From dda14207805d697463d025db98119d44ddefe767 Mon Sep 17 00:00:00 2001 From: James Jackson-South Date: Wed, 20 Jul 2016 18:20:41 +1000 Subject: [PATCH] Use qualifier Former-commit-id: e7f5254e6a05eef6e2c41a7113ec43117419f3ad Former-commit-id: d8fb7b19aa30b69f2c83f6e5e93a965f0e95a9ae Former-commit-id: 07ec0c3ba4120079b88203fbc98e3d73df7080bf --- .../Formats/Jpg/JpegEncoderCore.cs | 485 ++++++++++-------- 1 file changed, 258 insertions(+), 227 deletions(-) diff --git a/src/ImageProcessorCore/Formats/Jpg/JpegEncoderCore.cs b/src/ImageProcessorCore/Formats/Jpg/JpegEncoderCore.cs index f211e05f8..3274907d5 100644 --- a/src/ImageProcessorCore/Formats/Jpg/JpegEncoderCore.cs +++ b/src/ImageProcessorCore/Formats/Jpg/JpegEncoderCore.cs @@ -2,7 +2,6 @@ // Copyright (c) James Jackson-South and contributors. // Licensed under the Apache License, Version 2.0. // - namespace ImageProcessorCore.Formats { using System; @@ -11,173 +10,194 @@ 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 private const int app0Marker = 0xe0; + private const int app14Marker = 0xee; + private const int app15Marker = 0xef; // 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, }; + 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, + }; // 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 int[] { - 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 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, + }; private const int nQuantIndex = 2; + private const int nHuffIndex = 4; private enum quantIndex { - quantIndexLuminance = 0, - quantIndexChrominance = 1, + quantIndexLuminance = 0, + + quantIndexChrominance = 1, } private enum huffIndex { - huffIndexLuminanceDC = 0, - huffIndexLuminanceAC = 1, - huffIndexChrominanceDC = 2, - huffIndexChrominanceAC = 3, + huffIndexLuminanceDC = 0, + + huffIndexLuminanceAC = 1, + + huffIndexChrominanceDC = 2, + + huffIndexChrominanceAC = 3, } // unscaledQuant are the unscaled quantization tables in zig-zag order. Each // encoder copies and scales the tables according to its quality parameter. // The values are derived from section K.1 after converting from natural to // zig-zag order. - private byte[,] unscaledQuant = new byte[,] { - // 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, - }, - // 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, - }, - }; + private byte[,] unscaledQuant = new byte[,] + { + { + // 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, + }, + { + // 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, + }, + }; private class huffmanSpec { - public huffmanSpec(byte[] c, byte[] v) { count = c; values = v; } + public huffmanSpec(byte[] c, byte[] v) + { + this.count = c; + this.values = v; + } + public byte[] count; + public byte[] values; } // theHuffmanSpec is the Huffman encoding specifications. // This encoder uses the same Huffman encoding for all images. - private huffmanSpec[] theHuffmanSpec = new huffmanSpec[] { + private huffmanSpec[] theHuffmanSpec = new[] + { // Luminance DC. 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 }), + 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 }), new huffmanSpec( - new byte[] { 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, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, 0xf8, - 0xf9, 0xfa}), + 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, + 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 }, - new byte[] { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 }), + new byte[] + { + 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 }, 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, - }) + 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, + }) }; // huffmanLUT is a compiled look-up table representation of a huffmanSpec. @@ -194,11 +214,10 @@ namespace ImageProcessorCore.Formats foreach (var v in s.values) { - if (v > maxValue) - maxValue = v; + if (v > maxValue) maxValue = v; } - values = new uint[maxValue + 1]; + this.values = new uint[maxValue + 1]; int code = 0; int k = 0; @@ -208,10 +227,11 @@ namespace ImageProcessorCore.Formats int nBits = (i + 1) << 24; for (int j = 0; j < s.count[i]; j++) { - values[s.values[k]] = (uint)(nBits | code); + this.values[s.values[k]] = (uint)(nBits | code); code++; k++; } + code <<= 1; } } @@ -220,21 +240,28 @@ namespace ImageProcessorCore.Formats // w is the writer to write to. err is the first error encountered during // writing. All attempted writes after the first error become no-ops. private Stream outputStream; + // buf is a scratch buffer. private byte[] buf = new byte[16]; + // bits and nBits are accumulated bits to write to w. - private uint bits, nBits; + private uint bits; + + private uint nBits; + // quant is the scaled quantization tables, in zig-zag order. - private byte[][] quant = new byte[nQuantIndex][];//[Block.blockSize]; + private byte[][] quant = new byte[nQuantIndex][]; // [Block.blockSize]; + // theHuffmanLUT are compiled representations of theHuffmanSpec. private huffmanLUT[] theHuffmanLUT = new huffmanLUT[4]; + private JpegSubsample subsample; private void writeByte(byte b) { var data = new byte[1]; data[0] = b; - outputStream.Write(data, 0, 1); + this.outputStream.Write(data, 0, 1); } // emit emits the least significant nBits bits of bits to the bit-stream. @@ -247,12 +274,12 @@ namespace ImageProcessorCore.Formats while (nBits >= 8) { byte b = (byte)(bits >> 24); - writeByte(b); - if (b == 0xff) - writeByte(0x00); + this.writeByte(b); + if (b == 0xff) this.writeByte(0x00); bits <<= 8; nBits -= 8; } + this.bits = bits; this.nBits = nBits; } @@ -260,8 +287,8 @@ namespace ImageProcessorCore.Formats // emitHuff emits the given value with the given Huffman encoder. private void emitHuff(huffIndex h, int v) { - uint x = theHuffmanLUT[(int)h].values[v]; - emit(x & ((1 << 24) - 1), x >> 24); + uint x = this.theHuffmanLUT[(int)h].values[v]; + this.emit(x & ((1 << 24) - 1), x >> 24); } // emitHuffRLE emits a run of runLength copies of value encoded with the given @@ -275,46 +302,45 @@ namespace ImageProcessorCore.Formats a = -v; b = v - 1; } + uint nBits = 0; - if (a < 0x100) - nBits = bitCount[a]; - else - nBits = 8 + (uint)bitCount[a >> 8]; + if (a < 0x100) nBits = this.bitCount[a]; + else nBits = 8 + (uint)this.bitCount[a >> 8]; - emitHuff(h, (int)((uint)(runLength << 4) | nBits)); - if (nBits > 0) emit((uint)b & (uint)((1 << ((int)nBits)) - 1), nBits); + this.emitHuff(h, (int)((uint)(runLength << 4) | nBits)); + 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) { - buf[0] = 0xff; - buf[1] = marker; - buf[2] = (byte)(markerlen >> 8); - buf[3] = (byte)(markerlen & 0xff); - outputStream.Write(buf, 0, 4); + 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); - writeMarkerHeader(dqtMarker, markerlen); + this.writeMarkerHeader(dqtMarker, markerlen); for (int i = 0; i < nQuantIndex; i++) { - writeByte((byte)i); - outputStream.Write(quant[i], 0, quant[i].Length); + 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 = new byte[] { 0x22, 0x11, 0x11 }; - byte[] chroma = new byte[] { 0x00, 0x01, 0x01 }; + // "default" to 4:2:0 + byte[] subsamples = { 0x22, 0x11, 0x11 }; + byte[] chroma = { 0x00, 0x01, 0x01 }; - switch (subsample) + switch (this.subsample) { case JpegSubsample.Ratio444: subsamples = new byte[] { 0x11, 0x11, 0x11 }; @@ -325,31 +351,34 @@ namespace ImageProcessorCore.Formats } int markerlen = 8 + 3 * nComponent; - writeMarkerHeader(sof0Marker, markerlen); - buf[0] = 8; // 8-bit color. - buf[1] = (byte)(hei >> 8); - buf[2] = (byte)(hei & 0xff); - buf[3] = (byte)(wid >> 8); - buf[4] = (byte)(wid & 0xff); - buf[5] = (byte)(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) { - buf[6] = 1; + this.buf[6] = 1; + // No subsampling for grayscale image. - buf[7] = 0x11; - buf[8] = 0x00; + this.buf[7] = 0x11; + this.buf[8] = 0x00; } else { for (int i = 0; i < nComponent; i++) { - buf[3 * i + 6] = (byte)(i + 1); + this.buf[3 * i + 6] = (byte)(i + 1); + // We use 4:2:0 chroma subsampling. - buf[3 * i + 7] = subsamples[i]; - buf[3 * i + 8] = chroma[i]; + this.buf[3 * i + 7] = subsamples[i]; + this.buf[3 * i + 8] = chroma[i]; } } - outputStream.Write(buf, 0, 3 * (nComponent - 1) + 9); + + this.outputStream.Write(this.buf, 0, 3 * (nComponent - 1) + 9); } // writeDHT writes the Define Huffman Table marker. @@ -357,12 +386,12 @@ namespace ImageProcessorCore.Formats { byte[] headers = new byte[] { 0x00, 0x10, 0x01, 0x11 }; int markerlen = 2; - huffmanSpec[] specs = theHuffmanSpec; + huffmanSpec[] specs = this.theHuffmanSpec; if (nComponent == 1) { // Drop the Chrominance tables. - specs = new huffmanSpec[] { theHuffmanSpec[0], theHuffmanSpec[1] }; + specs = new[] { this.theHuffmanSpec[0], this.theHuffmanSpec[1] }; } foreach (var s in specs) @@ -370,14 +399,14 @@ namespace ImageProcessorCore.Formats markerlen += 1 + 16 + s.values.Length; } - writeMarkerHeader(dhtMarker, markerlen); + this.writeMarkerHeader(dhtMarker, markerlen); for (int i = 0; i < specs.Length; i++) { var s = specs[i]; - writeByte(headers[i]); - outputStream.Write(s.count, 0, s.count.Length); - outputStream.Write(s.values, 0, s.values.Length); + this.writeByte(headers[i]); + this.outputStream.Write(s.count, 0, s.count.Length); + this.outputStream.Write(s.values, 0, s.values.Length); } } @@ -389,8 +418,8 @@ namespace ImageProcessorCore.Formats FDCT.Transform(b); // Emit the DC delta. - int dc = div(b[0], 8 * quant[(int)q][0]); - emitHuffRLE((huffIndex)(2 * (int)q + 0), 0, dc - prevDC); + int dc = div(b[0], 8 * this.quant[(int)q][0]); + this.emitHuffRLE((huffIndex)(2 * (int)q + 0), 0, dc - prevDC); // Emit the AC components. var h = (huffIndex)(2 * (int)q + 1); @@ -398,7 +427,7 @@ namespace ImageProcessorCore.Formats for (int zig = 1; zig < Block.BlockSize; zig++) { - int ac = div(b[unzig[zig]], 8 * quant[(int)q][zig]); + int ac = div(b[unzig[zig]], 8 * this.quant[(int)q][zig]); if (ac == 0) { @@ -408,16 +437,16 @@ namespace ImageProcessorCore.Formats { while (runLength > 15) { - emitHuff(h, 0xf0); + this.emitHuff(h, 0xf0); runLength -= 16; } - emitHuffRLE(h, runLength, ac); + this.emitHuffRLE(h, runLength, ac); runLength = 0; } } - if (runLength > 0) - emitHuff(h, 0x00); + + if (runLength > 0) this.emitHuff(h, 0x00); return dc; } @@ -460,48 +489,46 @@ namespace ImageProcessorCore.Formats } // sosHeaderY is 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, - }; + // - 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, }; // sosHeaderYCbCr is 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", - // - component 2 uses DC table 1 and AC table 1 "\x02\x11", - // - component 3 uses DC table 1 and AC table 1 "\x03\x11", - // - 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[] { - 0xff, 0xda, 0x00, 0x0c, 0x03, 0x01, 0x00, 0x02, - 0x11, 0x03, 0x11, 0x00, 0x3f, 0x00, + // - the marker length "\x00\x0c", + // - the number of components "\x03", + // - component 1 uses DC table 0 and AC table 0 "\x01\x00", + // - component 2 uses DC table 1 and AC table 1 "\x02\x11", + // - component 3 uses DC table 1 and AC table 1 "\x03\x11", + // - 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[] + { + 0xff, 0xda, 0x00, 0x0c, 0x03, 0x01, 0x00, 0x02, 0x11, 0x03, 0x11, + 0x00, 0x3f, 0x00, }; - // writeSOS writes the StartOfScan marker. private void writeSOS(PixelAccessor pixels) { - outputStream.Write(sosHeaderYCbCr, 0, sosHeaderYCbCr.Length); + this.outputStream.Write(this.sosHeaderYCbCr, 0, this.sosHeaderYCbCr.Length); - switch (subsample) + switch (this.subsample) { case JpegSubsample.Ratio444: - encode444(pixels); + this.encode444(pixels); break; case JpegSubsample.Ratio420: - encode420(pixels); + this.encode420(pixels); break; } // Pad the last byte with 1's. - emit(0x7f, 7); + this.emit(0x7f, 7); } private void encode444(PixelAccessor pixels) @@ -515,10 +542,10 @@ namespace ImageProcessorCore.Formats { for (int x = 0; x < pixels.Width; x += 8) { - toYCbCr(pixels, x, y, b, cb, cr); - prevDCY = writeBlock(b, (quantIndex)0, prevDCY); - prevDCCb = writeBlock(cb, (quantIndex)1, prevDCCb); - prevDCCr = writeBlock(cr, (quantIndex)1, prevDCCr); + 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); } } } @@ -542,37 +569,43 @@ namespace ImageProcessorCore.Formats int xOff = (i & 1) * 8; int yOff = (i & 2) * 4; - toYCbCr(pixels, x + xOff, y + yOff, b, cb[i], cr[i]); - prevDCY = writeBlock(b, (quantIndex)0, prevDCY); + this.toYCbCr(pixels, x + xOff, y + yOff, b, cb[i], cr[i]); + prevDCY = this.writeBlock(b, (quantIndex)0, prevDCY); } - scale_16x16_8x8(b, cb); - prevDCCb = writeBlock(b, (quantIndex)1, prevDCCb); - scale_16x16_8x8(b, cr); - prevDCCr = writeBlock(b, (quantIndex)1, prevDCCr); + + 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 subsample) + public void Encode(Stream stream, ImageBase image, int quality, JpegSubsample sample) { - this.outputStream = stream; - this.subsample = subsample; + Guard.NotNull(image, nameof(image)); + Guard.NotNull(stream, nameof(stream)); - for (int i = 0; i < theHuffmanSpec.Length; i++) + ushort max = JpegConstants.MaxLength; + if (image.Width >= max || image.Height >= max) { - theHuffmanLUT[i] = new huffmanLUT(theHuffmanSpec[i]); + throw new ImageFormatException($"Image is too large to encode at {image.Width}x{image.Height}."); } - for (int i = 0; i < nQuantIndex; i++) + this.outputStream = stream; + this.subsample = sample; + + // TODO: This should be static should it not? + for (int i = 0; i < this.theHuffmanSpec.Length; i++) { - quant[i] = new byte[Block.BlockSize]; + this.theHuffmanLUT[i] = new huffmanLUT(this.theHuffmanSpec[i]); } - if (image.Width >= (1 << 16) || image.Height >= (1 << 16)) + for (int i = 0; i < nQuantIndex; i++) { - throw new ImageFormatException($"Image is too large to encode at {image.Width}x{image.Height}."); + this.quant[i] = new byte[Block.BlockSize]; } if (quality < 1) quality = 1; @@ -594,11 +627,11 @@ namespace ImageProcessorCore.Formats { for (int j = 0; j < Block.BlockSize; j++) { - int x = unscaledQuant[i, j]; + int x = this.unscaledQuant[i, j]; x = (x * scale + 50) / 100; if (x < 1) x = 1; if (x > 255) x = 255; - quant[i][j] = (byte)x; + this.quant[i][j] = (byte)x; } } @@ -606,39 +639,37 @@ namespace ImageProcessorCore.Formats int nComponent = 3; // Write the Start Of Image marker. - buf[0] = 0xff; - buf[1] = 0xd8; - stream.Write(buf, 0, 2); + this.buf[0] = 0xff; + this.buf[1] = 0xd8; + stream.Write(this.buf, 0, 2); // Write the quantization tables. - writeDQT(); + this.writeDQT(); // Write the image dimensions. - writeSOF0(image.Width, image.Height, nComponent); + this.writeSOF0(image.Width, image.Height, nComponent); // Write the Huffman tables. - writeDHT(nComponent); + this.writeDHT(nComponent); // Write the image data. using (PixelAccessor pixels = image.Lock()) { - writeSOS(pixels); + this.writeSOS(pixels); } // Write the End Of Image marker. - buf[0] = 0xff; - buf[1] = 0xd9; - stream.Write(buf, 0, 2); + this.buf[0] = 0xff; + this.buf[1] = 0xd9; + stream.Write(this.buf, 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) { - if (a >= 0) - return (a + (b >> 1)) / b; - else - return -((-a + (b >> 1)) / b); + if (a >= 0) return (a + (b >> 1)) / b; + else return -((-a + (b >> 1)) / b); } } }