diff options
Diffstat (limited to 'src/main/dither-predithered.c')
| -rw-r--r-- | src/main/dither-predithered.c | 44 |
1 files changed, 19 insertions, 25 deletions
diff --git a/src/main/dither-predithered.c b/src/main/dither-predithered.c index df5b71a..d58e6bf 100644 --- a/src/main/dither-predithered.c +++ b/src/main/dither-predithered.c @@ -1,5 +1,5 @@ /* - * "$Id: dither-predithered.c,v 1.2 2004/09/17 18:38:20 rleigh Exp $" + * "$Id: dither-predithered.c,v 1.3 2005/07/28 01:00:51 rlk Exp $" * * Very fast dither algorithm * @@ -36,23 +36,19 @@ static inline void print_color_very_fast(const stpi_dither_t *d, stpi_dither_channel_t *dc, - int val, int x, int y, unsigned char bit, - unsigned bits, int length) + int val, int x, int y, unsigned bit, int length) { - int j; - if (bits && val) - { - unsigned char *tptr = dc->ptr + d->ptr_offset; + int i, j; + unsigned char *tptr = dc->ptr + d->ptr_offset; - /* - * Lay down all of the bits in the pixel. - */ - set_row_ends(dc, x); - for (j = 1; j <= bits; j += j, tptr += length) - { - if (j & bits) - tptr[0] |= bit; - } + /* + * Lay down all of the bits in the pixel. + */ + set_row_ends(dc, x); + for (i = 0, j = 1; i < dc->signif_bits; i++, j += j, tptr += length) + { + if (j & val) + tptr[0] |= bit; } } @@ -67,7 +63,6 @@ stpi_dither_predithered(stp_vars_t *v, stpi_dither_t *d = (stpi_dither_t *) stp_get_component_data(v, "Dither"); int x, length; - unsigned char *bit_patterns; unsigned char bit; int i; int one_bit_only = 1; @@ -85,14 +80,14 @@ stpi_dither_predithered(stp_vars_t *v, xmod = d->src_width % d->dst_width; xerror = 0; - bit_patterns = stp_zalloc(sizeof(unsigned char) * CHANNEL_COUNT(d)); for (i = 0; i < CHANNEL_COUNT(d); i++) { stpi_dither_channel_t *dc = &(CHANNEL(d, i)); - if (dc->nlevels > 0) - bit_patterns[i] = dc->ranges[dc->nlevels - 1].upper->bits; - if (bit_patterns[i] != 1) - one_bit_only = 0; + if (dc->signif_bits > 1) + { + one_bit_only = 0; + break; + } } if (one_bit_only) { @@ -102,7 +97,7 @@ stpi_dither_predithered(stp_vars_t *v, { for (i = 0; i < CHANNEL_COUNT(d); i++) { - if (raw[i]) + if (raw[i] & 1) { set_row_ends(&(CHANNEL(d, i)), x); CHANNEL(d, i).ptr[d->ptr_offset] |= bit; @@ -123,12 +118,11 @@ stpi_dither_predithered(stp_vars_t *v, { if (CHANNEL(d, i).ptr && raw[i]) print_color_very_fast(d, &(CHANNEL(d, i)), raw[i], x, row, - bit, bit_patterns[i], length); + bit, length); } } ADVANCE_UNIDIRECTIONAL(d, bit, raw, CHANNEL_COUNT(d), xerror, xstep, xmod); } } - stp_free(bit_patterns); } |