// jpge.cpp - C++ class for JPEG compression. Richard Geldreich <[email protected]> // Supports grayscale, H1V1, H2V1, and H2V2 chroma subsampling factors, one or two pass Huffman table optimization, libjpeg-style quality 1-100 quality factors. // Also supports using luma quantization tables for chroma. // // Released under two licenses. You are free to choose which license you want: // License 1: // Public Domain // // License 2: // Licensed under the Apache License, Version 2.0 (the "License"); // you may not use this file except in compliance with the License. // You may obtain a copy of the License at // // http://www.apache.org/licenses/LICENSE-2.0 // // Unless required by applicable law or agreed to in writing, software // distributed under the License is distributed on an "AS IS" BASIS, // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. // See the License for the specific language governing permissions and // limitations under the License. // // v1.01, Dec. 18, 2010 - Initial release // v1.02, Apr. 6, 2011 - Removed 2x2 ordered dither in H2V1 chroma subsampling method load_block_16_8_8(). (The rounding factor was 2, when it should have been 1. Either way, it wasn't helping.) // v1.03, Apr. 16, 2011 - Added support for optimized Huffman code tables, optimized dynamic memory allocation down to only 1 alloc. // Also from Alex Evans: Added RGBA support, linear memory allocator (no longer needed in v1.03). // v1.04, May. 19, 2012: Forgot to set m_pFile ptr to NULL in cfile_stream::close(). Thanks to Owen Kaluza for reporting this bug. // Code tweaks to fix VS2008 static code analysis warnings (all looked harmless). // Code review revealed method load_block_16_8_8() (used for the non-default H2V1 sampling mode to downsample chroma) somehow didn't get the rounding factor fix from v1.02. // v1.05, March 25, 2020: Added Apache 2.0 alternate license #include "jpge.h" #include <stdlib.h> #include <string.h> #define JPGE_MAX(a,b) … #define JPGE_MIN(a,b) … namespace jpge { static inline void* jpge_malloc(size_t nSize) { … } static inline void jpge_free(void* p) { … } // Various JPEG enums and tables. enum { … }; enum { … }; static uint8 s_zag[64] = …; static int16 s_std_lum_quant[64] = …; static int16 s_std_croma_quant[64] = …; // Table from http://www.imagemagick.org/discourse-server/viewtopic.php?f=22&t=20333&p=98008#p98008 // This is mozjpeg's default table, in zag order. static int16 s_alt_quant[64] = …; static uint8 s_dc_lum_bits[17] = …; static uint8 s_dc_lum_val[DC_LUM_CODES] = …; static uint8 s_ac_lum_bits[17] = …; static uint8 s_ac_lum_val[AC_LUM_CODES] = …; static uint8 s_dc_chroma_bits[17] = …; static uint8 s_dc_chroma_val[DC_CHROMA_CODES] = …; static uint8 s_ac_chroma_bits[17] = …; static uint8 s_ac_chroma_val[AC_CHROMA_CODES] = …; // Low-level helper functions. template <class T> inline void clear_obj(T& obj) { … } const int YR = …, YG = …, YB = …, CB_R = …, CB_G = …, CB_B = …, CR_R = …, CR_G = …, CR_B = …; static inline uint8 clamp(int i) { … } static inline int left_shifti(int val, uint32 bits) { … } static void RGB_to_YCC(uint8* pDst, const uint8* pSrc, int num_pixels) { … } static void RGB_to_Y(uint8* pDst, const uint8* pSrc, int num_pixels) { … } static void RGBA_to_YCC(uint8* pDst, const uint8* pSrc, int num_pixels) { … } static void RGBA_to_Y(uint8* pDst, const uint8* pSrc, int num_pixels) { … } static void Y_to_YCC(uint8* pDst, const uint8* pSrc, int num_pixels) { … } // Forward DCT - DCT derived from jfdctint. enum { … }; #define DCT_DESCALE(x, n) … #define DCT_MUL(var, c) … #define DCT1D(s0, s1, s2, s3, s4, s5, s6, s7) … static void DCT2D(int32* p) { … } struct sym_freq { … }; // Radix sorts sym_freq[] array by 32-bit key m_key. Returns ptr to sorted values. static inline sym_freq* radix_sort_syms(uint num_syms, sym_freq* pSyms0, sym_freq* pSyms1) { … } // calculate_minimum_redundancy() originally written by: Alistair Moffat, [email protected], Jyrki Katajainen, [email protected], November 1996. static void calculate_minimum_redundancy(sym_freq* A, int n) { … } // Limits canonical Huffman code table's max code size to max_code_size. static void huffman_enforce_max_code_size(int* pNum_codes, int code_list_len, int max_code_size) { … } // Generates an optimized offman table. void jpeg_encoder::optimize_huffman_table(int table_num, int table_len) { … } // JPEG marker generation. void jpeg_encoder::emit_byte(uint8 i) { … } void jpeg_encoder::emit_word(uint i) { … } void jpeg_encoder::emit_marker(int marker) { … } // Emit JFIF marker void jpeg_encoder::emit_jfif_app0() { … } // Emit quantization tables void jpeg_encoder::emit_dqt() { … } // Emit start of frame marker void jpeg_encoder::emit_sof() { … } // Emit Huffman table. void jpeg_encoder::emit_dht(uint8* bits, uint8* val, int index, bool ac_flag) { … } // Emit all Huffman tables. void jpeg_encoder::emit_dhts() { … } // emit start of scan void jpeg_encoder::emit_sos() { … } // Emit all markers at beginning of image file. void jpeg_encoder::emit_markers() { … } // Compute the actual canonical Huffman codes/code sizes given the JPEG huff bits and val arrays. void jpeg_encoder::compute_huffman_table(uint* codes, uint8* code_sizes, uint8* bits, uint8* val) { … } // Quantization table generation. void jpeg_encoder::compute_quant_table(int32* pDst, int16* pSrc) { … } // Higher-level methods. void jpeg_encoder::first_pass_init() { … } bool jpeg_encoder::second_pass_init() { … } bool jpeg_encoder::jpg_open(int p_x_res, int p_y_res, int src_channels) { … } void jpeg_encoder::load_block_8_8_grey(int x) { … } void jpeg_encoder::load_block_8_8(int x, int y, int c) { … } void jpeg_encoder::load_block_16_8(int x, int c) { … } void jpeg_encoder::load_block_16_8_8(int x, int c) { … } void jpeg_encoder::load_quantized_coefficients(int component_num) { … } void jpeg_encoder::flush_output_buffer() { … } void jpeg_encoder::put_bits(uint bits, uint len) { … } void jpeg_encoder::code_coefficients_pass_one(int component_num) { … } void jpeg_encoder::code_coefficients_pass_two(int component_num) { … } void jpeg_encoder::code_block(int component_num) { … } void jpeg_encoder::process_mcu_row() { … } bool jpeg_encoder::terminate_pass_one() { … } bool jpeg_encoder::terminate_pass_two() { … } bool jpeg_encoder::process_end_of_image() { … } void jpeg_encoder::load_mcu(const void* pSrc) { … } void jpeg_encoder::clear() { … } jpeg_encoder::jpeg_encoder() { … } jpeg_encoder::~jpeg_encoder() { … } bool jpeg_encoder::init(output_stream* pStream, int width, int height, int src_channels, const params& comp_params) { … } void jpeg_encoder::deinit() { … } bool jpeg_encoder::process_scanline(const void* pScanline) { … } // Higher level wrappers/examples (optional). #include <stdio.h> class cfile_stream : public output_stream { … }; // Writes JPEG image to file. bool compress_image_to_jpeg_file(const char* pFilename, int width, int height, int num_channels, const uint8* pImage_data, const params& comp_params) { … } class memory_stream : public output_stream { … }; bool compress_image_to_jpeg_file_in_memory(void* pDstBuf, int& buf_size, int width, int height, int num_channels, const uint8* pImage_data, const params& comp_params) { … } } // namespace jpge
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