From e286054fcf00ca06e64959cade5dca3adc92c468 Mon Sep 17 00:00:00 2001 From: Devedse Date: Wed, 31 Oct 2018 01:14:09 +0100 Subject: [PATCH] This should write transparency --- src/ImageSharp/Formats/Png/PngDecoderCore.cs | 16 +++--- src/ImageSharp/Formats/Png/PngEncoderCore.cs | 56 ++++++++++++++++++-- src/ImageSharp/Formats/Png/PngMetaData.cs | 8 +-- 3 files changed, 65 insertions(+), 15 deletions(-) diff --git a/src/ImageSharp/Formats/Png/PngDecoderCore.cs b/src/ImageSharp/Formats/Png/PngDecoderCore.cs index 024bd6221..87c22a2ad 100644 --- a/src/ImageSharp/Formats/Png/PngDecoderCore.cs +++ b/src/ImageSharp/Formats/Png/PngDecoderCore.cs @@ -656,8 +656,8 @@ namespace SixLabors.ImageSharp.Formats.Png scanlineSpan, rowSpan, pngMetaData.HasTrans, - pngMetaData.Luminance16Trans, - pngMetaData.LuminanceTrans); + pngMetaData.Luminance16Trans.GetValueOrDefault(), + pngMetaData.LuminanceTrans.GetValueOrDefault()); break; @@ -690,8 +690,8 @@ namespace SixLabors.ImageSharp.Formats.Png this.bytesPerPixel, this.bytesPerSample, pngMetaData.HasTrans, - pngMetaData.Rgb48Trans, - pngMetaData.Rgb24Trans); + pngMetaData.Rgb48Trans.GetValueOrDefault(), + pngMetaData.Rgb24Trans.GetValueOrDefault()); break; @@ -740,8 +740,8 @@ namespace SixLabors.ImageSharp.Formats.Png pixelOffset, increment, pngMetaData.HasTrans, - pngMetaData.Luminance16Trans, - pngMetaData.LuminanceTrans); + pngMetaData.Luminance16Trans.GetValueOrDefault(), + pngMetaData.LuminanceTrans.GetValueOrDefault()); break; @@ -779,8 +779,8 @@ namespace SixLabors.ImageSharp.Formats.Png this.bytesPerPixel, this.bytesPerSample, pngMetaData.HasTrans, - pngMetaData.Rgb48Trans, - pngMetaData.Rgb24Trans); + pngMetaData.Rgb48Trans.GetValueOrDefault(), + pngMetaData.Rgb24Trans.GetValueOrDefault()); break; diff --git a/src/ImageSharp/Formats/Png/PngEncoderCore.cs b/src/ImageSharp/Formats/Png/PngEncoderCore.cs index 411d5d69b..c76dc308b 100644 --- a/src/ImageSharp/Formats/Png/PngEncoderCore.cs +++ b/src/ImageSharp/Formats/Png/PngEncoderCore.cs @@ -292,7 +292,7 @@ namespace SixLabors.ImageSharp.Formats.Png if (pngMetaData.HasTrans) { - //Write transparency header + this.WriteTransparencyMarkers(stream, pngMetaData); } this.WritePhysicalChunk(stream, metaData); @@ -305,6 +305,50 @@ namespace SixLabors.ImageSharp.Formats.Png quantized?.Dispose(); } + /// + /// Writes the transparency markers to the stream + /// + /// The containing image data. + /// The image meta data. + private void WriteTransparencyMarkers(Stream stream, PngMetaData pngMetaData) + { + if (pngMetaData.ColorType == PngColorType.Rgb) + { + if (pngMetaData.Rgb48Trans != null) + { + var r = BitConverter.GetBytes(pngMetaData.Rgb48Trans.Value.R); + var g = BitConverter.GetBytes(pngMetaData.Rgb48Trans.Value.R); + var B = BitConverter.GetBytes(pngMetaData.Rgb48Trans.Value.B); + + var alphaArray = r.Concat(g).Concat(B).ToArray(); + + this.WriteChunk(stream, PngChunkType.PaletteAlpha, alphaArray, 0, alphaArray.Length); + } + else if (pngMetaData.Rgb24Trans != null) + { + var alphaArray = new byte[6]; + alphaArray[0] = pngMetaData.Rgb24Trans.Value.R; + alphaArray[2] = pngMetaData.Rgb24Trans.Value.G; + alphaArray[4] = pngMetaData.Rgb24Trans.Value.B; + this.WriteChunk(stream, PngChunkType.PaletteAlpha, alphaArray, 0, alphaArray.Length); + } + } + else if (pngMetaData.ColorType == PngColorType.Grayscale) + { + if (pngMetaData.Luminance16Trans != null) + { + var alphaArray = BitConverter.GetBytes(pngMetaData.Luminance16Trans.Value); + + this.WriteChunk(stream, PngChunkType.PaletteAlpha, alphaArray, 0, alphaArray.Length); + } + else if (pngMetaData.LuminanceTrans != null) + { + var alphaArray = new byte[2]; + alphaArray[0] = pngMetaData.LuminanceTrans.Value; + } + } + } + /// public void Dispose() { @@ -848,7 +892,10 @@ namespace SixLabors.ImageSharp.Formats.Png /// Writes the chunk end to the stream. /// /// The containing image data. - private void WriteEndChunk(Stream stream) => this.WriteChunk(stream, PngChunkType.End, null); + private void WriteEndChunk(Stream stream) + { + this.WriteChunk(stream, PngChunkType.End, null); + } /// /// Writes a chunk to the stream. @@ -856,7 +903,10 @@ namespace SixLabors.ImageSharp.Formats.Png /// The to write to. /// The type of chunk to write. /// The containing data. - private void WriteChunk(Stream stream, PngChunkType type, byte[] data) => this.WriteChunk(stream, type, data, 0, data?.Length ?? 0); + private void WriteChunk(Stream stream, PngChunkType type, byte[] data) + { + this.WriteChunk(stream, type, data, 0, data?.Length ?? 0); + } /// /// Writes a chunk of a specified length to the stream at the given offset. diff --git a/src/ImageSharp/Formats/Png/PngMetaData.cs b/src/ImageSharp/Formats/Png/PngMetaData.cs index 0014defbb..765222795 100644 --- a/src/ImageSharp/Formats/Png/PngMetaData.cs +++ b/src/ImageSharp/Formats/Png/PngMetaData.cs @@ -47,22 +47,22 @@ namespace SixLabors.ImageSharp.Formats.Png /// /// Gets or sets the Rgb 24 transparent color. This represents any color in an 8 bit Rgb24 encoded png that should be transparent /// - public Rgb24 Rgb24Trans { get; set; } + public Rgb24? Rgb24Trans { get; set; } /// /// Gets or sets the Rgb 48 transparent color. This represents any color in a 16 bit Rgb24 encoded png that should be transparent /// - public Rgb48 Rgb48Trans { get; set; } + public Rgb48? Rgb48Trans { get; set; } /// /// Gets or sets the 8 bit grayscale transparent color. This represents any color in an 8 bit grayscale encoded png that should be transparent /// - public byte LuminanceTrans { get; set; } + public byte? LuminanceTrans { get; set; } /// /// Gets or sets the 16 bit grayscale transparent color. This represents any color in a 16 bit grayscale encoded png that should be transparent /// - public ushort Luminance16Trans { get; set; } + public ushort? Luminance16Trans { get; set; } /// /// Gets or sets a value indicating whether the image has transparency chunk and markers were decoded