Pillow/src/libImaging/UnpackYCC.c

/*
 * The Python Imaging Library.
 * $Id$
 *
 * code to convert and unpack PhotoYCC data
 *
 * history:
 * 97-01-25 fl Moved from PcdDecode.c
 *
 * Copyright (c) Fredrik Lundh 1996-97.
 * Copyright (c) Secret Labs AB 1997.
 *
 * See the README file for information on usage and redistribution.
 */

#include "Imaging.h"

/* Tables generated by pcdtables.py, based on transforms taken from
   the "Colour Space Conversions FAQ" by Roberts/Ford. */

static INT16 L[] = {
    0,   1,   3,   4,   5,   7,   8,   10,  11,  12,  14,  15,  16,  18,  19,  20,
    22,  23,  24,  26,  27,  29,  30,  31,  33,  34,  35,  37,  38,  39,  41,  42,
    43,  45,  46,  48,  49,  50,  52,  53,  54,  56,  57,  58,  60,  61,  62,  64,
    65,  67,  68,  69,  71,  72,  73,  75,  76,  77,  79,  80,  82,  83,  84,  86,
    87,  88,  90,  91,  92,  94,  95,  96,  98,  99,  101, 102, 103, 105, 106, 107,
    109, 110, 111, 113, 114, 115, 117, 118, 120, 121, 122, 124, 125, 126, 128, 129,
    130, 132, 133, 134, 136, 137, 139, 140, 141, 143, 144, 145, 147, 148, 149, 151,
    152, 153, 155, 156, 158, 159, 160, 162, 163, 164, 166, 167, 168, 170, 171, 173,
    174, 175, 177, 178, 179, 181, 182, 183, 185, 186, 187, 189, 190, 192, 193, 194,
    196, 197, 198, 200, 201, 202, 204, 205, 206, 208, 209, 211, 212, 213, 215, 216,
    217, 219, 220, 221, 223, 224, 225, 227, 228, 230, 231, 232, 234, 235, 236, 238,
    239, 240, 242, 243, 245, 246, 247, 249, 250, 251, 253, 254, 255, 257, 258, 259,
    261, 262, 264, 265, 266, 268, 269, 270, 272, 273, 274, 276, 277, 278, 280, 281,
    283, 284, 285, 287, 288, 289, 291, 292, 293, 295, 296, 297, 299, 300, 302, 303,
    304, 306, 307, 308, 310, 311, 312, 314, 315, 317, 318, 319, 321, 322, 323, 325,
    326, 327, 329, 330, 331, 333, 334, 336, 337, 338, 340, 341, 342, 344, 345, 346};

static INT16 CB[] = {
    -345, -343, -341, -338, -336, -334, -332, -329, -327, -325, -323, -321, -318, -316,
    -314, -312, -310, -307, -305, -303, -301, -298, -296, -294, -292, -290, -287, -285,
    -283, -281, -278, -276, -274, -272, -270, -267, -265, -263, -261, -258, -256, -254,
    -252, -250, -247, -245, -243, -241, -239, -236, -234, -232, -230, -227, -225, -223,
    -221, -219, -216, -214, -212, -210, -207, -205, -203, -201, -199, -196, -194, -192,
    -190, -188, -185, -183, -181, -179, -176, -174, -172, -170, -168, -165, -163, -161,
    -159, -156, -154, -152, -150, -148, -145, -143, -141, -139, -137, -134, -132, -130,
    -128, -125, -123, -121, -119, -117, -114, -112, -110, -108, -105, -103, -101, -99,
    -97,  -94,  -92,  -90,  -88,  -85,  -83,  -81,  -79,  -77,  -74,  -72,  -70,  -68,
    -66,  -63,  -61,  -59,  -57,  -54,  -52,  -50,  -48,  -46,  -43,  -41,  -39,  -37,
    -34,  -32,  -30,  -28,  -26,  -23,  -21,  -19,  -17,  -15,  -12,  -10,  -8,   -6,
    -3,   -1,   0,    2,    4,    7,    9,    11,   13,   16,   18,   20,   22,   24,
    27,   29,   31,   33,   35,   38,   40,   42,   44,   47,   49,   51,   53,   55,
    58,   60,   62,   64,   67,   69,   71,   73,   75,   78,   80,   82,   84,   86,
    89,   91,   93,   95,   98,   100,  102,  104,  106,  109,  111,  113,  115,  118,
    120,  122,  124,  126,  129,  131,  133,  135,  138,  140,  142,  144,  146,  149,
    151,  153,  155,  157,  160,  162,  164,  166,  169,  171,  173,  175,  177,  180,
    182,  184,  186,  189,  191,  193,  195,  197,  200,  202,  204,  206,  208,  211,
    213,  215,  217,  220};

static INT16 GB[] = {
    67,  67,  66,  66,  65,  65,  65,  64,  64,  63,  63,  62,  62,  62,  61,  61,
    60,  60,  59,  59,  59,  58,  58,  57,  57,  56,  56,  56,  55,  55,  54,  54,
    53,  53,  52,  52,  52,  51,  51,  50,  50,  49,  49,  49,  48,  48,  47,  47,
    46,  46,  46,  45,  45,  44,  44,  43,  43,  43,  42,  42,  41,  41,  40,  40,
    40,  39,  39,  38,  38,  37,  37,  37,  36,  36,  35,  35,  34,  34,  34,  33,
    33,  32,  32,  31,  31,  31,  30,  30,  29,  29,  28,  28,  28,  27,  27,  26,
    26,  25,  25,  25,  24,  24,  23,  23,  22,  22,  22,  21,  21,  20,  20,  19,
    19,  19,  18,  18,  17,  17,  16,  16,  15,  15,  15,  14,  14,  13,  13,  12,
    12,  12,  11,  11,  10,  10,  9,   9,   9,   8,   8,   7,   7,   6,   6,   6,
    5,   5,   4,   4,   3,   3,   3,   2,   2,   1,   1,   0,   0,   0,   0,   0,
    -1,  -1,  -2,  -2,  -2,  -3,  -3,  -4,  -4,  -5,  -5,  -5,  -6,  -6,  -7,  -7,
    -8,  -8,  -8,  -9,  -9,  -10, -10, -11, -11, -11, -12, -12, -13, -13, -14, -14,
    -14, -15, -15, -16, -16, -17, -17, -18, -18, -18, -19, -19, -20, -20, -21, -21,
    -21, -22, -22, -23, -23, -24, -24, -24, -25, -25, -26, -26, -27, -27, -27, -28,
    -28, -29, -29, -30, -30, -30, -31, -31, -32, -32, -33, -33, -33, -34, -34, -35,
    -35, -36, -36, -36, -37, -37, -38, -38, -39, -39, -39, -40, -40, -41, -41, -42};

static INT16 CR[] = {
    -249, -247, -245, -243, -241, -239, -238, -236, -234, -232, -230, -229, -227, -225,
    -223, -221, -219, -218, -216, -214, -212, -210, -208, -207, -205, -203, -201, -199,
    -198, -196, -194, -192, -190, -188, -187, -185, -183, -181, -179, -178, -176, -174,
    -172, -170, -168, -167, -165, -163, -161, -159, -157, -156, -154, -152, -150, -148,
    -147, -145, -143, -141, -139, -137, -136, -134, -132, -130, -128, -127, -125, -123,
    -121, -119, -117, -116, -114, -112, -110, -108, -106, -105, -103, -101, -99,  -97,
    -96,  -94,  -92,  -90,  -88,  -86,  -85,  -83,  -81,  -79,  -77,  -76,  -74,  -72,
    -70,  -68,  -66,  -65,  -63,  -61,  -59,  -57,  -55,  -54,  -52,  -50,  -48,  -46,
    -45,  -43,  -41,  -39,  -37,  -35,  -34,  -32,  -30,  -28,  -26,  -25,  -23,  -21,
    -19,  -17,  -15,  -14,  -12,  -10,  -8,   -6,   -4,   -3,   -1,   0,    2,    4,
    5,    7,    9,    11,   13,   15,   16,   18,   20,   22,   24,   26,   27,   29,
    31,   33,   35,   36,   38,   40,   42,   44,   46,   47,   49,   51,   53,   55,
    56,   58,   60,   62,   64,   66,   67,   69,   71,   73,   75,   77,   78,   80,
    82,   84,   86,   87,   89,   91,   93,   95,   97,   98,   100,  102,  104,  106,
    107,  109,  111,  113,  115,  117,  118,  120,  122,  124,  126,  128,  129,  131,
    133,  135,  137,  138,  140,  142,  144,  146,  148,  149,  151,  153,  155,  157,
    158,  160,  162,  164,  166,  168,  169,  171,  173,  175,  177,  179,  180,  182,
    184,  186,  188,  189,  191,  193,  195,  197,  199,  200,  202,  204,  206,  208,
    209,  211,  213,  215};

static INT16 GR[] = {
    127, 126, 125, 124, 123, 122, 121,  121,  120,  119,  118,  117,  116,  115,  114,
    113, 112, 111, 110, 109, 108, 108,  107,  106,  105,  104,  103,  102,  101,  100,
    99,  98,  97,  96,  95,  95,  94,   93,   92,   91,   90,   89,   88,   87,   86,
    85,  84,  83,  83,  82,  81,  80,   79,   78,   77,   76,   75,   74,   73,   72,
    71,  70,  70,  69,  68,  67,  66,   65,   64,   63,   62,   61,   60,   59,   58,
    57,  57,  56,  55,  54,  53,  52,   51,   50,   49,   48,   47,   46,   45,   45,
    44,  43,  42,  41,  40,  39,  38,   37,   36,   35,   34,   33,   32,   32,   31,
    30,  29,  28,  27,  26,  25,  24,   23,   22,   21,   20,   19,   19,   18,   17,
    16,  15,  14,  13,  12,  11,  10,   9,    8,    7,    6,    6,    5,    4,    3,
    2,   1,   0,   0,   -1,  -2,  -3,   -4,   -5,   -5,   -6,   -7,   -8,   -9,   -10,
    -11, -12, -13, -14, -15, -16, -17,  -18,  -18,  -19,  -20,  -21,  -22,  -23,  -24,
    -25, -26, -27, -28, -29, -30, -31,  -31,  -32,  -33,  -34,  -35,  -36,  -37,  -38,
    -39, -40, -41, -42, -43, -44, -44,  -45,  -46,  -47,  -48,  -49,  -50,  -51,  -52,
    -53, -54, -55, -56, -56, -57, -58,  -59,  -60,  -61,  -62,  -63,  -64,  -65,  -66,
    -67, -68, -69, -69, -70, -71, -72,  -73,  -74,  -75,  -76,  -77,  -78,  -79,  -80,
    -81, -82, -82, -83, -84, -85, -86,  -87,  -88,  -89,  -90,  -91,  -92,  -93,  -94,
    -94, -95, -96, -97, -98, -99, -100, -101, -102, -103, -104, -105, -106, -107, -107,
    -108};

#define R 0
#define G 1
#define B 2
#define A 3

#define YCC2RGB(rgb, y, cb, cr)                       \
    {                                                 \
        int l = L[y];                                 \
        int r = l + CR[cr];                           \
        int g = l + GR[cr] + GB[cb];                  \
        int b = l + CB[cb];                           \
        rgb[0] = (r <= 0) ? 0 : (r >= 255) ? 255 : r; \
        rgb[1] = (g <= 0) ? 0 : (g >= 255) ? 255 : g; \
        rgb[2] = (b <= 0) ? 0 : (b >= 255) ? 255 : b; \
    }

void
ImagingUnpackYCC(UINT8 *out, const UINT8 *in, int pixels) {
    int i;
    /* PhotoYCC triplets */
    for (i = 0; i < pixels; i++) {
        YCC2RGB(out, in[0], in[1], in[2]);
        out[A] = 255;
        out += 4;
        in += 3;
    }
}

void
ImagingUnpackYCCA(UINT8 *out, const UINT8 *in, int pixels) {
    int i;
    /* PhotoYCC triplets plus premultiplied alpha */
    for (i = 0; i < pixels; i++) {
        /* Divide by alpha */
        UINT8 rgb[3];
        rgb[0] = (in[3] == 0) ? 0 : (((int)in[0] * 255) / in[3]);
        rgb[1] = (in[3] == 0) ? 0 : (((int)in[1] * 255) / in[3]);
        rgb[2] = (in[3] == 0) ? 0 : (((int)in[2] * 255) / in[3]);
        /* Convert non-multiplied data to RGB */
        YCC2RGB(out, rgb[0], rgb[1], rgb[2]);
        out[A] = in[3];
        out += 4;
        in += 4;
    }
}