Go to most recent revision | Details | Last modification | View Log | RSS feed
| Rev | Author | Line No. | Line |
|---|---|---|---|
| 4680 | right-hear | 1 | #include "fitz.h" |
| 2 | |||
| 3 | fz_halftone * |
||
| 4 | fz_new_halftone(int comps) |
||
| 5 | { |
||
| 6 | fz_halftone *ht; |
||
| 7 | int i; |
||
| 8 | |||
| 9 | ht = fz_malloc(sizeof(fz_halftone) + (comps-1)*sizeof(fz_pixmap *)); |
||
| 10 | ht->refs = 1; |
||
| 11 | ht->n = comps; |
||
| 12 | for (i = 0; i < comps; i++) |
||
| 13 | ht->comp[i] = NULL; |
||
| 14 | |||
| 15 | return ht; |
||
| 16 | } |
||
| 17 | |||
| 18 | fz_halftone * |
||
| 19 | fz_keep_halftone(fz_halftone *ht) |
||
| 20 | { |
||
| 21 | ht->refs++; |
||
| 22 | return ht; |
||
| 23 | } |
||
| 24 | |||
| 25 | void |
||
| 26 | fz_drop_halftone(fz_halftone *ht) |
||
| 27 | { |
||
| 28 | int i; |
||
| 29 | |||
| 30 | if (!ht || --ht->refs != 0) |
||
| 31 | return; |
||
| 32 | for (i = 0; i < ht->n; i++) |
||
| 33 | fz_drop_pixmap(ht->comp[i]); |
||
| 34 | fz_free(ht); |
||
| 35 | } |
||
| 36 | |||
| 37 | /* Default mono halftone, lifted from Ghostscript. */ |
||
| 38 | static unsigned char mono_ht[] = |
||
| 39 | { |
||
| 40 | 0x0E, 0x8E, 0x2E, 0xAE, 0x06, 0x86, 0x26, 0xA6, 0x0C, 0x8C, 0x2C, 0xAC, 0x04, 0x84, 0x24, 0xA4, |
||
| 41 | 0xCE, 0x4E, 0xEE, 0x6E, 0xC6, 0x46, 0xE6, 0x66, 0xCC, 0x4C, 0xEC, 0x6C, 0xC4, 0x44, 0xE4, 0x64, |
||
| 42 | 0x3E, 0xBE, 0x1E, 0x9E, 0x36, 0xB6, 0x16, 0x96, 0x3C, 0xBC, 0x1C, 0x9C, 0x34, 0xB4, 0x14, 0x94, |
||
| 43 | 0xFE, 0x7E, 0xDE, 0x5E, 0xF6, 0x76, 0xD6, 0x56, 0xFC, 0x7C, 0xDC, 0x5C, 0xF4, 0x74, 0xD4, 0x54, |
||
| 44 | 0x01, 0x81, 0x21, 0xA1, 0x09, 0x89, 0x29, 0xA9, 0x03, 0x83, 0x23, 0xA3, 0x0B, 0x8B, 0x2B, 0xAB, |
||
| 45 | 0xC1, 0x41, 0xE1, 0x61, 0xC9, 0x49, 0xE9, 0x69, 0xC3, 0x43, 0xE3, 0x63, 0xCB, 0x4B, 0xEB, 0x6B, |
||
| 46 | 0x31, 0xB1, 0x11, 0x91, 0x39, 0xB9, 0x19, 0x99, 0x33, 0xB3, 0x13, 0x93, 0x3B, 0xBB, 0x1B, 0x9B, |
||
| 47 | 0xF1, 0x71, 0xD1, 0x51, 0xF9, 0x79, 0xD9, 0x59, 0xF3, 0x73, 0xD3, 0x53, 0xFB, 0x7B, 0xDB, 0x5B, |
||
| 48 | 0x0D, 0x8D, 0x2D, 0xAD, 0x05, 0x85, 0x25, 0xA5, 0x0F, 0x8F, 0x2F, 0xAF, 0x07, 0x87, 0x27, 0xA7, |
||
| 49 | 0xCD, 0x4D, 0xED, 0x6D, 0xC5, 0x45, 0xE5, 0x65, 0xCF, 0x4F, 0xEF, 0x6F, 0xC7, 0x47, 0xE7, 0x67, |
||
| 50 | 0x3D, 0xBD, 0x1D, 0x9D, 0x35, 0xB5, 0x15, 0x95, 0x3F, 0xBF, 0x1F, 0x9F, 0x37, 0xB7, 0x17, 0x97, |
||
| 51 | 0xFD, 0x7D, 0xDD, 0x5D, 0xF5, 0x75, 0xD5, 0x55, 0xFF, 0x7F, 0xDF, 0x5F, 0xF7, 0x77, 0xD7, 0x57, |
||
| 52 | 0x02, 0x82, 0x22, 0xA2, 0x0A, 0x8A, 0x2A, 0xAA, 0x00, 0x80, 0x20, 0xA0, 0x08, 0x88, 0x28, 0xA8, |
||
| 53 | 0xC2, 0x42, 0xE2, 0x62, 0xCA, 0x4A, 0xEA, 0x6A, 0xC0, 0x40, 0xE0, 0x60, 0xC8, 0x48, 0xE8, 0x68, |
||
| 54 | 0x32, 0xB2, 0x12, 0x92, 0x3A, 0xBA, 0x1A, 0x9A, 0x30, 0xB0, 0x10, 0x90, 0x38, 0xB8, 0x18, 0x98, |
||
| 55 | 0xF2, 0x72, 0xD2, 0x52, 0xFA, 0x7A, 0xDA, 0x5A, 0xF0, 0x70, 0xD0, 0x50, 0xF8, 0x78, 0xD8, 0x58 |
||
| 56 | }; |
||
| 57 | |||
| 58 | fz_halftone *fz_get_default_halftone(int num_comps) |
||
| 59 | { |
||
| 60 | fz_halftone *ht = fz_new_halftone(num_comps); |
||
| 61 | assert(num_comps == 1); /* Only support 1 component for now */ |
||
| 62 | ht->comp[0] = fz_new_pixmap_with_data(NULL, 16, 16, mono_ht); |
||
| 63 | return ht; |
||
| 64 | } |
||
| 65 | |||
| 66 | /* Finally, code to actually perform halftoning. */ |
||
| 67 | static void make_ht_line(unsigned char *buf, fz_halftone *ht, int x, int y, int w) |
||
| 68 | { |
||
| 69 | /* FIXME: There is a potential optimisation here; in the case where |
||
| 70 | * the LCM of the halftone tile widths is smaller than w, we could |
||
| 71 | * form just one 'LCM' run, then copy it repeatedly. |
||
| 72 | */ |
||
| 73 | int k, n; |
||
| 74 | n = ht->n; |
||
| 75 | for (k = 0; k < n; k++) |
||
| 76 | { |
||
| 77 | fz_pixmap *tile = ht->comp[k]; |
||
| 78 | unsigned char *b = buf++; |
||
| 79 | unsigned char *t; |
||
| 80 | unsigned char *tbase; |
||
| 81 | int px = x + tile->x; |
||
| 82 | int py = y + tile->y; |
||
| 83 | int tw = tile->w; |
||
| 84 | int th = tile->h; |
||
| 85 | int w2 = w; |
||
| 86 | int len; |
||
| 87 | px = px % tw; |
||
| 88 | if (px < 0) |
||
| 89 | px += tw; |
||
| 90 | py = py % th; |
||
| 91 | if (py < 0) |
||
| 92 | py += th; |
||
| 93 | |||
| 94 | assert(tile->n == 1); |
||
| 95 | |||
| 96 | /* Left hand section; from x to tile width */ |
||
| 97 | tbase = tile->samples + py * tw; |
||
| 98 | t = tbase + px; |
||
| 99 | len = tw - px; |
||
| 100 | if (len > w2) |
||
| 101 | len = w2; |
||
| 102 | w2 -= len; |
||
| 103 | while (len--) |
||
| 104 | { |
||
| 105 | *b = *t++; |
||
| 106 | b += n; |
||
| 107 | } |
||
| 108 | |||
| 109 | /* Centre section - complete copies */ |
||
| 110 | w2 -= tw; |
||
| 111 | while (w2 >= 0) |
||
| 112 | { |
||
| 113 | len = tw; |
||
| 114 | t = tbase; |
||
| 115 | while (len--) |
||
| 116 | { |
||
| 117 | *b = *t++; |
||
| 118 | b += n; |
||
| 119 | } |
||
| 120 | w2 -= tw; |
||
| 121 | } |
||
| 122 | w2 += tw; |
||
| 123 | |||
| 124 | /* Right hand section - stragglers */ |
||
| 125 | t = tbase; |
||
| 126 | while (w2--) |
||
| 127 | { |
||
| 128 | *b = *t++; |
||
| 129 | b += n; |
||
| 130 | } |
||
| 131 | } |
||
| 132 | } |
||
| 133 | |||
| 134 | /* Inner mono thresholding code */ |
||
| 135 | static void do_threshold_1(unsigned char *ht_line, unsigned char *pixmap, unsigned char *out, int w) |
||
| 136 | { |
||
| 137 | int bit = 0x80; |
||
| 138 | int h = 0; |
||
| 139 | |||
| 140 | do |
||
| 141 | { |
||
| 142 | if (*pixmap < *ht_line++) |
||
| 143 | h |= bit; |
||
| 144 | pixmap += 2; /* Skip the alpha */ |
||
| 145 | bit >>= 1; |
||
| 146 | if (bit == 0) |
||
| 147 | { |
||
| 148 | *out++ = h; |
||
| 149 | h = 0; |
||
| 150 | bit = 0x80; |
||
| 151 | } |
||
| 152 | |||
| 153 | } |
||
| 154 | while (--w); |
||
| 155 | if (bit != 0x80) |
||
| 156 | *out++ = h; |
||
| 157 | } |
||
| 158 | |||
| 159 | fz_bitmap *fz_halftone_pixmap(fz_pixmap *pix, fz_halftone *ht) |
||
| 160 | { |
||
| 161 | fz_bitmap *out; |
||
| 162 | unsigned char *ht_line, *o, *p; |
||
| 163 | int w, h, x, y, n, pstride, ostride; |
||
| 164 | |||
| 165 | if (pix == NULL || ht == NULL) |
||
| 166 | return NULL; |
||
| 167 | |||
| 168 | assert(pix->n == 2); /* Mono + Alpha */ |
||
| 169 | |||
| 170 | n = pix->n-1; /* Remove alpha */ |
||
| 171 | ht_line = fz_malloc(pix->w * n); |
||
| 172 | out = fz_new_bitmap(pix->w, pix->h, n); |
||
| 173 | o = out->samples; |
||
| 174 | p = pix->samples; |
||
| 175 | |||
| 176 | h = pix->h; |
||
| 177 | x = pix->x; |
||
| 178 | y = pix->y; |
||
| 179 | w = pix->w; |
||
| 180 | ostride = out->stride; |
||
| 181 | pstride = pix->w * pix->n; |
||
| 182 | while (h--) |
||
| 183 | { |
||
| 184 | make_ht_line(ht_line, ht, x, y++, w); |
||
| 185 | do_threshold_1(ht_line, p, o, w); |
||
| 186 | o += ostride; |
||
| 187 | p += pstride; |
||
| 188 | } |
||
| 189 | return out; |
||
| 190 | } |