tiffmedian.c

tiff文件开发库

				iptr = &histogram[ir][ig][ptr->bmin];
				for (ib = ptr->bmin; ib <= ptr->bmax; ++ib)
					*histp += *iptr++;
			}
			histp++;
	        }
	        first = ptr->gmin;
		last = ptr->gmax;
	        break;
	case BLUE:
	        histp = &hist2[ptr->bmin];
	        for (ib = ptr->bmin; ib <= ptr->bmax; ++ib) {
			*histp = 0;
			for (ir = ptr->rmin; ir <= ptr->rmax; ++ir) {
				iptr = &histogram[ir][ptr->gmin][ib];
				for (ig = ptr->gmin; ig <= ptr->gmax; ++ig) {
					*histp += *iptr;
					iptr += B_LEN;
				}
			}
			histp++;
	        }
	        first = ptr->bmin;
		last = ptr->bmax;
	        break;
	}
	/* find median point */
	sum2 = ptr->total / 2;
	histp = &hist2[first];
	sum = 0;
	for (i = first; i <= last && (sum += *histp++) < sum2; ++i)
		;
	if (i == first)
		i++;

	/* Create new box, re-allocate points */
	new = freeboxes;
	freeboxes = new->next;
	if (freeboxes)
		freeboxes->prev = NULL;
	if (usedboxes)
		usedboxes->prev = new;
	new->next = usedboxes;
	usedboxes = new;

	histp = &hist2[first];
	for (sum1 = 0, j = first; j < i; j++)
		sum1 += *histp++;
	for (sum2 = 0, j = i; j <= last; j++)
	    sum2 += *histp++;
	new->total = sum1;
	ptr->total = sum2;

	new->rmin = ptr->rmin;
	new->rmax = ptr->rmax;
	new->gmin = ptr->gmin;
	new->gmax = ptr->gmax;
	new->bmin = ptr->bmin;
	new->bmax = ptr->bmax;
	switch (axis) {
	case RED:
		new->rmax = i-1;
	        ptr->rmin = i;
	        break;
	case GREEN:
	        new->gmax = i-1;
	        ptr->gmin = i;
	        break;
	case BLUE:
	        new->bmax = i-1;
	        ptr->bmin = i;
	        break;
	}
	shrinkbox(new);
	shrinkbox(ptr);
}

static void
shrinkbox(Colorbox* box)
{
	register uint32 *histp;
	register int	ir, ig, ib;

	if (box->rmax > box->rmin) {
		for (ir = box->rmin; ir <= box->rmax; ++ir)
			for (ig = box->gmin; ig <= box->gmax; ++ig) {
				histp = &histogram[ir][ig][box->bmin];
			        for (ib = box->bmin; ib <= box->bmax; ++ib)
					if (*histp++ != 0) {
						box->rmin = ir;
						goto have_rmin;
					}
			}
	have_rmin:
		if (box->rmax > box->rmin)
			for (ir = box->rmax; ir >= box->rmin; --ir)
				for (ig = box->gmin; ig <= box->gmax; ++ig) {
					histp = &histogram[ir][ig][box->bmin];
					ib = box->bmin;
					for (; ib <= box->bmax; ++ib)
						if (*histp++ != 0) {
							box->rmax = ir;
							goto have_rmax;
						}
			        }
	}
have_rmax:
	if (box->gmax > box->gmin) {
		for (ig = box->gmin; ig <= box->gmax; ++ig)
			for (ir = box->rmin; ir <= box->rmax; ++ir) {
				histp = &histogram[ir][ig][box->bmin];
			        for (ib = box->bmin; ib <= box->bmax; ++ib)
				if (*histp++ != 0) {
					box->gmin = ig;
					goto have_gmin;
				}
			}
	have_gmin:
		if (box->gmax > box->gmin)
			for (ig = box->gmax; ig >= box->gmin; --ig)
				for (ir = box->rmin; ir <= box->rmax; ++ir) {
					histp = &histogram[ir][ig][box->bmin];
					ib = box->bmin;
					for (; ib <= box->bmax; ++ib)
						if (*histp++ != 0) {
							box->gmax = ig;
							goto have_gmax;
						}
			        }
	}
have_gmax:
	if (box->bmax > box->bmin) {
		for (ib = box->bmin; ib <= box->bmax; ++ib)
			for (ir = box->rmin; ir <= box->rmax; ++ir) {
				histp = &histogram[ir][box->gmin][ib];
			        for (ig = box->gmin; ig <= box->gmax; ++ig) {
					if (*histp != 0) {
						box->bmin = ib;
						goto have_bmin;
					}
					histp += B_LEN;
			        }
		        }
	have_bmin:
		if (box->bmax > box->bmin)
			for (ib = box->bmax; ib >= box->bmin; --ib)
				for (ir = box->rmin; ir <= box->rmax; ++ir) {
					histp = &histogram[ir][box->gmin][ib];
					ig = box->gmin;
					for (; ig <= box->gmax; ++ig) {
						if (*histp != 0) {
							box->bmax = ib;
							goto have_bmax;
						}
						histp += B_LEN;
					}
			        }
	}
have_bmax:
	;
}

static C_cell *
create_colorcell(int red, int green, int blue)
{
	register int ir, ig, ib, i;
	register C_cell *ptr;
	int mindist, next_n;
	register int tmp, dist, n;

	ir = red >> (COLOR_DEPTH-C_DEPTH);
	ig = green >> (COLOR_DEPTH-C_DEPTH);
	ib = blue >> (COLOR_DEPTH-C_DEPTH);
	ptr = (C_cell *)_TIFFmalloc(sizeof (C_cell));
	*(ColorCells + ir*C_LEN*C_LEN + ig*C_LEN + ib) = ptr;
	ptr->num_ents = 0;

	/*
	 * Step 1: find all colors inside this cell, while we're at
	 *	   it, find distance of centermost point to furthest corner
	 */
	mindist = 99999999;
	for (i = 0; i < num_colors; ++i) {
		if (rm[i]>>(COLOR_DEPTH-C_DEPTH) != ir  ||
		    gm[i]>>(COLOR_DEPTH-C_DEPTH) != ig  ||
		    bm[i]>>(COLOR_DEPTH-C_DEPTH) != ib)
			continue;
		ptr->entries[ptr->num_ents][0] = i;
		ptr->entries[ptr->num_ents][1] = 0;
		++ptr->num_ents;
	        tmp = rm[i] - red;
	        if (tmp < (MAX_COLOR/C_LEN/2))
			tmp = MAX_COLOR/C_LEN-1 - tmp;
	        dist = tmp*tmp;
	        tmp = gm[i] - green;
	        if (tmp < (MAX_COLOR/C_LEN/2))
			tmp = MAX_COLOR/C_LEN-1 - tmp;
	        dist += tmp*tmp;
	        tmp = bm[i] - blue;
	        if (tmp < (MAX_COLOR/C_LEN/2))
			tmp = MAX_COLOR/C_LEN-1 - tmp;
	        dist += tmp*tmp;
	        if (dist < mindist)
			mindist = dist;
	}

	/*
	 * Step 3: find all points within that distance to cell.
	 */
	for (i = 0; i < num_colors; ++i) {
		if (rm[i] >> (COLOR_DEPTH-C_DEPTH) == ir  &&
		    gm[i] >> (COLOR_DEPTH-C_DEPTH) == ig  &&
		    bm[i] >> (COLOR_DEPTH-C_DEPTH) == ib)
			continue;
		dist = 0;
	        if ((tmp = red - rm[i]) > 0 ||
		    (tmp = rm[i] - (red + MAX_COLOR/C_LEN-1)) > 0 )
			dist += tmp*tmp;
	        if ((tmp = green - gm[i]) > 0 ||
		    (tmp = gm[i] - (green + MAX_COLOR/C_LEN-1)) > 0 )
			dist += tmp*tmp;
	        if ((tmp = blue - bm[i]) > 0 ||
		    (tmp = bm[i] - (blue + MAX_COLOR/C_LEN-1)) > 0 )
			dist += tmp*tmp;
	        if (dist < mindist) {
			ptr->entries[ptr->num_ents][0] = i;
			ptr->entries[ptr->num_ents][1] = dist;
			++ptr->num_ents;
	        }
	}

	/*
	 * Sort color cells by distance, use cheap exchange sort
	 */
	for (n = ptr->num_ents - 1; n > 0; n = next_n) {
		next_n = 0;
		for (i = 0; i < n; ++i)
			if (ptr->entries[i][1] > ptr->entries[i+1][1]) {
				tmp = ptr->entries[i][0];
				ptr->entries[i][0] = ptr->entries[i+1][0];
				ptr->entries[i+1][0] = tmp;
				tmp = ptr->entries[i][1];
				ptr->entries[i][1] = ptr->entries[i+1][1];
				ptr->entries[i+1][1] = tmp;
				next_n = i;
		        }
	}
	return (ptr);
}

static void
map_colortable(void)
{
	register uint32 *histp = &histogram[0][0][0];
	register C_cell *cell;
	register int j, tmp, d2, dist;
	int ir, ig, ib, i;

	for (ir = 0; ir < B_LEN; ++ir)
		for (ig = 0; ig < B_LEN; ++ig)
			for (ib = 0; ib < B_LEN; ++ib, histp++) {
				if (*histp == 0) {
					*histp = -1;
					continue;
				}
				cell = *(ColorCells +
				    (((ir>>(B_DEPTH-C_DEPTH)) << C_DEPTH*2) +
				    ((ig>>(B_DEPTH-C_DEPTH)) << C_DEPTH) +
				    (ib>>(B_DEPTH-C_DEPTH))));
				if (cell == NULL )
					cell = create_colorcell(
					    ir << COLOR_SHIFT,
					    ig << COLOR_SHIFT,
					    ib << COLOR_SHIFT);
				dist = 9999999;
				for (i = 0; i < cell->num_ents &&
				    dist > cell->entries[i][1]; ++i) {
					j = cell->entries[i][0];
					d2 = rm[j] - (ir << COLOR_SHIFT);
					d2 *= d2;
					tmp = gm[j] - (ig << COLOR_SHIFT);
					d2 += tmp*tmp;
					tmp = bm[j] - (ib << COLOR_SHIFT);
					d2 += tmp*tmp;
					if (d2 < dist) {
						dist = d2;
						*histp = j;
					}
				}
			}
}

/*
 * straight quantization.  Each pixel is mapped to the colors
 * closest to it.  Color values are rounded to the nearest color
 * table entry.
 */
static void
quant(TIFF* in, TIFF* out)
{
	unsigned char	*outline, *inputline;
	register unsigned char	*outptr, *inptr;
	register uint32 i, j;
	register int red, green, blue;

	inputline = (unsigned char *)_TIFFmalloc(TIFFScanlineSize(in));
	outline = (unsigned char *)_TIFFmalloc(imagewidth);
	for (i = 0; i < imagelength; i++) {
		if (TIFFReadScanline(in, inputline, i, 0) <= 0)
			break;
		inptr = inputline;
		outptr = outline;
		for (j = 0; j < imagewidth; j++) {
			red = *inptr++ >> COLOR_SHIFT;
			green = *inptr++ >> COLOR_SHIFT;
			blue = *inptr++ >> COLOR_SHIFT;
			*outptr++ = histogram[red][green][blue];
		}
		if (TIFFWriteScanline(out, outline, i, 0) < 0)
			break;
	}
	_TIFFfree(inputline);
	_TIFFfree(outline);
}

#define	SWAP(type,a,b)	{ type p; p = a; a = b; b = p; }

#define	GetInputLine(tif, row, bad)				\
	if (TIFFReadScanline(tif, inputline, row, 0) <= 0)	\
		bad;						\
	inptr = inputline;					\
	nextptr = nextline;					\
	for (j = 0; j < imagewidth; ++j) {			\
		*nextptr++ = *inptr++;				\
		*nextptr++ = *inptr++;				\
		*nextptr++ = *inptr++;				\
	}
#define	GetComponent(raw, cshift, c)				\
	cshift = raw;						\
	if (cshift < 0)						\
		cshift = 0;					\
	else if (cshift >= MAX_COLOR)				\
		cshift = MAX_COLOR-1;				\
	c = cshift;						\
	cshift >>= COLOR_SHIFT;

static void
quant_fsdither(TIFF* in, TIFF* out)
{
	unsigned char *outline, *inputline, *inptr;
	short *thisline, *nextline;
	register unsigned char	*outptr;
	register short *thisptr, *nextptr;
	register uint32 i, j;
	uint32 imax, jmax;
	int lastline, lastpixel;

	imax = imagelength - 1;
	jmax = imagewidth - 1;
	inputline = (unsigned char *)_TIFFmalloc(TIFFScanlineSize(in));
	thisline = (short *)_TIFFmalloc(imagewidth * 3 * sizeof (short));
	nextline = (short *)_TIFFmalloc(imagewidth * 3 * sizeof (short));
	outline = (unsigned char *) _TIFFmalloc(TIFFScanlineSize(out));

	GetInputLine(in, 0, goto bad);		/* get first line */
	for (i = 1; i <= imagelength; ++i) {
		SWAP(short *, thisline, nextline);
		lastline = (i >= imax);
		if (i <= imax)
			GetInputLine(in, i, break);
		thisptr = thisline;
		nextptr = nextline;
		outptr = outline;
		for (j = 0; j < imagewidth; ++j) {
			int red, green, blue;
			register int oval, r2, g2, b2;

			lastpixel = (j == jmax);
			GetComponent(*thisptr++, r2, red);
			GetComponent(*thisptr++, g2, green);
			GetComponent(*thisptr++, b2, blue);
			oval = histogram[r2][g2][b2];
			if (oval == -1) {
				int ci;
				register int cj, tmp, d2, dist;
				register C_cell	*cell;

				cell = *(ColorCells +
				    (((r2>>(B_DEPTH-C_DEPTH)) << C_DEPTH*2) +
				    ((g2>>(B_DEPTH-C_DEPTH)) << C_DEPTH ) +
				    (b2>>(B_DEPTH-C_DEPTH))));
				if (cell == NULL)
					cell = create_colorcell(red,
					    green, blue);
				dist = 9999999;
				for (ci = 0; ci < cell->num_ents && dist > cell->entries[ci][1]; ++ci) {
					cj = cell->entries[ci][0];
					d2 = (rm[cj] >> COLOR_SHIFT) - r2;
					d2 *= d2;
					tmp = (gm[cj] >> COLOR_SHIFT) - g2;
					d2 += tmp*tmp;
					tmp = (bm[cj] >> COLOR_SHIFT) - b2;
					d2 += tmp*tmp;
					if (d2 < dist) {
						dist = d2;
						oval = cj;
					}
				}
				histogram[r2][g2][b2] = oval;
			}
			*outptr++ = oval;
			red -= rm[oval];
			green -= gm[oval];
			blue -= bm[oval];
			if (!lastpixel) {
				thisptr[0] += blue * 7 / 16;
				thisptr[1] += green * 7 / 16;
				thisptr[2] += red * 7 / 16;
			}
			if (!lastline) {
				if (j != 0) {
					nextptr[-3] += blue * 3 / 16;
					nextptr[-2] += green * 3 / 16;
					nextptr[-1] += red * 3 / 16;
				}
				nextptr[0] += blue * 5 / 16;
				nextptr[1] += green * 5 / 16;
				nextptr[2] += red * 5 / 16;
				if (!lastpixel) {
					nextptr[3] += blue / 16;
				        nextptr[4] += green / 16;
				        nextptr[5] += red / 16;
				}
				nextptr += 3;
			}
		}
		if (TIFFWriteScanline(out, outline, i-1, 0) < 0)
			break;
	}
bad:
	_TIFFfree(inputline);
	_TIFFfree(thisline);
	_TIFFfree(nextline);
	_TIFFfree(outline);
}