1// jpge.cpp - C++ class for JPEG compression. Richard Geldreich <richgel99@gmail.com>
2// Supports grayscale, H1V1, H2V1, and H2V2 chroma subsampling factors, one or two pass Huffman table optimization, libjpeg-style quality 1-100 quality factors.
3// Also supports using luma quantization tables for chroma.
4//
5// Released under two licenses. You are free to choose which license you want:
6// License 1:
7// Public Domain
8//
9// License 2:
10// Licensed under the Apache License, Version 2.0 (the "License");
11// you may not use this file except in compliance with the License.
12// You may obtain a copy of the License at
13//
14// http://www.apache.org/licenses/LICENSE-2.0
15//
16// Unless required by applicable law or agreed to in writing, software
17// distributed under the License is distributed on an "AS IS" BASIS,
18// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
19// See the License for the specific language governing permissions and
20// limitations under the License.
21//
22// v1.01, Dec. 18, 2010 - Initial release
23// 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.)
24// v1.03, Apr. 16, 2011 - Added support for optimized Huffman code tables, optimized dynamic memory allocation down to only 1 alloc.
25// Also from Alex Evans: Added RGBA support, linear memory allocator (no longer needed in v1.03).
26// 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.
27// Code tweaks to fix VS2008 static code analysis warnings (all looked harmless).
28// 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.
29// v1.05, March 25, 2020: Added Apache 2.0 alternate license
30
31#include "jpge.h"
32
33#include <stdlib.h>
34#include <string.h>
35
36#define JPGE_MAX(a,b) (((a)>(b))?(a):(b))
37#define JPGE_MIN(a,b) (((a)<(b))?(a):(b))
38
39namespace jpge {
40
41 static inline void* jpge_malloc(size_t nSize) { return malloc(nSize); }
42 static inline void jpge_free(void* p) { free(p); }
43
44 // Various JPEG enums and tables.
45 enum { M_SOF0 = 0xC0, M_DHT = 0xC4, M_SOI = 0xD8, M_EOI = 0xD9, M_SOS = 0xDA, M_DQT = 0xDB, M_APP0 = 0xE0 };
46 enum { DC_LUM_CODES = 12, AC_LUM_CODES = 256, DC_CHROMA_CODES = 12, AC_CHROMA_CODES = 256, MAX_HUFF_SYMBOLS = 257, MAX_HUFF_CODESIZE = 32 };
47
48 static uint8 s_zag[64] = { 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 };
49 static int16 s_std_lum_quant[64] = { 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 };
50 static int16 s_std_croma_quant[64] = { 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 };
51
52 // Table from http://www.imagemagick.org/discourse-server/viewtopic.php?f=22&t=20333&p=98008#p98008
53 // This is mozjpeg's default table, in zag order.
54 static int16 s_alt_quant[64] = { 16,16,16,16,17,16,18,20,20,18,25,27,24,27,25,37,34,31,31,34,37,56,40,43,40,43,40,56,85,53,62,53,53,62,53,85,75,91,74,69,74,91,75,135,106,94,94,106,135,156,131,124,131,156,189,169,169,189,238,226,238,311,311,418 };
55
56 static uint8 s_dc_lum_bits[17] = { 0,0,1,5,1,1,1,1,1,1,0,0,0,0,0,0,0 };
57 static uint8 s_dc_lum_val[DC_LUM_CODES] = { 0,1,2,3,4,5,6,7,8,9,10,11 };
58 static uint8 s_ac_lum_bits[17] = { 0,0,2,1,3,3,2,4,3,5,5,4,4,0,0,1,0x7d };
59 static uint8 s_ac_lum_val[AC_LUM_CODES] =
60 {
61 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,
62 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,
63 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,
64 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,
65 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,
66 0xf9,0xfa
67 };
68 static uint8 s_dc_chroma_bits[17] = { 0,0,3,1,1,1,1,1,1,1,1,1,0,0,0,0,0 };
69 static uint8 s_dc_chroma_val[DC_CHROMA_CODES] = { 0,1,2,3,4,5,6,7,8,9,10,11 };
70 static uint8 s_ac_chroma_bits[17] = { 0,0,2,1,2,4,4,3,4,7,5,4,4,0,1,2,0x77 };
71 static uint8 s_ac_chroma_val[AC_CHROMA_CODES] =
72 {
73 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,
74 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,
75 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,
76 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,
77 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,
78 0xf9,0xfa
79 };
80
81 // Low-level helper functions.
82 template <class T> inline void clear_obj(T& obj) { memset(&obj, 0, sizeof(obj)); }
83
84 const int YR = 19595, YG = 38470, YB = 7471, CB_R = -11059, CB_G = -21709, CB_B = 32768, CR_R = 32768, CR_G = -27439, CR_B = -5329;
85 static inline uint8 clamp(int i) { if (static_cast<uint>(i) > 255U) { if (i < 0) i = 0; else if (i > 255) i = 255; } return static_cast<uint8>(i); }
86
87 static inline int left_shifti(int val, uint32 bits)
88 {
89 return static_cast<int>(static_cast<uint32>(val) << bits);
90 }
91
92 static void RGB_to_YCC(uint8* pDst, const uint8* pSrc, int num_pixels)
93 {
94 for (; num_pixels; pDst += 3, pSrc += 3, num_pixels--)
95 {
96 const int r = pSrc[0], g = pSrc[1], b = pSrc[2];
97 pDst[0] = static_cast<uint8>((r * YR + g * YG + b * YB + 32768) >> 16);
98 pDst[1] = clamp(128 + ((r * CB_R + g * CB_G + b * CB_B + 32768) >> 16));
99 pDst[2] = clamp(128 + ((r * CR_R + g * CR_G + b * CR_B + 32768) >> 16));
100 }
101 }
102
103 static void RGB_to_Y(uint8* pDst, const uint8* pSrc, int num_pixels)
104 {
105 for (; num_pixels; pDst++, pSrc += 3, num_pixels--)
106 pDst[0] = static_cast<uint8>((pSrc[0] * YR + pSrc[1] * YG + pSrc[2] * YB + 32768) >> 16);
107 }
108
109 static void RGBA_to_YCC(uint8* pDst, const uint8* pSrc, int num_pixels)
110 {
111 for (; num_pixels; pDst += 3, pSrc += 4, num_pixels--)
112 {
113 const int r = pSrc[0], g = pSrc[1], b = pSrc[2];
114 pDst[0] = static_cast<uint8>((r * YR + g * YG + b * YB + 32768) >> 16);
115 pDst[1] = clamp(128 + ((r * CB_R + g * CB_G + b * CB_B + 32768) >> 16));
116 pDst[2] = clamp(128 + ((r * CR_R + g * CR_G + b * CR_B + 32768) >> 16));
117 }
118 }
119
120 static void RGBA_to_Y(uint8* pDst, const uint8* pSrc, int num_pixels)
121 {
122 for (; num_pixels; pDst++, pSrc += 4, num_pixels--)
123 pDst[0] = static_cast<uint8>((pSrc[0] * YR + pSrc[1] * YG + pSrc[2] * YB + 32768) >> 16);
124 }
125
126 static void Y_to_YCC(uint8* pDst, const uint8* pSrc, int num_pixels)
127 {
128 for (; num_pixels; pDst += 3, pSrc++, num_pixels--) { pDst[0] = pSrc[0]; pDst[1] = 128; pDst[2] = 128; }
129 }
130
131 // Forward DCT - DCT derived from jfdctint.
132 enum { CONST_BITS = 13, ROW_BITS = 2 };
133#define DCT_DESCALE(x, n) (((x) + (((int32)1) << ((n) - 1))) >> (n))
134#define DCT_MUL(var, c) (static_cast<int16>(var) * static_cast<int32>(c))
135#define DCT1D(s0, s1, s2, s3, s4, s5, s6, s7) \
136 int32 t0 = s0 + s7, t7 = s0 - s7, t1 = s1 + s6, t6 = s1 - s6, t2 = s2 + s5, t5 = s2 - s5, t3 = s3 + s4, t4 = s3 - s4; \
137 int32 t10 = t0 + t3, t13 = t0 - t3, t11 = t1 + t2, t12 = t1 - t2; \
138 int32 u1 = DCT_MUL(t12 + t13, 4433); \
139 s2 = u1 + DCT_MUL(t13, 6270); \
140 s6 = u1 + DCT_MUL(t12, -15137); \
141 u1 = t4 + t7; \
142 int32 u2 = t5 + t6, u3 = t4 + t6, u4 = t5 + t7; \
143 int32 z5 = DCT_MUL(u3 + u4, 9633); \
144 t4 = DCT_MUL(t4, 2446); t5 = DCT_MUL(t5, 16819); \
145 t6 = DCT_MUL(t6, 25172); t7 = DCT_MUL(t7, 12299); \
146 u1 = DCT_MUL(u1, -7373); u2 = DCT_MUL(u2, -20995); \
147 u3 = DCT_MUL(u3, -16069); u4 = DCT_MUL(u4, -3196); \
148 u3 += z5; u4 += z5; \
149 s0 = t10 + t11; s1 = t7 + u1 + u4; s3 = t6 + u2 + u3; s4 = t10 - t11; s5 = t5 + u2 + u4; s7 = t4 + u1 + u3;
150
151 static void DCT2D(int32* p)
152 {
153 int32 c, * q = p;
154 for (c = 7; c >= 0; c--, q += 8)
155 {
156 int32 s0 = q[0], s1 = q[1], s2 = q[2], s3 = q[3], s4 = q[4], s5 = q[5], s6 = q[6], s7 = q[7];
157 DCT1D(s0, s1, s2, s3, s4, s5, s6, s7);
158 q[0] = left_shifti(s0, ROW_BITS); q[1] = DCT_DESCALE(s1, CONST_BITS - ROW_BITS); q[2] = DCT_DESCALE(s2, CONST_BITS - ROW_BITS); q[3] = DCT_DESCALE(s3, CONST_BITS - ROW_BITS);
159 q[4] = left_shifti(s4, ROW_BITS); q[5] = DCT_DESCALE(s5, CONST_BITS - ROW_BITS); q[6] = DCT_DESCALE(s6, CONST_BITS - ROW_BITS); q[7] = DCT_DESCALE(s7, CONST_BITS - ROW_BITS);
160 }
161 for (q = p, c = 7; c >= 0; c--, q++)
162 {
163 int32 s0 = q[0 * 8], s1 = q[1 * 8], s2 = q[2 * 8], s3 = q[3 * 8], s4 = q[4 * 8], s5 = q[5 * 8], s6 = q[6 * 8], s7 = q[7 * 8];
164 DCT1D(s0, s1, s2, s3, s4, s5, s6, s7);
165 q[0 * 8] = DCT_DESCALE(s0, ROW_BITS + 3); q[1 * 8] = DCT_DESCALE(s1, CONST_BITS + ROW_BITS + 3); q[2 * 8] = DCT_DESCALE(s2, CONST_BITS + ROW_BITS + 3); q[3 * 8] = DCT_DESCALE(s3, CONST_BITS + ROW_BITS + 3);
166 q[4 * 8] = DCT_DESCALE(s4, ROW_BITS + 3); q[5 * 8] = DCT_DESCALE(s5, CONST_BITS + ROW_BITS + 3); q[6 * 8] = DCT_DESCALE(s6, CONST_BITS + ROW_BITS + 3); q[7 * 8] = DCT_DESCALE(s7, CONST_BITS + ROW_BITS + 3);
167 }
168 }
169
170 struct sym_freq { uint m_key, m_sym_index; };
171
172 // Radix sorts sym_freq[] array by 32-bit key m_key. Returns ptr to sorted values.
173 static inline sym_freq* radix_sort_syms(uint num_syms, sym_freq* pSyms0, sym_freq* pSyms1)
174 {
175 const uint cMaxPasses = 4;
176 uint32 hist[256 * cMaxPasses]; clear_obj(hist);
177 for (uint i = 0; i < num_syms; i++) { uint freq = pSyms0[i].m_key; hist[freq & 0xFF]++; hist[256 + ((freq >> 8) & 0xFF)]++; hist[256 * 2 + ((freq >> 16) & 0xFF)]++; hist[256 * 3 + ((freq >> 24) & 0xFF)]++; }
178 sym_freq* pCur_syms = pSyms0, * pNew_syms = pSyms1;
179 uint total_passes = cMaxPasses; while ((total_passes > 1) && (num_syms == hist[(total_passes - 1) * 256])) total_passes--;
180 for (uint pass_shift = 0, pass = 0; pass < total_passes; pass++, pass_shift += 8)
181 {
182 const uint32* pHist = &hist[pass << 8];
183 uint offsets[256], cur_ofs = 0;
184 for (uint i = 0; i < 256; i++) { offsets[i] = cur_ofs; cur_ofs += pHist[i]; }
185 for (uint i = 0; i < num_syms; i++)
186 pNew_syms[offsets[(pCur_syms[i].m_key >> pass_shift) & 0xFF]++] = pCur_syms[i];
187 sym_freq* t = pCur_syms; pCur_syms = pNew_syms; pNew_syms = t;
188 }
189 return pCur_syms;
190 }
191
192 // calculate_minimum_redundancy() originally written by: Alistair Moffat, alistair@cs.mu.oz.au, Jyrki Katajainen, jyrki@diku.dk, November 1996.
193 static void calculate_minimum_redundancy(sym_freq* A, int n)
194 {
195 int root, leaf, next, avbl, used, dpth;
196 if (n == 0) return; else if (n == 1) { A[0].m_key = 1; return; }
197 A[0].m_key += A[1].m_key; root = 0; leaf = 2;
198 for (next = 1; next < n - 1; next++)
199 {
200 if (leaf >= n || A[root].m_key < A[leaf].m_key) { A[next].m_key = A[root].m_key; A[root++].m_key = next; }
201 else A[next].m_key = A[leaf++].m_key;
202 if (leaf >= n || (root < next && A[root].m_key < A[leaf].m_key)) { A[next].m_key += A[root].m_key; A[root++].m_key = next; }
203 else A[next].m_key += A[leaf++].m_key;
204 }
205 A[n - 2].m_key = 0;
206 for (next = n - 3; next >= 0; next--) A[next].m_key = A[A[next].m_key].m_key + 1;
207 avbl = 1; used = dpth = 0; root = n - 2; next = n - 1;
208 while (avbl > 0)
209 {
210 while (root >= 0 && (int)A[root].m_key == dpth) { used++; root--; }
211 while (avbl > used) { A[next--].m_key = dpth; avbl--; }
212 avbl = 2 * used; dpth++; used = 0;
213 }
214 }
215
216 // Limits canonical Huffman code table's max code size to max_code_size.
217 static void huffman_enforce_max_code_size(int* pNum_codes, int code_list_len, int max_code_size)
218 {
219 if (code_list_len <= 1) return;
220
221 for (int i = max_code_size + 1; i <= MAX_HUFF_CODESIZE; i++) pNum_codes[max_code_size] += pNum_codes[i];
222
223 uint32 total = 0;
224 for (int i = max_code_size; i > 0; i--)
225 total += (((uint32)pNum_codes[i]) << (max_code_size - i));
226
227 while (total != (1UL << max_code_size))
228 {
229 pNum_codes[max_code_size]--;
230 for (int i = max_code_size - 1; i > 0; i--)
231 {
232 if (pNum_codes[i]) { pNum_codes[i]--; pNum_codes[i + 1] += 2; break; }
233 }
234 total--;
235 }
236 }
237
238 // Generates an optimized offman table.
239 void jpeg_encoder::optimize_huffman_table(int table_num, int table_len)
240 {
241 sym_freq syms0[MAX_HUFF_SYMBOLS], syms1[MAX_HUFF_SYMBOLS];
242 syms0[0].m_key = 1; syms0[0].m_sym_index = 0; // dummy symbol, assures that no valid code contains all 1's
243 int num_used_syms = 1;
244 const uint32* pSym_count = &m_huff_count[table_num][0];
245 for (int i = 0; i < table_len; i++)
246 if (pSym_count[i]) { syms0[num_used_syms].m_key = pSym_count[i]; syms0[num_used_syms++].m_sym_index = i + 1; }
247 sym_freq* pSyms = radix_sort_syms(num_used_syms, syms0, syms1);
248 calculate_minimum_redundancy(pSyms, num_used_syms);
249
250 // Count the # of symbols of each code size.
251 int num_codes[1 + MAX_HUFF_CODESIZE]; clear_obj(num_codes);
252 for (int i = 0; i < num_used_syms; i++)
253 num_codes[pSyms[i].m_key]++;
254
255 const uint JPGE_CODE_SIZE_LIMIT = 16; // the maximum possible size of a JPEG Huffman code (valid range is [9,16] - 9 vs. 8 because of the dummy symbol)
256 huffman_enforce_max_code_size(num_codes, num_used_syms, JPGE_CODE_SIZE_LIMIT);
257
258 // Compute m_huff_bits array, which contains the # of symbols per code size.
259 clear_obj(m_huff_bits[table_num]);
260 for (int i = 1; i <= (int)JPGE_CODE_SIZE_LIMIT; i++)
261 m_huff_bits[table_num][i] = static_cast<uint8>(num_codes[i]);
262
263 // Remove the dummy symbol added above, which must be in largest bucket.
264 for (int i = JPGE_CODE_SIZE_LIMIT; i >= 1; i--)
265 {
266 if (m_huff_bits[table_num][i]) { m_huff_bits[table_num][i]--; break; }
267 }
268
269 // Compute the m_huff_val array, which contains the symbol indices sorted by code size (smallest to largest).
270 for (int i = num_used_syms - 1; i >= 1; i--)
271 m_huff_val[table_num][num_used_syms - 1 - i] = static_cast<uint8>(pSyms[i].m_sym_index - 1);
272 }
273
274 // JPEG marker generation.
275 void jpeg_encoder::emit_byte(uint8 i)
276 {
277 m_all_stream_writes_succeeded = m_all_stream_writes_succeeded && m_pStream->put_obj(i);
278 }
279
280 void jpeg_encoder::emit_word(uint i)
281 {
282 emit_byte(uint8(i >> 8)); emit_byte(uint8(i & 0xFF));
283 }
284
285 void jpeg_encoder::emit_marker(int marker)
286 {
287 emit_byte(uint8(0xFF)); emit_byte(uint8(marker));
288 }
289
290 // Emit JFIF marker
291 void jpeg_encoder::emit_jfif_app0()
292 {
293 emit_marker(M_APP0);
294 emit_word(2 + 4 + 1 + 2 + 1 + 2 + 2 + 1 + 1);
295 emit_byte(0x4A); emit_byte(0x46); emit_byte(0x49); emit_byte(0x46); /* Identifier: ASCII "JFIF" */
296 emit_byte(0);
297 emit_byte(1); /* Major version */
298 emit_byte(1); /* Minor version */
299 emit_byte(0); /* Density unit */
300 emit_word(1);
301 emit_word(1);
302 emit_byte(0); /* No thumbnail image */
303 emit_byte(0);
304 }
305
306 // Emit quantization tables
307 void jpeg_encoder::emit_dqt()
308 {
309 for (int i = 0; i < ((m_num_components == 3) ? 2 : 1); i++)
310 {
311 emit_marker(M_DQT);
312 emit_word(64 + 1 + 2);
313 emit_byte(static_cast<uint8>(i));
314 for (int j = 0; j < 64; j++)
315 emit_byte(static_cast<uint8>(m_quantization_tables[i][j]));
316 }
317 }
318
319 // Emit start of frame marker
320 void jpeg_encoder::emit_sof()
321 {
322 emit_marker(M_SOF0); /* baseline */
323 emit_word(3 * m_num_components + 2 + 5 + 1);
324 emit_byte(8); /* precision */
325 emit_word(m_image_y);
326 emit_word(m_image_x);
327 emit_byte(m_num_components);
328 for (int i = 0; i < m_num_components; i++)
329 {
330 emit_byte(static_cast<uint8>(i + 1)); /* component ID */
331 emit_byte((m_comp_h_samp[i] << 4) + m_comp_v_samp[i]); /* h and v sampling */
332 emit_byte(i > 0); /* quant. table num */
333 }
334 }
335
336 // Emit Huffman table.
337 void jpeg_encoder::emit_dht(uint8* bits, uint8* val, int index, bool ac_flag)
338 {
339 emit_marker(M_DHT);
340
341 int length = 0;
342 for (int i = 1; i <= 16; i++)
343 length += bits[i];
344
345 emit_word(length + 2 + 1 + 16);
346 emit_byte(static_cast<uint8>(index + (ac_flag << 4)));
347
348 for (int i = 1; i <= 16; i++)
349 emit_byte(bits[i]);
350
351 for (int i = 0; i < length; i++)
352 emit_byte(val[i]);
353 }
354
355 // Emit all Huffman tables.
356 void jpeg_encoder::emit_dhts()
357 {
358 emit_dht(m_huff_bits[0 + 0], m_huff_val[0 + 0], 0, false);
359 emit_dht(m_huff_bits[2 + 0], m_huff_val[2 + 0], 0, true);
360 if (m_num_components == 3)
361 {
362 emit_dht(m_huff_bits[0 + 1], m_huff_val[0 + 1], 1, false);
363 emit_dht(m_huff_bits[2 + 1], m_huff_val[2 + 1], 1, true);
364 }
365 }
366
367 // emit start of scan
368 void jpeg_encoder::emit_sos()
369 {
370 emit_marker(M_SOS);
371 emit_word(2 * m_num_components + 2 + 1 + 3);
372 emit_byte(m_num_components);
373 for (int i = 0; i < m_num_components; i++)
374 {
375 emit_byte(static_cast<uint8>(i + 1));
376 if (i == 0)
377 emit_byte((0 << 4) + 0);
378 else
379 emit_byte((1 << 4) + 1);
380 }
381 emit_byte(0); /* spectral selection */
382 emit_byte(63);
383 emit_byte(0);
384 }
385
386 // Emit all markers at beginning of image file.
387 void jpeg_encoder::emit_markers()
388 {
389 emit_marker(M_SOI);
390 emit_jfif_app0();
391 emit_dqt();
392 emit_sof();
393 emit_dhts();
394 emit_sos();
395 }
396
397 // Compute the actual canonical Huffman codes/code sizes given the JPEG huff bits and val arrays.
398 void jpeg_encoder::compute_huffman_table(uint* codes, uint8* code_sizes, uint8* bits, uint8* val)
399 {
400 int i, l, last_p, si;
401 uint8 huff_size[257];
402 uint huff_code[257];
403 uint code;
404
405 int p = 0;
406 for (l = 1; l <= 16; l++)
407 for (i = 1; i <= bits[l]; i++)
408 huff_size[p++] = (char)l;
409
410 huff_size[p] = 0; last_p = p; // write sentinel
411
412 code = 0; si = huff_size[0]; p = 0;
413
414 while (huff_size[p])
415 {
416 while (huff_size[p] == si)
417 huff_code[p++] = code++;
418 code <<= 1;
419 si++;
420 }
421
422 memset(codes, 0, sizeof(codes[0]) * 256);
423 memset(code_sizes, 0, sizeof(code_sizes[0]) * 256);
424 for (p = 0; p < last_p; p++)
425 {
426 codes[val[p]] = huff_code[p];
427 code_sizes[val[p]] = huff_size[p];
428 }
429 }
430
431 // Quantization table generation.
432 void jpeg_encoder::compute_quant_table(int32* pDst, int16* pSrc)
433 {
434 int32 q;
435 if (m_params.m_quality < 50)
436 q = 5000 / m_params.m_quality;
437 else
438 q = 200 - m_params.m_quality * 2;
439 for (int i = 0; i < 64; i++)
440 {
441 int32 j = *pSrc++; j = (j * q + 50L) / 100L;
442 *pDst++ = JPGE_MIN(JPGE_MAX(j, 1), 255);
443 }
444 }
445
446 // Higher-level methods.
447 void jpeg_encoder::first_pass_init()
448 {
449 m_bit_buffer = 0; m_bits_in = 0;
450 memset(m_last_dc_val, 0, 3 * sizeof(m_last_dc_val[0]));
451 m_mcu_y_ofs = 0;
452 m_pass_num = 1;
453 }
454
455 bool jpeg_encoder::second_pass_init()
456 {
457 compute_huffman_table(&m_huff_codes[0 + 0][0], &m_huff_code_sizes[0 + 0][0], m_huff_bits[0 + 0], m_huff_val[0 + 0]);
458 compute_huffman_table(&m_huff_codes[2 + 0][0], &m_huff_code_sizes[2 + 0][0], m_huff_bits[2 + 0], m_huff_val[2 + 0]);
459 if (m_num_components > 1)
460 {
461 compute_huffman_table(&m_huff_codes[0 + 1][0], &m_huff_code_sizes[0 + 1][0], m_huff_bits[0 + 1], m_huff_val[0 + 1]);
462 compute_huffman_table(&m_huff_codes[2 + 1][0], &m_huff_code_sizes[2 + 1][0], m_huff_bits[2 + 1], m_huff_val[2 + 1]);
463 }
464 first_pass_init();
465 emit_markers();
466 m_pass_num = 2;
467 return true;
468 }
469
470 bool jpeg_encoder::jpg_open(int p_x_res, int p_y_res, int src_channels)
471 {
472 m_num_components = 3;
473 switch (m_params.m_subsampling)
474 {
475 case Y_ONLY:
476 {
477 m_num_components = 1;
478 m_comp_h_samp[0] = 1; m_comp_v_samp[0] = 1;
479 m_mcu_x = 8; m_mcu_y = 8;
480 break;
481 }
482 case H1V1:
483 {
484 m_comp_h_samp[0] = 1; m_comp_v_samp[0] = 1;
485 m_comp_h_samp[1] = 1; m_comp_v_samp[1] = 1;
486 m_comp_h_samp[2] = 1; m_comp_v_samp[2] = 1;
487 m_mcu_x = 8; m_mcu_y = 8;
488 break;
489 }
490 case H2V1:
491 {
492 m_comp_h_samp[0] = 2; m_comp_v_samp[0] = 1;
493 m_comp_h_samp[1] = 1; m_comp_v_samp[1] = 1;
494 m_comp_h_samp[2] = 1; m_comp_v_samp[2] = 1;
495 m_mcu_x = 16; m_mcu_y = 8;
496 break;
497 }
498 case H2V2:
499 {
500 m_comp_h_samp[0] = 2; m_comp_v_samp[0] = 2;
501 m_comp_h_samp[1] = 1; m_comp_v_samp[1] = 1;
502 m_comp_h_samp[2] = 1; m_comp_v_samp[2] = 1;
503 m_mcu_x = 16; m_mcu_y = 16;
504 }
505 }
506
507 m_image_x = p_x_res; m_image_y = p_y_res;
508 m_image_bpp = src_channels;
509 m_image_bpl = m_image_x * src_channels;
510 m_image_x_mcu = (m_image_x + m_mcu_x - 1) & (~(m_mcu_x - 1));
511 m_image_y_mcu = (m_image_y + m_mcu_y - 1) & (~(m_mcu_y - 1));
512 m_image_bpl_xlt = m_image_x * m_num_components;
513 m_image_bpl_mcu = m_image_x_mcu * m_num_components;
514 m_mcus_per_row = m_image_x_mcu / m_mcu_x;
515
516 if ((m_mcu_lines[0] = static_cast<uint8*>(jpge_malloc(m_image_bpl_mcu * m_mcu_y))) == NULL) return false;
517 for (int i = 1; i < m_mcu_y; i++)
518 m_mcu_lines[i] = m_mcu_lines[i - 1] + m_image_bpl_mcu;
519
520 if (m_params.m_use_std_tables)
521 {
522 compute_quant_table(m_quantization_tables[0], s_std_lum_quant);
523 compute_quant_table(m_quantization_tables[1], m_params.m_no_chroma_discrim_flag ? s_std_lum_quant : s_std_croma_quant);
524 }
525 else
526 {
527 compute_quant_table(m_quantization_tables[0], s_alt_quant);
528 memcpy(m_quantization_tables[1], m_quantization_tables[0], sizeof(m_quantization_tables[1]));
529 }
530
531 m_out_buf_left = JPGE_OUT_BUF_SIZE;
532 m_pOut_buf = m_out_buf;
533
534 if (m_params.m_two_pass_flag)
535 {
536 clear_obj(m_huff_count);
537 first_pass_init();
538 }
539 else
540 {
541 memcpy(m_huff_bits[0 + 0], s_dc_lum_bits, 17); memcpy(m_huff_val[0 + 0], s_dc_lum_val, DC_LUM_CODES);
542 memcpy(m_huff_bits[2 + 0], s_ac_lum_bits, 17); memcpy(m_huff_val[2 + 0], s_ac_lum_val, AC_LUM_CODES);
543 memcpy(m_huff_bits[0 + 1], s_dc_chroma_bits, 17); memcpy(m_huff_val[0 + 1], s_dc_chroma_val, DC_CHROMA_CODES);
544 memcpy(m_huff_bits[2 + 1], s_ac_chroma_bits, 17); memcpy(m_huff_val[2 + 1], s_ac_chroma_val, AC_CHROMA_CODES);
545 if (!second_pass_init()) return false; // in effect, skip over the first pass
546 }
547 return m_all_stream_writes_succeeded;
548 }
549
550 void jpeg_encoder::load_block_8_8_grey(int x)
551 {
552 uint8* pSrc;
553 sample_array_t* pDst = m_sample_array;
554 x <<= 3;
555 for (int i = 0; i < 8; i++, pDst += 8)
556 {
557 pSrc = m_mcu_lines[i] + x;
558 pDst[0] = pSrc[0] - 128; pDst[1] = pSrc[1] - 128; pDst[2] = pSrc[2] - 128; pDst[3] = pSrc[3] - 128;
559 pDst[4] = pSrc[4] - 128; pDst[5] = pSrc[5] - 128; pDst[6] = pSrc[6] - 128; pDst[7] = pSrc[7] - 128;
560 }
561 }
562
563 void jpeg_encoder::load_block_8_8(int x, int y, int c)
564 {
565 uint8* pSrc;
566 sample_array_t* pDst = m_sample_array;
567 x = (x * (8 * 3)) + c;
568 y <<= 3;
569 for (int i = 0; i < 8; i++, pDst += 8)
570 {
571 pSrc = m_mcu_lines[y + i] + x;
572 pDst[0] = pSrc[0 * 3] - 128; pDst[1] = pSrc[1 * 3] - 128; pDst[2] = pSrc[2 * 3] - 128; pDst[3] = pSrc[3 * 3] - 128;
573 pDst[4] = pSrc[4 * 3] - 128; pDst[5] = pSrc[5 * 3] - 128; pDst[6] = pSrc[6 * 3] - 128; pDst[7] = pSrc[7 * 3] - 128;
574 }
575 }
576
577 void jpeg_encoder::load_block_16_8(int x, int c)
578 {
579 uint8* pSrc1, * pSrc2;
580 sample_array_t* pDst = m_sample_array;
581 x = (x * (16 * 3)) + c;
582 for (int i = 0; i < 16; i += 2, pDst += 8)
583 {
584 pSrc1 = m_mcu_lines[i + 0] + x;
585 pSrc2 = m_mcu_lines[i + 1] + x;
586 pDst[0] = ((pSrc1[0 * 3] + pSrc1[1 * 3] + pSrc2[0 * 3] + pSrc2[1 * 3] + 2) >> 2) - 128; pDst[1] = ((pSrc1[2 * 3] + pSrc1[3 * 3] + pSrc2[2 * 3] + pSrc2[3 * 3] + 2) >> 2) - 128;
587 pDst[2] = ((pSrc1[4 * 3] + pSrc1[5 * 3] + pSrc2[4 * 3] + pSrc2[5 * 3] + 2) >> 2) - 128; pDst[3] = ((pSrc1[6 * 3] + pSrc1[7 * 3] + pSrc2[6 * 3] + pSrc2[7 * 3] + 2) >> 2) - 128;
588 pDst[4] = ((pSrc1[8 * 3] + pSrc1[9 * 3] + pSrc2[8 * 3] + pSrc2[9 * 3] + 2) >> 2) - 128; pDst[5] = ((pSrc1[10 * 3] + pSrc1[11 * 3] + pSrc2[10 * 3] + pSrc2[11 * 3] + 2) >> 2) - 128;
589 pDst[6] = ((pSrc1[12 * 3] + pSrc1[13 * 3] + pSrc2[12 * 3] + pSrc2[13 * 3] + 2) >> 2) - 128; pDst[7] = ((pSrc1[14 * 3] + pSrc1[15 * 3] + pSrc2[14 * 3] + pSrc2[15 * 3] + 2) >> 2) - 128;
590 }
591 }
592
593 void jpeg_encoder::load_block_16_8_8(int x, int c)
594 {
595 uint8* pSrc1;
596 sample_array_t* pDst = m_sample_array;
597 x = (x * (16 * 3)) + c;
598 for (int i = 0; i < 8; i++, pDst += 8)
599 {
600 pSrc1 = m_mcu_lines[i + 0] + x;
601 pDst[0] = ((pSrc1[0 * 3] + pSrc1[1 * 3] + 1) >> 1) - 128; pDst[1] = ((pSrc1[2 * 3] + pSrc1[3 * 3] + 1) >> 1) - 128;
602 pDst[2] = ((pSrc1[4 * 3] + pSrc1[5 * 3] + 1) >> 1) - 128; pDst[3] = ((pSrc1[6 * 3] + pSrc1[7 * 3] + 1) >> 1) - 128;
603 pDst[4] = ((pSrc1[8 * 3] + pSrc1[9 * 3] + 1) >> 1) - 128; pDst[5] = ((pSrc1[10 * 3] + pSrc1[11 * 3] + 1) >> 1) - 128;
604 pDst[6] = ((pSrc1[12 * 3] + pSrc1[13 * 3] + 1) >> 1) - 128; pDst[7] = ((pSrc1[14 * 3] + pSrc1[15 * 3] + 1) >> 1) - 128;
605 }
606 }
607
608 void jpeg_encoder::load_quantized_coefficients(int component_num)
609 {
610 int32* q = m_quantization_tables[component_num > 0];
611 int16* pDst = m_coefficient_array;
612 for (int i = 0; i < 64; i++)
613 {
614 sample_array_t j = m_sample_array[s_zag[i]];
615 if (j < 0)
616 {
617 if ((j = -j + (*q >> 1)) < *q)
618 *pDst++ = 0;
619 else
620 *pDst++ = static_cast<int16>(-(j / *q));
621 }
622 else
623 {
624 if ((j = j + (*q >> 1)) < *q)
625 *pDst++ = 0;
626 else
627 *pDst++ = static_cast<int16>((j / *q));
628 }
629 q++;
630 }
631 }
632
633 void jpeg_encoder::flush_output_buffer()
634 {
635 if (m_out_buf_left != JPGE_OUT_BUF_SIZE)
636 m_all_stream_writes_succeeded = m_all_stream_writes_succeeded && m_pStream->put_buf(m_out_buf, JPGE_OUT_BUF_SIZE - m_out_buf_left);
637 m_pOut_buf = m_out_buf;
638 m_out_buf_left = JPGE_OUT_BUF_SIZE;
639 }
640
641 void jpeg_encoder::put_bits(uint bits, uint len)
642 {
643 m_bit_buffer |= ((uint32)bits << (24 - (m_bits_in += len)));
644 while (m_bits_in >= 8)
645 {
646 uint8 c;
647#define JPGE_PUT_BYTE(c) { *m_pOut_buf++ = (c); if (--m_out_buf_left == 0) flush_output_buffer(); }
648 JPGE_PUT_BYTE(c = (uint8)((m_bit_buffer >> 16) & 0xFF));
649 if (c == 0xFF) JPGE_PUT_BYTE(0);
650 m_bit_buffer <<= 8;
651 m_bits_in -= 8;
652 }
653 }
654
655 void jpeg_encoder::code_coefficients_pass_one(int component_num)
656 {
657 if (component_num >= 3) return; // just to shut up static analysis
658 int i, run_len, nbits, temp1;
659 int16* src = m_coefficient_array;
660 uint32* dc_count = component_num ? m_huff_count[0 + 1] : m_huff_count[0 + 0], * ac_count = component_num ? m_huff_count[2 + 1] : m_huff_count[2 + 0];
661
662 temp1 = src[0] - m_last_dc_val[component_num];
663 m_last_dc_val[component_num] = src[0];
664 if (temp1 < 0) temp1 = -temp1;
665
666 nbits = 0;
667 while (temp1)
668 {
669 nbits++; temp1 >>= 1;
670 }
671
672 dc_count[nbits]++;
673 for (run_len = 0, i = 1; i < 64; i++)
674 {
675 if ((temp1 = m_coefficient_array[i]) == 0)
676 run_len++;
677 else
678 {
679 while (run_len >= 16)
680 {
681 ac_count[0xF0]++;
682 run_len -= 16;
683 }
684 if (temp1 < 0) temp1 = -temp1;
685 nbits = 1;
686 while (temp1 >>= 1) nbits++;
687 ac_count[(run_len << 4) + nbits]++;
688 run_len = 0;
689 }
690 }
691 if (run_len) ac_count[0]++;
692 }
693
694 void jpeg_encoder::code_coefficients_pass_two(int component_num)
695 {
696 int i, j, run_len, nbits, temp1, temp2;
697 int16* pSrc = m_coefficient_array;
698 uint* codes[2];
699 uint8* code_sizes[2];
700
701 if (component_num == 0)
702 {
703 codes[0] = m_huff_codes[0 + 0]; codes[1] = m_huff_codes[2 + 0];
704 code_sizes[0] = m_huff_code_sizes[0 + 0]; code_sizes[1] = m_huff_code_sizes[2 + 0];
705 }
706 else
707 {
708 codes[0] = m_huff_codes[0 + 1]; codes[1] = m_huff_codes[2 + 1];
709 code_sizes[0] = m_huff_code_sizes[0 + 1]; code_sizes[1] = m_huff_code_sizes[2 + 1];
710 }
711
712 temp1 = temp2 = pSrc[0] - m_last_dc_val[component_num];
713 m_last_dc_val[component_num] = pSrc[0];
714
715 if (temp1 < 0)
716 {
717 temp1 = -temp1; temp2--;
718 }
719
720 nbits = 0;
721 while (temp1)
722 {
723 nbits++; temp1 >>= 1;
724 }
725
726 put_bits(codes[0][nbits], code_sizes[0][nbits]);
727 if (nbits) put_bits(temp2 & ((1 << nbits) - 1), nbits);
728
729 for (run_len = 0, i = 1; i < 64; i++)
730 {
731 if ((temp1 = m_coefficient_array[i]) == 0)
732 run_len++;
733 else
734 {
735 while (run_len >= 16)
736 {
737 put_bits(codes[1][0xF0], code_sizes[1][0xF0]);
738 run_len -= 16;
739 }
740 if ((temp2 = temp1) < 0)
741 {
742 temp1 = -temp1;
743 temp2--;
744 }
745 nbits = 1;
746 while (temp1 >>= 1)
747 nbits++;
748 j = (run_len << 4) + nbits;
749 put_bits(codes[1][j], code_sizes[1][j]);
750 put_bits(temp2 & ((1 << nbits) - 1), nbits);
751 run_len = 0;
752 }
753 }
754 if (run_len)
755 put_bits(codes[1][0], code_sizes[1][0]);
756 }
757
758 void jpeg_encoder::code_block(int component_num)
759 {
760 DCT2D(m_sample_array);
761 load_quantized_coefficients(component_num);
762 if (m_pass_num == 1)
763 code_coefficients_pass_one(component_num);
764 else
765 code_coefficients_pass_two(component_num);
766 }
767
768 void jpeg_encoder::process_mcu_row()
769 {
770 if (m_num_components == 1)
771 {
772 for (int i = 0; i < m_mcus_per_row; i++)
773 {
774 load_block_8_8_grey(i); code_block(0);
775 }
776 }
777 else if ((m_comp_h_samp[0] == 1) && (m_comp_v_samp[0] == 1))
778 {
779 for (int i = 0; i < m_mcus_per_row; i++)
780 {
781 load_block_8_8(i, 0, 0); code_block(0); load_block_8_8(i, 0, 1); code_block(1); load_block_8_8(i, 0, 2); code_block(2);
782 }
783 }
784 else if ((m_comp_h_samp[0] == 2) && (m_comp_v_samp[0] == 1))
785 {
786 for (int i = 0; i < m_mcus_per_row; i++)
787 {
788 load_block_8_8(i * 2 + 0, 0, 0); code_block(0); load_block_8_8(i * 2 + 1, 0, 0); code_block(0);
789 load_block_16_8_8(i, 1); code_block(1); load_block_16_8_8(i, 2); code_block(2);
790 }
791 }
792 else if ((m_comp_h_samp[0] == 2) && (m_comp_v_samp[0] == 2))
793 {
794 for (int i = 0; i < m_mcus_per_row; i++)
795 {
796 load_block_8_8(i * 2 + 0, 0, 0); code_block(0); load_block_8_8(i * 2 + 1, 0, 0); code_block(0);
797 load_block_8_8(i * 2 + 0, 1, 0); code_block(0); load_block_8_8(i * 2 + 1, 1, 0); code_block(0);
798 load_block_16_8(i, 1); code_block(1); load_block_16_8(i, 2); code_block(2);
799 }
800 }
801 }
802
803 bool jpeg_encoder::terminate_pass_one()
804 {
805 optimize_huffman_table(0 + 0, DC_LUM_CODES); optimize_huffman_table(2 + 0, AC_LUM_CODES);
806 if (m_num_components > 1)
807 {
808 optimize_huffman_table(0 + 1, DC_CHROMA_CODES); optimize_huffman_table(2 + 1, AC_CHROMA_CODES);
809 }
810 return second_pass_init();
811 }
812
813 bool jpeg_encoder::terminate_pass_two()
814 {
815 put_bits(0x7F, 7);
816 flush_output_buffer();
817 emit_marker(M_EOI);
818 m_pass_num++; // purposely bump up m_pass_num, for debugging
819 return true;
820 }
821
822 bool jpeg_encoder::process_end_of_image()
823 {
824 if (m_mcu_y_ofs)
825 {
826 if (m_mcu_y_ofs < 16) // check here just to shut up static analysis
827 {
828 for (int i = m_mcu_y_ofs; i < m_mcu_y; i++)
829 memcpy(m_mcu_lines[i], m_mcu_lines[m_mcu_y_ofs - 1], m_image_bpl_mcu);
830 }
831
832 process_mcu_row();
833 }
834
835 if (m_pass_num == 1)
836 return terminate_pass_one();
837 else
838 return terminate_pass_two();
839 }
840
841 void jpeg_encoder::load_mcu(const void* pSrc)
842 {
843 const uint8* Psrc = reinterpret_cast<const uint8*>(pSrc);
844
845 uint8* pDst = m_mcu_lines[m_mcu_y_ofs]; // OK to write up to m_image_bpl_xlt bytes to pDst
846
847 if (m_num_components == 1)
848 {
849 if (m_image_bpp == 4)
850 RGBA_to_Y(pDst, Psrc, m_image_x);
851 else if (m_image_bpp == 3)
852 RGB_to_Y(pDst, Psrc, m_image_x);
853 else
854 memcpy(pDst, Psrc, m_image_x);
855 }
856 else
857 {
858 if (m_image_bpp == 4)
859 RGBA_to_YCC(pDst, Psrc, m_image_x);
860 else if (m_image_bpp == 3)
861 RGB_to_YCC(pDst, Psrc, m_image_x);
862 else
863 Y_to_YCC(pDst, Psrc, m_image_x);
864 }
865
866 // Possibly duplicate pixels at end of scanline if not a multiple of 8 or 16
867 if (m_num_components == 1)
868 memset(m_mcu_lines[m_mcu_y_ofs] + m_image_bpl_xlt, pDst[m_image_bpl_xlt - 1], m_image_x_mcu - m_image_x);
869 else
870 {
871 const uint8 y = pDst[m_image_bpl_xlt - 3 + 0], cb = pDst[m_image_bpl_xlt - 3 + 1], cr = pDst[m_image_bpl_xlt - 3 + 2];
872 uint8* q = m_mcu_lines[m_mcu_y_ofs] + m_image_bpl_xlt;
873 for (int i = m_image_x; i < m_image_x_mcu; i++)
874 {
875 *q++ = y; *q++ = cb; *q++ = cr;
876 }
877 }
878
879 if (++m_mcu_y_ofs == m_mcu_y)
880 {
881 process_mcu_row();
882 m_mcu_y_ofs = 0;
883 }
884 }
885
886 void jpeg_encoder::clear()
887 {
888 m_mcu_lines[0] = NULL;
889 m_pass_num = 0;
890 m_all_stream_writes_succeeded = true;
891 }
892
893 jpeg_encoder::jpeg_encoder()
894 {
895 clear();
896 }
897
898 jpeg_encoder::~jpeg_encoder()
899 {
900 deinit();
901 }
902
903 bool jpeg_encoder::init(output_stream* pStream, int width, int height, int src_channels, const params& comp_params)
904 {
905 deinit();
906 if (((!pStream) || (width < 1) || (height < 1)) || ((src_channels != 1) && (src_channels != 3) && (src_channels != 4)) || (!comp_params.check())) return false;
907 m_pStream = pStream;
908 m_params = comp_params;
909 return jpg_open(width, height, src_channels);
910 }
911
912 void jpeg_encoder::deinit()
913 {
914 jpge_free(m_mcu_lines[0]);
915 clear();
916 }
917
918 bool jpeg_encoder::process_scanline(const void* pScanline)
919 {
920 if ((m_pass_num < 1) || (m_pass_num > 2)) return false;
921 if (m_all_stream_writes_succeeded)
922 {
923 if (!pScanline)
924 {
925 if (!process_end_of_image()) return false;
926 }
927 else
928 {
929 load_mcu(pScanline);
930 }
931 }
932 return m_all_stream_writes_succeeded;
933 }
934
935 // Higher level wrappers/examples (optional).
936#include <stdio.h>
937
938 class cfile_stream : public output_stream
939 {
940 cfile_stream(const cfile_stream&);
941 cfile_stream& operator= (const cfile_stream&);
942
943 FILE* m_pFile;
944 bool m_bStatus;
945
946 public:
947 cfile_stream() : m_pFile(NULL), m_bStatus(false) { }
948
949 virtual ~cfile_stream()
950 {
951 close();
952 }
953
954 bool open(const char* pFilename)
955 {
956 close();
957 m_pFile = fopen(pFilename, "wb");
958 m_bStatus = (m_pFile != NULL);
959 return m_bStatus;
960 }
961
962 bool close()
963 {
964 if (m_pFile)
965 {
966 if (fclose(m_pFile) == EOF)
967 {
968 m_bStatus = false;
969 }
970 m_pFile = NULL;
971 }
972 return m_bStatus;
973 }
974
975 virtual bool put_buf(const void* pBuf, int len)
976 {
977 m_bStatus = m_bStatus && (fwrite(pBuf, len, 1, m_pFile) == 1);
978 return m_bStatus;
979 }
980
981 uint get_size() const
982 {
983 return m_pFile ? ftell(m_pFile) : 0;
984 }
985 };
986
987 // Writes JPEG image to file.
988 bool compress_image_to_jpeg_file(const char* pFilename, int width, int height, int num_channels, const uint8* pImage_data, const params& comp_params)
989 {
990 cfile_stream dst_stream;
991 if (!dst_stream.open(pFilename))
992 return false;
993
994 jpge::jpeg_encoder dst_image;
995 if (!dst_image.init(&dst_stream, width, height, num_channels, comp_params))
996 return false;
997
998 for (uint pass_index = 0; pass_index < dst_image.get_total_passes(); pass_index++)
999 {
1000 for (int i = 0; i < height; i++)
1001 {
1002 const uint8* pBuf = pImage_data + i * width * num_channels;
1003 if (!dst_image.process_scanline(pBuf))
1004 return false;
1005 }
1006 if (!dst_image.process_scanline(NULL))
1007 return false;
1008 }
1009
1010 dst_image.deinit();
1011
1012 return dst_stream.close();
1013 }
1014
1015 class memory_stream : public output_stream
1016 {
1017 memory_stream(const memory_stream&);
1018 memory_stream& operator= (const memory_stream&);
1019
1020 uint8* m_pBuf;
1021 uint m_buf_size, m_buf_ofs;
1022
1023 public:
1024 memory_stream(void* pBuf, uint buf_size) : m_pBuf(static_cast<uint8*>(pBuf)), m_buf_size(buf_size), m_buf_ofs(0) { }
1025
1026 virtual ~memory_stream() { }
1027
1028 virtual bool put_buf(const void* pBuf, int len)
1029 {
1030 uint buf_remaining = m_buf_size - m_buf_ofs;
1031 if ((uint)len > buf_remaining)
1032 return false;
1033 memcpy(m_pBuf + m_buf_ofs, pBuf, len);
1034 m_buf_ofs += len;
1035 return true;
1036 }
1037
1038 uint get_size() const
1039 {
1040 return m_buf_ofs;
1041 }
1042 };
1043
1044 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)
1045 {
1046 if ((!pDstBuf) || (!buf_size))
1047 return false;
1048
1049 memory_stream dst_stream(pDstBuf, buf_size);
1050
1051 buf_size = 0;
1052
1053 jpge::jpeg_encoder dst_image;
1054 if (!dst_image.init(&dst_stream, width, height, num_channels, comp_params))
1055 return false;
1056
1057 for (uint pass_index = 0; pass_index < dst_image.get_total_passes(); pass_index++)
1058 {
1059 for (int i = 0; i < height; i++)
1060 {
1061 const uint8* pScanline = pImage_data + i * width * num_channels;
1062 if (!dst_image.process_scanline(pScanline))
1063 return false;
1064 }
1065 if (!dst_image.process_scanline(NULL))
1066 return false;
1067 }
1068
1069 dst_image.deinit();
1070
1071 buf_size = dst_stream.get_size();
1072 return true;
1073 }
1074
1075} // namespace jpge
1076
1077