aseprite/src/raster/algofill.cpp

335 lines
8.2 KiB
C++

// The floodfill routine.
// By Shawn Hargreaves.
// Adapted to Aseprite by David Capello
//
// This source file is distributed under a Allegro license, please
// read allegro4-LICENSE.txt for more information.
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include "raster/algo.h"
#include "raster/image.h"
#include "raster/primitives.h"
#include <allegro.h>
#include <allegro/internal/aintern.h>
#include <limits.h>
#include <math.h>
namespace raster {
typedef struct FLOODED_LINE /* store segments which have been flooded */
{
short flags; /* status of the segment */
short lpos, rpos; /* left and right ends of segment */
short y; /* y coordinate of the segment */
int next; /* linked list if several per line */
} FLOODED_LINE;
/* Note: a 'short' is not sufficient for 'next' above in some corner cases. */
static int flood_count; /* number of flooded segments */
#define FLOOD_IN_USE 1
#define FLOOD_TODO_ABOVE 2
#define FLOOD_TODO_BELOW 4
#define FLOOD_LINE(c) (((FLOODED_LINE *)_scratch_mem) + c)
static inline bool color_equal_32(color_t c1, color_t c2, int tolerance)
{
if (tolerance == 0)
return (c1 == c2) || (rgba_geta(c1) == 0 && rgba_geta(c2) == 0);
else {
int r1 = rgba_getr(c1);
int g1 = rgba_getg(c1);
int b1 = rgba_getb(c1);
int a1 = rgba_geta(c1);
int r2 = rgba_getr(c2);
int g2 = rgba_getg(c2);
int b2 = rgba_getb(c2);
int a2 = rgba_geta(c2);
if (a1 == 0 && a2 == 0)
return true;
return ((ABS(r1-r2) <= tolerance) &&
(ABS(g1-g2) <= tolerance) &&
(ABS(b1-b2) <= tolerance) &&
(ABS(a1-a2) <= tolerance));
}
}
static inline bool color_equal_16(color_t c1, color_t c2, int tolerance)
{
if (tolerance == 0)
return (c1 == c2) || (graya_geta(c1) == 0 && graya_geta(c2) == 0);
else {
int k1 = graya_getv(c1);
int a1 = graya_geta(c1);
int k2 = graya_getv(c2);
int a2 = graya_geta(c2);
if (a1 == 0 && a2 == 0)
return true;
return ((ABS(k1-k2) <= tolerance) &&
(ABS(a1-a2) <= tolerance));
}
}
static inline bool color_equal_8(color_t c1, color_t c2, int tolerance)
{
if (tolerance == 0)
return (c1 == c2);
else
return ABS((int)c1 - (int)c2) <= tolerance;
}
/* flooder:
* Fills a horizontal line around the specified position, and adds it
* to the list of drawn segments. Returns the first x coordinate after
* the part of the line which it has dealt with.
*/
static int flooder(Image *image, int x, int y,
color_t src_color, int tolerance, void *data, AlgoHLine proc)
{
FLOODED_LINE *p;
int left = 0, right = 0;
int c;
switch (image->getPixelFormat()) {
case IMAGE_RGB:
{
uint32_t* address = reinterpret_cast<uint32_t*>(image->getPixelAddress(0, y));
// Check start pixel
if (!color_equal_32((int)*(address+x), src_color, tolerance))
return x+1;
// Work left from starting point
for (left=x-1; left>=0; left--) {
if (!color_equal_32((int)*(address+left), src_color, tolerance))
break;
}
// Work right from starting point
for (right=x+1; right<image->getWidth(); right++) {
if (!color_equal_32((int)*(address+right), src_color, tolerance))
break;
}
}
break;
case IMAGE_GRAYSCALE:
{
uint16_t* address = reinterpret_cast<uint16_t*>(image->getPixelAddress(0, y));
// Check start pixel
if (!color_equal_16((int)*(address+x), src_color, tolerance))
return x+1;
// Work left from starting point
for (left=x-1; left>=0; left--) {
if (!color_equal_16((int)*(address+left), src_color, tolerance))
break;
}
// Work right from starting point
for (right=x+1; right<image->getWidth(); right++) {
if (!color_equal_16((int)*(address+right), src_color, tolerance))
break;
}
}
break;
case IMAGE_INDEXED:
{
uint8_t* address = image->getPixelAddress(0, y);
// Check start pixel
if (!color_equal_8((int)*(address+x), src_color, tolerance))
return x+1;
// Work left from starting point
for (left=x-1; left>=0; left--) {
if (!color_equal_8((int)*(address+left), src_color, tolerance))
break;
}
// Work right from starting point
for (right=x+1; right<image->getWidth(); right++) {
if (!color_equal_8((int)*(address+right), src_color, tolerance))
break;
}
}
break;
default:
// Check start pixel
if (get_pixel(image, x, y) != src_color)
return x+1;
// Work left from starting point
for (left=x-1; left>=0; left--) {
if (get_pixel(image, left, y) != src_color)
break;
}
// Work right from starting point
for (right=x+1; right<image->getWidth(); right++) {
if (get_pixel(image, right, y) != src_color)
break;
}
break;
}
left++;
right--;
/* draw the line */
(*proc)(left, y, right, data);
/* store it in the list of flooded segments */
c = y;
p = FLOOD_LINE(c);
if (p->flags) {
while (p->next) {
c = p->next;
p = FLOOD_LINE(c);
}
p->next = c = flood_count++;
_grow_scratch_mem(sizeof(FLOODED_LINE) * flood_count);
p = FLOOD_LINE(c);
}
p->flags = FLOOD_IN_USE;
p->lpos = left;
p->rpos = right;
p->y = y;
p->next = 0;
if (y > 0)
p->flags |= FLOOD_TODO_ABOVE;
if (y+1 < image->getHeight())
p->flags |= FLOOD_TODO_BELOW;
return right+2;
}
/* check_flood_line:
* Checks a line segment, using the scratch buffer is to store a list of
* segments which have already been drawn in order to minimise the required
* number of tests.
*/
static int check_flood_line(Image* image, int y, int left, int right,
int src_color, int tolerance, void *data, AlgoHLine proc)
{
int c;
FLOODED_LINE *p;
int ret = false;
while (left <= right) {
c = y;
for (;;) {
p = FLOOD_LINE(c);
if ((left >= p->lpos) && (left <= p->rpos)) {
left = p->rpos+2;
break;
}
c = p->next;
if (!c) {
left = flooder (image, left, y, src_color, tolerance, data, proc);
ret = true;
break;
}
}
}
return ret;
}
/* floodfill:
* Fills an enclosed area (starting at point x, y) with the specified color.
*/
void algo_floodfill(Image* image, int x, int y, int tolerance, void *data, AlgoHLine proc)
{
int c, done;
FLOODED_LINE *p;
/* make sure we have a valid starting point */
if ((x < 0) || (x >= image->getWidth()) ||
(y < 0) || (y >= image->getHeight()))
return;
/* what color to replace? */
color_t src_color = get_pixel(image, x, y);
/* set up the list of flooded segments */
_grow_scratch_mem(sizeof(FLOODED_LINE) * image->getHeight());
flood_count = image->getHeight();
p = (FLOODED_LINE*)_scratch_mem;
for (c=0; c<flood_count; c++) {
p[c].flags = 0;
p[c].lpos = SHRT_MAX;
p[c].rpos = SHRT_MIN;
p[c].y = y;
p[c].next = 0;
}
/* start up the flood algorithm */
flooder(image, x, y, src_color, tolerance, data, proc);
/* continue as long as there are some segments still to test */
do {
done = true;
/* for each line on the screen */
for (c=0; c<flood_count; c++) {
p = FLOOD_LINE(c);
/* check below the segment? */
if (p->flags & FLOOD_TODO_BELOW) {
p->flags &= ~FLOOD_TODO_BELOW;
if (check_flood_line(image, p->y+1, p->lpos, p->rpos,
src_color, tolerance, data, proc)) {
done = false;
p = FLOOD_LINE(c);
}
}
/* check above the segment? */
if (p->flags & FLOOD_TODO_ABOVE) {
p->flags &= ~FLOOD_TODO_ABOVE;
if (check_flood_line(image, p->y-1, p->lpos, p->rpos,
src_color, tolerance, data, proc)) {
done = false;
/* special case shortcut for going backwards */
if ((c < image->getHeight()) && (c > 0))
c -= 2;
}
}
}
} while (!done);
}
} // namespace raster