.NotNull(decoded.Sbit);
Assert.Equal(sbitData, decoded.Sbit.Value.Data);
}

[Fact]
public void RoundTrip_Sbit_GrayscaleWithAlpha_Preserved()
{
byte[] sbitData = [5, 8];
var png = Png.Builder()
.WithIhdr(CreateIhdr(ColorType.GrayscaleWithAlpha))
.WithSbit(new SbitChunkData { Data = sbitData })
.WithPixelData(new byte[2 * 2 * 2])
.Build();

var decoded = RoundTrip(png);

Assert.NotNull(decoded.Sbit);
Assert.Equal(sbitData, decoded.Sbit.Value.Data);
}

[Fact]
public void RoundTrip_Sbit_IndexedColor_Preserved()
{
byte[] sbitData = [5, 6, 5];
var png = Png.Builder()
.WithIhdr(CreateIhdr(ColorType.IndexedColor))
.WithPlte(new PlteChunkData { Entries = [255, 0, 0, 0, 255, 0, 0, 0, 255, 128, 128, 128] })
.WithSbit(new SbitChunkData { Data = sbitData })
.WithPixelData(new byte[2 * 2])
.Build();

var decoded = RoundTrip(png);

Assert.NotNull(decoded.Sbit);
Assert.Equal(sbitData, decoded.Sbit.Value.Data);
}

[Fact]
public void Builder_Sbit_WrongSizeForColorType_Throws()
{
Assert.Throws<InvalidOperationException>(() =>
Png.Builder()
.WithIhdr(CreateIhdr(ColorType.TrueColor))
.WithSbit(new SbitChunkData { Data = [8, 8] }) // should be 3 bytes
.WithPixelData(new byte[2 * 2 * 3])
.Build());
}

[Fact]
public void Builder_Sbit_ZeroValue_Throws()
{
Assert.Throws<InvalidOperationException>(() =>
Png.Builder()
.WithIhdr(CreateIhdr(ColorType.TrueColor))
.WithSbit(new SbitChunkData { Data = [0, 8, 8] })
.WithPixelData(new byte[2 * 2 * 3])
.Build());
}

[Fact]
public void Builder_Sbit_ExceedsBitDepth_Throws()
{
Assert.Throws<InvalidOperationException>(() =>
Png.Builder()
.WithIhdr(CreateIhdr(ColorType.Grayscale))
.WithSbit(new SbitChunkData { Data = [9] }) // 8-bit depth, max is 8
.WithPixelData(new byte[2 * 2])
.Build());
}

[Fact]
public void RoundTrip_NoSbit_ReturnsNull()
{
var png = Png.CreateRgba(2, 2, new byte[2 * 2 * 4]);
var decoded = RoundTrip(png);
Assert.Null(decoded.Sbit);
}
}
6 changes: 6 additions & 0 deletions PngSharp/Api/IRawPng.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -8,6 +8,9 @@
using PngSharp.Spec.Chunks.cHRM;
using PngSharp.Spec.Chunks.tIME;
using PngSharp.Spec.Chunks.tRNS;
using PngSharp.Spec.Chunks.sBIT;
using PngSharp.Spec.Chunks.iCCP;
using PngSharp.Spec.Chunks.eXIf;

namespace PngSharp.Api;

Expand All @@ -29,6 +32,9 @@ public interface IRawPng
ChrmChunkData? Chrm { get; }
TimeChunkData? Time { get; }
BkgdChunkData? Bkgd { get; }
SbitChunkData? Sbit { get; }
IccpChunkData? Iccp { get; }
ExifChunkData? Exif { get; }
IReadOnlyList<TextChunk> TxtChunks { get; }
IReadOnlyList<ZTextChunk> ZTxtChunks { get; }
IReadOnlyList<ITextChunk> ITxtChunks { get; }
Expand Down
6 changes: 6 additions & 0 deletions PngSharp/Api/IRawPngBuilder.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -8,6 +8,9 @@
using PngSharp.Spec.Chunks.cHRM;
using PngSharp.Spec.Chunks.tIME;
using PngSharp.Spec.Chunks.tRNS;
using PngSharp.Spec.Chunks.sBIT;
using PngSharp.Spec.Chunks.iCCP;
using PngSharp.Spec.Chunks.eXIf;

namespace PngSharp.Api;

Expand All @@ -23,6 +26,9 @@ public interface IRawPngBuilder
IRawPngBuilder WithChrm(ChrmChunkData chrm);
IRawPngBuilder WithTime(TimeChunkData time);
IRawPngBuilder WithBkgd(BkgdChunkData bkgd);
IRawPngBuilder WithSbit(SbitChunkData sbit);
IRawPngBuilder WithIccp(IccpChunkData iccp);
IRawPngBuilder WithExif(ExifChunkData exif);
IRawPngBuilder WithTxtChunk(TextChunk textChunk);
IRawPngBuilder WithZTxtChunk(ZTextChunk textChunk);
IRawPngBuilder WithITxtChunk(ITextChunk textChunk);
Expand Down
3 changes: 3 additions & 0 deletions PngSharp/Api/Png.cs
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Expand Up @@ -67,6 +67,9 @@ public static IRawPng DecodeFromStream(Stream inputStream)
Chrm = decoder.Chrm,
Time = decoder.Time,
Bkgd = decoder.Bkgd,
Sbit = decoder.Sbit,
Iccp = decoder.Iccp,
Exif = decoder.Exif,
TxtChunks = decoder.TxtChunks,
ZTxtChunks = decoder.ZTxtChunks,
ITxtChunks = decoder.ITxtChunks,
Expand Down
6 changes: 6 additions & 0 deletions PngSharp/Decoder/PngDecoder.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -10,6 +10,9 @@
using PngSharp.Spec.Chunks.cHRM;
using PngSharp.Spec.Chunks.tIME;
using PngSharp.Spec.Chunks.tRNS;
using PngSharp.Spec.Chunks.sBIT;
using PngSharp.Spec.Chunks.iCCP;
using PngSharp.Spec.Chunks.eXIf;

namespace PngSharp.Decoder;

Expand All @@ -28,6 +31,9 @@ internal sealed class PngDecoder : IDisposable, IAsyncDisposable
public ChrmChunkData? Chrm { get; set; }
public TimeChunkData? Time { get; set; }
public BkgdChunkData? Bkgd { get; set; }
public SbitChunkData? Sbit { get; set; }
public IccpChunkData? Iccp { get; set; }
public ExifChunkData? Exif { get; set; }
public List<TextChunk> TxtChunks { get; } = [];
public List<ZTextChunk> ZTxtChunks { get; } = [];
public List<ITextChunk> ITxtChunks { get; } = [];
Expand Down
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