| 0,0 → 1,190 |
|---|
| #include "fitz.h" |
| |
| fz_halftone * |
| fz_new_halftone(int comps) |
| { |
| fz_halftone *ht; |
| int i; |
| |
| ht = fz_malloc(sizeof(fz_halftone) + (comps-1)*sizeof(fz_pixmap *)); |
| ht->refs = 1; |
| ht->n = comps; |
| for (i = 0; i < comps; i++) |
| ht->comp[i] = NULL; |
| |
| return ht; |
| } |
| |
| fz_halftone * |
| fz_keep_halftone(fz_halftone *ht) |
| { |
| ht->refs++; |
| return ht; |
| } |
| |
| void |
| fz_drop_halftone(fz_halftone *ht) |
| { |
| int i; |
| |
| if (!ht || --ht->refs != 0) |
| return; |
| for (i = 0; i < ht->n; i++) |
| fz_drop_pixmap(ht->comp[i]); |
| fz_free(ht); |
| } |
| |
| /* Default mono halftone, lifted from Ghostscript. */ |
| static unsigned char mono_ht[] = |
| { |
| 0x0E, 0x8E, 0x2E, 0xAE, 0x06, 0x86, 0x26, 0xA6, 0x0C, 0x8C, 0x2C, 0xAC, 0x04, 0x84, 0x24, 0xA4, |
| 0xCE, 0x4E, 0xEE, 0x6E, 0xC6, 0x46, 0xE6, 0x66, 0xCC, 0x4C, 0xEC, 0x6C, 0xC4, 0x44, 0xE4, 0x64, |
| 0x3E, 0xBE, 0x1E, 0x9E, 0x36, 0xB6, 0x16, 0x96, 0x3C, 0xBC, 0x1C, 0x9C, 0x34, 0xB4, 0x14, 0x94, |
| 0xFE, 0x7E, 0xDE, 0x5E, 0xF6, 0x76, 0xD6, 0x56, 0xFC, 0x7C, 0xDC, 0x5C, 0xF4, 0x74, 0xD4, 0x54, |
| 0x01, 0x81, 0x21, 0xA1, 0x09, 0x89, 0x29, 0xA9, 0x03, 0x83, 0x23, 0xA3, 0x0B, 0x8B, 0x2B, 0xAB, |
| 0xC1, 0x41, 0xE1, 0x61, 0xC9, 0x49, 0xE9, 0x69, 0xC3, 0x43, 0xE3, 0x63, 0xCB, 0x4B, 0xEB, 0x6B, |
| 0x31, 0xB1, 0x11, 0x91, 0x39, 0xB9, 0x19, 0x99, 0x33, 0xB3, 0x13, 0x93, 0x3B, 0xBB, 0x1B, 0x9B, |
| 0xF1, 0x71, 0xD1, 0x51, 0xF9, 0x79, 0xD9, 0x59, 0xF3, 0x73, 0xD3, 0x53, 0xFB, 0x7B, 0xDB, 0x5B, |
| 0x0D, 0x8D, 0x2D, 0xAD, 0x05, 0x85, 0x25, 0xA5, 0x0F, 0x8F, 0x2F, 0xAF, 0x07, 0x87, 0x27, 0xA7, |
| 0xCD, 0x4D, 0xED, 0x6D, 0xC5, 0x45, 0xE5, 0x65, 0xCF, 0x4F, 0xEF, 0x6F, 0xC7, 0x47, 0xE7, 0x67, |
| 0x3D, 0xBD, 0x1D, 0x9D, 0x35, 0xB5, 0x15, 0x95, 0x3F, 0xBF, 0x1F, 0x9F, 0x37, 0xB7, 0x17, 0x97, |
| 0xFD, 0x7D, 0xDD, 0x5D, 0xF5, 0x75, 0xD5, 0x55, 0xFF, 0x7F, 0xDF, 0x5F, 0xF7, 0x77, 0xD7, 0x57, |
| 0x02, 0x82, 0x22, 0xA2, 0x0A, 0x8A, 0x2A, 0xAA, 0x00, 0x80, 0x20, 0xA0, 0x08, 0x88, 0x28, 0xA8, |
| 0xC2, 0x42, 0xE2, 0x62, 0xCA, 0x4A, 0xEA, 0x6A, 0xC0, 0x40, 0xE0, 0x60, 0xC8, 0x48, 0xE8, 0x68, |
| 0x32, 0xB2, 0x12, 0x92, 0x3A, 0xBA, 0x1A, 0x9A, 0x30, 0xB0, 0x10, 0x90, 0x38, 0xB8, 0x18, 0x98, |
| 0xF2, 0x72, 0xD2, 0x52, 0xFA, 0x7A, 0xDA, 0x5A, 0xF0, 0x70, 0xD0, 0x50, 0xF8, 0x78, 0xD8, 0x58 |
| }; |
| |
| fz_halftone *fz_get_default_halftone(int num_comps) |
| { |
| fz_halftone *ht = fz_new_halftone(num_comps); |
| assert(num_comps == 1); /* Only support 1 component for now */ |
| ht->comp[0] = fz_new_pixmap_with_data(NULL, 16, 16, mono_ht); |
| return ht; |
| } |
| |
| /* Finally, code to actually perform halftoning. */ |
| static void make_ht_line(unsigned char *buf, fz_halftone *ht, int x, int y, int w) |
| { |
| /* FIXME: There is a potential optimisation here; in the case where |
| * the LCM of the halftone tile widths is smaller than w, we could |
| * form just one 'LCM' run, then copy it repeatedly. |
| */ |
| int k, n; |
| n = ht->n; |
| for (k = 0; k < n; k++) |
| { |
| fz_pixmap *tile = ht->comp[k]; |
| unsigned char *b = buf++; |
| unsigned char *t; |
| unsigned char *tbase; |
| int px = x + tile->x; |
| int py = y + tile->y; |
| int tw = tile->w; |
| int th = tile->h; |
| int w2 = w; |
| int len; |
| px = px % tw; |
| if (px < 0) |
| px += tw; |
| py = py % th; |
| if (py < 0) |
| py += th; |
| |
| assert(tile->n == 1); |
| |
| /* Left hand section; from x to tile width */ |
| tbase = tile->samples + py * tw; |
| t = tbase + px; |
| len = tw - px; |
| if (len > w2) |
| len = w2; |
| w2 -= len; |
| while (len--) |
| { |
| *b = *t++; |
| b += n; |
| } |
| |
| /* Centre section - complete copies */ |
| w2 -= tw; |
| while (w2 >= 0) |
| { |
| len = tw; |
| t = tbase; |
| while (len--) |
| { |
| *b = *t++; |
| b += n; |
| } |
| w2 -= tw; |
| } |
| w2 += tw; |
| |
| /* Right hand section - stragglers */ |
| t = tbase; |
| while (w2--) |
| { |
| *b = *t++; |
| b += n; |
| } |
| } |
| } |
| |
| /* Inner mono thresholding code */ |
| static void do_threshold_1(unsigned char *ht_line, unsigned char *pixmap, unsigned char *out, int w) |
| { |
| int bit = 0x80; |
| int h = 0; |
| |
| do |
| { |
| if (*pixmap < *ht_line++) |
| h |= bit; |
| pixmap += 2; /* Skip the alpha */ |
| bit >>= 1; |
| if (bit == 0) |
| { |
| *out++ = h; |
| h = 0; |
| bit = 0x80; |
| } |
| |
| } |
| while (--w); |
| if (bit != 0x80) |
| *out++ = h; |
| } |
| |
| fz_bitmap *fz_halftone_pixmap(fz_pixmap *pix, fz_halftone *ht) |
| { |
| fz_bitmap *out; |
| unsigned char *ht_line, *o, *p; |
| int w, h, x, y, n, pstride, ostride; |
| |
| if (pix == NULL || ht == NULL) |
| return NULL; |
| |
| assert(pix->n == 2); /* Mono + Alpha */ |
| |
| n = pix->n-1; /* Remove alpha */ |
| ht_line = fz_malloc(pix->w * n); |
| out = fz_new_bitmap(pix->w, pix->h, n); |
| o = out->samples; |
| p = pix->samples; |
| |
| h = pix->h; |
| x = pix->x; |
| y = pix->y; |
| w = pix->w; |
| ostride = out->stride; |
| pstride = pix->w * pix->n; |
| while (h--) |
| { |
| make_ht_line(ht_line, ht, x, y++, w); |
| do_threshold_1(ht_line, p, o, w); |
| o += ostride; |
| p += pstride; |
| } |
| return out; |
| } |