📄 jfif.cpp
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//
// Title: JFIF Implementation
//
// Author: John M. Miano miano@colosseumbuilders.com
//
// Description:
//
// This module contains the RGB/YcbCr conversion functions specified
// by the JFIF standard. This functions are implemented using scaled
// integers.
//
// If you are using MS C++ you may wish to re-write this since that compile
// generates terrible code for these function. Borland C++ is great here,
// and G++ works well if you turn on optimizations.
//
#include "jfif.h"
#if ! defined (INLINECOLORCONVERSION)
const int ScaleFactor = 12 ;
const int ScaleValue = (1<<ScaleFactor) ;
const int Rounding = (1<<(ScaleFactor-1)) ;
namespace
{
inline int Scaled (double value)
{
return (int) (ScaleValue * value) ;
}
}
namespace ColosseumPrivate
{
JPEGSAMPLE YCbCrToR (int yy, int /*cb*/, int cr)
{
int result = yy + ((Scaled (1.402) * (cr - JPEGMIDPOINTSAMPLEVALUE) + Rounding) >> ScaleFactor) ;
if (result < 0)
result = 0 ;
else if (result > JPEGMAXSAMPLEVALUE)
result = JPEGMAXSAMPLEVALUE ;
return static_cast<JPEGSAMPLE>(result) ;
}
JPEGSAMPLE YCbCrToG (int yy, int cb, int cr)
{
int result = yy - ((Scaled (0.34414) * (cb - JPEGMIDPOINTSAMPLEVALUE)
+ Scaled (0.71414) * (cr - JPEGMIDPOINTSAMPLEVALUE)
+ Rounding) >> ScaleFactor) ;
if (result < 0)
result = 0 ;
else if (result > JPEGMAXSAMPLEVALUE)
result = JPEGMAXSAMPLEVALUE ;
return static_cast<JPEGSAMPLE>(result) ;
}
JPEGSAMPLE YCbCrToB (int yy, int cb, int /*cr*/)
{
int result = yy + ((Scaled (1.772) * (cb - JPEGMIDPOINTSAMPLEVALUE)
+ Rounding) >> ScaleFactor) ;
if (result < 0)
result = 0 ;
else if (result > JPEGMAXSAMPLEVALUE)
result = JPEGMAXSAMPLEVALUE ;
return static_cast<JPEGSAMPLE>(result) ;
}
JPEGSAMPLE RgbToY (JPEGSAMPLE red, JPEGSAMPLE green, JPEGSAMPLE blue)
{
int result = (Scaled (0.299) * red
+ Scaled (0.587) * green + Scaled (0.114) * blue
+ Rounding) >> ScaleFactor ;
if (result > JPEGMAXSAMPLEVALUE)
result = JPEGMAXSAMPLEVALUE ;
else if (result < JPEGMINSAMPLEVALUE)
result = JPEGMINSAMPLEVALUE ;
return static_cast<JPEGSAMPLE>(result) ;
}
JPEGSAMPLE RgbToCb (JPEGSAMPLE red, JPEGSAMPLE green, JPEGSAMPLE blue)
{
int result = ((JPEGMIDPOINTSAMPLEVALUE<<ScaleFactor)
+ Rounding - Scaled (0.1687) * red
- Scaled (0.3313) * green + Scaled (0.5) * blue) >> ScaleFactor ;
if (result > JPEGMAXSAMPLEVALUE)
result = JPEGMAXSAMPLEVALUE ;
else if (result < JPEGMINSAMPLEVALUE)
result = JPEGMINSAMPLEVALUE ;
return static_cast<JPEGSAMPLE>(result) ;
}
JPEGSAMPLE RgbToCr (JPEGSAMPLE red, JPEGSAMPLE green, JPEGSAMPLE blue)
{
int result = ((JPEGMIDPOINTSAMPLEVALUE<<ScaleFactor)
+ Rounding + Scaled (0.5) * red
- Scaled (0.4187) * green - Scaled (0.0813) * blue) >> ScaleFactor ;
if (result > JPEGMAXSAMPLEVALUE)
result = JPEGMAXSAMPLEVALUE ;
else if (result < JPEGMINSAMPLEVALUE)
result = JPEGMINSAMPLEVALUE ;
return static_cast<JPEGSAMPLE>(result) ;
}
}
#else
namespace ColosseumPrivate
{
// CrRTable [x] = ROUND (x * 1.402)
extern const long CrRTable [256] =
{
-179, -178, -177, -175, -174, -172, -171, -170,
-168, -167, -165, -164, -163, -161, -160, -158,
-157, -156, -154, -153, -151, -150, -149, -147,
-146, -144, -143, -142, -140, -139, -137, -136,
-135, -133, -132, -130, -129, -128, -126, -125,
-123, -122, -121, -119, -118, -116, -115, -114,
-112, -111, -109, -108, -107, -105, -104, -102,
-101, -100, -98, -97, -95, -94, -93, -91,
-90, -88, -87, -86, -84, -83, -81, -80,
-79, -77, -76, -74, -73, -72, -70, -69,
-67, -66, -64, -63, -62, -60, -59, -57,
-56, -55, -53, -52, -50, -49, -48, -46,
-45, -43, -42, -41, -39, -38, -36, -35,
-34, -32, -31, -29, -28, -27, -25, -24,
-22, -21, -20, -18, -17, -15, -14, -13,
-11, -10, -8, -7, -6, -4, -3, -1,
0, 1, 3, 4, 6, 7, 8, 10,
11, 13, 14, 15, 17, 18, 20, 21,
22, 24, 25, 27, 28, 29, 31, 32,
34, 35, 36, 38, 39, 41, 42, 43,
45, 46, 48, 49, 50, 52, 53, 55,
56, 57, 59, 60, 62, 63, 64, 66,
67, 69, 70, 72, 73, 74, 76, 77,
79, 80, 81, 83, 84, 86, 87, 88,
90, 91, 93, 94, 95, 97, 98, 100,
101, 102, 104, 105, 107, 108, 109, 111,
112, 114, 115, 116, 118, 119, 121, 122,
123, 125, 126, 128, 129, 130, 132, 133,
135, 136, 137, 139, 140, 142, 143, 144,
146, 147, 149, 150, 151, 153, 154, 156,
157, 158, 160, 161, 163, 164, 165, 167,
168, 170, 171, 172, 174, 175, 177, 178,
} ;
// CbGTable [x] = ROUND ((ii-128) << 16) * 0.33414)
extern const long CbGTable [256] =
{
-2802969, -2781071, -2759173, -2737275, -2715377, -2693478, -2671580, -2649682,
-2627784, -2605886, -2583987, -2562089, -2540191, -2518293, -2496395, -2474496,
-2452598, -2430700, -2408802, -2386904, -2365005, -2343107, -2321209, -2299311,
-2277413, -2255515, -2233616, -2211718, -2189820, -2167922, -2146024, -2124125,
-2102227, -2080329, -2058431, -2036533, -2014634, -1992736, -1970838, -1948940,
-1927042, -1905143, -1883245, -1861347, -1839449, -1817551, -1795652, -1773754,
-1751856, -1729958, -1708060, -1686161, -1664263, -1642365, -1620467, -1598569,
-1576670, -1554772, -1532874, -1510976, -1489078, -1467179, -1445281, -1423383,
-1401485, -1379587, -1357688, -1335790, -1313892, -1291994, -1270096, -1248197,
-1226299, -1204401, -1182503, -1160605, -1138706, -1116808, -1094910, -1073012,
-1051114, -1029215, -1007317, -985419, -963521, -941623, -919724, -897826,
-875928, -854030, -832132, -810233, -788335, -766437, -744539, -722641,
-700742, -678844, -656946, -635048, -613150, -591251, -569353, -547455,
-525557, -503659, -481760, -459862, -437964, -416066, -394168, -372269,
-350371, -328473, -306575, -284677, -262778, -240880, -218982, -197084,
-175186, -153287, -131389, -109491, -87593, -65695, -43796, -21898,
0, 21898, 43796, 65695, 87593, 109491, 131389, 153287,
175186, 197084, 218982, 240880, 262778, 284677, 306575, 328473,
350371, 372269, 394168, 416066, 437964, 459862, 481760, 503659,
525557, 547455, 569353, 591251, 613150, 635048, 656946, 678844,
700742, 722641, 744539, 766437, 788335, 810233, 832132, 854030,
875928, 897826, 919724, 941623, 963521, 985419, 1007317, 1029215,
1051114, 1073012, 1094910, 1116808, 1138706, 1160605, 1182503, 1204401,
1226299, 1248197, 1270096, 1291994, 1313892, 1335790, 1357688, 1379587,
1401485, 1423383, 1445281, 1467179, 1489078, 1510976, 1532874, 1554772,
1576670, 1598569, 1620467, 1642365, 1664263, 1686161, 1708060, 1729958,
1751856, 1773754, 1795652, 1817551, 1839449, 1861347, 1883245, 1905143,
1927042, 1948940, 1970838, 1992736, 2014634, 2036533, 2058431, 2080329,
2102227, 2124125, 2146024, 2167922, 2189820, 2211718, 2233616, 2255515,
2277413, 2299311, 2321209, 2343107, 2365005, 2386904, 2408802, 2430700,
2452598, 2474496, 2496395, 2518293, 2540191, 2562089, 2583987, 2605886,
2627784, 2649682, 2671580, 2693478, 2715377, 2737275, 2759173, 2781071,
} ;
// CrGTable [x] = ROUND ((ii-128) << 16) * 0.71414)
extern const long CrGTable [256] =
{
-5990641, -5943839, -5897037, -5850235, -5803433, -5756631, -5709829, -5663027,
-5616225, -5569424, -5522622, -5475820, -5429018, -5382216, -5335414, -5288612,
-5241810, -5195009, -5148207, -5101405, -5054603, -5007801, -4960999, -4914197,
-4867395, -4820594, -4773792, -4726990, -4680188, -4633386, -4586584, -4539782,
-4492980, -4446179, -4399377, -4352575, -4305773, -4258971, -4212169, -4165367,
-4118565, -4071763, -4024962, -3978160, -3931358, -3884556, -3837754, -3790952,
-3744150, -3697348, -3650547, -3603745, -3556943, -3510141, -3463339, -3416537,
-3369735, -3322933, -3276132, -3229330, -3182528, -3135726, -3088924, -3042122,
-2995320, -2948518, -2901717, -2854915, -2808113, -2761311, -2714509, -2667707,
-2620905, -2574103, -2527301, -2480500, -2433698, -2386896, -2340094, -2293292,
-2246490, -2199688, -2152886, -2106085, -2059283, -2012481, -1965679, -1918877,
-1872075, -1825273, -1778471, -1731670, -1684868, -1638066, -1591264, -1544462,
-1497660, -1450858, -1404056, -1357254, -1310453, -1263651, -1216849, -1170047,
-1123245, -1076443, -1029641, -982839, -936038, -889236, -842434, -795632,
-748830, -702028, -655226, -608424, -561623, -514821, -468019, -421217,
-374415, -327613, -280811, -234009, -187208, -140406, -93604, -46802,
0, 46802, 93604, 140406, 187208, 234009, 280811, 327613,
374415, 421217, 468019, 514821, 561623, 608424, 655226, 702028,
748830, 795632, 842434, 889236, 936038, 982839, 1029641, 1076443,
1123245, 1170047, 1216849, 1263651, 1310453, 1357254, 1404056, 1450858,
1497660, 1544462, 1591264, 1638066, 1684868, 1731670, 1778471, 1825273,
1872075, 1918877, 1965679, 2012481, 2059283, 2106085, 2152886, 2199688,
2246490, 2293292, 2340094, 2386896, 2433698, 2480500, 2527301, 2574103,
2620905, 2667707, 2714509, 2761311, 2808113, 2854915, 2901717, 2948518,
2995320, 3042122, 3088924, 3135726, 3182528, 3229330, 3276132, 3322933,
3369735, 3416537, 3463339, 3510141, 3556943, 3603745, 3650547, 3697348,
3744150, 3790952, 3837754, 3884556, 3931358, 3978160, 4024962, 4071763,
4118565, 4165367, 4212169, 4258971, 4305773, 4352575, 4399377, 4446179,
4492980, 4539782, 4586584, 4633386, 4680188, 4726990, 4773792, 4820594,
4867395, 4914197, 4960999, 5007801, 5054603, 5101405, 5148207, 5195009,
5241810, 5288612, 5335414, 5382216, 5429018, 5475820, 5522622, 5569424,
5616225, 5663027, 5709829, 5756631, 5803433, 5850235, 5897037, 5943839,
} ;
// CbBTable [X] = ROUND ((x-128) * 1.772)
extern const long CbBTable [256] =
{
-227, -225, -223, -222, -220, -218, -216, -214,
-213, -211, -209, -207, -206, -204, -202, -200,
-198, -197, -195, -193, -191, -190, -188, -186,
-184, -183, -181, -179, -177, -175, -174, -172,
-170, -168, -167, -165, -163, -161, -159, -158,
-156, -154, -152, -151, -149, -147, -145, -144,
-142, -140, -138, -136, -135, -133, -131, -129,
-128, -126, -124, -122, -120, -119, -117, -115,
-113, -112, -110, -108, -106, -105, -103, -101,
-99, -97, -96, -94, -92, -90, -89, -87,
-85, -83, -82, -80, -78, -76, -74, -73,
-71, -69, -67, -66, -64, -62, -60, -58,
-57, -55, -53, -51, -50, -48, -46, -44,
-43, -41, -39, -37, -35, -34, -32, -30,
-28, -27, -25, -23, -21, -19, -18, -16,
-14, -12, -11, -9, -7, -5, -4, -2,
0, 2, 4, 5, 7, 9, 11, 12,
14, 16, 18, 19, 21, 23, 25, 27,
28, 30, 32, 34, 35, 37, 39, 41,
43, 44, 46, 48, 50, 51, 53, 55,
57, 58, 60, 62, 64, 66, 67, 69,
71, 73, 74, 76, 78, 80, 82, 83,
85, 87, 89, 90, 92, 94, 96, 97,
99, 101, 103, 105, 106, 108, 110, 112,
113, 115, 117, 119, 120, 122, 124, 126,
128, 129, 131, 133, 135, 136, 138, 140,
142, 144, 145, 147, 149, 151, 152, 154,
156, 158, 159, 161, 163, 165, 167, 168,
170, 172, 174, 175, 177, 179, 181, 183,
184, 186, 188, 190, 191, 193, 195, 197,
198, 200, 202, 204, 206, 207, 209, 211,
213, 214, 216, 218, 220, 222, 223, 225,
} ;
} // End Namespace ColosseumPrivate
#endif
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