Anonymous user
Zhang-Suen thinning algorithm: Difference between revisions
→{{header|Java}}: added Java
(→{{header|Mathematica}}: Marked incomplete as although good to see, output is not that of Zhang-Suen algorithm. (Would be good to know what algo. this is)?) |
(→{{header|Java}}: added Java) |
||
Line 816:
# ####
</lang>
=={{header|Java}}==
{{works with|Java|7}}
<lang java>import java.util.*;
public class ZhangSuen {
final static String[] image = {
" ",
" ################# ############# ",
" ################## ################ ",
" ################### ################## ",
" ######## ####### ################### ",
" ###### ####### ####### ###### ",
" ###### ####### ####### ",
" ################# ####### ",
" ################ ####### ",
" ################# ####### ",
" ###### ####### ####### ",
" ###### ####### ####### ",
" ###### ####### ####### ###### ",
" ######## ####### ################### ",
" ######## ####### ###### ################## ###### ",
" ######## ####### ###### ################ ###### ",
" ######## ####### ###### ############# ###### ",
" "};
final static int[][] nbrs = {{0, -1}, {1, -1}, {1, 0}, {1, 1}, {0, 1},
{-1, 1}, {-1, 0}, {-1, -1}, {0, -1}};
final static int[][][] nbrGroups = {{{0, 2, 4}, {2, 4, 6}}, {{0, 2, 6},
{0, 4, 6}}};
static List<Integer[]> toWhite = new ArrayList<>();
static char[][] grid;
public static void main(String[] args) {
grid = new char[image.length][];
for (int r = 0; r < image.length; r++)
grid[r] = image[r].toCharArray();
thinImage();
}
static void thinImage() {
boolean firstStep = false;
boolean hasChanged;
do {
hasChanged = false;
firstStep = !firstStep;
for (int r = 1; r < grid.length - 1; r++) {
for (int c = 1; c < grid[0].length - 1; c++) {
if (grid[r][c] != '#')
continue;
int nn = numNeighbors(r, c);
if (nn < 2 || nn > 6)
continue;
if (numTransitions(r, c) != 1)
continue;
if (!atLeastOneIsWhite(r, c, firstStep ? 0 : 1))
continue;
toWhite.add(new Integer[]{r, c});
hasChanged = true;
}
}
for (Integer[] coords : toWhite)
grid[coords[0]][coords[1]] = ' ';
toWhite.clear();
} while (hasChanged || firstStep);
printResult();
}
static int numNeighbors(int r, int c) {
int count = 0;
for (int i = 0; i < nbrs.length - 1; i++)
if (grid[r + nbrs[i][1]][c + nbrs[i][0]] == '#')
count++;
return count;
}
static int numTransitions(int r, int c) {
int count = 0;
for (int i = 0; i < nbrs.length - 1; i++)
if (grid[r + nbrs[i][1]][c + nbrs[i][0]] == ' ') {
if (grid[r + nbrs[i + 1][1]][c + nbrs[i + 1][0]] == '#')
count++;
}
return count;
}
static boolean atLeastOneIsWhite(int r, int c, int step) {
int count = 0;
int[][] group = nbrGroups[step];
for (int i = 0; i < 2; i++)
for (int j = 0; j < group[i].length; j++) {
int[] nbr = nbrs[group[i][j]];
if (grid[r + nbr[1]][c + nbr[0]] == ' ') {
count++;
break;
}
}
return count > 1;
}
static void printResult() {
for (char[] row : grid)
System.out.println(row);
}
}</lang>
Output:
<pre>
# ########## #######
## # #### #
# # ##
# # #
# # #
# # #
############ #
# # #
# # #
# # #
# # #
# ##
# ############
### ### </pre>
=={{header|Mathematica}}==
| |||