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gimp/app/boundary.c

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/* The GIMP -- an image manipulation program
* Copyright (C) 1995 Spencer Kimball and Peter Mattis
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
#include <string.h>
#include "appenv.h"
#include "errors.h"
#include "boundary.h"
#include "tile.h"
#include "libgimp/gimpintl.h"
/* half intensity for mask */
#define HALF_WAY 127
/* BoundSeg array growth parameter */
#define MAX_SEGS_INC 2048
/* The array of vertical segments */
static int * vert_segs = NULL;
/* The array of segments */
static BoundSeg * tmp_segs = NULL;
static int num_segs = 0;
static int max_segs = 0;
/* static empty segment arrays */
static int * empty_segs_n = NULL;
static int num_empty_n = 0;
static int * empty_segs_c = NULL;
static int num_empty_c = 0;
static int * empty_segs_l = NULL;
static int num_empty_l = 0;
static int max_empty_segs = 0;
/* global state variables--improve parameter efficiency */
static PixelRegion * cur_PR;
/* local function prototypes */
static void find_empty_segs (PixelRegion *, int, int *, int, int *,
BoundaryType, int, int, int, int);
static void make_seg (int, int, int, int, int);
static void allocate_vert_segs (void);
static void allocate_empty_segs (void);
static void process_horiz_seg (int, int, int, int, int);
static void make_horiz_segs (int, int, int, int *, int, int);
static void generate_boundary (BoundaryType, int, int, int, int);
/* Function definitions */
static void
find_empty_segs (PixelRegion *maskPR,
int scanline,
int empty_segs[],
int max_empty,
int *num_empty,
BoundaryType type,
int x1,
int y1,
int x2,
int y2)
{
unsigned char *data;
int x;
int start, end;
int val, last;
int tilex;
Tile *tile = NULL;
int endx, l_num_empty, dstep = 0;
data = NULL;
start = 0;
end = 0;
*num_empty = 0;
if (scanline < maskPR->y || scanline >= (maskPR->y + maskPR->h))
{
empty_segs[(*num_empty)++] = 0;
empty_segs[(*num_empty)++] = G_MAXINT;
return;
}
if (type == WithinBounds)
{
if (scanline < y1 || scanline >= y2)
{
empty_segs[(*num_empty)++] = 0;
empty_segs[(*num_empty)++] = G_MAXINT;
return;
}
start = x1;
end = x2;
}
else if (type == IgnoreBounds)
{
start = maskPR->x;
end = maskPR->x + maskPR->w;
if (scanline < y1 || scanline >= y2)
x2 = -1;
}
tilex = -1;
empty_segs[(*num_empty)++] = 0;
last = -1;
l_num_empty = *num_empty;
for (x = start; x < end;)
{
/* Check to see if we must advance to next tile */
if ((x / TILE_WIDTH) != tilex)
{
if (tile)
tile_release (tile, FALSE);
tile = tile_manager_get_tile (maskPR->tiles, x, scanline, TRUE, FALSE);
data = (unsigned char*)tile_data_pointer (tile, x % TILE_WIDTH, scanline % TILE_HEIGHT) + (tile_bpp(tile) - 1);
tilex = x / TILE_WIDTH;
dstep = tile_bpp(tile);
}
endx = x + (TILE_WIDTH - (x%TILE_WIDTH));
endx = MINIMUM(end, endx);
if (type == IgnoreBounds && (endx > x1 || x < x2))
for (; x < endx; x++)
{
if (*data > HALF_WAY)
if (x >= x1 && x < x2)
val = -1;
else
val = 1;
else
val = -1;
data += dstep;
if (last != val)
empty_segs[l_num_empty++] = x;
last = val;
}
else
for (; x < endx; x++)
{
if (*data > HALF_WAY)
val = 1;
else
val = -1;
data += dstep;
if (last != val)
empty_segs[l_num_empty++] = x;
last = val;
}
}
*num_empty = l_num_empty;
if (last > 0)
empty_segs[(*num_empty)++] = x;
empty_segs[(*num_empty)++] = G_MAXINT;
if (tile)
tile_release (tile, FALSE);
}
static void
make_seg (int x1,
int y1,
int x2,
int y2,
int open)
{
if (num_segs >= max_segs)
{
max_segs += MAX_SEGS_INC;
tmp_segs = (BoundSeg *) g_realloc ((void *) tmp_segs,
sizeof (BoundSeg) * max_segs);
if (!tmp_segs)
gimp_fatal_error ("make_seg(): Unable to reallocate segments array for mask boundary.");
}
tmp_segs[num_segs].x1 = x1;
tmp_segs[num_segs].y1 = y1;
tmp_segs[num_segs].x2 = x2;
tmp_segs[num_segs].y2 = y2;
tmp_segs[num_segs].open = open;
num_segs ++;
}
static void
allocate_vert_segs (void)
{
int i;
/* allocate and initialize the vert_segs array */
vert_segs = (int *) g_realloc ((void *) vert_segs, (cur_PR->w + cur_PR->x + 1) * sizeof (int));
for (i = 0; i <= (cur_PR->w + cur_PR->x); i++)
vert_segs[i] = -1;
}
static void
allocate_empty_segs (void)
{
int need_num_segs;
/* find the maximum possible number of empty segments given the current mask */
need_num_segs = cur_PR->w + 2;
if (need_num_segs > max_empty_segs)
{
max_empty_segs = need_num_segs;
empty_segs_n = (int *) g_realloc (empty_segs_n, sizeof (int) * max_empty_segs);
empty_segs_c = (int *) g_realloc (empty_segs_c, sizeof (int) * max_empty_segs);
empty_segs_l = (int *) g_realloc (empty_segs_l, sizeof (int) * max_empty_segs);
if (!empty_segs_n || !empty_segs_l || !empty_segs_c)
gimp_fatal_error ("allocate_empty_segs(): Unable to reallocate empty segments array for mask boundary.");
}
}
static void
process_horiz_seg (int x1,
int y1,
int x2,
int y2,
int open)
{
/* This procedure accounts for any vertical segments that must be
drawn to close in the horizontal segments. */
if (vert_segs[x1] >= 0)
{
make_seg (x1, vert_segs[x1], x1, y1, !open);
vert_segs[x1] = -1;
}
else
vert_segs[x1] = y1;
if (vert_segs[x2] >= 0)
{
make_seg (x2, vert_segs[x2], x2, y2, open);
vert_segs[x2] = -1;
}
else
vert_segs[x2] = y2;
make_seg (x1, y1, x2, y2, open);
}
static void
make_horiz_segs (int start,
int end,
int scanline,
int empty[],
int num_empty,
int top)
{
int empty_index;
int e_s, e_e; /* empty segment start and end values */
for (empty_index = 0; empty_index < num_empty; empty_index += 2)
{
e_s = *empty++;
e_e = *empty++;
if (e_s <= start && e_e >= end)
process_horiz_seg (start, scanline, end, scanline, top);
else if ((e_s > start && e_s < end) ||
(e_e < end && e_e > start))
process_horiz_seg (MAXIMUM (e_s, start), scanline,
MINIMUM (e_e, end), scanline, top);
}
}
static void
generate_boundary (BoundaryType type,
int x1,
int y1,
int x2,
int y2)
{
int scanline;
int i;
int start, end;
int * tmp_segs;
start = 0;
end = 0;
/* array for determining the vertical line segments which must be drawn */
allocate_vert_segs ();
/* make sure there is enough space for the empty segment array */
allocate_empty_segs ();
num_segs = 0;
if (type == WithinBounds)
{
start = y1;
end = y2;
}
else if (type == IgnoreBounds)
{
start = cur_PR->y;
end = cur_PR->y + cur_PR->h;
}
/* Find the empty segments for the previous and current scanlines */
find_empty_segs (cur_PR, start - 1, empty_segs_l,
max_empty_segs, &num_empty_l,
type, x1, y1, x2, y2);
find_empty_segs (cur_PR, start, empty_segs_c,
max_empty_segs, &num_empty_c,
type, x1, y1, x2, y2);
for (scanline = start; scanline < end; scanline++)
{
/* find the empty segment list for the next scanline */
find_empty_segs (cur_PR, scanline + 1, empty_segs_n,
max_empty_segs, &num_empty_n,
type, x1, y1, x2, y2);
/* process the segments on the current scanline */
for (i = 1; i < num_empty_c - 1; i += 2)
{
make_horiz_segs (empty_segs_c [i], empty_segs_c [i+1],
scanline, empty_segs_l, num_empty_l, 1);
make_horiz_segs (empty_segs_c [i], empty_segs_c [i+1],
scanline+1, empty_segs_n, num_empty_n, 0);
}
/* get the next scanline of empty segments, swap others */
tmp_segs = empty_segs_l;
empty_segs_l = empty_segs_c;
num_empty_l = num_empty_c;
empty_segs_c = empty_segs_n;
num_empty_c = num_empty_n;
empty_segs_n = tmp_segs;
}
}
BoundSeg *
find_mask_boundary (PixelRegion *maskPR,
int *num_elems,
BoundaryType type,
int x1,
int y1,
int x2,
int y2)
{
BoundSeg * new_segs = NULL;
/* The mask paramater can be any PixelRegion. If the region
* has more than 1 bytes/pixel, the last byte of each pixel is
* used to determine the boundary outline.
*/
cur_PR = maskPR;
/* Calculate the boundary */
generate_boundary (type, x1, y1, x2, y2);
/* Set the number of X segments */
*num_elems = num_segs;
/* Make a copy of the boundary */
if (num_segs)
{
new_segs = (BoundSeg *) g_malloc (sizeof (BoundSeg) * num_segs);
memcpy (new_segs, tmp_segs, (sizeof (BoundSeg) * num_segs));
}
/* Return the new boundary */
return new_segs;
}
/************************/
/* Sorting a Boundary */
static int find_segment (BoundSeg *, int, int, int);
static int
find_segment (BoundSeg *segs,
int ns,
int x,
int y)
{
int index;
for (index = 0; index < ns; index++)
if (((segs[index].x1 == x && segs[index].y1 == y) || (segs[index].x2 == x && segs[index].y2 == y)) &&
segs[index].visited == FALSE)
return index;
return -1;
}
BoundSeg *
sort_boundary (BoundSeg *segs,
int ns,
int *num_groups)
{
int i;
int index;
int x, y;
int startx, starty;
int empty = (num_segs == 0);
BoundSeg *new_segs;
index = 0;
new_segs = NULL;
for (i = 0; i < ns; i++)
segs[i].visited = FALSE;
num_segs = 0;
*num_groups = 0;
while (! empty)
{
empty = TRUE;
/* find the index of a non-visited segment to start a group */
for (i = 0; i < ns; i++)
if (segs[i].visited == FALSE)
{
index = i;
empty = FALSE;
i = ns;
}
if (! empty)
{
make_seg (segs[index].x1, segs[index].y1,
segs[index].x2, segs[index].y2,
segs[index].open);
segs[index].visited = TRUE;
startx = segs[index].x1;
starty = segs[index].y1;
x = segs[index].x2;
y = segs[index].y2;
while ((index = find_segment (segs, ns, x, y)) != -1)
{
/* make sure ordering is correct */
if (x == segs[index].x1 && y == segs[index].y1)
{
make_seg (segs[index].x1, segs[index].y1,
segs[index].x2, segs[index].y2,
segs[index].open);
x = segs[index].x2;
y = segs[index].y2;
}
else
{
make_seg (segs[index].x2, segs[index].y2,
segs[index].x1, segs[index].y1,
segs[index].open);
x = segs[index].x1;
y = segs[index].y1;
}
segs[index].visited = TRUE;
}
if (x != startx || y != starty)
g_message ("sort_boundary(): Unconnected boundary group!");
/* Mark the end of a group */
*num_groups = *num_groups + 1;
make_seg (-1, -1, -1, -1, 0);
}
}
/* Make a copy of the boundary */
if (num_segs)
{
new_segs = (BoundSeg *) g_malloc (sizeof (BoundSeg) * num_segs);
memcpy (new_segs, tmp_segs, (sizeof (BoundSeg) * num_segs));
}
/* Return the new boundary */
return new_segs;
}
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