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More jpg cleanup 

Former-commit-id: 404825d34ba9f39abb1cac223330a3075c9498df
Former-commit-id: 56c5a78950278bcbd4af5b1e992e38ed1ddd3a9b
Former-commit-id: f75cdaa144f70e3c7ed8e7e750977dfa92866a26
af/merge-core
James Jackson-South 10 years ago
parent
96ed7e7c31
commit
0ad8ca517c
2 changed files with 346 additions and 301 deletions
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  1. 23
      src/ImageProcessorCore/Formats/Jpg/JpegConstants.cs
  2. 624
      src/ImageProcessorCore/Formats/Jpg/JpegEncoderCore.cs

23
src/ImageProcessorCore/Formats/Jpg/JpegConstants.cs
View File

@ -18,32 +18,32 @@ namespace ImageProcessorCore.Formats
/// <summary>
/// Represents high detail chroma horizontal subsampling.
/// </summary>
public static readonly byte[] ChromaFourFourFourHorizontal = { 0x1, 0x1, 0x1 };
public static readonly byte[] ChromaFourFourFourHorizontal = { 0x11, 0x11, 0x11 };
/// <summary>
/// Represents high detail chroma vertical subsampling.
/// </summary>
public static readonly byte[] ChromaFourFourFourVertical = { 0x1, 0x1, 0x1 };
public static readonly byte[] ChromaFourFourFourVertical = { 0x11, 0x11, 0x11 };
/// <summary>
/// Represents medium detail chroma horizontal subsampling.
/// </summary>
public static readonly byte[] ChromaFourTwoTwoHorizontal = { 0x2, 0x1, 0x1 };
public static readonly byte[] ChromaFourTwoTwoHorizontal = { 0x22, 0x11, 0x11 };
/// <summary>
/// Represents medium detail chroma vertical subsampling.
/// </summary>
public static readonly byte[] ChromaFourTwoTwoVertical = { 0x1, 0x1, 0x1 };
public static readonly byte[] ChromaFourTwoTwoVertical = { 0x11, 0x11, 0x11 };
/// <summary>
/// Represents low detail chroma horizontal subsampling.
/// </summary>
public static readonly byte[] ChromaFourTwoZeroHorizontal = { 0x2, 0x1, 0x1 };
public static readonly byte[] ChromaFourTwoZeroHorizontal = { 0x22, 0x11, 0x11 };
/// <summary>
/// Represents low detail chroma vertical subsampling.
/// </summary>
public static readonly byte[] ChromaFourTwoZeroVertical = { 0x2, 0x1, 0x1 };
public static readonly byte[] ChromaFourTwoZeroVertical = { 0x22, 0x11, 0x11 };
/// <summary>
/// Describes component ids for start of frame components.
@ -100,6 +100,15 @@ namespace ImageProcessorCore.Formats
/// </summary>
public const byte SOF0 = 0xc0;
/// <summary>
/// Start Of Frame (Extended Sequential DCT)
/// <remarks>
/// Indicates that this is a progressive DCT-based JPEG, and specifies the width, height, number of components,
/// and component subsampling (e.g., 4:2:0).
/// </remarks>
/// </summary>
public const byte SOF1 = 0xc1;
/// <summary>
/// Start Of Frame (progressive DCT)
/// <remarks>
@ -107,7 +116,7 @@ namespace ImageProcessorCore.Formats
/// and component subsampling (e.g., 4:2:0).
/// </remarks>
/// </summary>
public const byte SOF2 = 0xc0;
public const byte SOF2 = 0xc2;
/// <summary>
/// Define Huffman Table(s)

624
src/ImageProcessorCore/Formats/Jpg/JpegEncoderCore.cs
View File

@ -9,30 +9,6 @@ namespace ImageProcessorCore.Formats
internal class JpegEncoderCore
{
private const int sof0Marker = 0xc0; // Start Of Frame (Baseline).
private const int sof1Marker = 0xc1; // Start Of Frame (Extended Sequential).
private const int sof2Marker = 0xc2; // Start Of Frame (Progressive).
private const int dhtMarker = 0xc4; // Define Huffman Table.
private const int rst0Marker = 0xd0; // ReSTart (0).
private const int rst7Marker = 0xd7; // ReSTart (7).
private const int soiMarker = 0xd8; // Start Of Image.
private const int eoiMarker = 0xd9; // End Of Image.
private const int sosMarker = 0xda; // Start Of Scan.
private const int dqtMarker = 0xdb; // Define Quantization Table.
private const int driMarker = 0xdd; // Define Restart Interval.
private const int comMarker = 0xfe; // COMment.
// "APPlication specific" markers aren't part of the JPEG spec per se,
// but in practice, their use is described at
// http://www.sno.phy.queensu.ca/~phil/exiftool/TagNames/JPEG.html
@ -45,29 +21,29 @@ namespace ImageProcessorCore.Formats
// bitCount counts the number of bits needed to hold an integer.
private readonly byte[] bitCount =
{
0, 1, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4, 5, 5, 5, 5, 5, 5, 5, 5, 5,
5, 5, 5, 5, 5, 5, 5, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6,
6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
7, 7, 7, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
8, 8, 8, 8, 8, 8,
0, 1, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4, 5, 5, 5, 5, 5, 5, 5, 5, 5,
5, 5, 5, 5, 5, 5, 5, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6,
6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
7, 7, 7, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8,
8, 8, 8, 8, 8, 8,
};
// unzig maps from the zig-zag ordering to the natural ordering. For example,
// unzig[3] is the column and row of the fourth element in zig-zag order. The
// value is 16, which means first column (16%8 == 0) and third row (16/8 == 2).
private static readonly int[] unzig = new[]
{
0, 1, 8, 16, 9, 2, 3, 10, 17, 24, 32, 25, 18, 11, 4, 5, 12, 19, 26,
33, 40, 48, 41, 34, 27, 20, 13, 6, 7, 14, 21, 28, 35, 42, 49, 56, 57,
50, 43, 36, 29, 22, 15, 23, 30, 37, 44, 51, 58, 59, 52, 45, 38, 31,
39, 46, 53, 60, 61, 54, 47, 55, 62, 63,
};
{
0, 1, 8, 16, 9, 2, 3, 10, 17, 24, 32, 25, 18, 11, 4, 5, 12, 19, 26,
33, 40, 48, 41, 34, 27, 20, 13, 6, 7, 14, 21, 28, 35, 42, 49, 56, 57,
50, 43, 36, 29, 22, 15, 23, 30, 37, 44, 51, 58, 59, 52, 45, 38, 31,
39, 46, 53, 60, 61, 54, 47, 55, 62, 63,
};
private const int nQuantIndex = 2;
@ -75,20 +51,20 @@ namespace ImageProcessorCore.Formats
private enum quantIndex
{
quantIndexLuminance = 0,
quantIndexLuminance = 0,
quantIndexChrominance = 1,
quantIndexChrominance = 1,
}
private enum huffIndex
{
huffIndexLuminanceDC = 0,
huffIndexLuminanceDC = 0,
huffIndexLuminanceAC = 1,
huffIndexLuminanceAC = 1,
huffIndexChrominanceDC = 2,
huffIndexChrominanceDC = 2,
huffIndexChrominanceAC = 3,
huffIndexChrominanceAC = 3,
}
// unscaledQuant are the unscaled quantization tables in zig-zag order. Each
@ -99,19 +75,19 @@ namespace ImageProcessorCore.Formats
{
{
// Luminance.
16, 11, 12, 14, 12, 10, 16, 14, 13, 14, 18, 17, 16, 19, 24, 40,
26, 24, 22, 22, 24, 49, 35, 37, 29, 40, 58, 51, 61, 60, 57, 51,
56, 55, 64, 72, 92, 78, 64, 68, 87, 69, 55, 56, 80, 109, 81,
87, 95, 98, 103, 104, 103, 62, 77, 113, 121, 112, 100, 120, 92,
101, 103, 99,
},
16, 11, 12, 14, 12, 10, 16, 14, 13, 14, 18, 17, 16, 19, 24, 40,
26, 24, 22, 22, 24, 49, 35, 37, 29, 40, 58, 51, 61, 60, 57, 51,
56, 55, 64, 72, 92, 78, 64, 68, 87, 69, 55, 56, 80, 109, 81,
87, 95, 98, 103, 104, 103, 62, 77, 113, 121, 112, 100, 120, 92,
101, 103, 99,
},
{
// Chrominance.
17, 18, 18, 24, 21, 24, 47, 26, 26, 47, 99, 66, 56, 66, 99, 99,
99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99,
99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99,
99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99,
},
17, 18, 18, 24, 21, 24, 47, 26, 26, 47, 99, 66, 56, 66, 99, 99,
99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99,
99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99,
99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99, 99,
},
};
private class huffmanSpec
@ -135,68 +111,68 @@ namespace ImageProcessorCore.Formats
new huffmanSpec(
new byte[]
{
0, 1, 5, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0
},
new byte[] { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 }),
0, 1, 5, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0
},
new byte[] { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 }),
new huffmanSpec(
new byte[]
{
0, 2, 1, 3, 3, 2, 4, 3, 5, 5, 4, 4, 0, 0, 1, 125
},
0, 2, 1, 3, 3, 2, 4, 3, 5, 5, 4, 4, 0, 0, 1, 125
},
new byte[]
{
0x01, 0x02, 0x03, 0x00, 0x04, 0x11, 0x05, 0x12, 0x21,
0x31, 0x41, 0x06, 0x13, 0x51, 0x61, 0x07, 0x22, 0x71,
0x14, 0x32, 0x81, 0x91, 0xa1, 0x08, 0x23, 0x42, 0xb1,
0xc1, 0x15, 0x52, 0xd1, 0xf0, 0x24, 0x33, 0x62, 0x72,
0x82, 0x09, 0x0a, 0x16, 0x17, 0x18, 0x19, 0x1a, 0x25,
0x26, 0x27, 0x28, 0x29, 0x2a, 0x34, 0x35, 0x36, 0x37,
0x38, 0x39, 0x3a, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48,
0x49, 0x4a, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59,
0x5a, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69, 0x6a,
0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79, 0x7a, 0x83,
0x84, 0x85, 0x86, 0x87, 0x88, 0x89, 0x8a, 0x92, 0x93,
0x94, 0x95, 0x96, 0x97, 0x98, 0x99, 0x9a, 0xa2, 0xa3,
0xa4, 0xa5, 0xa6, 0xa7, 0xa8, 0xa9, 0xaa, 0xb2, 0xb3,
0xb4, 0xb5, 0xb6, 0xb7, 0xb8, 0xb9, 0xba, 0xc2, 0xc3,
0xc4, 0xc5, 0xc6, 0xc7, 0xc8, 0xc9, 0xca, 0xd2, 0xd3,
0xd4, 0xd5, 0xd6, 0xd7, 0xd8, 0xd9, 0xda, 0xe1, 0xe2,
0xe3, 0xe4, 0xe5, 0xe6, 0xe7, 0xe8, 0xe9, 0xea, 0xf1,
0x01, 0x02, 0x03, 0x00, 0x04, 0x11, 0x05, 0x12, 0x21,
0x31, 0x41, 0x06, 0x13, 0x51, 0x61, 0x07, 0x22, 0x71,
0x14, 0x32, 0x81, 0x91, 0xa1, 0x08, 0x23, 0x42, 0xb1,
0xc1, 0x15, 0x52, 0xd1, 0xf0, 0x24, 0x33, 0x62, 0x72,
0x82, 0x09, 0x0a, 0x16, 0x17, 0x18, 0x19, 0x1a, 0x25,
0x26, 0x27, 0x28, 0x29, 0x2a, 0x34, 0x35, 0x36, 0x37,
0x38, 0x39, 0x3a, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48,
0x49, 0x4a, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59,
0x5a, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69, 0x6a,
0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79, 0x7a, 0x83,
0x84, 0x85, 0x86, 0x87, 0x88, 0x89, 0x8a, 0x92, 0x93,
0x94, 0x95, 0x96, 0x97, 0x98, 0x99, 0x9a, 0xa2, 0xa3,
0xa4, 0xa5, 0xa6, 0xa7, 0xa8, 0xa9, 0xaa, 0xb2, 0xb3,
0xb4, 0xb5, 0xb6, 0xb7, 0xb8, 0xb9, 0xba, 0xc2, 0xc3,
0xc4, 0xc5, 0xc6, 0xc7, 0xc8, 0xc9, 0xca, 0xd2, 0xd3,
0xd4, 0xd5, 0xd6, 0xd7, 0xd8, 0xd9, 0xda, 0xe1, 0xe2,
0xe3, 0xe4, 0xe5, 0xe6, 0xe7, 0xe8, 0xe9, 0xea, 0xf1,
0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, 0xf8, 0xf9, 0xfa
}),
}),
new huffmanSpec(
new byte[]
{
0, 3, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0
},
0, 3, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0
},
new byte[] { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 }),
// Chrominance AC.
new huffmanSpec(
new byte[]
{
0, 2, 1, 2, 4, 4, 3, 4, 7, 5, 4, 4, 0, 1, 2, 119
},
0, 2, 1, 2, 4, 4, 3, 4, 7, 5, 4, 4, 0, 1, 2, 119
},
new byte[]
{
0x00, 0x01, 0x02, 0x03, 0x11, 0x04, 0x05, 0x21, 0x31,
0x06, 0x12, 0x41, 0x51, 0x07, 0x61, 0x71, 0x13, 0x22,
0x32, 0x81, 0x08, 0x14, 0x42, 0x91, 0xa1, 0xb1, 0xc1,
0x09, 0x23, 0x33, 0x52, 0xf0, 0x15, 0x62, 0x72, 0xd1,
0x0a, 0x16, 0x24, 0x34, 0xe1, 0x25, 0xf1, 0x17, 0x18,
0x19, 0x1a, 0x26, 0x27, 0x28, 0x29, 0x2a, 0x35, 0x36,
0x37, 0x38, 0x39, 0x3a, 0x43, 0x44, 0x45, 0x46, 0x47,
0x48, 0x49, 0x4a, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58,
0x59, 0x5a, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69,
0x6a, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79, 0x7a,
0x82, 0x83, 0x84, 0x85, 0x86, 0x87, 0x88, 0x89, 0x8a,
0x92, 0x93, 0x94, 0x95, 0x96, 0x97, 0x98, 0x99, 0x9a,
0xa2, 0xa3, 0xa4, 0xa5, 0xa6, 0xa7, 0xa8, 0xa9, 0xaa,
0xb2, 0xb3, 0xb4, 0xb5, 0xb6, 0xb7, 0xb8, 0xb9, 0xba,
0xc2, 0xc3, 0xc4, 0xc5, 0xc6, 0xc7, 0xc8, 0xc9, 0xca,
0xd2, 0xd3, 0xd4, 0xd5, 0xd6, 0xd7, 0xd8, 0xd9, 0xda,
0xe2, 0xe3, 0xe4, 0xe5, 0xe6, 0xe7, 0xe8, 0xe9, 0xea,
0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, 0xf8, 0xf9, 0xfa,
0x00, 0x01, 0x02, 0x03, 0x11, 0x04, 0x05, 0x21, 0x31,
0x06, 0x12, 0x41, 0x51, 0x07, 0x61, 0x71, 0x13, 0x22,
0x32, 0x81, 0x08, 0x14, 0x42, 0x91, 0xa1, 0xb1, 0xc1,
0x09, 0x23, 0x33, 0x52, 0xf0, 0x15, 0x62, 0x72, 0xd1,
0x0a, 0x16, 0x24, 0x34, 0xe1, 0x25, 0xf1, 0x17, 0x18,
0x19, 0x1a, 0x26, 0x27, 0x28, 0x29, 0x2a, 0x35, 0x36,
0x37, 0x38, 0x39, 0x3a, 0x43, 0x44, 0x45, 0x46, 0x47,
0x48, 0x49, 0x4a, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58,
0x59, 0x5a, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69,
0x6a, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79, 0x7a,
0x82, 0x83, 0x84, 0x85, 0x86, 0x87, 0x88, 0x89, 0x8a,
0x92, 0x93, 0x94, 0x95, 0x96, 0x97, 0x98, 0x99, 0x9a,
0xa2, 0xa3, 0xa4, 0xa5, 0xa6, 0xa7, 0xa8, 0xa9, 0xaa,
0xb2, 0xb3, 0xb4, 0xb5, 0xb6, 0xb7, 0xb8, 0xb9, 0xba,
0xc2, 0xc3, 0xc4, 0xc5, 0xc6, 0xc7, 0xc8, 0xc9, 0xca,
0xd2, 0xd3, 0xd4, 0xd5, 0xd6, 0xd7, 0xd8, 0xd9, 0xda,
0xe2, 0xe3, 0xe4, 0xe5, 0xe6, 0xe7, 0xe8, 0xe9, 0xea,
0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, 0xf8, 0xf9, 0xfa,
})
};
@ -242,7 +218,7 @@ namespace ImageProcessorCore.Formats
private Stream outputStream;
// buf is a scratch buffer.
private byte[] buf = new byte[16];
private byte[] buffer = new byte[16];
// bits and nBits are accumulated bits to write to w.
private uint bits;
@ -311,104 +287,6 @@ namespace ImageProcessorCore.Formats
if (nBits > 0) this.emit((uint)b & (uint)((1 << ((int)nBits)) - 1), nBits);
}
// writeMarkerHeader writes the header for a marker with the given length.
private void writeMarkerHeader(byte marker, int markerlen)
{
this.buf[0] = 0xff;
this.buf[1] = marker;
this.buf[2] = (byte)(markerlen >> 8);
this.buf[3] = (byte)(markerlen & 0xff);
this.outputStream.Write(this.buf, 0, 4);
}
// writeDQT writes the Define Quantization Table marker.
private void writeDQT()
{
int markerlen = 2 + nQuantIndex * (1 + Block.BlockSize);
this.writeMarkerHeader(dqtMarker, markerlen);
for (int i = 0; i < nQuantIndex; i++)
{
this.writeByte((byte)i);
this.outputStream.Write(this.quant[i], 0, this.quant[i].Length);
}
}
// writeSOF0 writes the Start Of Frame (Baseline) marker.
private void writeSOF0(int wid, int hei, int nComponent)
{
// "default" to 4:2:0
byte[] subsamples = { 0x22, 0x11, 0x11 };
byte[] chroma = { 0x00, 0x01, 0x01 };
switch (this.subsample)
{
case JpegSubsample.Ratio444:
subsamples = new byte[] { 0x11, 0x11, 0x11 };
break;
case JpegSubsample.Ratio420:
subsamples = new byte[] { 0x22, 0x11, 0x11 };
break;
}
int markerlen = 8 + 3 * nComponent;
this.writeMarkerHeader(sof0Marker, markerlen);
this.buf[0] = 8; // 8-bit color.
this.buf[1] = (byte)(hei >> 8);
this.buf[2] = (byte)(hei & 0xff);
this.buf[3] = (byte)(wid >> 8);
this.buf[4] = (byte)(wid & 0xff);
this.buf[5] = (byte)nComponent;
if (nComponent == 1)
{
this.buf[6] = 1;
// No subsampling for grayscale image.
this.buf[7] = 0x11;
this.buf[8] = 0x00;
}
else
{
for (int i = 0; i < nComponent; i++)
{
this.buf[3 * i + 6] = (byte)(i + 1);
// We use 4:2:0 chroma subsampling.
this.buf[3 * i + 7] = subsamples[i];
this.buf[3 * i + 8] = chroma[i];
}
}
this.outputStream.Write(this.buf, 0, 3 * (nComponent - 1) + 9);
}
// writeDHT writes the Define Huffman Table marker.
private void writeDHT(int nComponent)
{
byte[] headers = new byte[] { 0x00, 0x10, 0x01, 0x11 };
int markerlen = 2;
huffmanSpec[] specs = this.theHuffmanSpec;
if (nComponent == 1)
{
// Drop the Chrominance tables.
specs = new[] { this.theHuffmanSpec[0], this.theHuffmanSpec[1] };
}
foreach (var s in specs)
{
markerlen += 1 + 16 + s.values.Length;
}
this.writeMarkerHeader(dhtMarker, markerlen);
for (int i = 0; i < specs.Length; i++)
{
var s = specs[i];
this.writeByte(headers[i]);
this.outputStream.Write(s.count, 0, s.count.Length);
this.outputStream.Write(s.values, 0, s.values.Length);
}
}
// writeBlock writes a block of pixel data using the given quantization table,
// returning the post-quantized DC value of the DCT-transformed block. b is in
@ -418,7 +296,7 @@ namespace ImageProcessorCore.Formats
FDCT.Transform(b);
// Emit the DC delta.
int dc = div(b[0], 8 * this.quant[(int)q][0]);
int dc = Round(b[0], 8 * this.quant[(int)q][0]);
this.emitHuffRLE((huffIndex)(2 * (int)q + 0), 0, dc - prevDC);
// Emit the AC components.
@ -427,7 +305,7 @@ namespace ImageProcessorCore.Formats
for (int zig = 1; zig < Block.BlockSize; zig++)
{
int ac = div(b[unzig[zig]], 8 * this.quant[(int)q][zig]);
int ac = Round(b[unzig[zig]], 8 * this.quant[(int)q][zig]);
if (ac == 0)
{
@ -488,16 +366,26 @@ namespace ImageProcessorCore.Formats
}
}
// sosHeaderY is the SOS marker "\xff\xda" followed by 8 bytes:
// The SOS marker "\xff\xda" followed by 8 bytes:
// - the marker length "\x00\x08",
// - the number of components "\x01",
// - component 1 uses DC table 0 and AC table 0 "\x01\x00",
// - the bytes "\x00\x3f\x00". Section B.2.3 of the spec says that for
// sequential DCTs, those bytes (8-bit Ss, 8-bit Se, 4-bit Ah, 4-bit Al)
// should be 0x00, 0x3f, 0x00<<4 | 0x00.
private readonly byte[] sosHeaderY = new byte[] { 0xff, 0xda, 0x00, 0x08, 0x01, 0x01, 0x00, 0x00, 0x3f, 0x00, };
private readonly byte[] SOSHeaderY =
{
JpegConstants.Markers.XFF, JpegConstants.Markers.SOS,
0x00, 0x08, // Length (high byte, low byte), must be 6 + 2 * (number of components in scan)
0x01, // Number of components in a scan, 1
0x01, // Component Id Y
0x00, // DC/AC Huffman table
0x00, // Ss - Start of spectral selection.
0x3f, // Se - End of spectral selection.
0x00 // Ah + Ah (Successive approximation bit position high + low)
};
// sosHeaderYCbCr is the SOS marker "\xff\xda" followed by 12 bytes:
// The SOS marker "\xff\xda" followed by 12 bytes:
// - the marker length "\x00\x0c",
// - the number of components "\x03",
// - component 1 uses DC table 0 and AC table 0 "\x01\x00",
@ -506,81 +394,22 @@ namespace ImageProcessorCore.Formats
// - the bytes "\x00\x3f\x00". Section B.2.3 of the spec says that for
// sequential DCTs, those bytes (8-bit Ss, 8-bit Se, 4-bit Ah, 4-bit Al)
// should be 0x00, 0x3f, 0x00<<4 | 0x00.
private readonly byte[] sosHeaderYCbCr = new byte[]
private readonly byte[] SOSHeaderYCbCr =
{
0xff, 0xda, 0x00, 0x0c, 0x03, 0x01, 0x00, 0x02, 0x11, 0x03, 0x11,
0x00, 0x3f, 0x00,
JpegConstants.Markers.XFF, JpegConstants.Markers.SOS,
0x00, 0x0c, // Length (high byte, low byte), must be 6 + 2 * (number of components in scan)
0x03, // Number of components in a scan, 3
0x01, // Component Id Y
0x00, // DC/AC Huffman table
0x02, // Component Id Cb
0x11, // DC/AC Huffman table
0x03, // Component Id Cr
0x11, // DC/AC Huffman table
0x00, // Ss - Start of spectral selection.
0x3f, // Se - End of spectral selection.
0x00 // Ah + Ah (Successive approximation bit position high + low)
};
// writeSOS writes the StartOfScan marker.
private void writeSOS(PixelAccessor pixels)
{
this.outputStream.Write(this.sosHeaderYCbCr, 0, this.sosHeaderYCbCr.Length);
switch (this.subsample)
{
case JpegSubsample.Ratio444:
this.encode444(pixels);
break;
case JpegSubsample.Ratio420:
this.encode420(pixels);
break;
}
// Pad the last byte with 1's.
this.emit(0x7f, 7);
}
private void encode444(PixelAccessor pixels)
{
Block b = new Block();
Block cb = new Block();
Block cr = new Block();
int prevDCY = 0, prevDCCb = 0, prevDCCr = 0;
for (int y = 0; y < pixels.Height; y += 8)
{
for (int x = 0; x < pixels.Width; x += 8)
{
this.toYCbCr(pixels, x, y, b, cb, cr);
prevDCY = this.writeBlock(b, (quantIndex)0, prevDCY);
prevDCCb = this.writeBlock(cb, (quantIndex)1, prevDCCb);
prevDCCr = this.writeBlock(cr, (quantIndex)1, prevDCCr);
}
}
}
private void encode420(PixelAccessor pixels)
{
Block b = new Block();
Block[] cb = new Block[4];
Block[] cr = new Block[4];
int prevDCY = 0, prevDCCb = 0, prevDCCr = 0;
for (int i = 0; i < 4; i++) cb[i] = new Block();
for (int i = 0; i < 4; i++) cr[i] = new Block();
for (int y = 0; y < pixels.Height; y += 16)
{
for (int x = 0; x < pixels.Width; x += 16)
{
for (int i = 0; i < 4; i++)
{
int xOff = (i & 1) * 8;
int yOff = (i & 2) * 4;
this.toYCbCr(pixels, x + xOff, y + yOff, b, cb[i], cr[i]);
prevDCY = this.writeBlock(b, (quantIndex)0, prevDCY);
}
this.scale_16x16_8x8(b, cb);
prevDCCb = this.writeBlock(b, (quantIndex)1, prevDCCb);
this.scale_16x16_8x8(b, cr);
prevDCCr = this.writeBlock(b, (quantIndex)1, prevDCCr);
}
}
}
// Encode writes the Image m to w in JPEG 4:2:0 baseline format with the given
// options. Default parameters are used if a nil *Options is passed.
public void Encode(Stream stream, ImageBase image, int quality, JpegSubsample sample)
@ -636,40 +465,247 @@ namespace ImageProcessorCore.Formats
}
// Compute number of components based on input image type.
int nComponent = 3;
int componentCount = 3;
// Write the Start Of Image marker.
this.buf[0] = 0xff;
this.buf[1] = 0xd8;
stream.Write(this.buf, 0, 2);
// TODO: JFIF header etc.
this.buffer[0] = 0xff;
this.buffer[1] = 0xd8;
stream.Write(this.buffer, 0, 2);
// Write the quantization tables.
this.writeDQT();
this.WriteDQT();
// Write the image dimensions.
this.writeSOF0(image.Width, image.Height, nComponent);
this.WriteSOF0(image.Width, image.Height, componentCount);
// Write the Huffman tables.
this.writeDHT(nComponent);
this.WriteDHT(componentCount);
// Write the image data.
using (PixelAccessor pixels = image.Lock())
{
this.writeSOS(pixels);
this.WriteSOS(pixels);
}
// Write the End Of Image marker.
this.buf[0] = 0xff;
this.buf[1] = 0xd9;
stream.Write(this.buf, 0, 2);
this.buffer[0] = 0xff;
this.buffer[1] = 0xd9;
stream.Write(this.buffer, 0, 2);
stream.Flush();
}
// div returns a/b rounded to the nearest integer, instead of rounded to zero.
private static int div(int a, int b)
/// <summary>
/// Gets the quotient of the two numbers rounded to the nearest integer, instead of rounded to zero.
/// </summary>
/// <param name="dividend">The value to divide.</param>
/// <param name="divisor">The value to divide by.</param>
/// <returns>The <see cref="int"/></returns>
private static int Round(int dividend, int divisor)
{
if (dividend >= 0)
{
return (dividend + (divisor >> 1)) / divisor;
}
return -((-dividend + (divisor >> 1)) / divisor);
}
/// <summary>
/// Writes the Define Quantization Marker and tables.
/// </summary>
private void WriteDQT()
{
int markerlen = 2 + nQuantIndex * (1 + Block.BlockSize);
this.WriteMarkerHeader(JpegConstants.Markers.DQT, markerlen);
for (int i = 0; i < nQuantIndex; i++)
{
this.writeByte((byte)i);
this.outputStream.Write(this.quant[i], 0, this.quant[i].Length);
}
}
/// <summary>
/// Writes the Start Of Frame (Baseline) marker
/// </summary>
/// <param name="width">The width of the image</param>
/// <param name="height">The height of the image</param>
/// <param name="componentCount"></param>
private void WriteSOF0(int width, int height, int componentCount)
{
// "default" to 4:2:0
byte[] subsamples = { 0x22, 0x11, 0x11 };
byte[] chroma = { 0x00, 0x01, 0x01 };
switch (this.subsample)
{
case JpegSubsample.Ratio444:
subsamples = new byte[] { 0x11, 0x11, 0x11 };
break;
case JpegSubsample.Ratio420:
subsamples = new byte[] { 0x22, 0x11, 0x11 };
break;
}
// Length (high byte, low byte), 8 + components * 3.
int markerlen = 8 + 3 * componentCount;
this.WriteMarkerHeader(JpegConstants.Markers.SOF0, markerlen);
this.buffer[0] = 8; // Data Precision. 8 for now, 12 and 16 bit jpegs not supported
this.buffer[1] = (byte)(height >> 8);
this.buffer[2] = (byte)(height & 0xff); // (2 bytes, Hi-Lo), must be > 0 if DNL not supported
this.buffer[3] = (byte)(width >> 8);
this.buffer[4] = (byte)(width & 0xff); // (2 bytes, Hi-Lo), must be > 0 if DNL not supported
this.buffer[5] = (byte)componentCount; // Number of components (1 byte), usually 1 = grey scaled, 3 = color YCbCr or YIQ, 4 = color CMYK)
if (componentCount == 1)
{
this.buffer[6] = 1;
// No subsampling for grayscale images.
this.buffer[7] = 0x11;
this.buffer[8] = 0x00;
}
else
{
for (int i = 0; i < componentCount; i++)
{
this.buffer[3 * i + 6] = (byte)(i + 1);
// We use 4:2:0 chroma subsampling by default.
this.buffer[3 * i + 7] = subsamples[i];
this.buffer[3 * i + 8] = chroma[i];
}
}
this.outputStream.Write(this.buffer, 0, 3 * (componentCount - 1) + 9);
}
/// <summary>
/// Writes the Define Huffman Table marker and tables.
/// </summary>
/// <param name="nComponent">The number of components to write.</param>
private void WriteDHT(int nComponent)
{
byte[] headers = { 0x00, 0x10, 0x01, 0x11 };
int markerlen = 2;
huffmanSpec[] specs = this.theHuffmanSpec;
if (nComponent == 1)
{
// Drop the Chrominance tables.
specs = new[] { this.theHuffmanSpec[0], this.theHuffmanSpec[1] };
}
foreach (var s in specs)
{
markerlen += 1 + 16 + s.values.Length;
}
this.WriteMarkerHeader(JpegConstants.Markers.DHT, markerlen);
for (int i = 0; i < specs.Length; i++)
{
huffmanSpec spec = specs[i];
this.writeByte(headers[i]);
this.outputStream.Write(spec.count, 0, spec.count.Length);
this.outputStream.Write(spec.values, 0, spec.values.Length);
}
}
/// <summary>
/// Writes the StartOfScan marker.
/// </summary>
/// <param name="pixels">The pixel accessor providing acces to the image pixels.</param>
private void WriteSOS(PixelAccessor pixels)
{
// TODO: We should allow grayscale writing.
this.outputStream.Write(this.SOSHeaderYCbCr, 0, this.SOSHeaderYCbCr.Length);
switch (this.subsample)
{
case JpegSubsample.Ratio444:
this.Encode444(pixels);
break;
case JpegSubsample.Ratio420:
this.Encode420(pixels);
break;
}
// Pad the last byte with 1's.
this.emit(0x7f, 7);
}
/// <summary>
/// Encodes the image with no subsampling.
/// </summary>
/// <param name="pixels">The pixel accessor providing acces to the image pixels.</param>
private void Encode444(PixelAccessor pixels)
{
Block b = new Block();
Block cb = new Block();
Block cr = new Block();
int prevDCY = 0, prevDCCb = 0, prevDCCr = 0;
for (int y = 0; y < pixels.Height; y += 8)
{
for (int x = 0; x < pixels.Width; x += 8)
{
this.toYCbCr(pixels, x, y, b, cb, cr);
prevDCY = this.writeBlock(b, (quantIndex)0, prevDCY);
prevDCCb = this.writeBlock(cb, (quantIndex)1, prevDCCb);
prevDCCr = this.writeBlock(cr, (quantIndex)1, prevDCCr);
}
}
}
/// <summary>
/// Encodes the image with subsampling. The Cb and Cr components are each subsampled
/// at a factor of 2 both horizontally and vertically.
/// </summary>
/// <param name="pixels">The pixel accessor providing acces to the image pixels.</param>
private void Encode420(PixelAccessor pixels)
{
Block b = new Block();
Block[] cb = new Block[4];
Block[] cr = new Block[4];
int prevDCY = 0, prevDCCb = 0, prevDCCr = 0;
for (int i = 0; i < 4; i++) cb[i] = new Block();
for (int i = 0; i < 4; i++) cr[i] = new Block();
for (int y = 0; y < pixels.Height; y += 16)
{
for (int x = 0; x < pixels.Width; x += 16)
{
for (int i = 0; i < 4; i++)
{
int xOff = (i & 1) * 8;
int yOff = (i & 2) * 4;
this.toYCbCr(pixels, x + xOff, y + yOff, b, cb[i], cr[i]);
prevDCY = this.writeBlock(b, (quantIndex)0, prevDCY);
}
this.scale_16x16_8x8(b, cb);
prevDCCb = this.writeBlock(b, (quantIndex)1, prevDCCb);
this.scale_16x16_8x8(b, cr);
prevDCCr = this.writeBlock(b, (quantIndex)1, prevDCCr);
}
}
}
/// <summary>
/// Writes the header for a marker with the given length.
/// </summary>
/// <param name="marker">The marker to write.</param>
/// <param name="length">The marker length.</param>
private void WriteMarkerHeader(byte marker, int length)
{
if (a >= 0) return (a + (b >> 1)) / b;
else return -((-a + (b >> 1)) / b);
// Markers are always prefixed with with 0xff.
this.buffer[0] = JpegConstants.Markers.XFF;
this.buffer[1] = marker;
this.buffer[2] = (byte)(length >> 8);
this.buffer[3] = (byte)(length & 0xff);
this.outputStream.Write(this.buffer, 0, 4);
}
}
}

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